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Instrumental Methods of Examination, X-rays and Radioisotopic diagnostics in Urological diseases

The Urinary system


Types of Catheters


Preliminary procedures

Hello everyone! This is the second Urological Hub I am publishing in a day. Whew! As much as it is an achievement, its also a challenge, taking up the mantle just immediately after exams. Well, this hub is published to give each and everyone of us an idea of the instruments and tools used in urological analysis. Sometimes, we need to have an idea of such things so that whenever we approach the Doctor in related situations, we will can easily comprehend and blend with what the doctor is saying.

Diagnostic imaging is a dynamic recent development in medical practice with great potential for benefiting patient care. Nothing has contributed more to the improvement of existing anatomic imaging devices and the development of new ones than digital computers and their related electronics. With computers, the vast numbers of data collected in analog fashion by the basic imaging  mechanics of radiography, Ultrasonography, computerized tomography (CT scanning), tomography are converted electronically into digits corresponding to the different intensities of the original bits of information. These \digits are store in the computer and can be recalled, combined, and manipulated in various ways to achieve reconverted analog images. Hard copies of selected images can be made at the time of the study, or the information can be stored permanently in digital form for subsequent retrieval and conversion to analog images.

Radiography (roentgenography) is the oldest method of urologic imaging, having been used to demonstrate radiopaque urinary calculi shortly after the discovery of X-rays by Wilhelm Roentgen in 1895. Since then, it has continued to be used for diagnosis in every branch of medicine, and it is currently the most widely available method of medical imaging. More recently and other body imaging procedures still in their very early development, eg, magnetic resonance tomography- are competing with, complementing, and in some instances, replacing long established uroradiographic tachniques.

Aseptic Technique

Although bacteria are present in the distal urethra, the urinary tract is considered sterile. Therefore, any instrument entering the tract should be sterile. Instruments made of metal, rubber, and plastic may be autoclaved, but those containing optical devices must be gas-sterilized or soaked for a sufficient time in an approved solution of glutaraldehyde and then thoroughly rinsed in sterile water. The foreskin should be retracted and the glans penis washed thoroughly with cleansing solution. Th vulva must be cleansed and the labia held apart as the instrument is introduced.

Lubrication of Urethra

All transurethral maneuvers require lubrication. In women, application of lubricant to the instrument is sufficient. However, this method does not provide adequate lubrication for the entire male urethra, because the meatus tends to remove most of the lubricant as the instrument is passed. The male urethra should be lubricated by instilling at least 15 mL of a sterile, water soluble lubricant by means of a blunt, cone-tipped syringe. Oils (e.g, mineral or Olive oil) must not be used, since fatal oil emboli may result. The syringe allows introduction of the lubricant with constant, low, steady pressure, which helps overcome the normal tone of the external sphincter. This resistance may be markedly increased in apprehensive patients, leading the inexperienced instrumentalist to an erroneous diagnosis of urethral stricture.


A simple procedure such as passage of a urethral catheter may be done without anesthesia. If more complex or painful manipulations are planned, sedation or topical, regional, or general anesthesia will be necessary. Sedation may be achieved with barbiturates, tranquilizing agents, or narcotics. Topical anesthesia of the urethral mucosa may be obtained with cocaine, tetracaine, or lidocaine. In females, a cotton applicator moistened with the anesthetic may be placed in the urethra for 5 minutes. In males, these agents in liquid form are rapidly absorbed into the circulation through the posterior urethra. Contact with traumatized mucosa or injection under pressure increases the absorption. This can lead to seizures, circulatory collapse, and cardiopulmonary arrest. Dyclonine, 0.5% has been used without toxicity in males. Wherever these drugs are used as topical anesthetics for the urethra, resuscitation equipment should be available. Lidocaine as a 2% solution in carboxymethylcellulose gel provides lubrication as well as safe topical anesthesia. The drug is less readily absorbed in this form and can be used in both the male and female urethra. In females, approximately 3-5mL of the jelly is instilled into the urethra. To occlude the meatus, a cotton swab lubricated with jelly may be placed in the distal urethra or a sponge may be placed in the distal vagina. In males, 15-30mL of the jelly is instilled 5-10 minutes prior to the procedure, a penile clamp is placed at the corona; and a small amount of jelly is instilled in the distal urethra. Topical anesthesia is effective on the mucosa only and will not prevent pain from pressure or from distortion of underlying structures during manipulation. Regional or general anesthesia should be planned if more painful procedures (eg, resection or bipsy) are contemplated or if the patient is very apprehensive. The regional anesthetic must reach the third lumbar segment to provide the necessary sensory ablation during transurethral resection; thus, spinal or epidural anesthesia rather than a sacral block must be used. General anesthesia must be used when cystourethroscopy is done in pediatric patients.

Warning to Patients

Instrumentation is uncomfortable and may be painful. A forewarned, cooperative patient will be of help. Explaining the proposed maneuvers as one proceeds may reduce the patient's anxiety. The instrument must be introduced gently and advanced gradually. Gentle, sure maneuvering with adequate lubrication is essential. No movement should be rough or abrupt. Discomfort will increase as the instrument passes through the prostatic urethra, and men must be warned to anticipate some discomfort as this area is approached. Once spasm of the external sphincter develops, it may be impossible to complete the instrumentation. A very high bladder neck will cause marked angulation of the urethra that may preclude instrumentation under topical anesthesia.

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Other Instrumental procedures and examinations in urology



Urological sub-department of the department of Surgery, Ternopil State Medical University

Urological sub-department of the department of Surgery, Ternopil State Medical University


Instrumental Methods of Examination in Urology

In most cases, a good knowledge in such instruments gives us the platform to ask constructive and intelligent questions to the medical personnel. Hence in as much as this is very good for the medical practitioner, it is also very good to the general public, and as usual, I will try and make it as simplified as possible for easy digestion. As for the Doctors and Nurses, in every urological practice, instrumental and Endoscopic methods of Examination of Urinary bladder in patients play very important role and so therefore, learning the usuage of catheters, uretherscopy and cystoscopy is very essential. Also, X-ray diagnostic has a great importance in our present medical world. Without X-ray and radioisotopic methods of diagnostic, any of urological diseases is impossible to diagnose.


Types of catheters

In general, straight rubber catheters are used for routine diagnostic catheterization. However, a coude (elbow) catheter, which is stiffer and has a curved tip, may be more readily manipulated over an enlarged prostate that has elevated the bladder neck. Uretheral catheters are: Foley, Whistle-tip, Pezzer, Malecot, Robinson, Coude.

The method of catheterization of urinary canal with plastic catheter

After proper cleansing and lubrication, the catheter can be manipulated with a sterile-gloved hand. However, it may be simpler to grasp the catheter near its tip with a sterile clamp and hold the other end of the catheter between the fourth and fifth fingers of the same hand. The catheter can then be advanced with the clamp without being touched by the unsterile hand. Begin catheterization with the penis pointed slightly drawn out.

Method of catheterization of Urinary canal with metallic catheter (in women and men)

After proper urethral lubrication, the tip of the conductor enters the urethra. The conductor is in the horizontal position over the groin. The penis is pulled out on the conductor, which is advanced down the Urethra and move simultaneously to the midline; its handle is gradually moved to the vertical position. The conductor will usually pass through the external urinary sphincter if gentle pressure is exerted on the handle at right angles to its shaft with one finger. When the conductor has passed all the way into the bladder it should be possible to rotate it freely.

Ureteral catheterization

These techniques are utilized in the evaluation of hematuria, chronic or recurrent urinary infection, unexplained urologic symptoms (eg, enuresis, frequency), and evaluation of congenital anomalies. They are also useful in any clinical situation in which excretory urogram have suggested pathologic change but have furnished all the information necessary for definitive diagnoses and treatment.

Filiform and followers

Filiform and followers are instruments used to dilate narrow strictures. Filiforms have woven fiber cores with a coated surface; they are very pliable and smooth. Useful sizes are 3-6F. The follower is made of metal or of woven of pliable fiber. Useful sizes are 8-30F. After lubrication jelly has been instilled into the urethra, the filiform is introduced. If it is arrested, it must be partially withdrawn, and readvanced. If this fails, one or file should be added to the first and all manipulation should be repeated.


A cystogram is a radiogram showing radiopaque outlining of the bladder cavity. Cystograms are seen as part of ordinary excretory urograms, but direct radiographic cystograms can be obtained by instilling a radipaque fluid directly into the bladder. The contrast medium is usually instilled via a transurethral catheter, but when necessary, it can be administered via percutaneous suprapubic bladder puncture. Radiograms of the filled bladder are taken using standard overhead X-ray tube equipment, or less frequently, "spot" films are taken during real-time, direct image-intensidied fluoroscopy.

Modern cystourethroscopes have a metal sheath ranging in size from 8F to 26F and interchangeable fiberoptic telescopes allowing a view from 0 to 170 degrees. The 0 to 30 degrees lenses are best for visualizing the urethra, whereas the bladder walls are best inspected with the 70 degrees lens. A retrograde (170-degrees0 lens must be used to see the vesical side of the bladder neck, particularly where prostatic tissue obstructs the view. Complete endoscopic studies are among the most precise diagnostic tests in all medicine. Any urethral lesion (e.g, Verrucae, tumors, strictures and diverticular), as well as the size and configuration of the prostate and bladder neck, are noted before the bladder is inspected. When the bladder is entered, the trigone is visualized and the size, shape, position and number of ureteral orifices noted. The bladder wall is carefully inspected for tumors, stones, diverticula, ulcers, trabeculation, hemorrhage, and edema. The normal and abnormal cystourethreoscopic findings must be specifically described.

Contraindications of cystoscopy

Cystoscopy is contraindicated in acute tract urinary infection, because trauma may exacerbate the infection and lead to sepsis. It is relatively contraindicated in the presence of severe symptoms of prostatic obstruction, since trauma may produce just enough edema of the bladder neck to cause complete urinary retention. Of course, if cystoscopy is essential, this risk must be accepted. The conditions in which cystoscopy is unnecessary are: when the volume of Urine in the bladder is more than 75ml and the environment around the bladder is transparent. A normal cystoscopic picture shows a dynamic bladder wall in which as bladder fills, small lesions will move away and may escape the examiner's field. Special care must be taken not to overdistend the bladder and to make sure that all areas have been completely inspected, often with the bladder minimally filled initially. In Adults, most of the bladder wall cannot be seen if the bladder contains more than 200-300mL of Urine.

Method of Puncture of Urinary bladder

A suprapubic catheter is useful in males when the urethra is impassable (e.g, traumatic disruption or stricture). When there is epididymitis or severe urethritis, or when prolonged bladder drainage by means of an indwelling catheter is necessary. An indwelling urethral catheter predisposes to meatitis, urethritis and epididymitis. The skin of the suprapubic area is prepared and infiltrated with a local anesthetic. If the patient is in Urinary retention, the bladder is usually readily palpated. The bladder must usually contain a minimum of 200-300mL of Urine before a suprapubic catheter can be inserted successfully. The patient may be placed in the Trendelenburg position to move the intestine upwards. A thin lumbar punctur needle is inserted above the symphisis pubica and angled toward the perineum to locate the bladder a trocar is inserted into the bladder and the suprapubic tube passed. Size 8F, 10F, and 12F suprapubic catheters are available in prepackage sets.

X-ray diagnostics

It is no longer considered necessary that patients should be dehydrated in preparation for urography. Indeed, dehydration is to be avoided in infants, debilitated and aged patients, and patients with diabetes mellitus renal failure, multiple myeloma, or hyperuricemic states. On the other hand, preliminary bowed cleansing is very desirable, although children under age 10 years usually need no bowel preparation for urography.

Urography (KUB)

A plain film of the abdomen, frequnelty called a KUB (Kidney-Ureter-bladder) film, is the simplest uroradiologic study and the first performed in any radiographic examination of the abdomen or urinary tract. It is usually the preliminary radiogram in more extended radiologic examinations of the urinary tract, such as urography. The size of normal kidneys varies widely, not only between like individuals but also with age, sex and body stature. The long diameter of the kidney is the most widely used and most convenient radiographic measurement. The average adult kidney is about 12-14cm long, and the left kidney is ordinarily slightly longer than the right one.

X-ray contrastive stones, and their diagnostics

Identification on the plain film of calcification or calculi anywhere in the urinary tract may help to identify specific kidney diseases (eg, the calcifications occasionally seen in a Kidney cancer) or may suggest primary disease elsewhere (eg, the occasional patient with nephrocalcinosis whose underlying primary disease is hyperparathyroidism) Contrastive substances or radiographic contrast media include Liquids (almost all fo whih contain iodine), gels, solids (eg, barium preparations), and gases (most commonly air nitrous oxide and carbon dioxide). Some contrast media can only be administered by one route, which limits their usefulness for multisystem anatomic imaging.

Excretory Urography

The excretory urogram, formerly called an intravenous pyelogram, is most commonly used. Excretory urograms can demonstrate a wide variety of urinary tract lesions, are simple to perform, and are well tolerate by most patients. Ocassionally, however, retrograde urograms may be required if the excretory urogram is unsatisfactory or the patient has a history of significant adverse reaction to intravascular contrast media. The advent of excretory urography using high volumes of radiopaque contrast media and ureteral compression has decreased the need for retrograde urograms. Abdominal (ureteral) compression devices that temporarily obstruct the upper urinary tracts during excretory urograms dramatically improve the filling of renal collecting structures.

Retrograde Urography

This is a moderately invasive procedure that requires cystoscopy and the placement of catheters in the urethers. A radiopaque contrast medium is introduces into the ureters or renal placement of catheters in the ureters. A radiopaque contrast medium is introduced into the ureters or renal collecting structures through the ureteral catheters and radiograms of the abdomen are then taken. The study, which is more difficult than an excretory urogram, must be performed by a urologist. Some type of local or general anesthesia must be used, and the procedure can occasionally cause later morbidity or urinary tract infection.

Infusional Urography

The use od greater than average amounts of standard contrast medium- and thus greater amounts of iodine per Kilogram of body weight- may be indicated in selected patients. The high volumes may be injected either rapidly as a bolus or more slowly as an infusion; the bolus method produces better visualization and a better urographic nephrogram than the infusion method.


This method of outlining the renal collecting structures and ureters is occasionally used when urinary tract imaging is necessary but excretory or retrograde urography has failed or is contraindicated or when there is a nephrostomy tube in place and delineation of the collecting system of the upper urinary tract is desired. The contrast medium is introduced either through nephrstomy tubes, if these are present (nephrostogram), or by direct injection into the renal collecting structures via a percutaneous puncture through the patient's back.


arteriographic study of the Kidneys is performed almost exclusively by percutaneous needle puncture and catheterization of the common femoral arteries or, much less often, the axillary arteries. Rapid serial radiograms are obstained during and after bolus injection of suitable radiopaque contrast medium into the aorta at the level of the renal arteries (aortorenal arteriogram, "flush" abdominal aortogram) or into one of the renal arteries (selective renal arteriogram).

Isotopic renography

Radioisotopic techniques provie a means of investigating the structure and function of internal organs without disturbing normal physiologic processes. Currently, 4 general types of renal readioisotopic labels are used. Classified according to the mechanisms of labeling, they are as follows;

  1. renal cortex labels, which are retained in the renal tubular cells,
  2. intravascular compartment labels;
  3. renal tubular function labels, which briefly lable the renal cortex as they are accumulated by renal tubular cells and then are passed into the urine and cleared from the Kidney; and
  4. Substances cleared solely by glomerular filtration, which allow determination of the glomerular filtration rate.

Metal sounds

Metal (stainless steel or nickel-plated steel) sounds are used for uretral dilatation.

In Men

With the Penis stretched taut and the instrument held almost horizontally (over the groin), the tip of the sound is introduced into the lubricated urethra. When the tip reaches the bulb (at the external sphincter), the handle is brought to the vertical position, which usually enables the tip to pass through the sphincter. Moving the handle to the horizontal position (parallel to the thighs0 causes the sound to advance into the bladder. The first sound passed should be a 24F, even though the patient says he has a narrow stricture. This size has a broad tip that will not perforate a friable urethral wall and is therefore ideal for urethral exploration. if a 24F sound cannot be passed, smaller sounds can be tired. If a 20F will not pass, do not use the smaller sizes, because their tips are relatively sharp and may pierce the urethral wall. In such cases, filiforms and followers may be used.

In women

Due to the short and relatively straight canal of the female urethra, the passage, of sounds is quite simple in women. Significant stricture is rare.


The resectoscope is a commonly used visual instrument with which transurethral resection of the prostate or of vesical carcinoma is performed. Resectoscopes remove tissue by means of the electrocauterizing retractile loop that makes multiple passes and cuts away the tissue in strips ("chips"). Hemostasis is obtained by cautery of individual blood vessels as they are visualized. Newer continuous-flow models have a double sheath that allows continuous inflow and outflow of irrigant, which provides a constantly clear view and stable bladder pressure. When the flow rate is properly set, this system allows nearly nonstop resecting, because the bladder never becomes completely distended. Due to the continuous flow allows the bladder wall to remain in a relatively stable position, this instrument is useful in resecting large bladder tumors.


Current models allow direct visualization. Simple lithotrites have metal jaws that crush small vesical calculi. Electrohydraulic and ultrasonic lithotrites trnasmit energy through special catheters place by means of the cystourethroscope; when the catheter is touched to the calculus and energy is applied, the calculus disintegrates.

Needle Biopsy of the Prostate

Various types of soft-tissue biopsy needles that remove cores of tissue from a suspicious area are available. In addition, needle aspiration to obtain specimens for cytologic examination is promising. The prostate may be approached via the perineal or transrectal route. After a local anesthetic is injected into the perieal skin, a finger in the rectum guides the tip of the needle (which is outside the rectal wall) to the suspicious area. The transrectal route does not require mucosal anesthesia but may be difficult to use in patients with tight anal sphincters. An enema given before the transrectal procedure is useful. It may be easier to biopsy small nodules via the transrectal route since the needle and the palpating finger are in direct contact. A needle biopsy may be done under general or spinal anesthesia in conjunction with cystoscopy.

X-ray Machine

A classic contemporary X-ray Machine

A classic contemporary X-ray Machine


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Complejo Hospitalario Universitario de Albacete on January 15, 2011:

Use of the Trendelenburg position by critical care nurses: Trendelenburg survey

CL Ostrow


BACKGROUND: Little evidence indicates that changing a patient's body position to the Trendelenburg (head lower than feet) or the modified Trendelenburg (only the legs elevated) position significantly improves blood pressure or low cardiac output. This intervention is still used and is often the first measure implemented for treatment of hypotension. OBJECTIVES: The purpose of this research was to assess the degree of use of Trendelenburg positions by critical care nurses, the clinical uses of these positions, and the sources of knowledge and beliefs of nurses about the efficacy of the positions. METHOD: A survey was mailed to 1000 nurses whose names were randomly selected from the membership list of the American Association of Critical-Care Nurses. RESULTS: The return rate was 49.4%. Ninety-nine percent of the respondents had used the Trendelenburg position, and 80% had used the modified Trendelenburg position, mostly for treatment of hypotension. Most used this intervention as an independent nursing action, and most learned about these positions from their nursing education, nurse colleagues, supervisors, and physicians. The Trendelenburg position was used for many nonemergent reasons; the most frequent use was for insertion of central IV catheters. Although 80% of the respondents believed that use of the Trendelenburg position improves hypotension almost always or sometimes, many respondents recognized several adverse effects associated with use of this position. DISCUSSION AND CONCLUSIONS: The results provide evidence that tradition-based therapy still underlies some interventions used in the care of critically ill patients and that some nurses may be relying on an outdated knowledge base that is not supported by the current literature.

U. S. Air Force Regional Hospital on January 15, 2011:

Trendelenburg position

Type: Term Pronunciation: tren?d?-l?n-b?rg Definitions: 1. a supine position in which the feet are higher than the head; used in patients who become acutely hypotensive.

Found on

Trendelenburg position

In the `Trendelenburg position` the body is laid flat on the back (supine position) with the feet higher than the head, in contrast to the `reverse Trendelenburg position`, where the body is tilted in the opposite direction. This is a standard position used in abdominal and gynecological surgery. It allows better access to the pelvic organs as gravity pulls the intestines towards the head. It was named after the German surgeon Friedrich Trendelen...

Found on

Trendelenburg position

one in which the patient is on the back on a table or bed whose upper section is inclined 45 degrees so that the head is lower than the rest of the body; the adjustable lower section of the table or bed is bent so that the patient's legs and knees are flexed. There is support to keep the patient from slipping.

Found on

Trendelenburg Position

A position in which an individual is laid flat on the back with their feet higher than the head. This position is used during pregnancy when a woman is at risk for delivering the baby prematurely. The position may also be used in labor when the cervix is swollen and will not dilate to a full 10 centimeters or when the baby is lying in an unfavora...

Found on

Trendelenburg's position

A supine position on the operating table, which is inclined at varying angles so that the pelvis is higher than the head with the knees flexed and legs hanging over the end of the table; used during and after operations in the pelvis or for shock. ... (05 Mar 2000) ...

Found on

Children's Medical Center of Dallas on January 15, 2011:

Background When the level achieved by a spinal anaesthetic is too low to perform surgery, patients are usually placed in the Trendelenburg position. However, cephalad spread of the hyperbaric spinal anaesthetics may be limited by the lumbar lordosis. The Trendelenburg position with the lumbar lordosis flattened by hip flexion was evaluated as a method to extend the analgesic level after the administration of hyperbaric local anaesthetic.

Methods When the pinprick block level was lower than T10 5 min after intrathecal injection of hyperbaric bupivacaine (13 mg), patients were recruited to the study and randomly allocated to one of the two positions: the Trendelenburg position with hip flexion (hip flexion group, n = 20) and the Trendelenburg position without hip flexion (control group, n = 20). Each assigned position was maintained for 5 min and then patients were returned to the horizontal supine position. Spinal block level was assessed by pinprick, cold sensation, and modified Bromage scale at intervals for the following 150 min.

Results The maximum level of pinprick and cold sensory block [median (range)] was higher in the hip flexion group [T4 (T8–C6) and T3 (T6–C2)] compared with the control group [T7 (T12–T4) and T5 (T11–T3)] (P < 0.001). The maximum motor blockade median (range) was not different between the two groups being 3 (3–3) in the hip flexion group vs 3 (0–3) in the control group.

Summa Health System on January 15, 2011:

Use of the Trendelenburg Position as the Resuscitation Position: To T or Not to T?

By Natalie Bridges, RN, BSN and Adrian A. Jarquin-Valdivia, MD, RDMS

From the Neurointensive Care Unit, Vanderbilt University Medical Center, Nashville, Tenn.


• Objective To review the literature on use of the Trendelenburg position as a position for resuscitation of patients who are hypotensive.

• Methods PubMed online, cited bibliographies, critical care textbooks, and Advanced Cardiac Life Support guidelines were searched for information on the position used for resuscitation. Because of the heterogeneity of the data, only pertinent articles and chapters were summarized.

• Results Eight peer-reviewed publications on the position used for resuscitation were found. Pertinent information from 2 critical care textbooks and from the Advanced Cardiac Life Support guidelines was included in the review. Literature on the position was scarce, lacked strength, and seemed to be guided by "expert opinion."

• Conclusion The general "slant" of the available data seems to indicate that the Trendelenburg position is probably not a good position for resuscitation of patients who are hypotensive. Further clinical studies are needed to determine the optimal position for resuscitation.

Shock is a relatively common life-threatening condition in out-of-hospital and in-hospital acute care settings such as emergency departments, operating rooms, and intensive care units. Optimal positioning of patients during the resuscitation period, either to maximize effort and outcome or to minimize further injury, seems like a basic consideration to bear in mind and is probably clinically relevant.

The Trendelenburg position was originally used to improve surgical exposure of the pelvic organs.1 It is credited to German surgeon Friedrich Trendelenburg (1844–1924).2 After World War I, use of the Trendelenburg position became common practice in managing patients with shock. The position was later used to prevent air embolism during central venous cannulation and to enhance the effects of spinal anesthesia.1

In the Trendelenburg position, the patient is supine and the head is tilted down, allowing the patient’s feet and legs to remain above the level of the heart. Health-care workers have continued to use this position on the assumption that it will divert blood from the lower extremities into the central circulation. The diversion of blood augments cardiac filling, central blood volume, and cardiac stroke volume, thus providing rapid and temporary management of shock.3

Data to support the use of the Trendelenburg position during shock are limited and do not reveal beneficial or sustained changes in systolic blood pressure or cardiac output.

An alternative position for resuscitation is the modified Trendelenburg position, or passive leg elevation.4 In this position, the patient is supine and the lower extremities are lifted up above the cardiac level (the degree of elevation remains unclear). Supposedly, in this position, blood is displaced from the veins in the lower extremities into the central body compartment. In consequence, right and left ventricular preloads, stroke volume, and cardiac output are increased.5

With the increasing emphasis on evidence-based practice,6,7 we reviewed the published literature to summarize recent views and clinical studies on the use of the Trendelenburg position for resuscitation of patients who have hypotension or shock.


We searched PubMed for the years 1966 through 2004. We limited the search to articles in the English language, on humans and used the following search criteria: (shock OR hypotension) AND Trendelenburg position, and (shock OR hypotension) AND resuscitation position.

Articles pertinent to the issue of resuscitation in shock, hypotension, or both were extracted. The bibliographies in these articles were used to find other publications.


Winnipeg Regional Health Authority on January 15, 2011:

position /po·si·tion/ (pah-zish´un)

1. a bodily posture or attitude.

2. the relationship of a given point on the presenting part of the fetus to a designated point of the maternal pelvis.

anatomical position that of the human body standing erect with palms turned forward, used as the position of reference in designating the site or direction of structures of the body.

Bozeman's position the knee-elbow position with straps used for support.

decubitus position see decubitus.

Fowler's position that in which the head of the patient's bed is raised 18–20 inches above the level, with the knees also elevated.

knee-chest position the patient resting on knees and upper chest.

knee-elbow position the patient resting on knees and elbows with the chest elevated.

lithotomy position the patient supine with hips and knees flexed and thighs abducted and externally rotated.

Mayer position a radiographic position that gives a unilateral superoinferior view of the temporomandibular joint, external auditory canal, and mastoid and petrous processes.

Rose's position a supine position with the head over the table edge in full extension, to prevent aspiration or swallowing of blood.

semi-Fowler position one similar to Fowler's position but with the head less elevated.

Sims position the patient on the left side and chest, the right knee and thigh drawn up, the left arm along the back.

Trendelenburg position the patient is supine on a surface inclined 45 degrees, head at the lower end and legs flexed over the upper end.

verticosubmental position a radiographic position that gives an axial projection of the mandible, including the coronoid and condyloid processes of the rami, the base of the skull and its foramina, the petrous pyramids, the sphenoidal, posterior ethmoid, and maxillary sinuses, and the nasal septum.

Waters' position a radiographic position that gives a posteroanterior view of the maxillary sinus, maxilla, orbits, and zygomatic arches.


Ospedale Pediatrico Bambino Gesu on January 15, 2011:

In the Trendelenburg position the body is laid flat on the back (supine position) with the feet higher than the head, in contrast to the reverse Trendelenburg position, where the body is tilted in the opposite direction. This is a standard position used in abdominal and gynecological surgery. It allows better access to the pelvic organs as gravity pulls the intestines away from the pelvis. It was named after the German surgeon Friedrich Trendelenburg.[1] It is not recommended for the treatment of hypovolaemic shock.


Hypotensive patients (patients with low blood pressure) have historically been placed in the Trendelenburg position in hopes of increasing their cerebral perfusion pressure (the blood pressure in the brain). A 2005 literature review found the "Literature on the position was scarce, lacked strength, and seemed to be guided by 'expert opinion.'"[3] A 2008 meta-analysis found adverse consequences to the use of the Trendelenburg position and recommended it be avoided.[4] However, the passive leg raising test is a useful clinical guide to fluid resuscitation and can be used for effective autotransfusion.[5]

The Trendelenburg position used to be the standard first aid position for shock.[6]

The Trendelenburg position was used for injured scuba divers.[7] Many experienced divers still believe this position is appropriate, but current scuba first aid professionals no longer advocate elevating the feet higher than the head. The Trendelenburg position in this case increases regurgitation and airway problems, causes the brain to swell, increases breathing difficulty, and has not been proven to be of any value.[8] "Supine is fine" is a good, general rule for victims of submersion injuries unless they have fluid in the airway or are breathing, in which case they should be positioned on the side.

Perhaps because of its effect on breathing difficulty and airway problems, the Trendelenburg position is used in waterboarding.

The Trendelenburg position may be used in childbirth when a woman's cervix is too swollen and won't quite dilate to 10 centimeters, or during the incidence of a prolapsed umbilical cord to take pressure off the cord and get more oxygen to the fetus, or it can be used to help rotate a posterior fetus either during pregnancy or the birth itself.

Trendelenburg position is helpful in surgical reduction of an abdominal hernia.[9]

The Trendelenburg position is also used when placing a Central Venous Line.[10] Trendelenburg position uses gravity to assist in the filling and distension of the upper central veins when placing a central line in the internal jugular or subclavian veins. It is also used in the placement of an external jugular peripheral line for the same reason. It plays no role in the placement of a femoral central venous line.

Women's and Children's Hospital Adelaide on January 15, 2011:


It is postulated that once UPEC is established on the catheter surface, flagellum-mediated motility is important for the ascent of this uropathogen from the catheter to the bladder and subsequently to the upper urinary tract (ureter and kidney). The synthesis of the flagellar structure is coordinated in a complex regulon consisting of several operons arranged in a hierarchical system (discussed in detail in a review by Fernández and Berenguer [96]). The filament of flagella consists of flagellin, the major filament subunit encoded by the fliC gene, that extends into the extracellular milieu from the outer membrane. The filament is connected to the flagellar hook FlgE through its attachment to the junction proteins FlgK and FlgL and the filament scaffolding protein FlgD (96). Two recent mutagenesis studies by Lane et al. (208) and Wright et al. (459) demonstrated that flagella, while not absolutely required for virulence during UTIs, greatly enhanced the persistence and fitness of UPEC during this type of infection. Therefore, flagellum-mediated motility should likely be considered to be important for the movement of UPEC on the catheter surface and from the catheter surface to the uroepithelium. This, however, has not been directly demonstrated.

Invasion and Biofilm Formation

Once initial attachment and permanent adherence commence on either the surface of catheters or uroepithelial cells, the establishment of UPEC infection occurs through the colonization of the bladder by the invasion of host cells and the subsequent formation of biofilms. As demonstrated in murine models, UPEC has developed mechanisms to invade host cells, and several reviews discussed this phenomenon in detail (32, 271). UPEC strains have been observed in vitro and in vivo to be internalized by bladder epithelial cells (103, 241, 251) and renal epithelial cells (82, 294, 380, 442). Several adhesins and toxins have been implicated to be involved in the process of invasion, including type 1 fimbriae, the Afa/Dr adhesin family (Dr, Dr-II, F1845, Afa-1, and Afa-3), S pili, P pili, and CNF1. Type 1 fimbria-mediated invasion is dependent upon FimH expression (241). E. coli strains that express Dr adhesins have been observed to invade epithelial cells including Caco-2 intestinal cells (115, 286). Dr adhesin-mediated invasion of uroepithelial cells is dependent upon the presence of the decay-accelerating factor receptor on host cells (117) and may contribute to persistence within the upper urinary tract (271). Research into the roles of S and P pili (241) during bacterial invasion of epithelial cells has not been studied in depth. However, it has been proposed that these pili, in conjunction with toxins, may facilitate the invasion of host tissues (115, 116).

CNF1, discussed later in the review, has been implicated in the invasion of UPEC into uroepithelial cells. This secreted toxin enters the host via the low-pH-mediated endocytotic pathway (54) and then constitutively activates key Rho GTPases that signal the reorganization of the actin cytoskeleton in the host cell. CNF1 has been shown to induce apoptosis in bladder epithelial cells via terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling. Thus, this toxin may play a role in bladder cell shedding in vivo and exposing the underlying tissue for bacterial invasion (257).

The ability of UPEC strains to persist in the urinary tract has been demonstrated by Justice et al. to reside within the superficial umbrella cells of C3H and BALB/c murine bladders due to the formation of biofilm structures known as intracellular bacterial communities (IBCs) (175). These IBCs are formed in a sequential manner. First, during murine cystitis, UPEC cells are attached to the cell surface by type 1 fimbriae and then invade the uroepithelium (240, 241) 1 to 3 h after the initial inoculation. Localized actin rearrangements occur and engulf the bound organism via zipper-like phagocytosis (240). After being internalized in the murine superficial bladder cell, UPEC replicates rapidly, forming clusters known as early IBCs (175). Recently, type 1 fimbriae have been shown to have an additional intracellular role during this stage of IBC formation (460). As IBCs mature, around 6 to 8 h after inoculation of the murine bladder (175), they more closely resemble classical biofilm structures (88), where the bacterial doubling time is increased (from approximately 30 to 60 min) and the bacterial cell length is shortened (0.7 µm versus 3 µm). At this stage, pod-like protrusions are observed on the surface of murine bladder epithelial cells (8). Around 12 h postinoculation, bacterial detachment is observed (175) as either a whole community or individual highly motile cells that burst out of the murine bladder lumen in a process referred to as fluxing (7). It is postulated that IBCs and biofilms contribute to the persistence of these organisms due to the increase in resistance to antibiotics and the host immune response. IBC formation has not yet been substantiated in humans.

There are several factors that are known to contribute to the formation of biofilms by E. coli. These include fimbriae, curli, flagella, antigen 43, and extracellular matrix molecules including cellulose, colanic acid, and poly-?-1,6-N-acetyl-D-glucosamine (67, 68, 74, 81, 437, 469). Specifically, biofilm formation mediated by type 1 fimbriae may assist in the colonization of urinary catheter surfaces (271).

There have been recent studies examining biofilm formation on catheters and UPEC. Ferrières et al. (97) showed that certain catheter materials such as silicone and silicone-latex actually select for and promote biofilm formation for the most virulent UPEC strains, whereas asymptomatic bacteriuria strains form better biofilms on polystyrene and glass (Fig. 3). Koseoglu et al. (194) revealed that UPEC type O4 had formed mature biofilms after 12 to 24 h and developed biofilms completely in almost all latex/silicone balloon catheter samples after 4 to 7 days as examined by scanning electron microscopy.

Oxford Radcliffe Hospitals on January 15, 2011:


UPEC strains and other uropathogens must attach to uroepithelial cells and the catheter surface to colonize and initiate CAUTI and may express a variety of adhesins to assist in this initial attachment. These adhesins also contribute to the direct triggering of host and bacterial signaling pathways, assisting in the delivery of bacterial products to host tissues, and promoting bacterial invasion into host cells (271). A study by Reid et al. (321) suggested that nonspecific adhesins, not specific fimbriae, expressed by UPEC are responsible for attachment to urinary catheter material. It is unknown which specific adhesin molecules are involved in the colonization of UPEC on catheter surfaces. However, potential adhesins associated with UTIs, including type 1, P, S, FC1, and F9 fimbriae and Iha and Dr adhesins, could possibly play a role during CAUTIs. The most extensively studied adherence factors of UPEC are type 1 and P fimbriae (271); an in-depth description of these structures has been reported previously (96, 271).

Type 1 fimbriae, the most frequently expressed virulence factor of UPEC (80 to 100% of strains), are composite helical cell surface structures consisting of repeating major pilin FimA subunits, tip fibrillum (FimF and FimG), and tip adhesin FimH assembled via the chaperone (FimC)-usher (FimD) pathway (344). These pili undergo phase variation and are regulated by the recombinases FimB and FimE.

In a study by Mobley et al. (261) examining urine cultures of 51 long-term catheterization patients over a year, type 1 fimbriae were expressed by a significantly higher number of UPEC isolates causing the most persistent infections than by strains causing transient infections. These pili are thought to be critical for the interaction of UPEC with uroepithelial cells during colonization of the bladder (59, 211, 272, 403). FimH of type 1 pili is thought to be involved in the adherence of these organisms to the bladder epithelium through the recognition and binding of the mannosylated integral membrane glycoproteins uroplakin Ia (467) and uroplakin Ib located on superficial epithelial cells. This tip adhesin also recognizes extracellular matrix proteins including collagen (types I and IV), fibronectin, and laminin as well as Tamm-Horsfall protein. Therefore, these bacterial adhesive structures are able to recognize epithelia (bladder and kidney), immune cells (macrophages, neutrophils, and mast cells), erythrocytes, and extracellular matrix proteins. This tip adhesin may also mediate bacterial autoaggregation and biofilm formation (313, 347, 348).

In addition, type 1 pili are believed to induce an inflammatory response associated with UPEC attachment and invasion (202) through the binding of FimH to specific mast cell receptors that initiate this response by the secretion of inflammatory mediators (1). Lastly, Snyder et al. (377) demonstrated that the expression of type 1 fimbriae coordinately affects the expression of P fimbriae in an inverse manner that may coordinate sequential events during colonization during UTIs in vitro and in vivo as examined by CFT073-specific DNA microarray analysis and mutagenesis studies using a mouse model. This adhesin has been associated with the invasion process as will be discussed later in the review. As these pili have been suggested to be expressed for the initial interactions between UPEC and various surfaces, it is speculated that type 1 pili could be involved in the initial interactions with the catheter surface or in interactions with uroepithelial cells during CAUTIs associated with UPEC.

P fimbriae or pyelonephritis-associated pili (pap) are the second most common virulence factors associated with UPEC uropathogenesis. The genetic determinants responsible for the production of these fimbriae are encoded on the UPEC chromosome by the papABCDEFGHIJK operon. P fimbriae are composed of heteropolymeric fibers consisting of different protein subunits (148), including proteins involved in the structure of the pilus (major pilin PapA, pilus anchor PapH, tip fibrillum PapKEF, and tip adhesin PapG), pilus assembly (periplasmic chaperone PapD and outer membrane usher PapC), and pilus regulation (PapB and PapI). Some studies have shown that P pili are needed by UPEC strains during UTIs; others have failed to show this requirement. UPEC strains expressing P fimbriae attach to globoside residues present on human kidney epithelial cells, which is suggested to play a role in the virulence associated with pyelonephritis (present in 80% of pyelonephritic E. coli strains) as well as ascending UTI (79, 310). Attachment to uroepithelial cell digalactoside receptors mediated by these fimbriae has been shown to induce cytokine secretion (interleukin-6 [IL-6] and IL-8) by this cell type in vitro (137). Studies have proposed that P pili may be important in establishing a bacterial reservoir in the intestinal mucosa (113, 233). However, experimental evidence suggests that these adhesins appear to have a less important role in colonizing abnormal or obstructed urinary tracts (156, 416). Based on these findings, it is thought that P pili may have either no role or a limited role during CAUTIs caused by UPEC.

UPEC is capable of expressing other surface adhesins including S pili (271), F1C pili, F9 fimbriae, IrgA adhesin, and Dr adhesins (271). S pili, consisting of the major subunit SfaA and the minor subunits SfaG, SfaH, and SfaS, recognize and bind sialyl galactosides on human kidney epithelial cells (191) and have been shown to play a role in UTIs caused by UPEC in rats (238). F1C pili, encoded by 14% of UPEC isolates, recognize and attach to kidney epithelial (distal tubules and collecting ducts) and endothelial (bladder and kidney) cells (183). Recently, Ulett et al. described a novel fimbria for UPEC strain CFT073 known as F9 fimbriae (420). These fimbriae were suggested to play a role during biofilm formation and are found in other UPEC and other pathogenic E. coli strains. The precise role of these surface structures during infection is currently unknown. UPEC expresses an iron-regulated gene homologue adhesin IrgA, designated Iha, during UTIs. This outer membrane protein is prevalent among clinical UPEC strains (38 to 74%) (16, 166) compared to fecal E. coli isolates (14 to 22%). Recombinant Iha from the pyelonephritogenic E. coli isolate CFT073 conferred adherence to cultured T-24 human uroepithelial cells to nonadherent E. coli strain ORN172 (163). In addition, a mutant in iha was more attenuated in a mouse model of ascending UTI than wild-type strain CFT073 and UPEC76 (CFT073 pap mutant) (163).

The Dr adhesin family of UPEC includes the uropathogen-associated fimbrial adhesin Dr and nonfimbrial adhesins (AFA-I, AFA-II, AFA-IV, Nfa-I, and Dr-II) (271) and has been associated with cystitis (30 to 50%) in children (114). The Dr operon consists of six genes encoding the main structural subunit DraA, the chaperone DraB (308), the usher DraC (308), the potential invasin DraD (106), DraP, and the adhesin DraE (465). The structural adhesin DraE determines the receptor-binding specificity of Dr adhesins (285). This adhesin is believed to be important in bacterial persistence in the urinary tract through the invasion of bladder and kidney epithelia via the interaction of these fimbriae with decay-accelerating factor (CD55) (286), a regulatory protein that protects tissues from autologous complement-mediated damage. The Dr adhesin also binds type IV collagen (286) and integrins, thus promoting recognition and the adherence of these organisms to interstitial compartments of the kidney, neutrophils, and erythrocytes. Strains of UPEC expressing Dr adhesin were capable of causing chronic experimental pyelonephritis in C3H/HeJ mice (114). They were also capable of long-term survival in human epithelial cells and persisting in the kidneys of experimental animals for months (215). It is unknown if this family of adhesins is expressed during CAUTIs caused by UPEC.

In summary, UPEC is known to express a number of adherence factors that assist in its ability to persist in the urinary tract. However, there is limit

Long Island Jewish Medical Center on January 15, 2011:

During the course of researching literature for this review, it was surprising how little research has been directed specifically towards virulence associated with CAUTIs given the staggering number of patients that develop this type of infection annually. As a reflection of this finding, the majority of this review will discuss the virulence factors that are involved in the pathogenesis of UTIs caused by two gram-negative bacterial etiologic agents associated with CAUTIs, Escherichia coli and Proteus mirabilis, and how these factors may contribute to infections associated with indwelling catheters. When applicable, known virulence factors that are associated with the pathogenesis of CAUTIs will be described. Lastly, the review will conclude with methods used for the prevention and treatment of patients who develop these infections.






E. coli, undoubtedly the most researched microorganism, is a facultative anaerobe that is a member of the family Enterobacteriaceae. While both commensal and uropathogenic E. coli (UPEC) strains colonize the large intestines of humans, only UPEC strains are primarily selected for growth in the urinary tract. Virulence factors that differentiate these avirulent commensals from virulent strains of E. coli were acquired on mobile genetic elements by horizontal gene transfer; examples of such transfer can be found on the E. coli chromosome in the form of pathogenicity islands (125). These virulence factors enable E. coli strains to colonize and persist in the human host despite highly effective host defenses (278). E. coli strains have evolved to cause a variety of human diseases including sepsis, meningitis, diarrhea, and UTIs (276). These organisms are serotypically diverse, spanning over 250 serotypes based on O, H, and K antigens (292). Strains of E. coli associated with infections of the urinary tract are referred to as UPEC strains and are a subset of strains called extraintestinal pathogenic E. coli strains, which cause UTI, sepsis, and meningitis.

UPEC strains are the most commonly isolated organisms in community-acquired UTIs (70 to 90%) and among the most commonly isolated in nosocomially acquired UTIs (50%) including CAUTIs (202). E. coli has been identified as the causative agent in 90% of all case of UTI in ambulatory patients (167). UPEC strains can be classified into four phylogenetic groups, designated A, B1, B2, and D, with strains classified as B2 and D usually causing the most extraintestinal infections including UTIs (287). Since these organisms are capable of colonizing the intestinal and vaginal tracts as well, these sites can serve as potential reservoirs for UTIs and CAUTIs (83, 160).

As with other organisms, UPEC strains possess an arsenal of virulence factors that specifically contribute to their ability to cause disease in the human urinary tract. Genes encoding hemolysin, P fimbriae, S fimbriae, and cytotoxic necrotizing factor 1 (CNF1), for example, have been identified on various pathogenicity islands in different UPEC strains (125). This genetically heterogenous group of organisms varies in its capacity to colonize and persist in the urinary tract (99, 158). DNA microarray analysis of E. coli CFT073, a pyelonephritis strain, compared transcriptional profiles of this strain grown in LB, in human urine, and in the murine bladder cystitis model of infection (126, 376) and verified the in vivo expression of type 1 pili, iron acquisition proteins, and capsule (15, 335, 336, 345). In a prevalence study conducted by Kanamaru et al. (180), who compared 427 E. coli strains (377 UTI isolates and 50 fecal isolates) using PCR assays, the putative virulence factors iroN, iha, kpsMT, ompT, and usp were found 2.0 to 4.3 times more frequently in UTI isolates than in fecal isolates and were strongly associated with a specific anatomical site of infection (i.e., kidney or bladder).

Since UPEC strains are more commonly associated with infections of the intact urinary tract, it is thought that less-virulent organisms are capable of causing complicated UTIs such as CAUTIs. These bacteria may express less and perhaps different virulence factors during this process compared to organisms that are able to infect structurally and functionally normal urinary tracts (261). It has been implied that UPEC strains that infect the catheterized urinary tract have a reduction in the expression of P fimbriae and possibly other factors such as hemolysin, serum resistance, colicin production, and certain H, O, and K serotypes (261). An analysis of 70 clinical urinary strains of E. coli isolated from patients with spinal injuries undergoing long-term bladder catheterization identified that these strains rarely possess a complete arsenal of virulence factors possessed by strains isolated from cases of uncomplicated UTI (26). Among 70 urinary isolates, the prevalences of virulence factors were as follows: mannose-resistant hemagglutinins, 30%; P fimbriae, 17%; hemolysin, 27%; K antigens, 28%; and aerobactin, 33% by bioassay and 39% by gene probe (26). These findings indicate that the presence of a urinary catheter and a neuropathic bladder increases susceptibility to colonization of the urinary tract (26). Despite its prominent role in CAUTIs, limited research specifically addressing UPEC and its ability to cause these types of infections has been performed. Because of this, we will focus on the most recent developments in the research on UPEC and its role in UTIs and, when applicable, any research that is devoted to the field of bacterial virulence during CAUTIs.


Ehealthconnection Catholic Healthcare Partners on January 15, 2011:

Many uropathogens use flagellum-mediated motility and type IV pilus-mediated (twitching) motility to facilitate the spread of infection from the initial colonization site to the urinary tract. Twitching motility via type IV pili cycles through periods of extension, attachment, and retraction in gram-negative bacteria (33, 256) and is thought to play a significant role in virulence (128).

Once colonized on the catheter and uroepithelium, uropathogens must adapt to the urinary tract environment and acquire nutrients. The production and secretion of degradative enzymes and toxins into the local environment may lead to a breakdown of tissue, releasing nutrients. As iron is a limiting nutrient in the human host (447), uropathogens have developed complex iron acquisition systems such as heme transporters, ferric and ferrous iron transport systems, and siderophore iron uptake systems to circumvent host iron-sequestering mechanisms. Certain uropathogens are capable of using urea, found in high concentrations in human urine (up to 500 mM) (35, 170), as a nitrogen source due to the expression of urease. As a consequence of urease-mediated hydrolysis of urea to ammonia and carbon dioxide, the local environment becomes alkalinized, which leads to the precipitation of polyvalent ions that become enmeshed in the biofilms on catheters and urinary epithelial surfaces (118). These crystalline biofilms must be removed from the host to completely resolve the infection, since antimicrobial agents may be ineffective at eliminating biofilm-associated bacterial populations.

To maintain an infection in the human urinary tract, pathogens must be capable of evading the host immune response. Gram-negative uropathogens enact a number of mechanisms of host immune evasion, including the production of capsules, immunoglobulin A (IgA) proteases, and lipopolysaccharides (LPSs). Capsules, comprised of repeating units of polysaccharides, play a role in evading the immune system by resisting phagocytosis, antimicrobial peptides, and the bactericidal effects of human serum (46, 311, 454). Capsular structures elicit a poor immunogenic response due to their structural similarities to polysialic acid residues found on human cells (415). Additionally, this barrier plays a role in late biofilm development (346) and protects against desiccation and phage attack. It also assists in accelerating the urinary stone crystallization process via electrostatic interactions that accumulate urinary ions at the bacterial surface (55, 87, 408). During the course of UTIs, antibodies that recognize antigenic components of uropathogens are produced. However, proteases targeting immunoglobins and other host defense components such as complement (C1q and C3) and antimicrobial peptides (human beta-defensin 1 [hBD1] and human cathelicidin LL-37) protect uropathogens from the host response (24). LPS, a requisite constituent of gram-negative bacterial outer membranes, is composed of three components: a lipid A molecule that anchors LPS to the membrane, a core consisting of polysaccharides, and a variable O antigen. This macromolecule elicits a potent inflammatory response that initiates the development of septic shock in systemic infections. Various components of LPS have been demonstrated to be important for resistance to antimicrobial peptides (95) and complement-mediated lysis. A summary of virulence factors expressed by gram-negative bacteria


Universitätsklinikum Carl Gustav Carus Dresden on January 15, 2011:

Despite innate mechanical safeguards against microbial infection of the intact human urinary tract, specific organisms are capable of colonizing and persisting in this environmental niche. Similar to other mucosal pathogens, uropathogens employ specific strategies to infect the urinary tract, including colonization of a urinary catheter and/or mucosal site (uroepithelial cells), evasion of host defenses, replication, and damage to host cells. The insertion of a foreign body such as an indwelling catheter into the bladder increases the susceptibility of a patient to UTIs, as these devices serve as the initiation site of infection by introducing opportunistic organisms into the urinary tract. The majority of these uropathogens are fecal contaminants or skin residents from the patient's own native or transitory microflora that colonize the periurethral area (56, 66, 217, 288, 462). Transitory microflora that originate from hospital personnel or from contact with other patients may represent antibiotic-resistant nosocomial strains, complicating treatment for these infections. Bacterial entry into the bladder can occur at the time of catheter insertion, through the catheter lumen, or along the catheter-urethral interface (439). The preferred mechanism of bladder entry during CAUTIs is extraluminal (66%), where organisms ascend from the urethral meatus along the catheter urethral interface. Organisms can also enter the bladder intraluminally (34%), where the bacteria migrate into the bladder as a result of manipulation of the catheter system (400, 440).

Indwelling urinary catheters further favor the colonization of uropathogens by providing a surface for the attachment of host cell binding receptors that are recognized by bacterial adhesins, thus enhancing microbial adhesion. Upon insertion, urinary catheters may damage the protective uroepithelial mucosa, which leads to the exposure of new binding sites for bacterial adhesins (108). Lastly, the presence of the indwelling catheter in the urinary tract disrupts normal host mechanical defenses, resulting in an overdistension of the bladder and incomplete voiding that leaves residual urine for microbial growth (133).

Organisms capable of infecting the urinary tract during catheterization use approaches to establish infection that are similar to those used by organisms that cause uncomplicated UTIs. However, due to the introduction of a foreign body, organisms causing CAUTIs require fewer recognized virulence factors to colonize and establish infection than those required by pathogens to infect a fully functional urinary tract.

Bacterial adhesins initiate attachment by recognizing host cell receptors located on surfaces of the host cell or catheter. Adhesins initiate adherence by overcoming the electrostatic repulsion observed between bacterial cell membranes and surfaces to allow intimate interactions to occur (61). These factors are differentially expressed during the course of infection not only for the recognition of different surfaces and cell types that the uropathogen encounters (e.g., in bladder versus the kidney) but also to evade the host immune response. These bacterial cell surface structures recognize specific host cell surface and extracellular matrix components such as proteins, glycoproteins, glycolipids, and carbohydrates. Gram-negative uropathogens produce an assortment of adhesins including those attached to the tip of hair-like projections, known as fimbriae or pili, as well as adhesins anchored directly within bacterial cell membranes, known as nonfimbrial adhesins.

Once firmly attached on the catheter surface or the uroepithelium, bacteria begin to phenotypically change, producing exopolysaccharides that entrap and protect bacteria. These attached bacteria replicate and form microcolonies that eventually mature into biofilms (Fig. 1). During biofilm development, intracellular communication by quorum sensing regulates formation and detachment from biofilms through the collective expression of genes after cellular populations reach a threshold concentration. The rate of genetic material exchange occurring within the biofilm is greater than that between planktonic cells (134, 326), thereby allowing the potential spread of antibiotic resistance genes and other traits. Once established, biofilms inherently protect uropathogens from antibiotics and the host immune response (63). The shedding of daughter cells from actively growing cells and the shearing of biofilm aggregates from the mature biofilm seed other sections of the catheter and bladder.


Hamilton Health Sciences on January 15, 2011:

Department of Microbiology and Immunology, School of Medicine, University of Maryland—Baltimore, 655 W. Baltimore Street, Baltimore, Maryland 21201,1 Cardiff School of Biosciences, Cardiff University, Cardiff, Wales CF10 3TL, United Kingdom,2 Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan 48109,3 Department of Biomedical Sciences, Dental School, University of Maryland—Baltimore, 650 W. Baltimore Street, Baltimore, Maryland 212014







Invasion and Biofilm Formation

Avoidance of Host Immune Response

Damage to the Host and Acquisition of Nutrients




Biofilm Formation

Avoidance of Host Immune Response

Damage to the Host and Acquisition of Nutrients


Limiting Catheter Usage

Condom and Suprapubic Catheters and Intermittent Catheterization

Closed-System Foley Catheters and Proper Use by Health Care Professionals

Prevention of Bacterial Colonization of the Urinary Meatus and Urinary Tract

Novel Surfaces

Catheters Containing Antimicrobial Agents


Future Promising Technologies








Catheter-associated urinary tract infections (CAUTIs) represent the most common type of nosocomial infection and are a major health concern due to the complications and frequent recurrence. These infections are often caused by Escherichia coli and Proteus mirabilis. Gram-negative bacterial species that cause CAUTIs express a number of virulence factors associated with adhesion, motility, biofilm formation, immunoavoidance, and nutrient acquisition as well as factors that cause damage to the host. These infections can be reduced by limiting catheter usage and ensuring that health care professionals correctly use closed-system Foley catheters. A number of novel approaches such as condom and suprapubic catheters, intermittent catheterization, new surfaces, catheters with antimicrobial agents, and probiotics have thus far met with limited success. While the diagnosis of symptomatic versus asymptomatic CAUTIs may be a contentious issue, it is generally agreed that once a catheterized patient is believed to have a symptomatic urinary tract infection, the catheter is removed if possible due to the high rate of relapse. Research focusing on the pathogenesis of CAUTIs will lead to a better understanding of the disease process and will subsequently lead to the development of new diagnosis, prevention, and treatment options.






Indwelling urinary catheters are standard medical devices utilized in both hospital and nursing home settings to relieve urinary retention and urinary incontinence. Of the almost 100 million catheters that are sold annually worldwide, one-quarter of them are sold in the United States (50). The most common urinary catheter in use is the Foley indwelling urethral catheter, a closed sterile system that is comprised of a tube inserted through the urethra and held in place by an inflatable balloon to allow urinary drainage of the bladder. Although these devices were originally designed for short-term use in patients, indwelling catheter use is now commonplace in the long-term setting.

Due to the frequent and sometimes unnecessary use of indwelling catheters during hospitalization (21 to 50% of patients) (153), many patients are placed at risk for complications associated with the use of these devices. A study of 1,540 nursing home residents determined that the risk of hospitalization, length of hospitalization, and length of antibiotic therapy were three times higher in catheterized residents than in noncatheterized residents (205). The most notable complication associated with indwelling urinary catheters is the development of nosocomial urinary tract infections (UTIs), known as catheter-associated UTIs (CAUTIs). Infections of the urinary tract associated with catheter use are significant not only due their high incidence and subsequent economic cost but also because of the severe sequelae that can result.

CAUTIs, the most common type of nosocomial infection, account for over 1 million cases annually (401) or over 40% of all nosocomial infections in hospitals and nursing homes (382, 383, 438) and constitute 80% of all nosocomial UTIs (132). Due to this high incidence, the overall cost for medical intervention of nosocomial UTIs is staggering, with an estimated $424 million to $451 million spent annually in the United States to manage these infections (157). Furthermore, catheter-associated bacteremia is estimated to cost approximately $2,900 per episode (339). Costs for treatment of nosocomial UTIs include antimicrobial therapy, increases in length of stay during hospitalization, physician visits, and morbidity (98). These costs will inevitably rise due to advances in preventive medicine that extend life expectancy, increasing the elderly population. This population today (those 65 years old) accounts for approximately 12.6% (37,849,672) of the total population of the United States (301,139,947) (422); their care accounts for about one-third (6) of the estimated $1 trillion in U.S. health expenditures (279).

Individuals requiring an indwelling catheter are predisposed to the development of CAUTIs due to the presence of an indwelling catheter device and potentially pathogenic multidrug-resistant organisms in the hospital setting. Despite the imminent threat of infection from these potent opportunistic nosocomial multiresistant strains, most cases of catheter-associated bacteriuria or the presence of bacteria in the urine are asymptomatic.

However, when an episode of CAUTI becomes symptomatic, the resulting sequelae can range from mild (fever, urethritis, and cystitis) to severe (acute pyelonephritis, renal scarring, calculus formation, and bacteremia). Left untreated, these infections can lead to urosepsis and death (284, 438). These complicated infections commonly recur and result in long-term morbidity due to the presence of encrustation and blockage of the catheter by crystalline biofilms that increase resistance to the host immune response and to antibiotics (394). Since the incidence of symptomatic CAUTIs is a major health concern due to the complications and recurrence associated with this type of infection, research directed at understanding the pathogenesis of CAUTIs is warranted and should lead to new and improved diagnosis, prevention, and treatment options.

from on January 15, 2011:

INTRODUCTIONSometimes the homeostasis of the urinary system becomes upset, making thenormal function of micturition impossible. There may be a need then for catheterization.Health care providers must strive to make this a safe, efficient, and non-traumaticexperience for the patient.4-2.PURPOSES OF CATHETERIZATIONThere are a number of reasons why catheterization may be performed. Includedare the following:a. Obtain a sterile urine specimen.b. Measure the amount of residual urine in the bladder.c. Relieve a distended bladder in the patient who is unable to void.d. Provide continuous drainage or irrigation.e. Administer medications such as a chemotherapeutic solution.f. Measure the urinary output.g. Prepare a patient for a surgical procedure or obstetrical delivery (childbirth).h. Assist the patient following surgery.4-3.INDICATIONS FOR CATHETERIZATIONIndications for catheterization include the following:a. The patient's bladder is severely distended.b. Urinary output is severely decreased.c. There is a significant outflow obstruction.d. The patient is in shock or pre-shock status.e. The patient has an acute spinal cord injury


Ontario Community Care Access Centres on January 15, 2011:

The study was conducted at St John Hospital and Medical Center, a 769-bed tertiary care teaching hospital in Detroit, Mich. The authors examined 532 instances in which urinary catheters were placed in emergency room patients over a 12-week study period. After reviewing whether the catheter's placement conformed to established guidelines, the authors determined that half of the female patients 80 years or older who were subjected to urinary tract catheterization did not meet institutional guidelines. Women were 1.9 times more likely than men, and the very elderly (greater than 80 years) were 2.9 times more likely than those 50 years and younger, to have a urinary catheter inappropriately placed.

"We found that it was twice as likely for women to have a non-indicated UC [urinary catheter] placement compared to men," the authors conclude. "Our results confirm what has been reported in previous studies, and underscore the significant risk of the very elderly (80 years or older) for inappropriate UC utilization."

The study's findings point to an area of concern among healthcare professionals tackling preventable hospital infections. Urinary tract catheterization is a major risk factor for developing urinary tract infections. The researchers note that at present, urinary tract infections account for more than one-third of all hospital-acquired infections. If urinary catheters are inappropriately placed at high rate in very elderly women, this vulnerable group of patients is at increased risk for developing an infection, according to the investigators.

"The inappropriate UC [urinary catheter] utilization has been a ubiquitous problem in the hospital setting," say the study's authors. "This translates to additional preventable or avoidable urinary tract infections and other complications related to UCs."

The federal government's Centers for Medicare & Medicaid Services considers catheter-associated urinary tract infections to be reasonably preventable through application of evidence-based best practices and as such no longer reimburses for these hospital-acquired infections. The authors noted that the majority of U.S. hospitals do not have formal systems to monitor urinary catheter utilization.


Univesity of California San Diego Medical Center Moores Cancer Center / Ucsd Cancer Center on January 15, 2011:


Biofilm problem:

Catheter associated urinary tract infections caused by the formation of biofilms on urinary catheter surfaces. Bacteria imbedded in the biofilm are very difficult to control with currently available technoogy.

Market size:

US $7 billion worldwide urinary catheter market. Infections caused by urinary catheters account for 40% of all hospital acquired infections and cost the healthcare system over US $1 billion per year in the United States alone.

Kane Biotech solution:

Aledex™(formerly called PS/CHX), a novel combination of FDA approved agents for coating urinary catheters for bacterial control and biofilm prevention and dispersal.

Technology status:

Aledex™, Kane Biotech’s lead urinary catheter coating product has shown its efficacy and broad spectrum activity in preventing catheter related infections in vitro and in vivo.

Pre-clinical results: Catheter related infections with Aledex™ coated catheters

Catheters coated with Aledex™were significantly less likely to cause catheter related infection* in animal studies.

According to the US Centre for Disease Control (CDC), the urinary tract is the most common site of infections acquired in a hospital, or hospital-like setting, accounting for more than 40% of the total number reported by acute-care hospitals and affecting an estimated 600,000 patients a per year. Most of these infections - 66% to 88% - are as a result of urinary catheterization.

There is an urgent need to control and reduce the number of infections acquired by patients after their admission to the hospital. These hospital acquired (nosocomial) infections, many of which are caused by in-dwelling medical devices, pose a threat to any patient admitted to a hospital and contribute considerably to the costs and morbidity associated with hospitalization.

In-dwelling medical devices are responsible for the vast majority of nosocomial infections. The most common cause of device-related infection is the urinary catheter. Urinary catheterization is involved in up to 90% of all nosocomial urinary tract infections (UTI), as the catheter surface serves as a platform for the growth of bacteria as biofilm. As the duration of catheterization increases, catheter associated UTI rates approach 100%. Patients who acquire a UTI will stay longer in hospital an average of six days longer than those who do not, and will contribute to an extra $1.8B in hospital costs.

Recent studies have shown an abundance of evidence that anti-microbial catheters provided benefits when compared to standard uncoated catheters. Furthermore, there is a vast support for the assertion that the increased cost of an effective coated catheter is justified with even a modest reduction in the rate of UTI. Due to these facts, and the Centre for Disease Control and Prevention’s recommendations for the use of anti-microbial coated catheters, there is a growing market demand for these types of products. The current $175 million US anti-microbial coating market is forecast to grow to over $500 million by 2012.

Kane Biotech is building a pipeline of non-antibiotic catheter coatings for the prevention of catheter-associated infections. The Company’s lead coating for urinary catheters is Aledex™. In a recent study, Aledex™ was compared to silver hydrogel coated and uncoated commercially available catheters in a recognized in vivo model. Study results demonstrated that the Aledex™ coated urinary catheters were significantly less likely to be colonized b bacteria than either the silver-hydrogel coated or uncoated catheters. Furthermore, the study showed that Aledex™ coated urinary catheters were significantly less likely to cause catheter related infections than either the silver-hydrogel coated or uncoated catheters. All the results comparing Aledex™ to other test groups were statistically significant.

There are a limited number of coated urinary catheters in the market today, predominantly made up of those coated with silver. Although the anti-microbial activity of silver is documented, the use of silver on medical devices is continually debated based on lack of conclusive evidence supporting its ability to reduce infection. The results of the Kane Biotech study were consistent with the concerns cited regarding the efficacy of silver. Of even greater concern, multi-drug resistant bacterial strains continue to increase their prevalence in the hospital environment. According to leading experts, catheter associated UTI are perhaps the prime reservoir for antibiotic resistant pathogens. There is an opportunity for Kane Biotech’s non-antibiotic coating, Aledex™, to positively impact the antibiotic resistance problem by reducing the need for systematic antibiotics, while preventing the ability for dangerous resistant pathogens to take hold through the formation of biofilm on the catheter surface.


Greenwich Hospital Connecticut on January 15, 2011:

Urinary tract infections (UTI) associated with urinary catheters are the leading cause of secondary nosocomial bacteremia. Approximately 20 percent of hospital-acquired bacteremias arise from the urinary tract, and the mortality associated with this condition is about 10 percent [1].

Issues related to symptomatic and asymptomatic bacteriuria (both of which are subsets of UTI and are sometimes referred to as symptomatic or asymptomatic UTI) in patients with indwelling bladder catheters will be reviewed here.

Issues related to asymptomatic bacteriuria and cystitis in other circumstances, and the indications for placement, methods of catheterization, and management and complications of bladder catheters are discussed separately (see "Approach to the adult with asymptomatic bacteriuria" and "Acute cystitis in women" and "Acute cystitis and asymptomatic bacteriuria in men" and "Placement and management of urinary bladder catheters" and "Complications of urinary bladder catheters and preventive strategies").


Asymptomatic bacteriuria (with or without an indwelling catheter) is characterized by a urine culture with >10(5) colony forming units (cfu)/mL of uropathogenic bacteria in the absence of fever >38ºC, suprapubic tenderness or costovertebral angle pain or tenderness [2]. While the CDC has established a definition of >10(5) colony forming units (cfu)/mL, the IDSA has defined asymptomatic bacteriuria as a single catheterized specimen with isolation of a single organism in quantitative counts of ?10(2) cfu/mL [3]. The more sensitive definition reflects the lower threshold for diagnosis when urine is being sampled by direct bladder puncture or fresh diagnostic catheterization with careful pre-procedure site preparation; it is not so useful in the setting of indwelling catheters.

Symptomatic catheter-related bacteriuria (usually referred to as UTI since a clinically significant infection is inferred) is defined as the presence of fever >38ºC, suprapubic tenderness, costovertebral angle tenderness, or otherwise unexplained systemic symptoms such as altered mental status, hypotension, or evidence of a systemic inlammatory response syndrome, together with one of the following laboratory profiles


Vanderbilt Ingram Cancer Center on January 15, 2011:

Background Dense perineal block from epidural analgesia increases the risk of urinary catheterization in labour. Mobile epidurals using low-dose local anaesthetic in combination with opioid preserve maternal mobility and may reduce the risk of bladder dysfunction. We conducted a three-arm randomized controlled trial to compare high-dose epidural pain relief with two mobile epidural techniques.

Methods A total of 1054 primparous women were randomized to receive high-dose bupivacaine, epidural analgesia (Control), combined spinal epidural (CSE), or low-dose infusion (LDI). The requirement for urinary catheterization during labour and postpartum was recorded. Both end points were pre-specified secondary trial outcomes. Women were evaluated by postnatal interview, when their bladder function had returned to normal.

Results Relative to Control, more women who received mobile epidural techniques maintained the ability to void urine spontaneously at any time (Control 11%, CSE 31% and LDI 32%) and throughout labour (Control 3.7%, CSE 13% and LDI 14%), for both mobile techniques P

HealthPartners on January 15, 2011:

Urinary catheters are slender, flexible tubes used to drain urine from the bladder to the outside of the body. Catheters are often used to prevent skin damage from wet clothing and bedding in patients who are incontinent--unable to control the flow of their urine. Patients who are unable to urinate because of injury, surgery or a medical condition may also be catheterized to facilitate the flow of urine. Catheterization can cause side effects such as infection and injury, according to the National Institutes of Health, or NIH.


Long-term use of catheters can cause urinary tract infections, according to the American Urological Association Foundation, or AUAF. The catheter can become contaminated with fecal matter after a bowel movement or can be contaminated during insertion. Symptoms include pain, cloudy urine and fever. If the patient will need the catheter for more than two years, inserting it through an abdominal incision directly into the bladder may prevent contamination. Untreated urinary tract infections can lead to kidney damage or to serious, life-threatening blood infections or septicemia. Patients can prevent infections by drinking plenty of fluids, cleaning around the catheter every day and using good hygiene practices after bowel movements. Patients who self-catheterize should be meticulous about cleaning their equipment and catheters to avoid contamination.

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Urinary Tract Injury

Long-term use of a catheter can cause injury to the urethra or the bladder, according to the AUAF. The urethra, the tube that leads from the bladder to outside of the body, can become torn and swollen and the scrotum may also swell. Symptoms include blood in the urine and pain. Some injuries can be prevented by using the smallest catheter possible and taping the tubing to the leg to avoid tension on it, according to the National Institutes of Health.


Blood, sediment or a kink in the tubing can obstruct the flow of urine from the bladder to the collection bag. A severe blockage may cause urine to back up into the kidneys, causing renal damage. Drinking plenty of water, observing the flow into the bag periodically and irrigating the tubing can keep the urine flowing freely.

Bladder Spasms

Irritation of the bladder can cause it to spasm, according to the NIH. Bladder spasms can be painful and can impede the flow of urine. In some cases, the spams cause urine to leak around the catheter. The condition can be treated with medication, although some patients become used to the irritation and do not require treatment.

Allergic Reaction

Patients allergic to latex may have a sensitivity reaction that can range from mild itching to a life-threatening anaphylactic reaction if a caregiver mistakenly inserts a catheter made of latex into the bladder, according to the AUAF. Before performing a catheterization, the caregiver should ask about latex allergies and ensure that she uses a silicone- or Teflon-coated catheter if necessary. A hospitalized patient with a latex allergy should also be wearing a band or other type of identification that documents the allergy.

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Univerzitetni Klinicni Center Ljubljana on January 15, 2011:

Urethral catheterization is a procedure that involves introducing a flexible rubber (latex, silicone, or Teflon) tube through the urinary opening (urethra) into the bladder.

There are two types of urethral catheterization. In straight, or short-term, urethral catheterization, a catheter is inserted only long enough to drain the bladder of urine and is then removed. In indwelling catheterization, a specialized catheter is inserted into the bladder for an extended period (days to weeks) to allow continuous drainage of urine into a collection bag.

A straight catheterization may be performed to obtain a sample of urine for laboratory analysis in individuals in whom a urinary tract infection, urinary tract injury, or kidney dysfunction is suspected. Indwelling urinary catheterization is usually performed to monitor the urine output of individuals undergoing surgery or after trauma or obstruction (obstructive uropathy) of the urinary tract or to drain the bladder in individuals finding it difficult to void (frequently during serious illnesses). Urinary catheterization may be performed in individuals who have urinary incontinence or who cannot empty their bladder because of neurological damage.

Older adults may need catheterization if they are at high-risk for urinary tract infection (cystitis) due to incomplete emptying of the bladder associated with prostate enlargement (in men), a decreased level of consciousness, or immobility. Other risk factors for cystitis include bladder or urethral obstruction, sexual intercourse, insertion of instruments into the urinary tract (catheterization or cystoscopy), pregnancy, diabetes, or a history of urinary reflux (reflux nephropathy).

Kidney infection (pyelonephritis) most often occurs as a result of lower urinary tract infection (cystitis), particularly in those who have backflow of urine from the bladder into the ureter or kidney (urinary reflux). The risk of pyelonephritis is increased in those with a history of cystitis, kidney stones, urinary reflux, or urinary tract obstruction. Individuals who have chronic or recurrent urinary tract infections are also at increased risk and may in some cases benefit from indwelling catheterization. Crushing injuries to the pelvis, gunshot wounds, or stab wounds may result in urinary tract trauma and require catheterization.

Obstructive uropathy is a blockage of the normal flow of urine somewhere along the urinary tract. The obstruction increases the pressure on the kidney and can result in acute renal failure. Obstructive uropathy may be caused by kidney stones, narrowing of the urethra, adjacent tumors, scarring of the urethra from radiation therapy, urinary tract infections, and cancer. It is most common in individuals with neuromuscular disorders, diabetes mellitus, benign prostatic hypertrophy, or a history of kidney stones.

Urinary incontinence may occur in individuals with weakened pelvic muscles or malfunction of the bladder neck (vesicourethral junction) and urinary sphincter. Trauma to the urethral area, neurological injury, and some medications also may weaken the urinary sphincter muscle that normally prevents leakage of urine from the bladder.