7-Fundamentals of Instrumentation 177 and UrinaryTract Drainage

1. 7-Fundamentals ofInstrumentation 177and UrinaryTract Drainage Urethral Catheterization Indications The most common indications for the use of a bladder catheter can be broadly divided into two main categories: to obtain drainage or to allow the instillation of diagnostic or therapeutic agents. The relief of acute or chronic urinary retention due to either bladder outlet obstruction or neurogenic bladder dysfunction is probably the most common indication for urethral catheterization (UC). Following in frequency is its use to monitor urinary output

2. Catheter Selection The size and type of urinary catheter used depends on the indication for catheter insertion, age of the patient, and type of fluid expected to be drained. Currently there is a wide variety of catheter types. Catheters can be classified on the basis of material, coating, number of channels , and tip form 1french=0.33mm

5. Catheter Size Based on Age AGE IN YR CATHETER SIZE (FR) <5 5-8 5-10 8-10 10-14 10 >14 10-14

6. Silicone is relatively inert, causing less tissue reaction, and is associated with less bacterial adherence than other catheter materials . • Evidence suggests that the use of silicone catheters is associated with a lower incidence of urinary tract infections compared with those made of latex

7. Number of Channels The most basic catheters are constructed with a single lumen to permit urinary drainage or irrigation/instillation. Additional lumens are added to permit addition of a retention balloon (twoway catheter) and for simultaneous drainage and irrigation (threeway catheter). The ability to allow bidirectional flow with a three-way catheter is particularly useful when there is need to drain thick fluid such as pus or blood from the bladder because it allows thinning of the solute, preventing reaccumulation by rapid exchange of clean fluid in a washing effect. The insertion of a three-way catheter for continuous bladder irrigation is most often performed after transurethral resection procedures of the bladder or prostate, which additionally can be combined with a largevolume retention balloon (30 to 50 mL), which under slight traction can often achieve complete hemostasis of the resected prostatic fossa. It should be borne in mind, however, that the addition of a multichannel catheter is accomplished by decreasing the overall internal diameter or lumen of the main drainage channel; a 24-Fr three-way catheter has a smaller internal drainage diameter than a 24-Fr two-way, which has a narrower lumen than a 24-Fr one-way catheter.

8. Technique of Catheter Insertion The male urethra follows a sigmoid curse, with a proximal curve at the junction of the membranous and bulbar urethra and another at the junction of the bulbar and penile urethra. The adult male urethra is approximately 18 to 20 cm in length, and its diameter is variable, from a mere slit to 6 mm during the passage of urine

9. Only when the position of the catheter has been verified should the retaining balloon be inflated, with the amount of fluid indicated on the catheter. Most catheters do safely permit twice the indicated amount of fluid without risk of balloon rupture. Sterile water is the preferred solution for balloon inflation. Air is compressible and might leak, and electrolyte or glucose-based solutions can precipitate and occlude the tubing and valve mechanism

10. Difficult Catheterization Difficulty inserting a catheter into the bladder is most commonly due to prostatic growth, urethral stricture(s), bladder neck contracture, or false passage from previous urethral instrumentation. Rarely it is the result of phimosis or urethral calculi. If there is no clinical history of previous sexually transmitted infections (STIs), catheterization, trauma, urethral surgery, or radiotherapy in an adult male over 40 years of age, the most likely cause is prostatic enlargement. Using adequate urethral lubrication and a 16- or 18-Fr coudé tip silicone catheter is often successful in this scenario.

11. If multiple previously unsuccessful attempts have been made and urethral trauma is suspected due to the appearance of a bloody urethral discharge, a false passage or a stricture is likely. A single atraumatic attempt can be made using a 12-Fr silicon/straight or coudé tip catheter. If this maneuver is unsuccessful, then depending on the availability of equipment and the level of experience of the clinician, several other options can be considered. The authors’ preference is to use a flexible Cystoscope.

12. Complications of Urethral Catheterization UTIs account for 40% of all nosocomial infections. The major risk factor is the use of urethral catheters, which are responsible for up to (80%) of UTIs in the hospital setting . Risk factors for CAUTIs include patients requiring more than 6 days of catheterization, female gender, active nonurinary infection sites, preexisting medical conditions, malnutrition, renal insufficiency, catheter insertion other than in the operating room, and having drainage tubing or a bag elevated above the level of the bladder

13. A unique complication of urethral catheterization is the inability to remove the catheter from the bladder. problem may be due to a faulty valve, inflation channel blockage, or rarely crystallization within the balloon.

14. An inability to deflate a Foley balloon can be managed using a stepwise approach. One should first attempt to place another 1 to2 mL of fluid in the balloon to ensure normal balloon contour, which may be important with the large-volume balloons. Failing this maneuver, the next step is to cut the inflation port.

15. Other complications of urethral catheterization include hematuria, urethral and meatal strictures, urethral perforation, and allergic reactions including anaphylaxis . Especially at risk are patients with long-term indwelling catheters, in whom other complications may also include malignant neoplasms (2.3% to 10%), stone formation (46% to 53%), bladder neck and urethral erosions

16. Suprapubic Catheterization • Indications • Suprapubic catheter (SC) insertion is most often selected for those • patients in whom urethral access is not possible such as complete • urethral stenosis, bladder neck contracture, and traumatic urethral • disruption. Stent Complications Technique of Ureteral Stent Insertion Stent Symptoms From a patient perspective, stent morbidity can be significant. Lower urinary tract symptoms such as frequency, urgency, dysuria, and pain (flank or suprapubic) occur almost universally . More than 80% of patients experience stent-related pain affecting daily activities, 32% report sexual dysfunction, and 58% report reduced work capacity Urinary Tract Infection

18. Migrationrelated to a stent that was incorrectlysized for the patient’s height Forgotten Stent This is a source of considerable impact on patient well-being and a threat to renal function Encrustation Minor degrees of encrustation, particularly on the bladder curl, are not uncommon in many stented patients. More extensive encrustation often related to the forgotten/retained stent can be one of the most challenging tasks for the urologist requiring various endourologic interventions and on occasion open surgery. If left untreated, extreme degrees of encrustation may lead to compromise of the renal unit and even patient mortality

19. Nephrostomy Tube Drainage • One of the most common indications for acute nephrostomy tube • insertion is to establish urinary tract drainage following a failed • attempt at retrograde stent insertion. An inability to insert a retrograde • stent may be due to several reasons including an impacted • ureteral stone or malignant obstruction. In patients with highgrade • bilateral ureteric obstruction or obstruction of a solitary • renal unit leading to obstructive nephropathy and metabolic • derangements, the ability to place the nephrostomy tube in a Complications NT-related complications can occur at the time of obtaining initial renal access, and additionally those that occur as a result of the nephrostomy tube itself. It is estimated that the overall complication rate associated with NTs is approximately 8.8% to 10%. Complications related to the access procedure include hematuria ,clot colic; and pulmonary injuries (pneumothorax, empyema, hydrothorax or hemothorax), which may be as high as 8% to 12% with upper calyceal approaches and sepsis (1.3% to 2.2%). Rarer complications include injuries to nearby organs (liver, spleen, and bowel) and arteriovenous fistulas. The need for blood transfusionrelated to the NT insertion alone is reported to be as high as 3.2%in some series