2. Bladder Cancer
Bladder cancer occurs at an average patient age of 65 years with a 3:1 male to female ratio. Transitional cell carcinoma of the bladder is second to prostate adenocarcinoma as the most common malignancy of the male genitourinary tract. The association of cigarette smoking with bladder carcinoma results in coexistent coronary artery and chronic obstruc-tive pulmonary disease in many of these patients. Underlying renal impairment, when present, may be age related or secondary to urinary tract obstruc-tion. Staging includes cystoscopy and CT or MRI scans. Intravesical chemotherapy is used for super-ficial tumors, and transurethral resection of blad-der tumors (TURBT) is carried out via cystoscopy for low-grade, noninvasive bladder tumors. Some patients may receive preoperative radiation to shrink the tumor before radical cystectomy. Urinary diversion is usually performed immediately follow-ing the cystectomy.
TURBT differs from TURP in that the surgical resection is not necessarily carried out in the mid-line. Bladder tumors may occur at various sites within the bladder. Unfortunately, laterally located tumors may lie in proximity to the obturator nerve. In such cases, if spinal anesthesia or general anes-thesia without paralysis is administered, every use of the cautery resectoscope results in stimulation of the obturator nerve and adduction of the legs. Urologists rarely derive amusement from having their ear struck by the patient’s knee; thus, in contrast to TURP, TURBT procedures are more commonly per-formed with general anesthesia and neuromuscular blockade. TURBT, unlike TURP, is rarely associated with absorption of significant amounts of irrigating solution.
Radical cystectomy is a major operation that is often associated with significant blood loss. It is usually performed through a midline incision but is increas-ingly performed as a robot-assisted laparoscopic procedure. All anterior pelvic organs including the bladder, prostate, and seminal vesicles are removed in males; the bladder, uterus, cervix, ovaries, and part of the anterior vaginal vault may be removed in females. Pelvic node dissection and urinary diver-sion are also carried out.
These procedures typically require 4–6 h and frequently are associated with blood transfusion. General endotracheal anesthesia with a muscle relaxant provides optimal operating conditions. Controlled hypotensive anesthesia may reduce intra-operative blood loss and transfusion requirements. Many surgeons also believe controlled hypotension improves surgical visualization. Supplementation of general anesthesia with spinal or continuous epi-dural anesthesia can facilitate the induced hypoten-sion, decrease general anesthetic requirements, and provide highly effective postoperative analgesia.
Close monitoring of blood pressure, intravas-cular volume, and blood loss is always appropriate. Direct intraarterial pressure monitoring is indicated in most patients, and central venous catheters are often placed. Urinary output should be monitored and correlated with the progress of the operation, as the urinary path is interrupted at an early point during most of these procedures. As with all lengthy operative procedures, the risk of hypothermia should be minimized by utilizing a forced-air warm-ing blanket and an intravenous fluid warmer.
Urinary diversion is usually performed immedi-ately following radical cystectomy. Many proce-dures are currently used, but all entail implanting the ureters into a segment of bowel. The selected bowel segment is either left in situ, such as in ure-terosigmoidostomy, or divided with its mesenteric blood supply intact and attached to a cutaneous stoma or urethra. Moreover, the isolated bowel can either function as a conduit (eg, ileal conduit) or be reconstructed to form a continent reservoir (neo-bladder). Conduits may be formed from ileum, jejunum, or colon.
Major anesthetic goals for urinary diver-sion procedures include keeping the patient well hydrated and maintaining a brisk urinary output once the ureters are opened. Neuraxial anesthesia often produces unopposed parasympathetic activity due to sympathetic blockade, which results in a con-tracted, hyperactive bowel that makes construction of a continent ileal reservoir technically difficult. Papaverine (100–150 mg as a slow intravenous infu-sion over 2–3 h), a large dose of an anticholinergic (glycopyrrolate, 1 mg), or glucagon (1 mg) may alle-viate this problem.
Prolonged contact of urine with bowel mucosa (slow urine flow) may produce significant meta-bolic disturbances. Hyponatremia, hypochloremia, hyperkalemia, and metabolic acidosis can occur following construction of jejunal conduits. In con-trast, colonic and ileal conduits may be associated with hyperchloremic metabolic acidosis. The use of temporary ureteral stents and maintenance of high urinary flow help alleviate this problem in the early postoperative period.