Bladder discomfort secondary to an indwelling urinary catheter is very distressing and this is more so in patients awakening from anesthesia. It is not unusual to find patients catheterized during anesthesia complaining of an urge to void in the postoperative period because of catheter-related bladder irritation. Various treatments have been tried with varying degrees of success for managing this troublesome side effect (1). Tolterodine, a competitive muscarinic receptor antagonist, has been used successfully to treat overactive bladder (urgency, urge incontinence, and micturition frequency) (2).
The incidence and severity of bladder discomfort secondary to an indwelling urinary catheter has not been reported. We conducted this study to evaluate the incidence and severity of bladder discomfort in patients who were catheterized intraoperatively and to evaluate the efficacy of tolterodine in attenuating this discomfort.
After approval from the Institute's ethics committee and written informed consent from the patients, we initially conducted a pilot study of 50 surgical patients who were catheterized intraoperatively and observed that 26 (52%) of the patients complained of bladder discomfort in the postoperative period. Assuming that the incidence of bladder discomfort would decrease to 30% after tolterodine administration, we enrolled 165 patients in the control group (group C) and 50 in the tolterodine group (group T) for the results to be statistically significant with a power of 80% and α = 0.05. Therefore, 215 consecutive adults, ASA physical status I and II patients of either sex, undergoing elective endoscopic or open urologic surgery for the kidney and ureter and requiring catheterization were included in this prospective, randomized, double-blind, placebo-controlled study.
Patients were randomized with the help of a computer-generated table of random numbers into two groups. Group C (n = 165) received placebo and group T (n = 50) received tolterodine 2 mg (Detrusitol, Pharmacia Italia S.p.A). Both drugs were given orally 1 h before induction of anesthesia. Exclusion criteria were bladder outflow obstruction, transurethral resection of the prostate for benign prosthetic hyperplasia, elderly patients (age >60 yr), overactive bladder (frequency >3 times in the night or >8 times in 24 h), end-stage renal disease (urine output <500 mL/24 h).
The patients were premedicated with oral lorazepam 0.04 mg/kg the night before and 2 h before the induction of anesthesia. Induction of anesthesia was done with fentanyl 3 μg/kg and propofol 2 mg/kg. Vecuronium 0.1 mg/kg was given as muscle relaxant. Patients were catheterized using a 16F Foley catheter and its balloon was inflated with 10 mL of normal saline. Anesthesia was maintained using 70% nitrous oxide in oxygen and a propofol infusion of 50–150 μg · kg−1 · min−1 and intermittent fentanyl and vecuronium as required. At the end of surgery, the muscle relaxant was reversed using neostigmine 0.05 mg/kg and glycopyrrolate 0.01 mg/kg and patients were transferred to the postanesthesia care unit (PACU). In the PACU, all patients were connected to IV patient-controlled analgesia with fentanyl for pain management.
Bladder discomfort (urge to pass urine or discomfort in the suprapubic region) was assessed by an anesthesia senior resident, who was unaware of the type of medication received by the patient, on arrival in the PACU (0 h) and again at 1, 2, and 6 h later. Severity of bladder discomfort was recorded as mild (reported by the patient only on questioning), moderate (reported by the patient without questioning; not accompanied by any behavioral responses), or severe (reported by the patient and accompanied by behavioral responses). Behavioral responses observed were flailing limbs, strong vocal response, and attempts to remove the catheter.
The presence or absence of adverse effects, such as postoperative nausea and vomiting, facial flushing, dry mouth, blurred vision, and abdominal discomfort, were also noted. The incidence of bladder discomfort between groups was analyzed by Z test, whereas, severity of discomfort (mild, moderate, and severe) was analyzed by Fisher's exact test. SPSS 9.0 (SPSS Inc., Chicago, IL) was used for statistical analysis. P < 0.05 was considered as significant.
There was no significant difference in the patient characteristics and fentanyl requirement in the postoperative period in both groups (Table 1). No significant difference was observed in the percentage of patients undergoing endoscopic or open urologic procedures. In group C, 63% of patients underwent endoscopic surgery compared with 60% in group T.
The overall incidence of bladder discomfort was significantly less in group T compared with group C at all time points (Table 2). Absolute risk reduction with tolterodine was 19%, the relative risk reduction was 35%, and the number-needed-to-treat was 5.
In group T, 54% of patients reported a dry mouth at 0 h compared with only 22% in group C (P < 0.05). At 1 h, the incidence was 66% versus 47% (P < 0.05). There were no differences in the incidence of dry mouth at 2 and 6 h. Similarly, there were no differences in the incidence of other side effects between the groups at any time.
Our study demonstrates that the maximum incidence of bladder discomfort occurs at 1 hour after arrival in the PACU. In group C, 55% of the patients who were catheterized reported bladder discomfort compared with 36% in group T.
The increase in the incidence of bladder discomfort at 1 hour when compared with 0 hour could have been attributed to the fact that, on arrival in the PACU, patients might not have been able to comprehend and communicate their discomfort properly because of the residual effects of anesthetics.
The innervations of the urinary tract are derived from three sets of peripheral nerves: sacral parasympathetic, thoracolumbar sympathetic, and sacral somatic (primarily the pudendal nerves) (3). Overactive bladder is characterized by the symptoms of urinary frequency and urgency, with or without urge incontinence. These involuntary contractions of the bladder are mediated by muscarinic receptors (4,5). Therefore, antimuscarinic drugs are the mainstay of treatment of overactive bladder.
Tolterodine is the first antimuscarinic drug to be specifically developed for the treatment of overactive bladder. Tolterodine is a competitive pure muscarinic receptor antagonist. It is rapidly absorbed after oral administration, reaching peak plasma levels within 1–2 hours after administration (6). Chen et al. (7) evaluated the efficacy of tolterodine on bladder spasm caused by an indwelling catheter after prostate surgery. Tolterodine and its metabolite 5-HM showed functional selectivity for the bladder over the salivary glands in vivo compared with oxybutynin, another antimuscarinic drug (8).
A limitation of our study is that we have evaluated the response of a single dose of tolterodine on catheter-related bladder discomfort in patients undergoing urologic surgery. We did not evaluate the dose response titration, nor have we evaluated the effect of continuing the therapy in the postoperative period. We have not evaluated its role in patients undergoing all types of surgical procedures, even in patients who are catheterized for other medical procedures not requiring any surgical intervention. Further studies in these areas are suggested.
In conclusion, oral tolterodine (2 mg) administered 1 hour before surgery significantly reduced the incidence and severity of bladder discomfort in our patients. We therefore suggest that tolterodine can be safely given to patients preoperatively to minimize catheter-induced bladder discomfort.
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