Effects of Fentanyl or Clonidine on Postoperative Analgesia and Urinary Retention after Caudal Anesthesia / 대한마취과학회지

BACKGROUND: Caudal administration of local anesthetics, opioids, and the alpha2 adrenergic agonists is effective for postoperative pain. Intrathecal and epidural opioids may commonly result in urinary retention. The purpose of this study was to evaluate the effects of fentanyl or clonidine on postoperative analgesia and urinary retention. METHODS: Forty patients undergoing a hemorrhoidectomy were randomly assigned to receive 20ml of 2% lidocaine and 1 : 200,000 epinephrine plus clonidine 100 microgram (group C100, n = 10), clonidine 150 microgram (group C150, n = 10), fentanyl 50 microgram (group F50, n = 10), or fentanyl 100 microgram (group F100, n = 10) for caudal anesthesia. Mean arterial pressure (MAP) and heart rate (HR) were measured before anesthesia and immediately postanesthesia, and every 5 min after caudal administration for 30 min. The following variables were recorded: onset time, analgesic time, voiding time, and urinary retention. RESULTS: The MAP at 20, 25, and 30 min in group C150 (91 +/- 7, 91 +/- 6, and 90 +/- 7 mmHg, respectively) was less than in group F50 (99 +/- 4, 101 +/- 6, and 101 +/- 5 mmHg, respectively) (P < 0.05). There was no difference in HR and onset time of anesthesia among the groups. Analgesic times in groups C150, F50, and F100 (270 +/- 22, 265 +/- 23, and 323 +/- 82 min, respectively) were longer than in group C100 (207 +/- 59 min), (P < 0.05). The number of patients using a urinary catheter to void was much higher in group F100 (7 patients) than in the groups C100, C150, or F50 (4, 5, and 3 patients, respectively) (P < 0.05). The voiding time was longer in group C150 than in group C100 (369 +/- 122 min vs 266 +/- 83 min, P < 0.05). No side effects were reported. CONCLUSIONS: We conclude that clonidine 150 microgram is adequate to provide effective analgesia and a low incidence of urinary retention during caudal anesthesia.

Analgesic Effect of Epidural Clonidine after Cesarean Section / 대한마취과학회지

BACKGROUND: The importance of the intrinsic analgesic properties of the alpha 2-agonist is difficult to establish, but many studies have shown the beneficial effect of epidural clonidine in postoperative pain management. The authors examined the analgesic effect of clonidine, a preferential alpha 2-adrenergic agonist, upon hemodynamics, and side effects during the post-operative period in patients undergoing Cesarean section. METHODS: Sixty healthy parturients undergoing Cesarean section with general anesthesia were divided into two groups as follows: 1) Epidural Morphine group: An initial dose of morphine 3 mg diluted with 10 ml of 0.125% bupivacaine was injected epidurally at time of the peritoneal closure, followed by a continuous epidural infusion of morphine 7 mg and 100 ml of normal saline for the postoperative 2 days. 2) Epidural Clonidine group: An initial dose of clonidine 150 microgram diluted with 10 ml of 0.125% bupivacaine was injected epidurally at time of the peritoneal closure, followed by a continuous epidural infusion of clonidine 1800 microgram and 100 ml of normal saline for the postoperative 2 days. Postoperative analgesia was assessed by recording the VAS (Visual Analogue Scale), PHS (Prince Henry Score) at postoperative 1, 2, 3, 6, 12, 24, and 48 hours. Blood pressure, heart rate, sedation, and side effects were also recorded. RESULTS: There were no statistically significant differences in the VAS and hemodynamic changes between the two groups, but the epidural clonidine reduced the PHS significantly at 1, 2, 3 postoperative hours (P < 0.05). There were less side effects in the cases of epidural clonidine as compared with epidural morphine. CONCLUSION: In comparison to epidural morphine, epidural clonidine produces a similar degree of analgesia but less side effects.

Pharmacological Prevention of Post-Anesthetic Shivering: Clonidine Vs Meperidine: A Meta-Analysis of Randomized-Controlled Trials / 대한마취과학회지

BACKGROUND: Post-operative shivering is one of the potential complications for any surgical patient. Its incidence varies from 5% to 65%, and many preventive and treatment modalities have been reported. For the effective prevention of post-anesthetic shivering by using intravenous clonidine or meperidine, randomized controlled studies were reviewed. The overall incidence of shivering after clonidine or meperidine administration, and the anti-shivering effect of clonidine and meperidine were evaluated. METHODS: DATA SOURCES: Medline search from 1978 to March 1998. DATA SELECTION: We selected studies that had investigated the preventive anti-shivering effect of intravenous clonidine or meperidine by randomized controlled trials. Ten clinical trials were evaluated. RESULTS: The pooled odd ratio of the patients who received clonidine was 0.32 (95% confidence interval, 0.22~0.47) and it seemed to be effective. But these studies showed little evidence of significant homogeneity (P=0.01). In the subgroup analysis, the pooled odd ratio of group A (early administration or intra-operative infusion group) was 0.47 (95% CI 0.31~0.72) evidenced effectiveness but failed to prove homogeneity (P=0.047). But group B (the late intra-operative administration group) had a pooled odd ratio of 0.10 (95% CI 0.05~0.22) and showed homogeneity (P=0.98). In meperidine trials, the pooled odd ratio was 0.20 (95% CI 0.07~0.55). CONCLUSION: We present quantitative evidence based on a meta-analysis of pooled effect size from randomized trials that clonidine is more beneficial for the prevention of post-anesthetic shivering and more effective than meperidine when it is administrated during later period of surgery.