Anesthesia and analgesia
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Anesthesia and analgesia · Aug 2002
Randomized Controlled Trial Clinical TrialPostoperative pain relief using intermittent injections of 0.5% ropivacaine through a catheter after laparoscopic cholecystectomy.
Postoperative pain has been an important limiting factor for ambulatory laparoscopic cholecystectomy. We anesthetized 40 ASA physical status I-II patients using propofol for the induction and sevoflurane in oxygen and air for the maintenance of anesthesia. At the end of the anesthesia, the patients were randomized into one of two groups: Group P (Placebo) and Group R (0.5% Ropivacaine). Twenty milliliters of normal saline or ropivacaine, respectively, were injected intraperitoneally at the end of surgery via a catheter placed in the bed of the gall bladder. Postoperatively, intermittent injections (10 mL) of the study solution were given when required for pain. Ketobemidone 1-2 mg was given IV as rescue medication. Pain was assessed using a visual analog scale at 1, 2, 3, 4, 8, 12, 16, and 20 h after surgery and once each day for 1 wk at rest (deep pain), shoulder and incision sites, and pain during coughing. Recovery was assessed by the time to transfer from Phase 1 to 2, the ability to walk, drink, and eat, and the ability to void. Plasma concentrations of ropivacaine were measured in eight patients. Time to ability to walk, defecation, driving a car, and return to normal activities were also recorded through a questionnaire sent home with the patient. During the first 4 postoperative h, patients in Group R had lower scores for deep pain and during coughing compared with Group P (P < 0.05). No differences were found in the postoperative consumption of ketobemidone. Median times to recovery at home were similar between the groups. By the seventh day, 93% of the patients had returned to normal activities of daily living. We conclude that the early postoperative pain after ambulatory laparoscopic cholecystectomy could be relieved using intermittent injections of ropivacaine 0.5% into the bed of the gall bladder. ⋯ Early postoperative pain can be relieved by intermittent injections of ropivacaine 0.5% through a catheter placed in the bed of the gall bladder after ambulatory laparoscopic cholecystectomy.
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Anesthesia and analgesia · Aug 2002
Case ReportsFalsely increased bispectral index values in a series of patients undergoing cardiac surgery using forced-air-warming therapy of the head.
Falsely increased bispectral index (BIS) values of >70 occur during forced-warm-air therapy in patients undergoing cardiac surgery. When forced-warm-air therapy for the head is used (as in ultra-fast-tracking cardiac patients), BIS interpretation needs careful examination. Falsely increased BIS values can easily be recognized when the warm-air flow is stopped. Within 2-3 min, BIS returns to a much lower, "true" value.
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Anesthesia and analgesia · Aug 2002
Characterization of the interactions between volatile anesthetics and neuromuscular blockers at the muscle nicotinic acetylcholine receptor.
Volatile anesthetics enhance the neuromuscular blockade produced by nondepolarizing muscle relaxants (NDMRs). The neuromuscular junction is a postulated site of this interaction. We tested the hypothesis that volatile anesthetic enhancement of muscle relaxation is the result of combined drug effects on the nicotinic acetylcholine receptor. The adult mouse muscle nicotinic acetylcholine receptor (alpha(2), beta, delta, epsilon) was heterologously expressed in Xenopus laevis oocytes. Concentration-effect curves for the inhibition of acetylcholine-induced currents were established for vecuronium, d-tubocurarine, isoflurane, and sevoflurane. Subsequently, inhibitory effects of NDMRs were studied in the presence of the volatile anesthetics at a concentration equivalent to half the concentration producing a 50% inhibition alone. All individually tested compounds produced rapid and readily reversible concentration-dependent inhibition. The calculated 50% inhibitory concentration values were 9.9 nM (95% confidence interval [CI], 8.4-11.4 nM), 43.4 nM (95% CI, 33.6-53.3 nM), 897 microM (95% CI, 699-1150 microM), and 818 microM (95% CI, 685-1001 microM) for vecuronium, d-tubocurarine, isoflurane, and sevoflurane, respectively. Coapplication of either isoflurane or sevoflurane significantly enhanced the inhibitory effects of vecuronium and d-tubocurarine, especially so at small concentrations of NDMRs. Volatile anesthetics increase the potency of NDMRs, possibly by enhancing antagonist affinity at the receptor site. This effect may contribute to the clinically observable enhancement of neuromuscular blockade by volatile anesthetics. ⋯ Isoflurane and sevoflurane enhance the receptor blocking effects of nondepolarizing muscle relaxants on nicotinic acetylcholine receptors.
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Anesthesia and analgesia · Aug 2002
The technical aspects of epidural steroid injections: a national survey.
Although epidural steroid injections (ESIs) are a common treatment for chronic pain conditions, it is not clear whether there is consensus on their technical aspects. The current literature suggests that variations in technical aspects may affect ESI outcomes. The goal of the survey was to help establish a standard frame of reference for the performance of ESIs. We analyzed survey results from 68 academic anesthesia programs and 28 private practices in the United States. The main finding in this survey is that there is no clear-cut consensus as to the ideal method to perform ESI. There is a wide variation among individual practices in almost every technical aspect of ESI. Private practices use significantly more fluoroscopy than academic centers. The large difference was found in the cervical region where 73% of private practices and only 39% of academic institutions polled perform the ESIs with fluoroscopic guidance (P = 0.005). A similar discrepancy was found in approaches to the epidural space after laminectomy where 61% of private practices, but only 15% of academic centers, use the transforaminal approach. The study results indicate that there is no consensus, and that there is a wide variation in current practices. ⋯ A national survey of practices performing epidural steroid injections was conducted. The purpose was to establish whether consensus exists on technical aspects of this procedure. The study results indicate that there is no consensus, and that there is a wide variation in current practices.