Anesthesia and analgesia
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Anesthesia and analgesia · Mar 2000
Randomized Controlled Trial Comparative Study Clinical TrialThe efficacy of intravenous 0.15 versus 0.25 mg/kg intraoperative morphine for immediate postoperative analgesia after remifentanil-based anesthesia for major surgery.
We evaluated the effect of perioperative administration of two doses of morphine for postoperative analgesia after remifentanil-based anesthesia. The prospective, randomized study included 245 patients from 33 centers. All patients were scheduled for abdominal or urological surgery lasting more than 1 h. General anesthesia used remifentanil as the perioperative opioid (1 microg/kg as a bolus then, 0.5 microg/kg as a continuous infusion). A morphine bolus of 0. 15 mg/kg (0.15-mg group) or 0.25 mg/kg (0.25-mg group) was administered 30 min before the end of surgery. In the postanesthesia care unit, pain scores for patients were evaluated by using behavioral pain scores of 1-3, verbal pain scores of 0-3, and visual analog scale scores of 0-10). Postoperative analgesia was obtained by a morphine titration (3 mg every 5 min). Demographic and surgery characteristics were similar in both groups. The delay for first demand of morphine was similar in the 0.15-mg and the 0.25-mg groups (26 [9-60] and 30 [10-60] min, respectively). The frequency of morphine titration was similar in both groups (75% and 66%, respectively). The amount of morphine used in the postanesthesia care unit was smaller in the 0.25-mg group (0.16 [0.0-1.25] vs 0.10 [0.0-0.56] mg/kg; P = 0.008). In the 0.25-mg group, the behavioral pain score was lower at 15 min, the verbal pain score was lower at 60 min (P < 0.001), and similar at 30 min. The visual analog scale pain score at 30 min and 60 min was similar in both groups. The incidence of minor side effects was similar in both groups. However, three cases of postoperative respiratory depression occurred in the 0.25-mg group compared with no cases in the 0.15-mg group. In conclusion, perioperative administration of morphine alone does not provide entirely adequate immediate postoperative pain control after remifentanil-based anesthesia in major surgery. ⋯ The administration of 0.15 or 0.25 mg/kg perioperative morphine during remifentanil-based anesthesia for major surgery does not preclude additional morphine administration in the postanesthesia care unit. The larger dose of 0.25 mg/kg slightly improves postoperative analgesia; however, it may be responsible for postoperative respiratory depression.
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Anesthesia and analgesia · Mar 2000
Multicenter Study Comparative Study Clinical TrialThe effects of sevoflurane on serum creatinine and blood urea nitrogen concentrations: a retrospective, twenty-two-center, comparative evaluation of renal function in adult surgical patients.
Despite mounting clinical evidence that supports its safety, the question of the potential adverse effects of sevoflurane on renal function continues to generate some controversy. This study retrospectively evaluated pooled renal laboratory data from 22 different clinical trials that compared sevoflurane with three widely used anesthetics. The trials examined postoperative changes in serum creatinine and blood urea nitrogen levels from a total of 3, 436 ASA physical status I-IV adult surgical patients administered either sevoflurane (n = 1941) or a control drug (isoflurane, enflurane, or propofol; n = 1495) as the maintenance anesthetic. The incidences of increased serum creatinine and blood urea nitrogen concentrations were similar among patients administered sevoflurane and those administered control drugs. Additionally, no trends specific to sevoflurane were observed with respect to postoperative serum creatinine concentration and fresh gas flow rate, concurrent treatment with nephrotoxic antibiotics, or type of carbon dioxide absorbent. ⋯ Our data for changes in serum creatinine and blood urea nitrogen indicate that, for exposures of less than 4 minimum alveolar anesthetic concentration/h, sevoflurane is not associated with an increased risk of renal toxicity compared with other commonly used anesthetics. For clinical purposes, the pre- to postoperative changes in serum creatinine and blood urea nitrogen are appropriate measures of renal function in surgical patients.
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Anesthesia and analgesia · Mar 2000
Randomized Controlled Trial Comparative Study Clinical TrialReversal of rapacuronium block during propofol versus sevoflurane anesthesia.
We studied the antagonism of rapacuronium with edrophonium-atropine during propofol- or sevoflurane- based anesthesia in 60 healthy outpatients. After the induction of anesthesia with standardized doses of propofol and fentanyl, rapacuronium 1.5 mg/kg was administered to facilitate tracheal intubation. Patients were randomized to receive either a propofol infusion (100 microg. kg(-1). min(-1)) or sevoflurane (1.0%, end-tidal) in combination with nitrous oxide 66% for maintenance of anesthesia. Neuromuscular block was monitored by using electromyography at the wrist and reversed with edrophonium 1.0 mg/kg and atropine 0.015 mg/kg when the first twitch (T(1)) response of the train-of-four (TOF) stimulation recovered to 25% of the baseline value. The clinical duration of action (i.e., time to 25% T(1) recovery) was similar during both propofol (13.1 +/- 3.6 min) and sevoflu-rane (13.7 +/- 4.4 min) anesthesia. The time from 25% T(1) recovery to TOF ratio of 0.8 was also similar with propofol (3.4 +/- 2.1 min) and sevoflurane (5.9 +/- 8.7 min) (P > 0.05). Although none of the patients in the propofol group required more than 9 min to achieve a TOF ratio of 0. 8, two patients receiving sevoflurane required 31 min and 37 min. Adequate antagonism of rapacuronium block with edrophonium can be achieved within 10 min during propofol anesthesia. However, more prolonged recovery may occur in the presence of sevoflurane. ⋯ We studied the reversal of rapacuronium-induced block with edrophonium and found that the residual rapacuronium block can be readily antagonized during propofol-based anesthesia. However, reversal of rapacuronium appears to be less predictable during sevoflurane-based anesthesia.
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Anesthesia and analgesia · Mar 2000
Randomized Controlled Trial Comparative Study Clinical TrialA comparison of epidural analgesia with 0.125% ropivacaine with fentanyl versus 0.125% bupivacaine with fentanyl during labor.
We previously found that the extent of an epidural motor block produced by 0.125% ropivacaine was clinically indistinguishable from 0.125% bupivacaine in laboring patients. By adding fentanyl to the 0. 125% ropivacaine and bupivacaine solutions in an attempt to reduce hourly local anesthetic requirements, we hypothesized that differences in motor block produced by the two drugs may become apparent. Fifty laboring women were randomized to receive either 0. 125% ropivacaine with fentanyl 2 microg/mL or an equivalent concentration of bupivacaine/fentanyl using patient-controlled epidural analgesia (PCEA) with settings of: 6-mL/hr basal rate, 5-mL bolus, 10-min lockout, 30-mL/h dose limit. Analgesia, local anesthetic use, motor block, patient satisfaction, and side effects were assessed until the time of delivery. No differences in verbal pain scores, local anesthetic use, patient satisfaction, or side effects between groups were observed; however, patients administered ropivacaine/fentanyl developed significantly less motor block than patients administered bupivacaine/fentanyl. Ropivacaine 0.125% with fentanyl 2 microg/mL produces similar labor analgesia with significantly less motor block than an equivalent concentration of bupivacaine/fentanyl. Whether this statistical reduction in motor block improves clinical outcome or is applicable to anesthesia practices which do not use the PCEA technique remains to be determined. ⋯ By using a patient-controlled epidural analgesia technique, ropivacaine 0.125% with fentanyl 2 microg/mL produces similar analgesia with significantly less motor block than a similar concentration of bupivacaine with fentanyl during labor. Whether this statistical reduction in motor block improves clinical outcome or is applicable to anesthesia practices which do not use the patient-controlled epidural analgesia technique remains to be determined.
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Anesthesia and analgesia · Mar 2000
Comparative StudyComparing methods of clinical measurement: reporting standards for bland and altman analysis.
In this era of medical technology assessment and evidence-based medicine, evaluating new methods to measure physiologic variables is facilitated by standardization of reporting results. It has been proposed that assessing repeatability be followed by assessing agreement with an established technique. If the "limits of agreement" (mean bias +/- 2SD) are not clinically important, then one could use two measurements interchangeably. Generalizability to larger populations is facilitated by reporting confidence intervals. We identified 44 studies that compared methods of clinical measurement published during 1996 to 1998 in seven anesthesia journals. Although 42 of 44 (95.4%) used the limits of agreement methodology for analysis, several inadequacies and inconsistencies in reporting the results were noted. Limits of agreement were defined a priori in 7.1%, repeatability was evaluated in 21.4%, and relationship (pattern) between difference and average was evaluated in 7.1%. Only one of the articles reported confidence intervals. A computer macro for the Minitab statistical package (State College, PA) is described to facilitate reporting of Bland and Altman analysis with confidence intervals. We propose standardization of nomenclature in clinical measurement comparison studies. ⋯ A literature review of anesthesia journals revealed several inadequacies and inconsistencies in statistical reports of results of comparison studies with regard to interchangeability of measurement methods. We encourage journal editors to evaluate submissions on this subject carefully to ensure that their readers can draw valid conclusions about the value of new technologies.