Anesthesia and analgesia
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Anesthesia and analgesia · Mar 1998
Randomized Controlled Trial Clinical TrialFactors that predict the use of positive inotropic drug support after cardiac valve surgery.
Left ventricular dysfunction is common after cardiac surgery and is often treated with positive inotropic drugs (PIDs). We hypothesized that the use of PIDs after cardiac valve surgery would have significant associations with the valvular pathophysiology and surgical procedure, and unlike the case for patients undergoing coronary artery surgery, would be unrelated to duration of cardiopulmonary bypass (CPB) or of aortic clamping. One hundred forty-nine consenting patients undergoing cardiac valve surgery were studied. Patients with hepatic or renal failure, or New York Heart Association class IV cardiac symptoms, were excluded. Patients were considered to have received PIDs if they received an infusion of amrinone, dobutamine, epinephrine, or dopamine (> or = 5 microg x kg[-1] x min[-1]). PIDs were received by 78 patients (52%). In a univariate model, older age, history of congestive heart failure, decreasing left ventricular ejection fraction, longer durations of CPB, and concurrent coronary artery surgery significantly increased the likelihood of PID support. There was also significant variation by anesthesiologist in the administration of PIDs. The specific diseased valve and valvular stenosis or insufficiency did not influence the likelihood of receiving PID support. In a multivariable model, age, history of congestive heart failure, decreasing left ventricular ejection fraction, and anesthesiologist were significantly associated with the likelihood of PID support, but duration of CPB and concurrent coronary artery surgery were not. In conclusion, patient age and ventricular function, as well as physician preferences, predicted the need for inotropic drug support; however, neither the specific valvular lesion, nor duration of CPB were strongly predictive in a multivariable model. ⋯ We evaluated factors related to use of positive inotropic drugs after cardiac valve surgery. The likelihood of a patient receiving these drugs increases with advancing age and with more severe preoperative left ventricular dysfunction, but was not influenced by the specific diseased valve or the duration of cardiopulmonary bypass.
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Anesthesia and analgesia · Mar 1998
Randomized Controlled Trial Clinical TrialAlfentanil as an adjuvant to epidural bupivacaine in the management of postoperative pain after laparotomies: lack of evidence of spinal action.
In this double-blind study, we compared the efficacy of epidural versus i.v. administration of alfentanil in combination with small-dose bupivacaine for postoperative pain relief. Thirty-two patients were randomly allocated to one of two study groups. Patients from both groups received an epidural loading dose of 60 mg of bupivacaine (12 mL of 0.5%). Subsequently, patients in the epidural (EPI) group received an infusion (8 mL/h) of 0.125% bupivacaine (10 mg/h) plus alfentanil (0.36 mg/h) and an i.v. infusion (8 mL/h) of NaCl 0.9%. Patients in the i.v. group received an epidural infusion (8 mL/h) of 0.125% bupivacaine (10 mg/h) and an i.v. infusion (8 mL/h) of alfentanil (0.36 mg/h). Infusions were maintained for 24 h. These dose regimens were such that equivalent subanalgesic plasma concentrations of alfentanil were obtained. Patient-controlled analgesia with morphine was available to both groups. Time to onset of postoperative pain and morphine consumption were used as variables to compare the two regimens. Measured plasma concentrations of alfentanil during the postoperative observation period were similar (< 20 ng/mL) in both groups. Median times to onset of postoperative pain (EPI 600 min, i.v. 360 min) and total morphine consumption (EPI 11 mg, i.v. 10 mg) did not differ between the groups (P > 0.2). We conclude that, in combination with epidural bupivacaine 0.125%, an i.v. infusion of alfentanil is equally effective as an epidural infusion of alfentanil if the plasma concentrations are the same. The study did not demonstrate a spinal mechanism of action for alfentanil. ⋯ This randomized, double-blind study showed that, when combined with small-dose bupivacaine (0.125%), epidurally administered alfentanil is not more effective than i.v. administered alfentanil for postoperative pain management when the regimens are such that equivalent subanalgesic plasma alfentanil concentrations are obtained. A spinal mechanism of action for alfentanil could therefore not be demonstrated.
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Anesthesia and analgesia · Mar 1998
Randomized Controlled Trial Clinical TrialProphylactic ephedrine attenuates the hemodynamic response to propofol in elderly female patients.
In this study, we compared the effect of prophylactic administration of ephedrine against the hypotensive effect of propofol in elderly female patients scheduled for minor gynecological procedures. Ninety patients aged 60 yr or older were randomly allocated to one of three groups of 30 patients each to receive either normal saline, ephedrine 0.1 mg/kg, or ephedrine 0.2 mg/kg i.v. 1 min before the induction of anesthesia. Anesthesia was induced and maintained with propofol and fentanyl. Hemodynamic variables were measured before and 2, 5, 10, 15, 30, and 60 min after induction. The decrease in blood pressure and heart rate (HR) was significantly less in each of the ephedrine groups (P < 0.001). Furthermore, the decrease was less in the large-dose group compared with the small-dose group (P < 0.05). Twelve patients in the control group experienced a decrease in systolic blood pressure to < 80 mmHg, compared with only one patient in the ephedrine groups (P < 0.001). In conclusion, the prophylactic injection of ephedrine significantly attenuated, but did not completely abolish, the decrease in blood pressure associated with induction of anesthesia with fentanyl and propofol. Ephedrine 0.2 mg/kg was slightly more effective than ephedrine 0.1 mg/kg. ⋯ The prophylactic effect of ephedrine to counteract the hypotensive effect of propofol induction of anesthesia was investigated in three groups of elderly female patients given 0.1 or 0.2 mg of ephedrine or placebo before induction. Both ephedrine doses markedly attenuated, but neither of them abolished, the decrease in blood pressure.
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Anesthesia and analgesia · Mar 1998
Randomized Controlled Trial Clinical TrialDroperidol and the side effects of epidural morphine after cesarean section.
Epidural morphine produces analgesia with a high incidence of side effects that include pruritus, nausea, and vomiting. This study investigated whether epidural or i.v. droperidol could alleviate these symptoms. In a prospective, double-blind, randomized, controlled trial, 97 pregnant women undergoing cesarean section were randomly assigned to three groups. All received standard continuous epidural anesthesia. After delivery, each received 5 mg of epidural morphine with either no droperidol injection, 2.5 mg of epidural droperidol, or 2.5 mg of i.v. droperidol. The incidence, onset, duration, and severity of pruritus; the onset and severity of pain; and satisfaction were similar for each group, but the incidence and severity of nausea and vomiting was lower in the group that received i.v. droperidol (P < 0.01). Sedation was minimal throughout the study. Thus, epidural droperidol failed to alleviate the side effects caused by epidural morphine, but i.v.droperidol reduced both the incidence and severity of nausea and vomiting. These results suggest that droperidol acts systemically to counter the effects of epidural morphine but that it is not entirely effective. ⋯ A single dose of epidural morphine provides long-lasting pain relief for women who have undergone cesarean section, but it has some troublesome side effects (itching, nausea, vomiting). We performed a prospective, randomized, controlled trial in 97 such women to study whether droperidol could reduce these side effects. We found that i.v. droperidol reduced nausea and vomiting but did not prevent itching, and that epidural droperidol failed to prevent all side effects.
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Anesthesia and analgesia · Mar 1998
Randomized Controlled Trial Clinical TrialSmall doses of intrathecal morphine combined with systemic diclofenac for postoperative pain control after cesarean delivery.
Postoperative pain control after cesarean delivery under spinal anesthesia is effectively obtained with morphine 0.1-0.3 mg intrathecally, although there may be dose-dependent side effects. We evaluated the quality of analgesia and the incidence of side effects with smaller doses of intrathecal morphine combined with intramuscular (i.m.) diclofenac. One hundred-twenty pregnant patients were allocated into six groups, which received the following treatments: Groups 1, 3, and 5 received 0.1, 0.05, and 0.025 mg of intrathecal morphine, respectively, plus 75 mg of i.m. diclofenac every 8 h; Groups 2, 4, and 6 received 0.1, 0.05, and 0.025 mg of intrathecal morphine, respectively, plus i.m. diclofenac on demand. Spinal anesthesia was performed with 15 mg of 0.5% hyperbaric bupivacaine. Pain scores and side effects were evaluated hourly for the first 24 h. Groups 1 and 2 had lower pain scores than Groups 3, 4, 5, and 6. However, only patients in Groups 2, 4, and 6 requested additional analgesics. Severe pruritus was more frequent in Groups 1 and 2. No patient experienced respiratory depression. We conclude that there is no advantage in using doses larger than 0.025 mg of intrathecal morphine if they are combined with systemic diclofenac. ⋯ A multimodal approach to pain control may provide good quality analgesia while reducing drug-related side effects. In this study, a very small dose of intrathecal morphine, in association with intramuscular diclofenac, proved effective for controlling pain after cesarean delivery, with a low incidence of morphine-induced pruritus.