Anesthesia and analgesia
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Anesthesia and analgesia · Mar 1999
Randomized Controlled Trial Clinical TrialAnesthesia for in vitro fertilization: the addition of fentanyl to 1.5% lidocaine.
Ultrasonically guided transvaginal oocyte retrieval is relatively short procedure that is performed on an out-patient basis. The optimal anesthetic technique should allow good surgical anesthesia with minimal side effects, a short recovery time, and, if possible, a high rate of successful pregnancy. Spinal anesthesia is often used in this institution, as well as many others, for this procedure. The addition of fentanyl may be effective for both intraoperative and postoperative pain relief. We assessed the effect of adding fentanyl to 1.5% lidocaine in women undergoing ultrasonically guided oocyte retrieval. Seventy-eight women were randomized to receive 45 mg of hyperbaric 1.5% lidocaine with or without 10 microg of fentanyl. Visual analog scale (VAS) pain scores were lower in the operating room (OR) (P < 0.05) and postanesthesia care unit (PACU) (P < 0.0005) for the group that received fentanyl. In addition, the amount of narcotic required in the PACU was less in the fentanyl group (P < 0.005). There was no difference in VAS scores the evening of or 24 h after the procedure. The amount of analgesics and narcotics required after discharge was the same for both groups. Timed variables, such as time to urination, ambulation, and discharge, were the same for both groups of women. The addition of fentanyl to lidocaine for transvaginal oocyte retrieval results in a more comfortable patient in the OR and PACU. ⋯ This study demonstrates that when fentanyl is added to a local anesthetic, lidocaine, with spinal anesthesia for egg retrieval procedures, patients are more comfortable during the procedure compared with those who receive lidocaine alone. In addition, the narcotic requirements of patients are less in the postanesthesia care unit.
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Anesthesia and analgesia · Mar 1999
Randomized Controlled Trial Clinical TrialSpinal clonidine prolongs labor analgesia from spinal sufentanil and bupivacaine.
We sought to determine whether spinal clonidine 50 microg prolongs the analgesia from the spinal administration of sufentanil 7.5 microg and bupivacaine 2.5 mg early in the first stage of labor. Thirty patients were randomized to receive a 2-mL spinal injection of sufentanil 7.5 microg + bupivacaine 2.5 mg with or without clonidine 50 microg using a combined spinal-epidural (CSE) technique. Pain, nausea, pruritus, sedation, motor block, blood pressure, and heart rate were assessed until the patient requested additional analgesia. Analgesia was significantly prolonged in patients who received spinal sufentanil + bupivacaine + clonidine (197 +/- 70 vs 132 +/- 39 min; P = 0.004). Pain scores and side effects, including motor block, sedation, and hypotension, were similar between groups. Spinal clonidine significantly prolongs labor analgesia from spinal sufentanil and bupivacaine without producing serious adverse side effects. ⋯ We studied the effects of spinal clonidine administered with spinal sufentanil and bupivacaine on labor analgesia using a combined spinal-epidural technique and conclude that spinal clonidine significantly prolongs labor analgesia from spinal sufentanil and bupivacaine without producing serious adverse effects.
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Anesthesia and analgesia · Mar 1999
Randomized Controlled Trial Clinical TrialThe effect of heart rate control on myocardial ischemia among high-risk patients after vascular surgery.
Patients undergoing vascular surgery have a high risk of suffering major postoperative cardiac events. Preoperative myocardial ischemia as detected by Holter monitoring identifies a high-risk subgroup whose postoperative ischemia, similarly detected, seems to herald major cardiac events. In this study, we determined whether systematic, patient-specific postoperative heart rate control with beta-adrenergic blocker therapy decreases the incidence of postoperative ischemia among high-risk vascular surgery patients. A total of 26 of 150 patients who underwent elective vascular surgery and were monitored preoperatively by 24-h Holter were found to have significant myocardial ischemia as defined by ST-segment depression. The minimal heart rate at which this ST-segment depression occurred was identified (ischemic threshold), and these 26 patients were then randomized to receive continuous i.v. beta-blockade with esmolol or placebo plus usual medical therapy, aiming to reduce the postoperative heart rate to 20% below the ischemic threshold. All patients were monitored by Holter for 48 h postoperatively. Postoperative Holter readings were analyzed for the incidence of ischemia and for the number of hours during which heart rate was controlled below the ischemia threshold. Patients had a median of two episodes of preoperative ischemia lasting a median of 30 min (range 1-155 min). A total of 15 patients were randomized to receive esmolol, and 11 were randomized to receive placebo. The two groups were comparable with respect to clinical characteristics and incidence and duration of preoperative ischemia. Ischemia persisted in the postoperative period in 8 of 11 placebo patients (73%), but only 5 of 15 esmolol patients (33%) (P < 0.05). Of the 15 esmolol patients, 9 had mean heart rates below the ischemic threshold, and all 9 had no postoperative ischemia. A total of 4 of 11 placebo patients had mean heart rates below the ischemic threshold, and 3 of the 4 had no postoperative ischemia. There were two postoperative cardiac events among patients who had postoperative ischemia (one placebo, one esmolol) and whose mean heart rates exceeded the ischemic threshold. Our data suggest that patient-specific, strict heart rate control aiming for a predefined target based on individual preoperative ischemic threshold was associated with a significant reduction and frequent elimination of postoperative myocardial ischemia among high-risk patients and provide a rationale for a larger trial to examine this strategy's effect on cardiac risk. ⋯ Patients who undergo peripheral vascular surgery often experience transient cardiac complications and/or permanent heart damage just after surgery because of inadequate myocardial blood flow. In this study, we identified patients at high risk of cardiac complications after vascular surgery and showed that if their heart rate was carefully controlled for 48 h after surgery, myocardial ischemia, a common marker of heart injury, was markedly reduced.
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Anesthesia and analgesia · Mar 1999
Randomized Controlled Trial Clinical TrialThe intubating laryngeal mask airway with and without fiberoptic guidance.
We conducted this feasibility study using the intubating laryngeal mask airway (ILMA) and a polyvinyl chloride tracheal tube to compare success rates, hemodynamic effects, and postoperative morbidity with two methods of tracheal intubation. After ethics approval and informed consent, 90 healthy ASA physical status I or II women with normal airways were enrolled in the randomized, controlled study. After a standardized inhaled anesthesia induction protocol, tracheal intubations using ILMA with fiberoptic guidance (ILMA-FOB) and ILMA inserted blindly without fiberoptic guidance (ILMA-Blind) were compared with the control group of direct laryngoscopy (laryngoscopy group). All 90 patients were successfully ventilated. For tracheal intubation, success rates were equal in all three groups (97%). Total intubation times were longer for the ILMA-FOB group (77 s versus 48.5 s for laryngoscopy and 53.5 s for ILMA-Blind). The laryngoscopy group had a larger increase in mean arterial blood pressure to tracheal intubation. There were no differences in postoperative sore throat or hoarseness among the groups. In conclusion, success rates are equally high for tracheal intubation using ILMA-Blind and ILMA-FOB techniques in women with normal airways. ⋯ The intubating laryngeal mask airway (ILMA) can be used as a primary airway for oxygenation and ventilation. Both methods of tracheal intubation using the ILMA were equally successful. Postoperative morbidity in the ILMA groups was similar to that in the laryngoscopy group. For women with normal airways, both the ILMA inserted blindly and the ILMA with fiberoptic guidance are suitable alternatives to laryngoscopy for tracheal intubation.
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Anesthesia and analgesia · Mar 1999
Comparative Study Clinical TrialA comparison of myogenic motor evoked responses to electrical and magnetic transcranial stimulation during nitrous oxide/opioid anesthesia.
Transcranial motor evoked potentials (tc-MEPs) are used to monitor spinal cord integrity intraoperatively. We compared myogenic motor evoked responses with electrical and magnetic transcranial stimuli during nitrous oxide/opioid anesthesia. In 11 patients undergoing spinal surgery, anesthesia was induced with i.v. etomidate 0.3 mg/kg and sufentanil 1.5 microg/kg and was maintained with sufentanil 0.5 microg x kg(-1) x h(-1) and N2O 50% in oxygen. Muscle relaxation was kept at 25% of control with i.v. vecuronium. Electrical stimulation was accomplished with a transcranial stimulator set at maximal output (1200 V). Magnetic transcranial stimulation was accomplished with a transcranial stimulator set at maximal output (2 T). Just before skin incision, triplicate responses to single stimuli with both modes of cortical stimulation were randomly recorded from the tibialis anterior muscles. Amplitudes and latencies were compared using the Wilcoxon signed rank test. Bilateral tc-MEP responses were obtained in every patient with electrical stimulation. Magnetic stimulation evoked only unilateral responses in two patients. With electrical stimulation, the median tc-MEP amplitude was 401 microV (range 145-1145 microV), and latency was 32.8 +/- 2.3 ms. With magnetic stimulation, the tc-MEP amplitude was 287 microV (range 64-506 microV) (P < 0.05), and the latency was 34.7 +/- 2.1 ms (P < 0.05). We conclude that myogenic responses to magnetic transcranial stimulation are more sensitive to anesthetic-induced motoneural depression compared with those elicited by electrical transcranial stimulation. ⋯ Transcranial motor evoked potentials are used to monitor spinal cord integrity intraoperatively. We compared the relative efficacy of electrical and magnetic transcranial stimuli in anesthetized patients. It seems that myogenic responses to magnetic transcranial stimulation are more sensitive to anesthetic-induced motoneural depression compared with electrical transcranial stimulation.