Anesthesia and analgesia
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Anesthesia and analgesia · Sep 1998
Randomized Controlled Trial Multicenter Study Clinical TrialIntrathecal clonidine and fentanyl with hyperbaric bupivacaine improves analgesia during cesarean section.
Seventy-eight pregnant women at term, scheduled for elective cesarean section, were enrolled in this multicenter trial to compare the analgesic efficacy and side effect profile of a spinal block with hyperbaric bupivacaine alone (Group B) or combined with 75 microg of clonidine (Group BC) or with clonidine 75 microg and fentanyl 12.5 microg (Group BCF). Intraoperatively, clonidine increased the spread of the sensory block and decreased pain (pain scores 23+/-7 mm vs 17+/-6 and 2+/-1 mm for Group B versus Groups BC and BCF; P < 0.05) and analgesic supplementation. This improved analgesia was best with the clonidine-fentanyl combination (Group BC versus Group BCF; P < 0.05). Postoperative analgesia was prolonged only in Group BCF (215+/-79 min vs 137+/-35 and 183+/-80 min for Group BCF versus Groups B and BC; P < 0.05). Blood pressure and heart rate changes were not significantly different among groups, whereas sedation and pruritus were significantly more frequent in Group BCF. Nausea and vomiting were decreased in Groups BC and BCF. Apgar scores and umbilical artery blood pH were not different among groups. We conclude that adding a small dose of intrathecal clonidine to bupivacaine increases the quality of intraoperative analgesia and decreases pain during cesarean section. Combining clonidine with fentanyl further improved analgesia. ⋯ In this study, we demonstrate improved intraoperative spinal analgesia by adding 75 microg of clonidine to bupivacaine; side effects were not increased. The combination of clonidine and fentanyl further improved analgesia but moderately increased sedation and pruritus.
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Anesthesia and analgesia · Sep 1998
Randomized Controlled Trial Clinical TrialSimulation of an epidural test dose with intravenous isoproterenol in sevoflurane- and halothane-anesthetized children.
Isoproterenol has been suggested as an alternative marker for epidural test dosing in children receiving halothane anesthesia. The purpose of this prospective, randomized, double-blind study was to determine the chronotropic response to IV isoproterenol in sevoflurane-anesthetized children. Thirty-six ASA physical status I children (0.5-8 yr) were anesthetized with either halothane or sevoflurane at 1 minimum alveolar anesthetic concentration adjusted for age in 70% nitrous oxide. Patients received incremental IV injections of isoproterenol until their heart rate increased > or = 20 bpm above baseline. The minimal effective dose of isoproterenol required to produce an increase of > or = 20 bpm was 55 ng/kg (42-72 ng/kg; 95% confidence interval) in sevoflurane-anesthetized children and 32 ng/kg (26-38 ng/kg; 95% confidence interval) in halothane-anesthetized children (P < 0.05). This dose-response study suggests that sevoflurane antagonizes beta-adrenergic-mediated chronotropic responses to isoproterenol more than halothane. These observations also suggest that larger doses of isoproterenol will be necessary for epidural test dosing in children receiving sevoflurane rather than halothane anesthesia. ⋯ Isoproterenol has been suggested as an alternative marker for epidural test dosing in children receiving halothane anesthesia. This isoproterenol dose-response study indicates that larger doses of isoproterenol will be necessary for epidural test dosing in children undergoing sevoflurane rather than halothane anesthesia.
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Anesthesia and analgesia · Sep 1998
Randomized Controlled Trial Clinical TrialOral antihistamines reduce the side effects from rapid vancomycin infusion.
Rapid infusion of vancomycin causes histamine-mediated side effects, hypotension, and rash, known as "red man syndrome." In this prospective, randomized, double-blind, placebo-controlled study, we examined the ability of oral antihistamines to attenuate three clinical end points: rash, hypotension, and vancomycin discontinuation, and we compared these findings with those of a similar study using IV antihistamines. Patients (ASA physical status I-III) who required vancomycin prophylaxis for elective arthroplasty received either oral antihistamines (diphenhydramine < or = 1 mg/kg and cimetidine < or = 4 mg/kg, n = 20) or placebo (n = 10) 1 h before rapid vancomycin infusion (1 g over 10 min). The vancomycin infusion was discontinued if the mean arterial blood pressure decreased by > or = 20% or if itching was intolerable for the patient. Clinically significant hypotension developed in no treated patients, compared with five (50%) patients in the placebo group (P = 0.001). Rapid infusion was stopped for one treated patient (5%) and for five (50%) patients in the placebo group (P = 0.004). Incidence (P = 0.011) and severity of rash (P = 0.015) were also reduced in treated patients. Peak histamine levels were increased but were similar for patients in both groups (mean +/- SD, 1.9+/-2.5 vs 1.6+/-2.4 ng/mL; P = 0.75). Oral antihistamines were as effective as IV antihistamines. In conclusion, oral H1 and H2 antihistamine pretreatment is a practical, safe, and inexpensive option to attenuate histamine-mediated side effects associated with rapid vancomycin infusion. ⋯ Clinicians often must administer vancomycin faster than the 1-h recommended time, which can cause "red man syndrome" (rash, itching, hypotension). Our randomized, double-blind, placebo-controlled study showed that oral H1 and H2 antihistamine pretreatment significantly reduced the histamine-related side effects of rapid vancomycin infusion.
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Anesthesia and analgesia · Sep 1998
Randomized Controlled Trial Clinical TrialThe effects of maternal position during induction of combined spinal-epidural anesthesia for cesarean delivery.
Combined spinal-epidural anesthesia (CSE) is a popular technique for cesarean delivery. Regional blocks in obstetrics are often performed with the parturient in the sitting position because the midline may be recognized more easily than in the lateral decubitus position. When conventional spinal anesthesia is performed in the sitting position, the patient is placed supine immediately after drug injection. In contrast, when CSE is performed with the woman sitting, there is a delay in assuming the supine position because of epidural catheter placement, which may affect the incidence of hypotension. Healthy women, at term of pregnancy, about to undergo an elective cesarean section under CSE, were randomly assigned to the sitting or lateral recumbent position for initiation of the block. All parturients were given 1000 mL of lactated Ringer's solution in the 15 min preceding induction and an additional 300-500 mL while the actual block was being performed. On completion of the CSE, they were turned to the supine position with left uterine displacement. A second anesthesiologist, blinded to the woman's position during CSE, evaluated the sensory level of anesthesia, maternal heart rate, blood pressure, oxygen saturation, need for ephedrine, and occurrence of nausea and vomiting. Results are expressed as mean +/- SD. Twelve women were studied in the sitting group and 10 were studied in the lateral recumbent group. The severity and duration of hypotension were greater in those parturients who had CSE induced in the sitting (47%+/-7% and 6+/-3 min, respectively) compared with the lateral recumbent position (32%+/-14% and 3+/-2 min, respectively). Women in the sitting group also required twice as much ephedrine (38+/-18 mg) to correct hypotension compared with the other group (17+/-12 mg). In conclusion, the severity and duration of hypotension were greater when CSE was induced in the sitting compared with the lateral decubitus position. ⋯ We studied the induction of combined spinal-epidural anesthesia (CSE) in the sitting versus lateral recumbent positions in healthy women undergoing a scheduled cesarean delivery. The severity and duration of hypotension were greater when CSE was induced in the sitting position. Thus, the position used for induction of CSE should be among the factors considered when there is greater maternal or fetal risk from hypotension.