Anesthesia and analgesia
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Anesthesia and analgesia · Apr 2001
Meta AnalysisThe effects of an increase of central blood volume before spinal anesthesia for cesarean delivery: a qualitative systematic review.
We evaluated in this qualitative systematic review the efficacy of increasing central blood volume on the incidence of hypotension after spinal anesthesia for elective cesarean delivery. Randomized controlled trials investigating any method of increasing central blood volume before the initiation of obstetric spinal anesthesia were sought by using MEDLINE (1966-2000), Embase (January 1988-April 2000), and the Cochrane Library (Issue 1, 2000). Additional reports from retrieved and review articles, hand searching of non-MEDLINE journals, and abstracts of major anesthesia meetings (1994-1999) were located. The primary outcome was the incidence of hypotension. Secondary outcomes included: ephedrine use, Apgar scores, umbilical cord pH values, and maternal nausea and vomiting. Twenty-three articles met our inclusion criteria with the use of crystalloid preload, colloid preload, and mechanical methods of increasing central volume. Crystalloid preload was inconsistent in preventing hypotension, whereas colloid appeared to be effective in all but one study. Leg wrapping and thromboembolic stockings decreased the incidence of hypotension compared with leg elevation or control. Few differences in fetal outcomes or maternal nausea and vomiting were reported. Increasing central blood volume by using colloid and leg wrapping decreases but does not abolish the incidence of hypotension before spinal anesthesia for elective cesarean delivery. ⋯ We performed a systematic review to determine whether fluid loading reduced the incidence of low blood pressure after spinal anesthesia for cesarean delivery. Although no technique totally eliminates the occurrence of hypotension, colloid administration (starch or gelatin containing fluids) and leg wrapping were the most effective.
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Anesthesia and analgesia · Apr 2001
Randomized Controlled Trial Clinical TrialProphylactically-administered rectal acetaminophen does not reduce postoperative opioid requirements in infants and small children undergoing elective cleft palate repair.
Rectal acetaminophen (Ac) is often administered prophylactically at anesthesia induction for postoperative pain management in small children and is thought to have an opioid-sparing effect. We assessed in this double-blinded, prospective, randomized study early opioid requirements after three doses of Ac (10, 20, and 40 mg/kg versus placebo) in 80 children (ASA physical status I, age 11.4 +/- 9.9 mo) undergoing cleft palate repair. Single Ac plasma concentrations were measured. Pain scores assessed in the postanesthesia care unit of > or = 4 of 10 resulted in the IV administration of 25 microg/kg piritramide, a popular European mu receptor agonist (lockout time, 10 min; maximum 0.125 mg/kg). There were no significant differences between groups with regard to the early postoperative pain scores and the overall cumulative IV opioid requirements. Maximal plasma concentrations achieved were only subtherapeutic (Ac 10 mg/kg: 8 microg/mL; Ac 20 mg/kg: 13 microg/mL; Ac 40 mg/kg: 21 microg/mL after 122, 122, and 121 min, respectively). We conclude that rectal Ac up to 40 mg/kg has no opioid-sparing effect, does not result in analgesic Ac plasma concentrations, and lacks proof of its efficacy in infants and small children undergoing cleft palate repair, whereas titrated IV opioid boluses produced rapid and reliable pain relief. ⋯ Acetaminophen is widely used prophylactically for postoperative analgesia in children and is thought to have an opioid-sparing effect. We showed that rectal acetaminophen up to 40 mg/kg administered at anesthesia induction lacked proof of efficacy, whereas IV opioid boluses resulted in reliable pain relief in children undergoing cleft palate repair.
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Anesthesia and analgesia · Apr 2001
Randomized Controlled Trial Clinical TrialThe effect of bispectral index monitoring on anesthetic use and recovery in children anesthetized with sevoflurane in nitrous oxide.
The utility of bispectral index (BIS) monitoring to guide anesthetic administration has been demonstrated in adults. This prospective, randomized observer-blinded study was designed to evaluate the effect of BIS monitoring on anesthetic use and recovery characteristics in pediatric patients. After data collection in 38 historical controls, 202 patients age 0-18 yr were randomized into one of two groups: standard practice (SP) and BIS guided (BIS). Patients age 0-3 yr undergoing inguinal hernia repair (IH) and patients age 3-18 yr undergoing tonsillectomy and/or adenoidectomy (TA) were selected. All patients were anesthetized with sevoflurane in 60% N(2)O/O(2). Hernia patients also received a caudal epidural anesthetic before surgery. In the BIS group, anesthetic delivery was adjusted in an effort to achieve a target BIS of 45-60 during maintenance and 60-70 during the last 15 min of the procedure. BIS was recorded throughout surgery in all patients, but data were unavailable to the anesthesiologist in the SP group. In the TA patients, BIS monitoring was associated with a significant reduction in end-tidal sevoflurane concentration during maintenance (2.4 +/- 0.6%, SP and 1.8 +/- 0.4% BIS, mean +/- SD) and during the last 15 min of the procedure (2.1 +/- 0.7, SP and 1.6 +/- 0.6, BIS). There was a 25%-40% decrease in measured recovery times. In the patients 0-6 mo of age undergoing IH, sevoflurane concentrations during maintenance (2.0 +/- 0.4% SP, 0.9 +/- 0.8 BIS), during the last 15 min (1.6 +/- 0.4% SP, 0.6 +/- 0.6% BIS), and at the end of the procedure (1.1 +/- 0.6% SP, 0.3 +/- 0.3% BIS) were smaller in the BIS group. Emergence and recovery measures were unaffected by BIS titration. In the children 6 mo-3 yr of age, there were no significant differences between the SP and BIS groups in anesthetic use or recovery measures. ⋯ Bispectral index monitoring in children results in less anesthetic use and faster recovery than standard practice.
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Anesthesia and analgesia · Apr 2001
Randomized Controlled Trial Clinical TrialThe effect of insulin cardioplegia on atrial fibrillation after high-risk coronary bypass surgery: a double-blinded, randomized, controlled trial.
Atrial fibrillation after coronary bypass (CABG) surgery is an important cause of morbidity and increased resource utilization. Insulin-enhanced cardioplegia may reduce postoperative arrhythmias by improving aerobic myocardial metabolism and mitigating the deleterious effects of ischemia. We performed a double-blinded, randomized, controlled clinical trial to determine if insulin-enhanced cardioplegia decreases the risk of post-CABG atrial fibrillation in a high-risk patient population. We randomized 501 patients undergoing urgent CABG to receive insulin-enhanced (Humulin R 10 IU/L, Insulin group, n = 243) or standard (Control group, n = 258) blood cardioplegia during cardiopulmonary bypass. Patients were monitored by using continuous electrocardiography for a minimum of 3 days postoperatively. All standard cardiac medications, including beta-adrenergic blockers, were continued postoperatively. Insulin-enhanced cardioplegia did not result in a significant reduction in postoperative atrial fibrillation. Furthermore, we failed to detect a difference in the incidence of conduction defects, ventricular tachycardia, or pacemaker requirements between insulin and placebo patients. Atrial fibrillation was the most common arrhythmia, occurring in 31% of all patients. Independent predictors of atrial fibrillation were elderly age, preoperative atrial fibrillation, and renal insufficiency. Right bundle branch block was the most common conduction abnormality. Predictors of right bundle branch block were elderly age, female sex, and circumflex coronary artery disease. The incidence of postoperative ventricular tachycardia, left bundle branch block, and permanent pacemaker requirement was small. We conclude that insulin-enhanced cardioplegia does not reduce the incidence of postoperative atrial fibrillation in high-risk CABG patients. ⋯ We conducted a double-blinded, randomized, placebo-controlled trial of insulin-enhanced cardioplegia in 501 patients undergoing urgent coronary bypass surgery. Insulin did not decrease the incidence of postoperative atrial fibrillation when compared with placebo. We also failed to demonstrate a difference in the incidence of other postoperative arrhythmias between the two groups of patients.