Anesthesia and analgesia
-
Anesthesia and analgesia · Apr 1999
Randomized Controlled Trial Comparative Study Clinical TrialComparison of sevoflurane with propofol for laryngeal mask airway insertion in adults.
We performed a prospective, randomized, controlled trial to compare the quality and ease of laryngeal mask airway (LMA) insertion after either rapid inhaled sevoflurane or i.v. propofol induction of anesthesia. Seventy-six unpremedicated ASA physical status I or II patients were anesthetized with either a single vital capacity breath of sevoflurane 8% or i.v. propofol 3 mg/kg, which produced equally rapid loss of consciousness (40.5 +/- 13.9 vs 37.7 +/- 9.9 s; P > 0.05). The LMA was inserted more rapidly in patients in the propofol group (74 +/- 29 vs 127 +/- 35 s; P < 0.01) and required fewer attempts (1.2 vs 1.6; P < 0.05) than the sevoflurane group. There was a greater incidence of initially impossible mouth opening in the sevoflurane group (45% vs 21%; P < 0.05). Once mouth opening was possible, the degree of attenuation of laryngeal reflexes was similar. The overall incidence of complications related to LMA insertion, especially apnea (32% vs 0%; P < 0.01), was more frequent in the propofol group (82% vs 26%; P < 0.01). There were four failures of LMA insertion in the propofol group and none in the sevoflurane group. Both groups had stable hemodynamic profiles and good patient satisfaction. We conclude that sevoflurane vital capacity breath induction compares favorably with i.v. propofol induction for LMA insertion in adults. However, prolonged jaw tightness after the sevoflurane induction of anesthesia may delay LMA insertion. ⋯ In this randomized, controlled trial, we compared the ease of insertion of the laryngeal mask airway in adults after induction of anesthesia with either a sevoflurane vital capacity breath technique or propofol i.v.. We conclude that sevoflurane compares favorably with propofol, although prolonged jaw tightness may delay laryngeal mask airway insertion.
-
Anesthesia and analgesia · Apr 1999
Randomized Controlled Trial Clinical TrialThe effects of three graded doses of meperidine for spinal anesthesia in African men.
The intrathecal injection of 0.7-1 mg/kg meperidine provides spinal anesthesia of only short duration. In this study, we investigated the effects of three different doses of meperidine for spinal anesthesia on the duration and level of sensory block and the incidence of side effects. Forty-five African men were randomly allocated to receive one of three doses of intrathecal meperidine: Group A = 1.2 mg/kg, Group B = 1.5 mg/kg, and Group C = 1.8 mg/kg. The duration of sensory block was significantly longer after 1.5 mg/kg compared with 1.2 mg/kg meperidine (112 +/- 19 vs 79 +/- 27 min; P = 0.001). Increasing the dose to 1.8 mg/kg did not further increase the duration of block. The level and the onset of the block were not affected by the dose. Common side effects were fatigue (27%), pruritus (20%), and nausea (7%). Seven patients had respiratory depression and seven had a decrease of systolic arterial blood pressure (SAP) >30% from baseline. There was no difference in the incidence of any side effect among groups. Respiratory depression and decreases in SAP were observed 5-50 min after meperidine injection. Twenty-two patients had no pain after the sensory block had terminated. We conclude that increasing the dose of meperidine from 1.2 to 1.5 mg/kg increased the duration, but not the level, of sensory block without an increase in side effects. ⋯ Intrathecal meperidine 1 mg/kg provides surgical anesthesia for only 40-90 min. We investigated the effects of three larger doses of meperidine in 45 African men. The 1.5 and 1.8 mg/kg doses provide a longer duration of anesthesia compared with 1.2 mg/kg. Nausea, pruritus, and respiratory depression were common in all dose groups. We conclude that increasing the dose of meperidine from 1.2 to 1.5 mg/kg increased the duration, but not the level, of sensory block without an increase in side effects.
-
Anesthesia and analgesia · Apr 1999
Randomized Controlled Trial Clinical TrialEvaluating T-wave amplitude as a guide for detecting intravascular injection of a test dose in anesthetized children.
Previous reports have suggested that accidental intravascular injection of an epinephrine-containing test dose increases T-wave amplitude in anesthetized children. We designed this study to prospectively determine whether changes in T-wave amplitude could be a reliable indicator for detecting intravascular injection. We studied 32 ASA physical status I infants and children (3.4 +/- 1.7 yr) undergoing elective minor surgeries during 1.0 minimum alveolar anesthetic concentration of sevoflurane and 67% nitrous oxide in oxygen. After the i.v. administration of atropine 0.01 mg/kg, the patients were randomly assigned to receive either saline (n = 16) or a test dose consisting of 1% lidocaine (0.1 mL/kg) with 1:200,000 epinephrine (0.5 microg/kg, n = 16) via a peripheral vein to simulate the intravascular injection of the test dose. Heart rate (HR) and systolic blood pressure (SBP) were recorded every 20 and 30 s, respectively, and the T-wave amplitude of lead II was continuously recorded for subsequent analysis. Of the 16 children receiving the test dose, 16, 13, and 16 developed increases in HR, SBP, and T-wave amplitude > or = 10 bpm, > or = 15 mm Hg, and > or = 25%, occurring at 30 +/- 7, 70 +/- 31, and 20 +/- 5 s, respectively. Because no patient receiving saline met these criteria, sensitivity, specificity, and positive and negative predictive values were all 100% based on the criteria using the T-wave amplitude and the peak HR. Our results suggest that changes in T-wave amplitude are as effective as HR for detecting the intravascular injection of an epinephrine-containing test dose in sevoflurane-anesthetized children. ⋯ To determine whether an epidurally administered local anesthetic is unintentionally injected into a blood vessel, a small dose of epinephrine is often added to a local anesthetic. We found that increases in T-wave amplitude by > or = 25% in lead II monitor electrocardiography are as effective as a heart rate increase > or = 10 bpm for detecting intravascular injection in sevoflurane-anesthetized children.
-
Anesthesia and analgesia · Apr 1999
Clinical TrialA dose-response study of intravenous regional anesthesia with meperidine.
Intravenous regional anesthesia (IVRA) with meperidine in doses > or = 100 mg provides effective postoperative analgesia. However, this technique is associated with excessive opioid-related side effects, which limit its clinical usefulness. The minimal dose of meperidine that is effective for IVRA has yet to be established. We added 0, 10, 20, 30, 40, or 50 mg of meperidine to 0.5% lidocaine IVRA for either carpal tunnel or tenolysis surgery. Pain and sedation scores and the incidence of side effects were assessed in the postanesthesia care unit. The duration of analgesia, defined as the time to first request for pain medications, and use of acetaminophen/codeine (T3) tablets were measured. The duration of analgesia increased, in a dose-dependent manner, in the groups that received 0, 10, 20, and 30 mg of meperidine. There was no significant difference in the duration of analgesia for patients receiving > or = 30 mg of meperidine. T3 use was similar in the groups that received 0, 10, and 20 mg of meperidine and in the groups that received 30, 40, and 50 mg. T3 use was significantly lower in the larger dose groups. The incidence of sedation and of all other side effects was significantly higher in the groups that received 30-50 mg of meperidine compared with those that received smaller doses. We conclude that doses of meperidine large enough to produce the most effective postoperative analgesia with IVRA lidocaine causes a significant incidence of side effects, thus limiting its clinical usefulness. ⋯ Meperidine may be a useful addition to 0.5% lidocaine for i.v. regional anesthesia. We showed that 30 mg is the optimal dose of meperidine with respect to postoperative analgesia. However, this dose caused a significant incidence of sedation, dizziness, and postoperative nausea and vomiting.
-
Anesthesia and analgesia · Apr 1999
Tracheal intubation of healthy pediatric patients without muscle relaxant: a survey of technique utilization and perceptions of safety.
We conducted a survey of Society for Pediatric Anesthesia anesthesiologists practicing within the United States to determine the frequency of tracheal intubation of healthy infants and children using an inhaled anesthetic without muscle relaxation (IAWMR). We also examined reasons for the use of this technique. Of all responders who listed their most often used technique for tracheal intubation of healthy infants and children, IAWMR was chosen over intubation with a muscle relaxant by 38.1% and 43.6%, respectively. Anesthesiologists who most often used IAWMR for tracheal intubation of healthy infants and children had over twice the odds (odds ratio [OR] 2.30 for infants, 95% confidence interval [CI] 1.18-4.50; P = 0.015) of classifying their own practice as nonacademic, and one-third the odds (OR 0.34 for infants, 95% CI 0.17-0.68; P = 0.002) of conducting more than half of their cases in a supervisory role. Anesthesiologists who use IAWMR to tracheally intubate healthy pediatric patients most commonly selected as their reasons the lack of need for a muscle relaxant and the desire to avoid both succinylcholine and the excessive duration of nondepolarizing muscle relaxants. ⋯ Inhaled anesthetic without muscle relaxation is the most often used method of intubation for more than one third of Society for Pediatric Anesthesia anesthesiologists when tracheally intubating healthy, fasted pediatric patients undergoing elective procedures. The frequency of this practice seems to be highest in nonacademic practices.