Anesthesia and analgesia
-
Anesthesia and analgesia · Dec 1997
Randomized Controlled Trial Comparative Study Clinical TrialSevoflurane or halothane anesthesia: can we tell the difference?
This study was performed to evaluate the ability of anesthesiologists to differentiate between sevoflurane, a newer, more expensive anesthetic, and halothane. A total of 113 assessments were made by 36 anesthesiologists on 58 children, aged 6 mo to 6 yr, scheduled for bilateral myringotomy and tube placement. All patients received midazolam (0.5 mg/kg per os) approximately 30 min before the induction of anesthesia. Sevoflurane or halothane was randomly selected for anesthetic induction and maintenance. The anesthesiologists, who were unaware of the anesthetic being used, were asked to identify the anesthetic based on clinical signs and to assess the quality of induction, speed of induction, and speed of emergence using a visual analog scale (VAS; minimum score = 0, maximum score = 100). The anesthesiologists correctly identified the anesthetic only 56.6% of the time. This was not significantly different from the 50% that would result from random guessing (P = 0.08). Further, there were no significant differences in VAS scores between the two groups. This study suggests that in premedicated pediatric patients undergoing brief surgical procedures, anesthesiologists cannot correctly differentiate between sevoflurane and halothane. The lack of significant differences in VAS scores suggests that the speed of induction, the speed of emergence, and the quality of induction are similar under these clinical conditions. Any purported benefits of sevoflurane seem to be of minor consequence under the circumstances studied. ⋯ When the anesthetic halothane or sevoflurane is administered in a blind, randomized fashion, anesthesiologists could not reliably identify which drug was being used to anesthetize children for a brief surgical procedure. These results suggest that the differences between the two drugs in clinical practice are small and may not justify the additional cost of sevoflurane.
-
Anesthesia and analgesia · Dec 1997
Randomized Controlled Trial Comparative Study Clinical TrialPostoperative analgesic requirement after cesarean section: a comparison of anesthetic induction with ketamine or thiopental.
In a randomized, double-blind study, we compared postoperative pain and analgesic requirement in patients who underwent elective cesarean section under general anesthesia induced with thiopental 4 mg/kg (n = 20) or ketamine 1 mg/kg (n = 20). Anesthesia was maintained with nitrous oxide and isoflurane. Postoperative analgesia was provided by patient-controlled analgesia (PCA) using morphine. Median (range) time to first PCA demand was greater in the ketamine group (28 [3-134] min) compared with the thiopental group (20.5 [3-60] min; P = 0.04). Median (range) morphine consumption over 24 h was less in the ketamine group (24.3 [3-41] mg) compared with the thiopental group (35 [4-67] mg; P = 0.017). Visual analog scale pain scores were similar between groups. No patients had recall of intraoperative events or unpleasant dreams. Two patients in the thiopental group and one patient in the ketamine group had pleasant intraoperative dreams. Apgar scores were similar between groups. Median umbilical venous pH was higher (7.33 vs 7.31; P = 0.04) and attributable to lower median umbilical venous Pco2 (5.72 vs 6.14 kPa; P = 0.02) in the ketamine group compared with the thiopental group. Induction of anesthesia for cesarean section using ketamine is associated with a lower postoperative analgesic requirement compared with thiopental. ⋯ Patients who had anesthesia for cesarean section induced with ketamine required less analgesic drugs in the first 24 h compared with patients who received thiopental. Ketamine, unlike thiopental, has analgesic properties that may reduce sensitization of pain pathways and extend into the postoperative period.
-
Anesthesia and analgesia · Dec 1997
Randomized Controlled Trial Comparative Study Clinical TrialThe clinical neuromuscular pharmacology of cisatracurium versus vecuronium during outpatient anesthesia.
Neither comparisons of the clinical neuromuscular effects of cisatracurium and vecuronium nor comparative studies of their antagonism by neostigmine have been reported. In addition, the efficacy of administering cisatracurium in divided doses has not been investigated. Accordingly, we applied supramaximal electrical stimuli to the ulnar nerve of 165 ASA physical status I and II patients receiving nitrous oxide/alfentanil/propofol anesthesia. Forty-five patients received cisatracurium 5, 10, or 15 microg/kg, and the evoked response at the adductor pollicis was recorded for 15 min. One hundred-twenty patients received cisatracurium 5, 10, or 15 microg/kg or normal saline placebo followed 5 min later by either cisatracurium 100 microg/kg or vecuronium 100 microg/kg (always after placebo). Time to clinical onset (maximal ablation of single twitch response) was measured. When the evoked response spontaneously recovered to 10% of control height, neostigmine 5, 10, 30, or 50 microg/kg or placebo was administered, and recovery of neuromuscular function was recorded for the next 15 min. The clinical onset of vecuronium without priming (2.8 +/- 0.8 min) (mean +/- SD) was significantly (P < 0.05) faster than the onset of cisatracurium without priming (4.6 +/- 1.4 min). Cisatracurium 5, 10, or 15 microg/kg administered before cisatracurium 100 microg/kg significantly (P < 0.05) accelerated the time to complete ablation of the evoked response (3.9 +/- 0.9, 2.9 +/- 0.8, or 3.0 +/- 0.9 min, respectively) compared with cisatracurium 100 microg/kg without priming. The dose of neostigmine required to achieve 50% assisted recovery of the train-of-four ratio at 5 min was significantly (P < 0.05) smaller in patients who received vecuronium (29.1 [17.9-55.3] microg/kg) (mean [95% confidence interval]) compared with those who received cisatracurium (53.7 [31.6-131.5] microg/kg). Given its faster clinical onset and greater sensitivity to antagonism by neostigmine, we conclude that vecuronium may be more suitable than cisatracurium for use in outpatient anesthesia. ⋯ We investigated the onset of muscle relaxation using intravenous vecuronium and cisatracurium and assessed the ability of neostigmine to antagonize (reverse) this effect. Our results suggest that vecuronium works faster than cisatracurium and is more sensitive to neostigmine. Vecuronium therefore may be more useful than cisatracurium in outpatient anesthesia.
-
Anesthesia and analgesia · Dec 1997
Randomized Controlled Trial Comparative Study Clinical TrialThe UpsherScope in routine and difficult airway management: a randomized, controlled clinical trial.
The UpsherScope, a rigid fiberoptic laryngoscope, may facilitate tracheal intubation. We performed a randomized, controlled trial of tracheal intubation using the UpsherScope and compared the success rate with that of direct laryngoscopy. Three hundred patients were randomly assigned to either fiberoptic oral intubation using the UpsherScope (Group US, n = 148) or to direct laryngoscopy (Group DL, n = 152). No significant differences in airway variables were observed between the groups. US intubation was successful in 129 of 148 patients (87%). A second or third attempt was required in 15% and 3%, respectively, of the patients successfully intubated with US. The remaining patients were intubated using DL (n = 17) or the flexible fiberoptic bronchoscope (n = 2). The success rate of DL was significantly higher (97%; P < 0.05), with a second or third attempt required in only seven patients. Time needed to perform successful intubation was 50 +/- 41 s for the US group compared with 23 +/- 13 s for the DL group (P < 0.05). We found no advantage of the UpsherScope over direct laryngoscopy during routine and difficult airway management. Time needed, number of attempts required to perform intubation, and incidence of failure were significantly longer and higher in group US. ⋯ We studied tracheal intubation using the fiberoptic UpsherScope and compared the success rate with that of a control group of patients intubated using conventional laryngoscopy. No advantages of the new device were found. On the contrary, time needed, number of attempts required, and incidence of failure were even longer and higher.
-
Anesthesia and analgesia · Dec 1997
Comparative StudyArgon pneumoperitoneum is more dangerous than CO2 pneumoperitoneum during venous gas embolism.
We investigated the possibility of using argon, an inert gas, as a replacement for carbon dioxide (CO2). The tolerance of argon pneumoperitoneum was compared with that of CO2 pneumoperitoneum. Twenty pigs were anesthetized with enflurane 1.5%. Argon (n = 11) or CO2 (n = 9) pneumoperitoneum was created at 15 mm Hg over 20 min, and serial intravenous injections of each gas (ranging from 0.1 to 20 mL/kg) were made. Cardiorespiratory variables were measured. Transesophageal Doppler and capnographic monitoring were assessed in the detection of embolism. During argon pneumoperitoneum, there was no significant change from baseline in arterial pressure and pulmonary excretion of CO2, mean systemic arterial pressure (MAP), mean pulmonary artery pressure (PAP), or systemic and pulmonary vascular resistances, whereas CO2 pneumoperitoneum significantly increased these values (P < 0.05). During the embolic trial and from gas volumes of 2 and 0.2 mL/kg, the decrease in MAP and the increase in PAP were significantly higher with argon than with CO2 (P < 0.05). In contrast to CO2, argon pneumoperitoneum was not associated with significant changes in cardiorespiratory functions. However, argon embolism seems to be more deleterious than CO2 embolism. The possibility of using argon pneumoperitoneum during laparoscopy remains uncertain. ⋯ Laparoscopic surgery requires insufflation of gas into the peritoneal cavity. We compared the hemodynamic effects of argon, an inert gas, and carbon dioxide in a pig model of laparoscopic surgery. We conclude that argon carries a high risk factor in the case of an accidental gas embolism.