Anesthesia and analgesia
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Anesthesia and analgesia · Jul 2002
Randomized Controlled Trial Comparative Study Clinical TrialSupplementing desflurane-remifentanil anesthesia with small-dose ketamine reduces perioperative opioid analgesic requirements.
Relative large-dose intraoperative remifentanil could lead to the need for more postoperative analgesics. Intraoperative N-methyl-D-aspartate receptor antagonists, such as ketamine, decrease postoperative opioid use. We therefore tested the hypothesis that intraoperative small-dose ketamine improves postoperative analgesia after major abdominal surgery with remifentanil-based anesthesia. Fifty patients undergoing abdominal surgery under remifentanil-based anesthesia were randomly assigned to intraoperative ketamine or saline (control) supplementation. The initial ketamine dose of 0.15 mg/kg was followed by 2 microg. kg(-1). min(-1). In both groups, desflurane was kept constant at 0.5 minimum alveolar anesthetic concentration without N(2)O, and a remifentanil infusion was titrated to autonomic responses. All patients were given 0.15 mg/kg of morphine 30 min before the end of surgery. Pain scores and morphine consumption were recorded for 24 postoperative h. Less of the remifentanil was required in the Ketamine than in the Control group (P < 0.01). Pain scores were significantly larger in the Control group during the first 15 postoperative min but were subsequently similar in the two groups. The Ketamine patients required postoperative morphine later (P < 0.01) and received less morphine during the first 24 postoperative h: 46 mg (interquartile range, 34-58 mg) versus 69 mg (interquartile range, 41-87 mg, P < 0.01). No psychotomimetic symptoms were noted in either group. In conclusion, supplementing remifentanil-based anesthesia with small-dose ketamine decreases intraoperative remifentanil use and postoperative morphine consumption without increasing the incidence of side effects. Thus, intraoperative small-dose ketamine may be a useful adjuvant to intraoperative remifentanil. ⋯ Supplementing remifentanil-based anesthesia with small-dose ketamine decreased intraoperative remifentanil use and postoperative morphine consumption. These data demonstrate that N-methyl-D-aspartate antagonists, such as ketamine, can be a useful adjuvant to intraoperative remifentanil.
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Anesthesia and analgesia · Jul 2002
Randomized Controlled Trial Comparative Study Clinical TrialThe relative motor blocking potencies of epidural bupivacaine and ropivacaine in labor.
Minimal local analgesic concentrations (MLAC) have been used to determine the epidural analgesic potencies of bupivacaine and ropivacaine. There are no reports of the motor blocking potencies of these drugs. We sought to determine the motor block MLAC of both drugs and their relative potency ratio. Sixty ASA physical status I and II parturients were randomized to one of two groups, during the first stage of labor. Each received a 20-mL bolus of epidural bupivacaine or ropivacaine. The first woman in each group received 0.35%. Up-down sequential allocation was used to determine subsequent concentrations at a testing interval of 0.025%. Effective motor block was defined as a Bromage score <4 within 30 min. The up-down sequences were analyzed by using the Dixon and Massey method and probit regression to quantify the motor block minimal local analgesic concentration. Two-sided P < 0.05 defined significance. The motor block minimal local analgesic concentration for bupivacaine was 0.326% (95% confidence interval [CI], 0.285-0.367) and for ropivacaine was 0.497% (95% CI, 0.431-0.563) (P = 0.0008). The ropivacaine/bupivacaine potency ratio was 0.66 (95% CI, 0.52-0.82). This is the first MLAC study to estimate the motor blocking potencies of bupivacaine and ropivacaine. Ropivacaine was significantly less potent for motor block, at 66% that of bupivacaine. ⋯ The results of this study demonstrate that epidural ropivacaine is less potent than epidural bupivacaine in producing motor blockade during labor. The motor block potency relation is similar to the sensory potency ratio for these two drugs.
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Anesthesia and analgesia · Jul 2002
Randomized Controlled Trial Clinical TrialFentanyl attenuates the hemodynamic response to endotracheal intubation more than the response to laryngoscopy.
We examined the effectiveness of avoiding laryngoscopy in reducing the hemodynamic responses to orotracheal intubation during the induction of anesthesia. One hundred surgical patients who required orotracheal intubation were randomly allocated into four groups. The first and third groups underwent fiberoptic intubation, in which an anesthesiologist inserted the endotracheal tube into the trachea under TV monitoring through a bronchoscope, and the second and fourth groups underwent conventional orotracheal intubation using a rigid laryngoscope. The third and fourth groups were pretreated with 2 microg/kg fentanyl IV immediately before the induction of anesthesia. Blood pressure and heart rate were measured noninvasively. A significant reduction in hemodynamic response was seen in only the group treated with fentanyl and intubated using the fiberoptic technique. Without fentanyl, there was no significant difference in hemodynamic changes between the groups. We conclude that the administration of fentanyl suppresses the hemodynamic responses to endotracheal intubation more than it does to laryngoscopy. There was no significant difference in the hemodynamic responses to orotracheal intubation by fiberscopy and laryngoscopy without fentanyl pretreatment, whereas 2 microg/kg fentanyl significantly reduced the hemodynamic responses in the group intubated by fiberscopy. ⋯ We assessed the effectiveness of avoiding laryngoscopy for orotracheal intubation. There was no significant difference in the hemodynamic responses to orotracheal intubation by fiberscopy and laryngoscopy without fentanyl pretreatment, whereas 2 microg/kg fentanyl significantly reduced the hemodynamic responses in the group intubated by fiberscopy. Pretreatment of fentanyl and fiberoptic intubation might be recommended for avoiding hyperdynamic responses.
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Anesthesia and analgesia · Jul 2002
Randomized Controlled Trial Comparative Study Clinical TrialThe effect on lung mechanics in anesthetized children with rapacuronium: a comparative study with mivacurium.
The administration of rapacuronium increases the risk of severe bronchospasm. There have been no studies of pulmonary function directly demonstrating airway constriction with rapacuronium in children. In this study, 10 ASA physical status I or II patients (aged 2-6 yr) were randomly divided into 2 equal groups, receiving either rapacuronium or mivacurium. Anesthesia was induced with sevoflurane and maintained with remifentanil (0.2-0.3 microg. kg(-1). min(-1)) and propofol (200-250 microg. kg(-1). min(-1)) infusions. We performed three sets of pulmonary function tests: baseline, after the administration of muscle relaxant, and after the administration of a beta(2) agonist. In both groups, there were no changes in static respiratory compliance. The increase in total respiratory system resistance after the administration of rapacuronium did not reach statistical significance (214.4% +/- 122.65% of baseline, P approximately 0.1), whereas maximal expiratory flow at 10% of forced vital capacity (MEF)(10) and MEF(functional residual capacity) on partial flow-volume curves by the forced deflation technique decreased markedly (53.4% +/- 18.49%, P < 0.01 and 41.3% +/- 27.42%, P < 0.001, respectively). With the administration of mivacurium, no changes were observed in respiratory system resistance (109.5% +/- 30.28%). MEF(10) decreased slightly (77.0% +/- 9.03%, P < 0.005) whereas MEF(FRC) did not (81.2% +/- 29.85%, not significant). After the administration of a beta(2) agonist, all measurements returned to baseline. Thus, the administration of rapacuronium consistently results in lower airway obstruction with minimal changes in static respiratory compliance when compared with mivacurium. ⋯ Pulmonary function tests in the present study showed that rapacuronium consistently causes severe bronchoconstriction, confirming clinical case reports of bronchospasm. The bronchoconstriction is reversible with albuterol. Mivacurium also causes very mild subclinical bronchoconstriction.
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Anesthesia and analgesia · Jul 2002
Randomized Controlled Trial Clinical TrialSmall-dose ketamine improves the postoperative state of depressed patients.
We investigated whether ketamine is suitable for depressed patients who had undergone orthopedic surgery. We studied 70 patients with major depression and 25 patients as the control (Group C). The depressed patients were divided randomly into two groups; patients in Group A (n = 35) were induced with propofol, fentanyl, and ketamine and patients in Group B (n = 35) were induced with propofol and fentanyl, and all patients were maintained with 1.5%-2.0% isoflurane plus nitrous oxide. The mean Hamilton Depression Rating (HDR) score was 12.7 +/- 5.4 for Group A and 12.3 +/- 6.0 for Group B 2 days before surgery and 9.9 +/- 4.1 for Group A and 14.4 +/- 3.8 for Group B 1 day after surgery. The HDR score in Group A 1 day after surgery was significantly (P < 0.05) lower than that in Group B. The HDR score in Group C was 4.2 +/- 1.7 2 days before surgery and 4.8 +/- 1.6 1 day after surgery. Depressed mood, suicidal tendencies, somatic anxiety, and hypochondriasis significantly decreased in Group A as compared with Group B. Postoperative pain scores in Group A at 8 and 16 h after the end of anesthesia were 26.6 +/- 8.7 and 24.9 +/- 8.2, respectively, which were significantly (P < 0.05) lower than 34.3 +/- 12.0 and 31.1 +/- 8.8 in Group B. In conclusion, small-dose ketamine improved the postoperative depressive state and relieved postoperative pain in depressed patients. ⋯ NMDA receptor antagonists are reported to be effective for improving depression. It remains unclear whether ketamine, which is an NMDA receptor antagonist, postoperatively affects the psychological state in depressed patients. We investigated the effect of 1.0 mg/kg of ketamine on postoperative outcomes in depressed patients.