Anesthesia and analgesia
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Anesthesia and analgesia · Jul 1999
Randomized Controlled Trial Clinical TrialThe influence of the tonsillar gag on efficacy of seal, anatomic position, airway patency, and airway protection with the flexible laryngeal mask airway: a randomized, cross-over study of fresh adult cadavers.
We conducted a randomized, controlled, cross-over cadaver study to test the hypothesis that the efficacy of seal for ventilation and airway protection, anatomic position, and airway patency with the flexible laryngeal mask airway (FLMA) are altered by the application of a Boyle Davis (B-D) gag. We also determined the airway sealing pressure (ASP) at which the FLMA prevents aspiration when large volumes of fluid are placed above the cuff. We studied 20 adult cadavers (6-24 h postmortem). Efficacy of seal for ventilation and airway protection, anatomic position, and airway patency were determined with and without a B-D gag (two blade sizes: 8 and 10 cm) for the size 3, 4, and 5 FLMA in random order. Efficacy of seal for ventilation was determined by measuring the ASP at an intracuff pressure of 60 cm H2O. Efficacy of seal for airway protection was determined by flooding the mouth with 55-135 mL of water, reducing intracuff pressure until aspiration was detected fiberoptically and measuring ASP at this intracuff pressure. Anatomic position and airway patency were determined with a fiberoptic scope at an intracuff pressure of 60 cm H2O. In addition, in vivo compliance and ASP for the FLMA were measured in 10 cadavers and 10 paralyzed, anesthetized patients. Efficacy of seal for ventilation and airway protection, anatomic position, and airway patency did not change with the application of a gag for any mask size. The mean (range) ASP at which aspiration occurred when large volumes of fluid were placed above the cuff was 11 (7-15) cm H2O. The ASP for ventilation was always higher than the ASP for airway protection (P<0.0001). The FLMA had similar in vivo compliance and ASP in cadavers and anesthetized patients. We conclude that efficacy of seal for ventilation and airway protection, anatomic position and airway patency for the FLMA are unaffected by the application of a B-D gag in adults. ASP should be >15 cm H2O if there is a maximal risk of aspiration from above the cuff. ⋯ The flexible laryngeal mask airway forms an effective seal for ventilation and protection of the airway that is unaffected by the application of a mouth gag that provides surgical access to the oropharynx. The efficacy of the seal should be >15 cm H2O if there is a maximal risk of aspiration from above the cuff.
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Anesthesia and analgesia · Jul 1999
Randomized Controlled Trial Comparative Study Clinical TrialThe prophylactic effect of dexamethasone on postoperative nausea and vomiting in women undergoing thyroidectomy: a comparison of droperidol with saline.
The aim of this study was to evaluate the prophylactic effect of dexamethasone on postoperative nausea and vomiting (PONV) in women undergoing thyroidectomy. Droperidol and saline served as controls. One hundred twenty women (n = 40 in each of three groups) undergoing thyroidectomy under general anesthesia were enrolled in this randomized, double-blinded, placebo-controlled study. Immediately before the induction of anesthesia, Group 1 received IV dexamethasone 10 mg, whereas Groups 2 and 3 received IV droperidol 1.25 mg and saline, respectively. We found that both dexamethasone and droperidol significantly decreased the total incidence of PONV compared with saline, with an incidence of 32%, 35%, and 76%, respectively (P<0.01; Group 1 versus Group 3, Group 2 versus Group 3). Patients who received droperidol, however, reported a higher intensity of sore throat and a more frequent incidence of restlessness than those who received dexamethasone. We conclude that, although both dexamethasone and droperidol are effective as prophylactic antiemetics in women undergoing thyroidectomy, droperidol produces more side effects. ⋯ We compared the prophylactic administration of dexamethasone to prevent nausea and vomiting with droperidol and saline in women undergoing thyroidectomy. Both dexamethasone and droperidol significantly reduced postoperative nausea and vomiting, but droperidol produced more side effects, which suggests that dexamethasone is a useful treatment in these patients.
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Anesthesia and analgesia · Jul 1999
Randomized Controlled Trial Clinical TrialDexamethasone decreases epidural morphine-related nausea and vomiting.
The aim of our study was to compare the antiemetic effect of IV dexamethasone with saline control in preventing epidural morphine-related nausea and vomiting. Eighty patients requiring epidural anesthesia for abdominal total hysterectomy were enrolled in a randomized, double-blinded, and placebo-controlled study. At the end of surgery, all patients received epidural morphine 3 mg for relief of postoperative pain. Before the morphine injection, the dexamethasone group (n = 40) received IV dexamethasone 8 mg, whereas the saline group (n = 40) received IV saline. We found that the incidence of postoperative vomiting was 5% in the dexamethasone group and 25% in the saline group (P<0.05). The total incidence of nausea and vomiting was 16% in the dexamethasone group and 56% in the saline group (P<0.001). IV dexamethasone 8 mg significantly decreases the incidence of epidural morphine-related nausea and vomiting. ⋯ We evaluated IV dexamethasone versus saline control in preventing epidural morphine-related nausea and vomiting in patients receiving epidural morphine for postoperative pain control. We found that IV dexamethasone significantly decreased the total incidence of nausea and vomiting after epidural morphine. IV dexamethasone may be a valuable treatment for preventing epidural morphine-related nausea and vomiting.
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Anesthesia and analgesia · Jul 1999
Randomized Controlled Trial Clinical TrialPremedication with midazolam delays recovery after ambulatory sevoflurane anesthesia in children.
We studied the effect of oral premedication with midazolam on the recovery characteristics of sevoflurane anesthesia in small children. In a randomized, double-blinded study, 60 children (1-3 yr, ASA physical status I or II) undergoing ambulatory adenoidectomy received either midazolam 0.5 mg/kg (Group M) or placebo (Group P) PO approximately 30 min before the induction of anesthesia. All children received atropine 0.01 mg/kg IV and alfentanil 10 microg/kg IV before the induction of anesthesia with sevoflurane up to 8 vol% inspired concentration in N2O 67% in O2. Tracheal intubation was facilitated with mivacurium 0.2 mg/kg. Anesthesia was continued with sevoflurane adjusted to maintain hemodynamic stability. In the postanesthesia care unit, predetermined recovery end points (emergence, recovery, discharge) were recorded. A pain/ discomfort scale was used to determine the quality of recovery. A postoperative questionnaire was used to evaluate the well-being of the patient at home 24 h after surgery. Emergence (spontaneous eye opening), recovery (full points on the modified Aldrete scale), and discharge were achieved later in Group M than in Group P (15+/-6 vs. 11+/-3 min [P = 0.002], 25+/-17 vs. 16+/-6 min [P = 0.01], and 80+/-23 vs. 70+/-23 min [P = 0.03]). Side effects, postanesthetic excitement, and analgesic treatment did not differ significantly between groups. At home, more children in Group P (30%) experienced disturbed sleep during the night compared with those in Group M (4%) (P = 0.007). ⋯ In this randomized, double-blinded, placebo-controlled study, premedication with midazolam 0.5 mg/kg PO delayed recovery in children 1-3 yr of age after brief (<30 min) sevoflurane anesthesia. Except for more peaceful sleep at home, premedication did not affect the quality of recovery.
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Anesthesia and analgesia · Jul 1999
Randomized Controlled Trial Clinical TrialSmall-dose ketamine enhances morphine-induced analgesia after outpatient surgery.
Small-dose ketamine may enhance the analgesic effect of opiates. We studied the effect of IV coadministration of small-dose ketamine 50-100 microg/kg with morphine 50 microg/kg on postoperative morphine requirements and pain in 140 patients undergoing outpatient surgery. Midazolam 1-2 mg was administered in the holding area. Anesthesia was induced with propofol 2-2.5 mg/kg and was maintained with desflurane in a nitrous oxide/oxygen mixture. Patients received morphine 50 microg/kg with placebo (Group 1, n = 35) or ketamine 50 microg/kg IV (Group 2, n = 35), 75 microg/kg IV (Group 3, n = 35), or 100 microg/kg IV (Group 4, n = 35) 15 min before the end of the operation. Pain and drowsiness were assessed using visual analog scales on arrival in the recovery room, then every 15 min until the time of discharge to phase 2 recovery (phase 1 recovery). Morphine consumption in Groups 3 and 4 was approximately 40% less than that in the control group (91+/-9 and 89+/-8 microg/kg vs. 145+/-9 microg/kg; P<0.05 for both). Pain scores in Groups 3 and 4 were approximately 35% less than those in the control group at all time periods (P<0.0001 for all). There was no significant group difference in drowsiness scores. Small-dose ketamine 75-100 microg/kg IV, enhanced morphine-induced analgesia after outpatient surgery. Simultaneous use of small doses of ketamine with morphine enhances the pain relief produced by morphine. ⋯ Simultaneous use of small doses of ketamine with morphine enhances the pain relief produced by morphine.