Intravenous Delta-9-Tetrahydrocannabinol to Prevent Postoperative Nausea and Vomiting: A Randomized Controlled Trial.

BACKGROUND: Evidence suggests that cannabinoids can prevent chemotherapy-induced nausea and vomiting. The use of tetrahydrocannabinol (THC) has also been suggested for the prevention of postoperative nausea and vomiting (PONV), but evidence is very limited and inconclusive. To evaluate the effectiveness of IV THC in the prevention of PONV, we performed this double-blind, randomized, placebo-controlled trial with patient stratification according to the risk of PONV. Our hypothesis was that THC would reduce the relative risk of PONV by 25% compared with placebo. METHODS: With IRB approval and written informed consent, 40 patients at high risk for PONV received either 0.125 mg/kg IV THC or placebo at the end of surgery before emergence from anesthesia. The primary outcome parameter was PONV during the first 24 hours after emergence. Secondary outcome parameters included early and late nausea, emetic episodes and PONV, and side effects such as sedation or psychotropic alterations. RESULTS: The relative risk reduction of overall PONV in the THC group was 12% (95% confidence interval, -37% to 43%), potentially less than the clinically significant 25% relative risk reduction demonstrated by other drugs used for PONV prophylaxis. Calculation of the effect of treatment group on overall PONV by logistic regression adjusted for anesthesia time gave an odds ratio of 0.97 (95% confidence interval, 0.21 to 4.43, P = 0.97). Psychotropic THC side effects were clinically relevant and mainly consisted of sedation and confusion that were not tampered by the effects of anesthesia. The study was discontinued after 40 patients because of the inefficacy of THC against PONV and the finding of clinically unacceptable side effects that would impede the use of THC in the studied setting. CONCLUSIONS: Because of an unacceptable side effect profile and uncertain antiemetic effects, IV THC administered at the end of surgery before emergence from anesthesia cannot be recommended for the prevention of PONV in high-risk patients.

Performance of the pediatric-sized i-gel compared with the Ambu AuraOnce laryngeal mask in anesthetized and ventilated children.

BACKGROUND: This prospective, randomized, controlled trial compares the performance of the pediatric i-gel (Intersurgical Ltd., Wokingham, United Kingdom) with the Ambu AuraOnce laryngeal mask (Ambu A/S, Ballerup, Denmark) in anesthetized and ventilated children. METHODS: With ethics committee approval and written informed consent, the authors included 208 children, aged 0-17 yr, scheduled for elective day-surgery under general anesthesia. The primary outcome variable was oropharyngeal leak pressure. Other outcome variables were first-attempt and overall success, time to sufficient ventilation, and adverse events. RESULTS: Demographic data did not differ between groups. The leak pressure of the i-gel was significantly higher than the leak pressure of the Ambu (mean ± SD: 22 ± 5 cm H2O vs. 19 ± 3, P < 0.01). First-attempt success was 91% for the i-gel and 93% for the Ambu (P = 0.50). Overall success was 93% for the i-gel versus 98% for the Ambu (P = 0.10). Successfully inserted i-gels needed to be secured by taping in place to ensure the seal in 44% (0% with the Ambu, P < 0.01). Insertion was faster with the Ambu (24 ± 8 s vs. 27 ± 11, P = 0.02). There were no major side effects with either device. CONCLUSIONS: The leak pressure of the i-gel was statistically but not clinically significantly higher than the leak pressure of the Ambu. Time to insertion was longer with the i-gel. Both airway devices are suitable for positive pressure ventilation with high success rates in infants and children. Because the i-gel is prone to sliding out, it must be taped in place to avoid loss of the airway.

Crossover comparison of the laryngeal mask supreme and the i-gel in simulated difficult airway scenario in anesthetized patients.

BACKGROUND: The single-use supraglottic airway devices LMA-Supreme (LMA-S; Laryngeal Mask Company, Henley-on-Thames, United Kingdom) and i-gel (Intersurgical Ltd, Wokingham, Berkshire, United Kingdom) have a second tube for gastric tube insertion. Only the LMA-S has an inflatable cuff. They have the same clinical indications and might be useful for difficult airway management. This prospective, crossover, randomized controlled trial was performed in a simulated difficult airway scenario using an extrication collar limiting mouth opening and neck movement. METHODS: Sixty patients were included. Both devices were placed in random order in each patient. Primary outcome was overall success rate. Other measurements were time to successful ventilation, airway leak pressure, fiberoptic glottic view, and adverse events. RESULTS: Success rate for the LMA-S was 95% versus 93% for the i-gel (P = 1.000). LMA-S needed shorter insertion time (34 +/- 12 s vs. 42 +/- 23 s, P = 0.024). Tidal volumes and airway leak pressure were similar (LMA-S 26 +/- 8 cm H20; i-gel 27 +/- 9 cm H20; P = 0.441). Fiberoptic view through the i-gel showed less epiglottic downfolding. Overall agreement in insertion outcome was 54 (successes) and 1 (failure) or 55 (92%) of 60 patients. The difference in success rate was 1.7% (95% CI -11.3% to 7.6%). CONCLUSIONS: Both airway devices had similar insertion success and clinical performance in the simulated difficult airway situation. The authors found less epiglottic downfolding and better fiberoptic view but longer insertion time with the i-gel. Our study shows that both devices are feasible for emergency airway management in patients with reduced neck movement and limited mouth opening.