AUTHORS: Heard, Andrew FRCA et al
Anesthesia & Analgesia: April 2017 – Volume 124 – Issue 4 – p 1162–1167
BACKGROUND: Despite optimal preoxygenation, obese patients undergoing induction of general anesthesia exhibit significant hypoxemia after 2 to 4 minutes of apnea. Apneic oxygenation techniques can assist airway management by extending the safe apnea time. We hypothesized that a novel method of apneic oxygenation via the oral route would effectively prolong safe apnea in an obese surgical population.
METHODS: In this open-label, parallel-arm, randomized-controlled efficacy trial, 40 ASA physical status I–II obese patients with body mass index (BMI) 30–40 were randomly assigned to standard care (n = 20) or buccal oxygenation (n = 20) during induction of total IV anesthesia. Buccal oxygen was administered via a modified 3.5-mm Ring-Adair-Elwyn (RAE) tube apposed to the left internal cheek. Prolonged laryngoscopy maintained apnea with a patent airway until SpO2 dropped below 95% or 750 seconds elapsed. The primary outcome was time to reach SpO2 < 95%.
RESULTS: Patient characteristics were similar in both study arms. Recipients of buccal oxygenation were less likely to exhibit SpO2 < 95% during 750 seconds of apnea; hazard ratio 0.159 (95% confidence interval 0.044–0.226, P < .0001). Median (interquartile range [IQR]) apnea times with SpO2 ≥ 95% were prolonged in this group; 750 (389–750) versus 296 (244–314) seconds, P < .0001.
CONCLUSIONS: Clinically important prolongation of safe apnea times can be achieved delivering buccal oxygen to obese patients on induction of anesthesia. This novel use of apneic oxygenation via the oral route may improve management of the difficult airway and overcome some of the limitations of alternative techniques.