• Venkateswaran Ramkumar, Goneppanavar Umesh, and Frenny Ann Philip.
• Department of Anaesthesiology, Kasturba Medical College, Manipal 576 104, Karnataka, India.
• J Anesth. 2011 Apr 1;25(2):189-94.

PurposeFailed airway is the anesthesiologist's nightmare. Although conventional preoxygenation can provide time, atelectasis occurs in the dependent areas of the lungs immediately after anesthetic induction. Therefore, alternatives such as positive end-expiratory pressure (PEEP) and head-up tilt during preoxygenation have been explored. We compared the conventional preoxygenation technique (group C) with 20º head-up tilt (group H) and 5 cmH(2)O PEEP (group P) in non-obese individuals for non-hypoxic apnea duration.MethodsA total of 45 patients were enrolled (15 in each group). After 5 min of preoxygenation, intubation was performed after induction of anesthesia with thiopentone and succinylcholine. After confirming the tracheal intubation by esophageal detector device and capnogram, all patients were administered vecuronium to maintain neuromuscular blockade and midazolam to prevent awareness. Post-induction, patients in all groups were left apneic in supine position with the tracheal tube exposed to atmosphere till the SpO(2) dropped to 93% or 10 min of safe apnea was achieved.ResultsThe demographic data were comparable. Non-hypoxic apnea duration was higher with group H (452 ± 71 s) compared to group C (364 ± 83 s, P = 0.030). Group P did not show significant increase in the duration of non-hypoxic apnea (413 ± 86 s). There were no adverse outcomes or events.ConclusionsPreoxygenation is clinically and statistically more efficacious and by inference more efficient in the 20º head-up position than with conventional technique in non-obese healthy adults. Although application of 5 cmH(2)O PEEP provides longer duration of non-hypoxic apnea compared to conventional technique, it is not statistically significant.

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