Preoxygenation with 20º head-up tilt provides longer duration of non-hypoxic apnea than conventional preoxygenation in non-obese healthy adults
- 604 Downloads
Failed 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 cmH2O PEEP (group P) in non-obese individuals for non-hypoxic apnea duration.
A 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 SpO2 dropped to 93% or 10 min of safe apnea was achieved.
The 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.
Preoxygenation 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 cmH2O PEEP provides longer duration of non-hypoxic apnea compared to conventional technique, it is not statistically significant.
KeywordsPreoxygenation Apnea PEEP Head-up tilt
- 14.Nunn JF. Nunn’s applied respiratory physiology. 3rd ed. London: Butterworth Heinemann; 1987. p. 350–70.Google Scholar
- 17.Dixon BJ, Dixon JB, Carden JR, Burn AJ, Schachter LM, Playfair JM, Laurie CP, O’Brien PE. Preoxygenation is more effective in the 25 degrees head-up position than in the supine position in severely obese patients: a randomized controlled study. Anesthesiology. 2005;102:1110–5.PubMedCrossRefGoogle Scholar