Preoxygenation with 20[degrees] head-up tilt provides longer duration of non-hypoxic apnea than conventional preoxygenation in non-obese healthy adults

Purpose 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 ti...

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Bibliographic Details
Published in:Journal of anesthesia 2011-04, Vol.25 (2), p.189
Main Authors: Ramkumar, Venkateswaran, Umesh, Goneppanavar, Philip, Frenny Ann
Format: Article
Language:English
Subjects:
Adults
Anesthesia
Apnea
Comparative analysis
Neuromuscular blocking agents
Obesity
Thiopental
Online Access:Get full text
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Summary:Purpose 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 20[degrees] head-up tilt (group H) and 5 cm[H.sub.2]O PEEP (group P) in non-obese individuals for non-hypoxic apnea duration. Methods 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 Sp[O.sub.2] dropped to 93% or 10 min of safe apnea was achieved. Results The demographic data were comparable. Non-hypoxic apnea duration was higher with group H (452 [+ or -] 71 s) compared to group C (364 [+ or -] 83 s, P = 0.030). Group P did not show significant increase in the duration of non-hypoxic apnea (413 [+ or -] 86 s). There were no adverse outcomes or events. Conclusions Preoxygenation is clinically and statistically more efficacious and by inference more efficient in the 20[degrees] head-up position than with conventional technique in nonobese healthy adults. Although application of 5 cmH2O PEEP provides longer duration of non-hypoxic apnea compared to conventional technique, it is not statistically significant. Keywords Preoxygenation * Apnea * PEEP * Head-up tilt
ISSN:0913-8668
DOI:10.1007/s00540-011-1098-3