In addition to improving laryngeal view, there is now evidence that elevating the head of the bed prolongs apneic desaturation time. This makes good sense, and the tradition of intubating patients in the supine position should be added to the long list of Things We’ve Been Doing Wrong All This Time. Using semi-fowlers position also probably reduces the risk of regurgitation/aspiration, and is strongly recommended for all patients being intubated for upper GI bleed. But make it your routine and you will benefit when that extra little bit of glottic view, those extra few seconds of apnea, and that extra bit of protection against regurgitation really matter. There is no downside.
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° head-up tilt (group H) and 5 cmH2O 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 SpO2 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 ± 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.
Conclusions Preoxygenation is clinically and statistically more efficacious and by inference more efficient in the 20° 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 comparedto conventional technique, it is not statistically significant.
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