Extending the preoxygenation period from 4 to 8 mins in critically ill patients undergoing emergency intubation

To determine the effectiveness of increasing the preoxygenation period with 100% oxygen in the critically ill patient from 4 to 8 mins in preparation for emergency tracheal intubation.

Nonrandomized, controlled trial.

Large, level one trauma center, tertiary care intensive care unit.

Critically ill patients failing noninvasive respiratory support techniques who required tracheal intubation followed by mechanical ventilation.

A baseline arterial blood gas was obtained on noninvasive passive therapy and at 4, 6, and 8 mins of active preoxygenation efforts with 100% oxygen therapy with a noncollapsing resuscitator bag and mask. Best effort to achieve a tight fitting mask seal was pursued coupled with other mask ventilation maneuvers to optimize noninvasive oxygenation and ventilation.

Thirty-four patients consecutively intubated by the author during the 7-month study period were studied. The baseline PaO2 (mean +/- SD) with concurrent noninvasive support was 61.9 +/- 14.6 mm Hg (range: 44-109 mm Hg) and increased a mean of 22 mm Hg to 83.8 +/- 51.5 mm Hg after 4 mins of preoxygenation (p < 0.01). Continued preoxygenation efforts (6 mins) increased the PaO2 to 88.2 mm Hg +/- 48.5 and after 8 mins to 92.7 mm Hg +/- 55.2. At the 8-min mark, 5 of 34 patients achieved > 10% increase in their PaO2 and only two patients increased their 4-min PaO2 by > or = 50 mm Hg after the additional 4 mins of preoxygenation. One quarter of the patients experienced a reduction in their PaO2 from the 4 to the 8-min time period. Nearly, 50% of the patients met the criteria for desaturation during the intubation procedure.

Extending the preoxygenation period from the customary 4 mins to either 6 or 8 min seems to be marginally effective in the majority of patient suffering from cardiopulmonary deterioration and such an extension may jeopardize oxygenation efforts in some patients.