Objective: 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.
Design: Nonrandomized, controlled trial.
Setting: Large, level one trauma center, tertiary care intensive care unit.
Patients: Critically ill patients failing noninvasive respiratory support techniques who required tracheal intubation followed by mechanical ventilation.
Interventions: 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.
Measurements and main results: 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.
Conclusions: 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.