Not surprisingly, many critically ill ED patients often develop a metabolic acidosis.
To compensate, patients hyperventilate, thereby producing a respiratory alkalosis.
When these patients require intubation and mechanical ventilation, be sure to provide the same level of respiratory compensation when setting the ventilator.
Failing to provide a rate sufficient to compensate for the pre-intubation acidosis leads to a rapid drop in pH, bradycardia and eventually asystole.
In general, rates can be increased to about 30-35 breaths per minute, after which auto-PEEP becomes problematic.
References
Manthous CA. Avoiding circulatory complications during endotracheal intubation and initiation of positive pressure ventilation. JEM 2010; 38:622-31.
