Study objectives: Because efforts to secure adequate arterial oxygenation during cardiac resuscitation are more important than efforts to promote CO(2) elimination, we investigated whether continuous transtracheal oxygenation (TTO) could represent a potentially simpler alternative to conventional positive-pressure ventilation with 100% O(2) through an endotracheal tube.
Design: Controlled and randomized.
Setting: Animal laboratory.
Participants: Thirty male Sprague-Dawley rats.
Interventions: The technique for TTO was initially developed and tested in five rats. A model of ventricular fibrillation (VF) was then used to compare the effects of TTO (n = 5) with the effects of O(2) delivery through an endotracheal tube as part of positive-pressure ventilation (n = 5) or through a mask without additional airway intervention (n = 5). VF was induced and left untreated for 4 min, after which chest compression and one of the three oxygenation interventions was started. Defibrillation was attempted after 6 min of chest compression. In a subsequent series, defibrillation was attempted after 10 min of chest compression in rats treated with either TTO (n = 5) or endotracheal intubation (ET; n = 5).
Measurement and results: TTO and ET secured adequate arterial PO(2) during chest compression (213 +/- 77 mm Hg and 154 +/- 36 mm Hg; not significant), whereas the mask yielded an arterial PO(2) of only 49 +/- 38 mm Hg (p < 0.05). Each rat treated with TTO or ET was successfully resuscitated and survived the postresuscitation interval, but none of the rats treated with the mask survived. TTO maintained its efficacy after increased duration of chest compression.
Conclusion: TTO was as effective as conventional positive-pressure ventilation with 100% O(2) for securing oxygenation, resuscitation, and short-term survival and more effective than O(2) delivered through a mask.