Abstract 2045: Comparison of Ventilation Methods during Continuous Chest Compression Cardiopulmonary Resuscitation
Background: Optimal ventilation methods for intubated patients during mechanical chest compression are not known. In a swine model of cardiac arrest, we compared bag-valve ventilation (BV), bag-valve ventilation with an impedance threshold device (BV-ITD), and continuous insufflation of oxygen (CIO).
Methods: Ventricular fibrillation (VF) was induced in 18 anesthetized, intubated male swine (37.1 ± 6.6 kg), randomized to BV, BV-ITD, or CIO. Chest compressions (LUCAS device) and ventilation began 5 min later, continued for 7 min, paused for defibrillation, and resumed. For CIO, 15 l/min of 100% O2 was given via Boussignac tube. For BV and BV-ITD, 1 breath of 100% O2 was given every 6 sec without pausing. The primary endpoint was coronary perfusion pressure (CPP) averaged over the first 7 min of CPR. CPP was calculated from aortic and central venous pressures between compressions. Cerebral perfusion pressure (CePP) was calculated from aortic and intracranial pressures over the full compression-release cycle. Arterial oxygen tension (PaO2) was measured after 6.5 min of compressions.
Results: CPP and CePP were significantly lower for CIO than BV (p=0.02) and BV-ITD (p=0.02) groups, and not different between BV and BV-ITD (figure⇓). There was no significant difference in PaO2 between groups but 2 BV-ITD and 3 CIO animals had very low PaO2 (<80mmHg). Return of spontaneous circulation occurred in 5 of 6 BV, 5 of 6 BV-ITD, and 1 of 6 CIO animals (p=NS).
Conclusions: In this animal model of cardiac arrest, bag-valve ventilation with or without an ITD resulted in better hemodynamics than continuous insufflation of oxygen, and the ITD did not provide measurable benefit over bag-valve alone.