How should we be ventilating during resuscitation? The management of airway is still contentious. Bag Valve Mask (BVM) or Super-glottic Airway(SGA) are accepted and encouraged approaches to establishing the airway, although there is good evidence that a definitive airway ie., with endotracheal tube (ett) is the gold standard. However, this is not always achievable in out of hospital cardiac arrest. In the emergency department with adequate resources, it should still be the goal.
This study looked at ventilation modes in intubated cardiac arrest patients. It specifically looked at CCSV (Chest Compression Synchronised Ventilation) mode, where ventilation and chest compressions are synchronised and a small tidal volume is introduced during chest compressions. This was the 2nd phase of the SYMEVECA (synchronised mechanical ventilation in out-of-hospital cardiac arrest) trial, where IPPV mode was compared to a BVM (1)
CCSV (Chest Compression Synchronized Ventilation) is a ventilation mode specific for CPR, where ventilations are automatically synchronised to chest compressions. Each chest compression triggers a pressure-controlled, small volume, high flow, mechanical insufflation of 205 ms (time-cycled) that begins with the chest compression (2).
The Study
Hernandez-Tejedor A et al. Comparison of Ventilation modes in non-traumatic out-of-hospital cardiac arrest: SYMEVECA phase 2. Resuscitation 212 (2025) 110655
What They Did
The SYMEVECA study is a pragmatic, prospective, quasi-experimental, non-randomized study with two phases:
- Phase 1: IPPV vs resuscitator bag ventilation
- Phase 2, continued recruitment as in phase 1, and the addition of a CCSV group
What They Found
They found a potential benefit in patients mechanically ventilated during CPR, although one mode was not found to be better than another.
Blood gas results show some statistically significant differences between the groups:
- PaO2 was better in patients ventilated with CCSV
- pH was higher and PCO2 lower in mechanically ventilated patients
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