Phase-controlled intermittent intratracheal insufflation of oxygen during chest compression-active decompression mCPR improves coronary perfusion pressure over continuous insufflation.

Purpose: It has previously been shown that continuous intratracheal insufflation of oxygen (CIO) is superior to intermittent positive pressure ventilation (IPPV) regarding gas exchange and haemodynamics. The purpose of this study was to investigate gas exchange and haemodynamics with a new technique of phase-controlled intermittent insufflation of oxygen (PIIO) compared to CIO.

Method: Twenty (20) pigs were used, stratified into two groups (CIO, PIIO), with 10 animals each. Upon induction of ventricular fibrillation, standard ventilator support was replaced by either of CIO or PIIO ventilation. Chest compressions were delivered by the LUCAS I mCPR device. Following 20 min of CPR in normothermia, defibrillation was attempted.

Results: Return of spontaneous circulation (ROSC) occurrence was not significantly higher (P < 0.16) in the PIIO (9/10) than in the CIO (6/10) group. During the decompression phase the PIIO group showed significant increases in mean (P < 0.01), maximal (P < 0.02) and end-decompression (P < 0.01) coronary perfusion pressure (CPP), compared to the CIO group. PIIO resulted in increased compression phase aortic pressure (P < 0.03). Intratracheal pressure was 5-30 cmHO within both groups during mCPR, with a significantly lower (P < 0.02) mean for the PIIO group. Arterial and venous blood gas analysis showed comparable results between the groups, when taking base line values into account. An exception was that PIIO resulted in significantly higher (P < 0.05) oxygen partial pressure during mCPR, and lower (P < 0.05) arterial lactate following ROSC.

Conclusion: PIIO results in significantly higher CPP and compression phase aortic pressure during mCPR in a porcine population. Further studies are needed to validate these findings in humans. Study protocol conforming with ethic approval M174-15, issued by the Malmö/Lunds regionala djurförsöksetiska nämnd (REB).