Continuous intratracheal insufflation of oxygen improves the efficacy of mechanical chest compression-active decompression CPR.

Abstract

The aim of the present study was to compare the efficacy of intratracheal continuous insufflation of oxygen (CIO) with intermittent positive pressure ventilation (IPPV) regarding gas exchange and haemodynamics during mechanical chest compression-active decompression cardiopulmonary resuscitation (mCPR) provided by the LUCAS device. Ventricular fibrillation (VF) was induced electrically and ventilation was discontinued in 16 pigs, mean body weight 23 kg (range 22-27 kg). They were randomized into two groups (CIO versus IPPV). After 8 min of VF, mCPR was started and run for 30 min in normothermia, after which defibrillation was attempted during on-going mCPR. Return of spontaneous circulation was obtained in eight of eight CIO pigs and in four of eight IPPV pigs. Arterial oxygen tension (P < 0.05) and coronary perfusion pressure (P < 0.01) were significantly higher in the CIO pigs. Arterial CO(2)-tension was subnormal in both groups and significantly (P < 0.05) lower in the IPPV-pigs (around 4.5 versus 3.0 kPa). The intratracheal pressure differed significantly (P < 0.001) between the two groups. It was negative in each decompression phase in the IPPV pigs in spite of 6 mmHg of PEEP. The CIO pigs had a positive intratracheal pressure during the whole cycle of mCPR, with a minimum pressure of 8 mmHg during each decompression phase. To conclude, mCPR combined with CIO gave adequate ventilation and significantly better oxygenation and coronary perfusion pressure than mCPR combined with IPPV.