Chest Compression Synchronized Ventilation versus Intermitted Positive Pressure Ventilation during Cardiopulmonary Resuscitation in a Pig Model

BACKGROUND Guidelines recommend mechanical ventilation with Intermitted Positive Pressure Ventilation (IPPV) during resuscitation. The influence of the novel ventilator mode Chest Compression Synchronized Ventilation (CCSV) on gas exchange and arterial blood pressure compared with IPPV was investigated in a pig model. METHODS In 12 pigs (general anaesthesia/intubation) ventricular fibrillation was induced and continuous chest compressions were started after 3 min. Pigs were mechanically ventilated in a cross-over setting with 5 ventilation periods of 4 min each: Ventilation modes were during the first and last period IPPV (100% O2, tidal volumes = 7 ml/kgKG, respiratory rate = 10/min), during the 2nd, 3rd and 4th period CCSV (100% O2), a pressure-controlled and with each chest compression synchronized breathing pattern with three different presets in randomized order. Presets: CCSVA: P insp = 60 mbar, inspiratory time = 205 ms; CCSVB: P insp = 60 mbar, inspiratory time = 265 ms; CCSVC: P insp = 45 mbar, inspiratory time = 265 ms. Blood gas samples were drawn for each period, mean arterial (MAP) and central venous (CVP) blood pressures were continuously recorded. Results as median (25%/75%percentiles). RESULTS Ventilation with each CCSV mode resulted in higher PaO2 than IPPV: PaO2: IPPV first: 19.6(13.9/36.2)kPa, IPPV last: 22.7(5.4/36.9)kPa (p = 0.77 vs IPPV first), CCSVA: 48.9(29.0/58.2)kPa (p = 0.028 vs IPPV first, p = 0.0001 vs IPPV last), CCSVB: 54.0 (43.8/64.1) (p = 0.001 vs IPPV first, p = 0.0001 vs IPPV last), CCSVC: 46.0 (20.2/58.4) (p = 0.006 vs IPPV first, p = 0.0001 vs IPPV last). Both the MAP and the difference MAP-CVP did not decrease during twelve minutes CPR with all three presets of CCSV and were higher than the pressures of the last IPPV period. CONCLUSIONS All patterns of CCSV lead to a higher PaO2 and avoid an arterial blood pressure drop during resuscitation compared to IPPV in this pig model of cardiac arrest.