ObjectiveTo investigate the effects of different peak flow on the airway pressure to explore a preferable value of peak flow in ventilation during cardiopulmonary resuscitation (CPR) under volume control ventilation (VCV) mode and decreasing-wave. Methods30 patients who underwent CRP in the emergency unit between January 2012 and 2014 was recruited in the study. When the chest compressions came into a stable state by a same doctor,the peak flow was set at 50 L/min and 30 L/min respectively while other parameters fixed in the same patient. Then the pressure-time curve of a respiratory cycle was randomly frozen to achieve the highest peak pressure in inspiratory phase. ResultsThe highest peak airway pressures were (54.1±4.9)cm H2O and (35.5±5.3)cm H2O when the peak flow were set at 50 L/min and 30 L/min respectively with significant difference. The incidence of peak airway pressure greater than 40 cm H2O was 96.7% and 26.7%,and the incidence of peak airway pressure greater than 50 cm H2O was 76.7% and 0%,respectively. Compared with 50 L/min,the peak flow of 30 L/min obviously reduced the peak pressure (P=0.000). ConclusionIn the mechanical ventilation during CPR using VCV mode and decreasing-wave,compared with peak flow of 50 L/min,smaller peak flow of 30 L/min can significantly reduce peak airway pressure,and significantly reduce the adverse effects to ventilation by repeated violent changes in airway pressure caused by continuing chest compressions,and make airway peak pressure under 40 cm H2O in most patients,so it is a reasonable and safe choice.