Evaluation of Venturi Devices for CPAP Application in Emergency Setting: a Bench Study

CPAP (Continuous Positive Airway Pressure) is commonly utilized in emergency settings. For a successful CPAP application on adult patients a minimum airflow output of 60L/min is necessary. The objective of this study was to assess the efficacy and efficiency of different Venturi devices [EasyVent(Dimar), VentuPlus (Starmed), FlowOne (DEAS), FlowSafe (Mercury-Medical), Compact-HAR II and III (Harol)] by measuring the output flow under conditions of oxygen supply and PEEP (Positive End-Expiratory Pressure) commonly employed. A static test was conducted to assess airflow output by each device at 10 and 15L/min flow rates and three different PEEP levels: 5, 7.5 and 10cmH2O. To simulate the real condition of an out-of-hospital environment the oxygen was supplied at 1 and 3 bar, considering that oxygen cylinders deliver different pressure depending on the different brands and supplier. The oxygen source was connected to a circuit with two flow meters (TSI Mass FlowMeter 4143 and 4040) positioned before and after the Venturi devices. A manometer to monitor pressure levels and an oxygen analyzer (Maxtec MAX O2+) were also placed upstream of the PEEP valve.