Evaluation of bag-valve-mask ventilation by paramedics in simulated chemical, biological, radiological, or nuclear environments

INTRODUCTION:Bag-valve-mask ventilation is a key component of life support, but only one handheld resuscitator is designed to operate in contaminated or toxic atmospheres.METHODS:After Institutional Review Board approval, the efficacy of this device was evaluated. The distal trachea of a Laerdal Airway Management Trainer was connected to a mechanical Draeger Volumeter 3000, to enable determination of the minute volume delivered by BVM ventilation. Nineteen paramedics wearing chemical, biological, radiological, or nuclear (CBRN) protective equipment were asked to ventilate this modified airway trainer, either with or without a CBRN filter attached to the inlet filtration system of the AMBU Mark III Resuscitator. The maximum levels of minute ventilation achieved were compared. Values are given as mean +/-SD. A paired t-test was used to detect any differences between the two groups, p-values of <0.05 were defined to show statistical significance.RESULTS:The described model allowed a reproducible and reliable measurement of the delivered minute ventilation. All paramedics were able to operate the device without prior CBRN training. The maximum minute volume achieved without the filter was 9.5 +/-2.7 l/min. Use of the inlet CBRN filtration system reduced the maximum minute volume to 6.3 +/-2.0 l/min, reduction: 23%. The achieved maximum minute volumes ranged from 15 to 4.9 l/min in the controls and from 9.8 to 1.4 l/min in the CBRN group. Four paramedics were unable to achieve a minute volume >5 l/min in the CBRN group, one participant failed to achieve that value in the control group. The inherent breathing resistance of the CBRN filter appears to reduce the inflow of air into the self-inflatable bag. This delay in refilling may have resulted in a reduced achievable minute volume.CONCLUSIONS:The range of maximum minute volumes observed in both groups highlights the need for continuous BVM ventilator training