Physiologic effects of a self-contained self-rescuer.

Recently promulgated federal regulations mandate the provision of an emergency, self-contained, oxygen-supplying breathing device (self-contained self-rescuer, SCSR) to all underground coalminers. In order to assist in defining the potential limitations of this new device, we measured the responses of ten healthy coal mine inspectors to submaximal steady-state treadmill exercise with and without the SCSR. During the last minute of exercise, blood oxygen saturation averaged 98.3% and mouth pressure swing 15.6 cm H2O with the device, compared to 94.8% and 10.4 cm H2O without it. Mean respiratory rates were decreased to 25/min with the SCSR from 28/min without it. Blood pressure, core temperature and heart rate were unaffected. We conclude that in healthy individuals on submaximal exercise there is little evidence of a significant adverse effect of the new device.