Cryosurgicalprobes that employ nitrous oxide (N2O) may be hazardous, particularly to physicians working in treatment rooms with suboptimal ventilation and air recirculation.
A temporary decrement in psychomotor performance is, at present, the worst hazard, according to the Emergency Care Research Institute (ECRI) of Plymouth Meeting, Pa. Evidence from prior studies indicates that persons exposed to more than 50 ppm of N2O may suffer compromised motor and audiovisual skills, diminished dexterity, impaired cognition, and other neurological deficits. The ECRI is a 15-year-old independent, nonprofit, medical device testing corporation.
The solution is to scavenge the unit and vent the exhaust outdoors, but this is a measure more easily urged than implemented at present. Although manufacturers have responded favorably to ECRI's finding that N2O concentrations in three physicians' offices vastly exceeded the 25-ppm time-weighted average exposure recommended by the National Institute of Occupational Safety and Health, many