Hyperbaric nursing has become a specialty requiring high skill and knowledge. Nitrogen narcosis is a perceived risk for all inside hyperbaric chamber nurses. The actual degree of impairment at pressure has not been quantified. Twenty eight subjects participated in the study. Sixteen hyperbaric nurse candidates and five experienced hyperbaric nurses completed Trail Making Test A (TMTA) pre and post compression and at 180 kPa and 300 kPa. Seven experienced hyperbaric staff acted as an unpressurized reference. Time to completion of the test was recorded in seconds; pre-test anxiety and perceived symptoms of narcosis at 300 kPa were also recorded. There were no statistically significant differences in the corrected TMT A times at the four different time periods. There was a trend to poorer performance by the nurse candidates at 180 kPa however this was not statistically significant. Most subjects felt some degree of narcosis at 300 kPa. Most hyperbaric chamber nurses can overcome the effects of nitrogen narcosis at 180 and 300 kPa to maintain or improve performance in the TMT A. Poor performance by hyperbaric nurse candidates maybe due to individual susceptibility or lack of ability to compensate. Due to the risk of nitrogen narcosis outside chamber staff should continue to make clinical decisions about patient care.
