Journal of Anesthesiology and Pain

 Aims and Background: The most common used anesthetic gas in operating rooms is nitrous oxide which is a poor anesthetic agent. Moreover, the level of serum cortisol is resumed as an indicator of stress. As a result an increase of serum cortisol could indicate stress and nervous condition. The aim of this study was to evaluate the relationship between the concentrations of anesthetic agent, named nitrous oxide, on urinary cortisol levels of the operating room's personnel.

Materials and Methods: This study was a cross-sectional and correlational one. The Study population were the operating room's personnel (n=30) and the Official personnel (n=30) in Besat Hospital of Hamedan. The concentration of nitrous oxide was measured in operating room for a week in the morning and afternoon. To investigate the effect of the inhalation and absorption of harmful chemical agents on neurobiological factors, urine samples were taken at the beginning and at the end of each day continuously for 5 days from the test and control groups. To reach the goal, Cortisol level in urine samples was measured.

Findings: The concentration of anesthetic and antiseptic agents in the operating room space was 388.26 ± 101.4 ppm. Mean Cortisol level in urine samples of the operating room personnel( test group),  at the beginning and the end of the day ,for 5 days was 648.4± 2.74 ng/ml. Mean Urine Level of cortisol in the official personnel (control group), collected in the same manner was 579.2 ± 3.1ng/ml. Our findings showed that there is a significant difference between the mean concentration of the breathing gas nitrous oxide in operating rooms' and recovery workers at three-time sampling a day according to ANOVA test (P<0.05) (P=0.028). T test showed no significant difference in urinary free cortisol (ng per ml) between the two groups (P=0.559).  

Conclusions: Pearson correlation showed that there is a direct positive and incomplete relation between the concentration of nitrous oxide in the operating room space the and urinary free cortisol (ng/ml) of the operating room's personnel (r=0.857) (P=0.004). This means that increasing the concentration of nitrous oxide in the operating room space, increased urinary free cortisol levels. (P<0.05)