Iranian Journal of Health, Safety & Environment, Vol.1 No.3, pp138-144 138 Investigation of nitrous oxide concentration in operating rooms of educational hospitals of Ahvaz Jundishapur University in year 2012 Albooghobeish Masoumeh 1 , Neisi Abdolkazem *2 , Fattahi Mostafa 3 1) , Department of Anesthesiology, Paramedical School, Ahwaz University of Medical Sciences, Ahvaz, Iran 2) , Environmental Technologies Research Centre, Ahvaz Jundishapour University of Medical Sciences, Ahvaz, Iran. 3) , Paramedical School, Ahwaz University of Medical Sciences, Ahvaz, Iran. Author for Correspondence: akneisi@ajums.ac.ir Received: 19 Mar. 2014, Revised: 10 May 2014, Accepted: 25 May 2014 ABSTRACT Nitrous Oxide gas can affect the patient and also cause chronic complications in operating room staff in the short term. In the current survey, we measured the Nitrous Oxide gas levels in the operating room of the educational hospitals of the Ahvaz Jundishapur Medical University. 576 samples were taken from 32 operating rooms through 4 months. Sampling was done in 3 different working times (8:30-9:00, 10:30-11, 12:30-13:00) from 6 different sites in the operating room. Portable infrared spectrophotometer was used for measuring the concentration of nitrous oxide. The apparatus was calibrated by Nitrous Oxide gas capsule before each reading. Variance analysis was used to compare the means of Nitrous Oxide levels between places of sampling in the operating rooms. There was a significant difference between these amounts (p≤0.00(. Then LSD analysis was used to locate the variation factor. The exhaust of the anesthesia machine was the most noted place )p≤0.0001( and the other places did not show significant differences. There was a significant difference between measurements recorded when the air-conditioning system was on or off and if there was an air-conditioning system or not. These differences were observed at all the measurement times. According to the results from the current study, levels of Nitrous Oxide in operating rooms were higher than that recommended by international organizations (25 ppm) and it appears that exposure to this amount of gas could be potentially harmful for staff. It is recommended to take special safety measures and prevent the gas to be increased in the operating room using air conditioning and proper ventilation of the room. Keywords: Nitrous oxide, Anesthesia gas, Operating room, measurement, Ahvaz INTRODUCTION Nitrous Oxide is the most common anesthetic gas currently in use. Although inhalation anesthetics diethyl ether, nitrous oxide and chloroform have been used since 1840, the biological effects of occupational exposure to anesthetic agents remained unstudied until 1960. There have been reports on epidemiology, in vitro cellular and animal studies of exposure to anesthetic agents (1). Using nitrous oxide during general anesthesia reduces the pain and lessens the use of other agents. Using this gas could induce short term and long term side effects. Its short term side effects include a decrease in the renal and hepatic blood flow, and transient changes in the liver function tests during surgery (1, 2). Besides its short term effects, nitrous oxide also has some long term effects which mainly affect the people working in the operating room. Carcinogenesis is one of these effects. Epidemiological studies suggest that staff with exposure to even low levels of inhalation anesthetics have higher rates of cancer (2). Ellen Regina da Costa Paes et al. reported that exposure to anesthesia gases including nitrous oxide can cause DNA damage, increase plasma thiols and enzyme glutathione peroxidase GPX was higher at 16 and 22 months of exposure (3). Head BP, et al. concluded that nitrous oxide does have an additive toxicity effect when combined with other anesthetic agents (4). Long term exposure to nitrous oxide has detrimental effects on the genital system of the operating room staff (5) and evidently lowers the fertility (6) and increases the number of miscarriages (7). These aberrations which are recorded from different studies, attributes them to changes induced by nitrous oxide. Increased frequency of aberrations in chromosomes and sister chromatids is also repeatedly reported in people working in the operating room who are exposed to nitrous oxide alone or in combination with other halogenated gasses (8-11). Long term exposure to this gas could inactivate the methionine synthase and cause megaloblastic anemia through oxidation of vitamin B12 (12). Other side effects include lower mental performance, vision and hearing performance lowering, attention defect, dizziness, drowsiness, excitability, and behavioral disorders (13).