The effect of N2O gas on serum cobalamin and homocysteine in patients undergoing orthopedic surgery

Amir Mohammad Azizi Kolachahi, Mahmood Khosravy, Aidin Badanara Marzdashty, Mahmood Abedinzade


Nitrous oxide (N2O) is an inhaled anesthetic drug that uses during surgery and recently proposed as a treatment for mood disorder in a research setting. Exposure to N2O during surgery can cause hematopoietic and neural side effects. The purpose of this study was to the designation of serum cobalamin, homocysteine and CBC factors changes after exposure to nitrous oxide during orthopedic surgery. This study has been done on 30 patients undergoing orthopedic operations from 2016 until 2018. All patients are scheduled for orthopedic surgery. All patients received nitrous oxide during their anesthesia period. Blood samples were taken from patients 48 hours before surgery and 24 hours after surgery. All samples froze at -20°c immediately after collecting. Then samples transferred to the university laboratory with regards to keeping a cold chain for analysis. Paired T-test and Wilcoxon test were used for comparing vitamin B12, homocysteine, and CBC parameters. Nitrous oxide resulted in marked vitamin B12 and homocysteine level change. Mean concentration of vitamin B12 reduced after exposure to N2O. This difference was significant when analyzed using paired sample T-test (p=0.0001). homocysteine concentration means decreased after exposure to N2O and this difference was statistically significant (p=0.0001). Nitrous oxide will lead to a decrease in vitamin B12 and an increase in homocysteine and mean corpuscular volume in the early postoperative period.


Analgesic; Homocysteine; Nitrous oxide; Vitamin B12

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