Comparing Vitamin B12 and Nitrous Oxide Neurotoxicity in Operating Room Staff and other Hospital Staff: A Multicenter Study

Nitrous oxide (N2O) is an anesthetic widely used in operating rooms. Chronic exposure to N2O causes decrease in mental performance, peripheral neuropathy, and polyneuropathy. The aim of this study was to compare neurological complications caused by N2O exposure between operating room staff and other hospital staff. In this multicenter cohort study, operating room staff (n=110) and non-operating room staff (n= 224) in Arak Valiasr Hospital and Isfahan Al-zahra Hospital were randomly selected and individually matched. Both groups were examined for neuropathic symptoms and their medical history was recorded. Clinical neurological exams such as Romberg test were used in both groups. Patients with neuropathic sign and symptoms were referred to a neurology clinic to confirm any diagnosis. The two groups were significantly different in ataxia, numbness, weakness and paresthesia of upper and lower limb, Romberg test score, and levels of Vitamin B12 (P<0.05). No significant differences were observed between the two groups in mean Hemoglobin level, temperature sense, touch and two-point discrimination, stereo gnosis, tandem walking, and plantar and dorsal flexion (P≥ 0.05). Chronic exposure to nitrous oxide was found to decrease serum vitamin B12 levels and caused neurological symptoms and complications. Therefore, clinical and laboratory evaluations and monitoring of exposure to nitrous oxide is necessary.