Dose N2O Cause Paradoxical Reaction in Response to Noxious Stimulants During Inhalation Induction of Anesthesia in Pediatrics?

Bispectral Index is one of the qualitative methods of measuring of sedation and depth of anesthesia. In a few studies appeared a paradoxical effect of N2O on BIS in adults. In this study, the paradoxical effects of N2O during inhalation induction of anesthesia in pediatrics by halothane and isoflorane were evaluated. In a clinical trial study, eighty 1-6 year old age, ASA I and II pediatrics who candidate for abdominal and extremities elective surgeries were evaluated in 4 groups (Halothane, Isoflorane, Halothane plus N2O and Isoflorane plus N2O). Anesthesia was induced by gradual increase of vapor gas in 100% of O2 in groups 1 and 2 and in 50% of N2O in O2 in groups 3 and 4. BIS and other variables were measured before and after of laryngoscopy and surgical incision. The mean of percent changes of BIS after the laryngoscopy in comparison to pre-laryngoscopy in 4 groups were: 0.15 ± 13.95,16.57 ± 19.49, 4.90 ± 42.68, and 31.22 ± 28.19 (P = 0.287). The pre and after surgical incision BIS were: -3.88±23.30, 19.36 ± 9.17, 16.73 ± 2.33, and 7.75 ± 13.3 (P = 0.121). This study could not confirm appearance of paradoxical effects of N2O on BIS during inhalation induction of anesthesia in pediatrics.