Correspondence  |   June 2018
In Reply
Author Notes
  • Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa (R.I.B.). robert-block@uiowa.edu
  • (Accepted for publication March 9, 2018.)
    (Accepted for publication March 9, 2018.)×
Article Information
Correspondence
Correspondence   |   June 2018
In Reply
Anesthesiology 6 2018, Vol.128, 1261. doi:10.1097/ALN.0000000000002212
Anesthesiology 6 2018, Vol.128, 1261. doi:10.1097/ALN.0000000000002212
We thank Dr. Hogan for his interest in our article1  and for offering his interpretation of our findings. He is correct that 94% of our subjects exposed to general anesthesia received nitrous oxide. However, the duration of nitrous oxide exposure was variable and often brief. During the time that our cohort of subjects underwent their surgical procedures as infants, it was a common and prevailing practice at our study site to use nitrous oxide during induction only and discontinue it during maintenance. All subjects who received nitrous oxide also received one or more other anesthetics during their surgery. Therefore, our study findings cannot be attributed to the effect of nitrous oxide alone. Although we accept Hogan’s statement that nitrous oxide may inactivate methionine synthase, the only evidence that he cites that nitrous oxide causes demyelination, cerebral atrophy, and loss of developmental milestones is his own case report of a single child with 5,10-methylenetetrahydrofolate reductase deficiency.2