From Dental to Mental Institutions: Elmer McKesson's Secondary Saturation with Nitrous Oxide.

As popularized by Elmer McKesson, MD, "secondary saturation" with nitrous oxide could expose patients to a second burst of 100% laughing gas to relax their muscles to assist surgeons. On rare occasions, this technique could provide a second opportunity for hypoxic brain damage and possible admission postoperatively to insane asylums.