From Dental to Mental Institutions: A Quadruple Threat of Nitrous-Oxide Administration Before and During Mental Asylum Admission.

During the 19th century, patients undergoing anesthesia for surgical and dental procedures were at risk of being given hypoxic or dilute nitrous oxide on four separate occasions. Primary and secondary saturation during surgery could account for two administrations of 100% nitrous-oxide anesthesia, while both diagnostic and therapeutic doses of dilute nitrous oxide were frequently administered in mental asylums.