A

Nitrous oxide is a very weak anesthetic (MAC ≈ 105 %), so surgical anesthesia would require concentrations well above 70 %, leaving < 30 % oxygen in the inspired gas and causing unacceptable hypoxia; therefore it cannot be used as the sole general anesthetic agent [Hornbein, 1982, PMID 7201254; Hopkins, 2005, PMID 16013688].