Cyclopropane and helium.
D000698:Analgesia; D000758:Anesthesia; D000760:Anesthesia and Analgesia; D003521:Cyclopropanes; D006371:Helium
D003521:Cyclopropanes; D006371:Helium; C030797:cyclopropane
CYCLOPROPANE/anesthesia and analgesia; HELIUM