Table 1.

Arterial oxygen tension (PaO₂) and arterial carbon dioxide tension (PaCO₂) in mmHg measured 5 min before etorphine and 2 min before naltrexone administration (Pre) and 5 min after each respective drug (Post).

Etorphine	PaO2	PaCO2
Pre	98.1 (82.9–105.5)	41.7 (33.4–47.2)
Post	57.1 (26.9–93.6)	49.45 (40–61.3)

Naltrexone	PaO2	PaCO2
Pre	43.2 (30.5–61.9)	64.4 (57.6–68.9)
Post	63.5 (48.6–115.7)	46 (41.5–52.4)

Data are presented as median and range.