Changes in End-Tidal Carbon Dioxide Concentration during Controlled Bleeding

Abstract

Five adult dogs were bled at the rate of 40m1/kg per approximately 20 minutes. During the controlled bleeding, the end-tidal carbon dioxide concentration (ETCO₂) and the arterial carbon dioxide tension were measured. ETCO₂ decresed gradually with the increase of bleeding volume but PaCO₂ did not change. The results suggest that the decrease of ETCO₂ reflects the increase of bleeding volume than the decrese of PaCO₂ during the bleeding.