Endogenous production of carbon monoxide as measured simultaneously in blood and gas phase

Endogenous carbon monoxide (CO) production rates and total body haemoglobin content were determined simultaneously in blood and gas phase in 15 individuals. At 24% oxygen (O2) concentration in the closed rebreathing system, a correlation was obtained which revealed that a 1 mumole rise in CO in the gas phase of the system was the result of 48.94 +/- 5.3 (SE) mumoles of CO rise in the body. Three individuals had heat-damaged red cells reinjected intravenously to determine if the recovery rate of the subsequently produced CO was proportionate in both the gas phase and blood phase. Changes in blood CO concentration were not consistently detected by gas phase analysis. Prediction of CO production rates utilizing gas phase data alone did not reflect accurately CO production rates determined from blood carboxyhaemoglobin rises.