Rate of uptake of CO by hemoglobin in pig erythrocytes as a function of PO2

Te Nijenhuis, Francis C. A. M., Lydia Lin, Gerko H. Moens,Adrian Versprille, and Robert E. Forster. Rate of uptake of CO byhemoglobin in pig erythrocytes as a function ofPO₂. J. Appl.Physiol. 81(4): 1544-1549, 1996.This study wasinitiated to obtain data on the rate of carbon monoxide (CO) uptake(_CO) by hemoglobin in pigerythrocytes to derive, in a later study, the pulmonary capillary bloodvolume (Qc) in pigs from the Roughton-Forster relationship. Blood fromfive different female pigs was used. The_CO, the milliliters of CO takenup by 1 ml of whole blood per minute per Torr CO tension, wasdetermined on each blood sample with a continuous-flow rapid-mixingapparatus and double-beam spectrophotometry at 37°C and pH 7.4 atfour or five different PO₂ values.Because the individual regression lines of _CO vs.PO₂ were not significantly different,a common regression equation was calculated:1/_CO = 0.0084 PO₂ + 0.63. The slope of thisregression line is significantly steeper than the reported slopes ofthe regression lines for human and dog erythrocytes measured under thesame conditions. Our results revealed that calculation ofQc in pigs by using _CO valuesfor human or dog erythrocytes would result in an underestimation of 51 and 50%, respectively.