Metabolic changes in avian blood and their effects on determination of blood gases and pH

Oxygen consumption. MO2 and CO2 production rates, Cco2, of duck blood samples anaerobically stored at 41 degrees C were 0.041 and 0.036 mMol (L blood)minus 1 min minus 1, respectively, and were independent of O2 saturation in the range of 100 to 10% saturation; the resulting metabolic respiratory quotient of blood was 0.88. The pH decreased linearly with time at a rate of 0.0014 unit min minus 1. The lactic acid production rate was independent of Po2, and was about 0.033 MMol L minus 1 min minus 1. Errors were assessed that may be introduced in blood gas analysis when the high metabolic activity of avian blood is not accounted for. Thus the O2 dissociation curve established using the Van Slyke analysis will be shifted to the right; however, the displacement around P50 is only about 1 torr for a time lag of 5 min between sampling and analysis and is even less at higher Po2 values. When using electrodes, P02 will be underestimated and PCO2 overestimated. The magnitude of these errors depends on both delay time and slope of the dissociation curves. It is concluded that the standard blood gas analytical methods are applicable to avian blood, but that in some cases corrections for metabolic effects are neccessary. Any delay between blood sampling and analysis should be kept as short as possible; storage, if neccessary, should be on ice.