Blood gases, pH and hematology of montane and lowland coot embryos

Blood gases, air cell-blood gas differences, blood pH, and hematology were compared in embryonic coots (Fulica americana peruviana) at 4150 m and sea level in Peru. Neither arterialized nor venous O₂ tensions differed significantly between montane and lowland groups but blood CO₂ tensions of the two groups differed significantly. The air cell P_O2-arterialized blood P_O2 difference of montane eggs was less than half the value in lowland eggs. Both arterialized and venous CO₂ tensions differed substantially between montane and lowland groups. Despite these differences, plasma pH at both altitudes was statistically indistinguishable due in part to variation in plasma [HCO₃^-]. Hematocrits of montane embryos were significantly higher than that of their lowland counterparts.