Comparison of arterial and venous blood-gas values in anesthetized Dorset cross-bred lambs (Ovis aries) using a point-of-care analyzer.

Objective To determine the degree of agreement between arterial and venous blood gases in anesthetized lambs using a point-of-care analyzer. Study design Prospective experimental study. Animals A group of 12 female Dorset cross-bred lambs, weighing 37.3 +/- 7.4 kg (mean +/- standard deviation). Methods Lambs were anesthetized with isoflurane for catheterization of the jugular vein and femoral artery, and blood samples were collected simultaneously for analysis of pH, PCO2, PO2, base excess (BE), bicarbonate (HCO3-), total carbon dioxide (tCO(2)), oxygen saturation (SO2), ionized calcium (iCa) and potassium (K+) using the Vet Scan i-STAT handheld analyzer. The Bland-Altman method was used to calculate agreement between arterial and venous measurements. Results Strong agreement was identified between arterial and venous pH (bias = 0.04; 95% limits of agreement = 0.02-0.06), K+ (bias = -0.1 and 95% limits of agreement = -0.8 to 0.5) and iCa (bias = 0.04; 95% limits of agreement = -0.08 to 0.0003). There was poor agreement for PO2 (bias = 168.0; 95% limits of agreement = 77.4-258.7) and SO2 (bias = 9.1; 95% limits of agreement = 2.8-15.3), as these values were higher in arterial blood than in venous blood. Moderate agreement was present for BE (bias = 1.7; 95% limits of agreement = -2.7 to 6.1), PCO2 (bias = -2.1; 95% limits of agreement = -7.5 to 3.4), HCO3- (bias = 1.1; 95% limits of agreement = -3.1 to 5.3) and tCO(2) (bias = 1.0; 95% limits of agreement = -3.3 to 5.3). Conclusions and clinical relevance Venous blood can be used for the measurement of pH, K+ and iCa in anesthetized Dorset cross-bred lambs. Arterial blood is required for accurate measurement of PO2, SO2, PCO2, HCO3-, tCO(2) and BE to assess systemic blood oxygenation and pulmonary function in anesthetized Dorset cross-bred lambs.