| Abstract: | Oxygen transport data, prospectively collected from 52 critically ill children, were analyzed to determine whether any derived variable accurately estimated intrapulmonary shunt (Qsp/Qt). Arterial hemoglobin saturation was more closely correlated with Qsp/Qt than was PaO2, alveolar-arterial oxygen gradient, arterial mixed venous oxygen difference (Ca-v]O2), arterial/alveolar oxygen ratio, and the ratio of PaO2 to inspired oxygen (FIO2) (r = 0.8, p less than .0001). When C(a-v)O2 was normal, hemoglobin saturation became a very accurate (r = 0.96) assessment of Qsp/Qt. We conclude that various arterial blood gas derived variables do not accurately reflect Qsp/Qt in critically ill children. In these patients, a pulmonary artery catheter is needed to accurately assess intrapulmonary shunt. |
