Evaluation of haemodynamic and oxygen-derived parameters to predict outcome in patients with acute heart failure

Study objective: To evaluate the value of haemodynamic and oxygen-derived parameters in predicting outcome of patients admitted to the intensive care unit with acute heart failure (AHF). Design: Retrospective cohort study design. Patients: One hundred and forty-two patients hospitalised for AHF between 1983 and 1990 with cardiac index (CI) < 2.8 l/min/M2 and pulmonary artery wedge pressure (PAWP) > 18 mmHg. Patients with evidence of sepsis were excluded. Measurements: All 142 patients underwent pulmonary artery catheterisation at admission (T0). Haemodynamic and oxygen-derived parameters were obtained during the first two days following admission (T2) in 66 of the 142 patients. Results: At T0 similar results were observed both in the whole population (n=142) and in the subgroup of patients followed during the first two days. Left ventricular stroke work index (LVSWI) and mean arterial pressure (MAP) were significantly higher and heart rate (HR) lower in the group of patients who survived (group S) than in the group of patients who died (group NS). CI and oxygen-derived parameters did not differ in either whole or subgroups for S and NS. From T0 to T2 a parallel increase in oxygen delivery (DO2) was observed in groups S and NS. A significant decrease in oxygen extraction ratio (O2ER) was simultaneously observed in group S. At T2 LVSWI, MAP, DO2 and mixed venous oxygen saturation (SvO2) were significantly higher while HR and O2ER were lower in group S than in group NS. The presence of an O2ER < 35% at T2 was associated with the best outcome (predictive value of survival 81%). CI did not differ between groups. Conclusion: CI is neither a good indicator of the severity of cardiovascular dysfunction on admission nor a relevant therapeutic goal in the setting of AHF. At admission LVSWI, MAP and HR are the best indicators for outcome prediction in patients with AHF. After two days of treatment LVSWI, MAP, DO2, SvO2 and O2ER are the most relevant parameters for predicting outcome. In patients suffering from AHF a therapeutic regimen able to decrease O2ER below 35% could be an appropriate therapeutic goal to improve outcome.