A new, minimally invasive technique for measuring cardiac index: clinical comparison of continuous cardiac dynamic monitoring and pulmonary artery catheter methods.

To assess the utility of a relatively simple bedside method of estimating cardiac index during major surgery or in the intensive care unit, we conducted a prospective study in patients undergoing elective cardiac bypass surgery where a pulmonary artery catheter was inserted as part of routine monitoring. The cardiac index was estimated using standard techniques and compared with estimates from continuous cardiac dynamic monitoring using HEARTSMART software. Two hundred and seventy sets of measurements were suitable for comparison. The mean bias (95% limits of agreement), for the pre-bypass cardiac index was -0.09 (-1.26 to 1.08) l x min(-1) x m(-2), and post-bypass was 0.12 l x min(-1) x m(-2) (-1.32 to 1.56). These results suggest that continuous cardiac dynamic monitoring using HEARTSMART is sufficiently accurate for assessment of haemodynamic variables in critically ill patients, facilitating goal-directed therapies.