Bioreactance and arterial waveform analyses compared with bolus thermodilution cardiac output in high-risk surgeries

Monitoring cardiac function is essential when treating critically ill patients and patients undergoing high-risk surgeries. The gold standard for cardiac output monitoring is bolus thermodilution technique with pulmonary artery catheter. However, it is an invasive technique and can cause harm to patients. Therefore less invasive monitors have been developed. They are safer to use, but the results about their reliability are conflicting.

The aim of this study was to evaluate the interchangeability of less invasive cardiac output monitors with bolus thermodilution technique with pulmonary artery catheter in high-risk surgeries. The study monitors were a non-invasive bioreactance based device and two mini-invasive monitors based on arterial waveform analyses. The monitors were compared in the following high-risk surgeries: off-pump coronary artery bypass surgery, cardiac surgery with cardiopulmonary bypass and cytoreductive abdominal surgery with hyperthermic intraperitoneal chemotherapy.

The results showed, that the less invasive cardiac output monitors were not interchangeable with bolus thermodilution technique in measuring cardiac output. In addition to inaccuracy and imprecision, the less invasive monitors were not able to track changes in cardiac function reliably. In conclusion, the less invasive monitors were not reliable in monitoring cardiac output. Their use cannot be recommended in these high-risk surgeries.