Predicting Fluid Responsiveness in on Pump Coronary Artery Bypass Graft Using Extra Systoles

Hypovolemia, Coronary Artery Disease, Fluid Overload

Fluid responsiveness, Perioperative, Extra systoles, Coronary artery bypass, Systolic arterial pressure

The purpose of this study is to determine if extra systoles can be used to predict fluid responsiveness perioperatively in patients undergoing on pump coronary artery bypass graft (CABG) surgery. As an additional study we will investigate the ability of a mini fluid challenge to predict response of a larger volume of fluid.

From induction of anaesthesia to cardioplegia we will serve two fluid challenges. Before and after each challenge we will collect hemodynamic data and use this to asses our two hypotheses. Fluid responsiveness (the outcome to predict) will be defined as a 15% increase in stroke volume(SV) from immediately before fluid infusion is initiated (baseline) to after the full fluid infusion. Stroke volume is derived from the gold-standard pulmonary artery catheter measurement of cardiac output(CO), which is standard monitoring for these patients (SV = CO/heart rate). From subsequent offline analysis of the extracted curve data we will investigate if post-ectopic characteristics from identified extra systoles during the baseline period can predict fluid responsiveness (i.e. the SV change). This analysis addresses the primary hypothesis. Also, we will analyse the arterial waveform related to the mini fluid challenge for morphologic changes (comparing heart beats before the infusion with heart beats during the infusion) and see if such transient changes, e.g. in systolic blood pressure, are able to predict fluid responsiveness. This analysis addresses the secondary hypothesis.

Denmark