Evaluation of Hemodynamics at Various Stages of Off-Pump Coronary Artery Bypass Surgery

Abstract

At the National Institute of Cardiovascular Surgery in 2018, we used impedance cardiography in 78 off-pump coro-nary artery bypass grafting (CABG) procedures. We used impedance cardiography for the cardiac index (CI), stroke vol-ume index (SVI), oxygen delivery index and systemic vascular resistance index (SVRI) monitoring. We implemented the “beating heart” surgery technique using compression-type stabilizer. This technique requires extensive monitoring of the patient’s hemodynamics at all stages of the intervention. CI decrease was found at the stage of anastomosis placement (from 3.22±0.11 to 2.83±0.32, р=0.251) accompanied by the SVI decrease (from 42.86±5.64 to 37.62±3.26) and SVRI increase (from 2619.5±154.2 to 2876.2±185, р=0.288). CI decrease was found at the stage of induction of anaesthesia from 3.97±0.38 to 2.46±0.32 (р=0.003). SVI changes from 42.86±5.64 to 37.62±3.26 (р=0.422) at the stage of distal anastomosis placement and from 47.28±4.35 to 34.50±3.45 (р=0.023) at the stage of induction of anaesthesia were directly proportional to that of CI. During the CI decrease, we found that SVRI increased at the same stages of the surgical intervention.

Conclusion. Impedance cardiography is a good opportunity to study hemodynamics, to manage volemic load and trends and to detect hemodynamic changes during off-pump CABG; it helps to avoid complications and urgent switch to cardio-pulmonary bypass. Impedance cardiography is useful for prediction of low cardiac output syndrome. Cardiac output moni-toring helps to maintain hemodynamic stability in patients during dislocation of the heart for grafting of the distal ends of the coronary anastomoses in off-pump CABG surgery. Our study shows usefulness of routine use of cardiac output monitoring in all cases of off-pump CABG.