Introduction: Due to the increased risk of neurological complications related to cardiac surgery and extracorporeal circulation, monitoring of cerebral oxygenation during these procedures is highly significant. However the risk of complications is also noted during off-pump surgery. The use of continuous non-invasive cerebral oxygenation monitoring with near-infrared spectroscopy may affect the postoperative patient condition and ICU and hospital length stay .
Method: 42 patients with good heart function chosen for off-pump CABG operations were included for the study, having local ethical committee approval and patient informed consent. Patients were randomized and divided into two groups of 21, control (C) and investigated (I). Group I patients had bilateral frontal electrodes to measure rSO2 using INVOS 4100 apparatus (Somanetics). Values of rSO2 ≥75% compared to the pre-induction value was maintained by using blood pressure elevation (fluids and medicaments), PaCO2 change and surgical technique modification (stabilizer position). The anaesthetic method was the same for both groups. Artificial ventilation time, ICU and hospital length of stay, serious neurological complications after the operation and frequency of necessary rSO2 elevation interventions in group I were observed. ANOVA and Student's t- tests were used.
Results: Both groups were homogeneous regarding age, sex, number of bypasses and operation time. Artificial ventilation after the operation (5.7h vs. 11.9 h in group C P < 0.05), ICU (47.2 h vs. 58.2 h in group C P < 0.05) and hospital length stay (6.8 day vs. 8.4 day in group C P < 0.05) were various. There was one ischaemic stroke in group C. There were no deaths. There were rSO2 interventions in 50% of group I.
Discussion: The posterior heart wall exposure by the surgeon during the off-pump procedure often leads to transient episodes of CVP elevation and blood pressure decrease and as a result, perfusion pressure drops and cerebral oxygenation decreases . Typical ICU extubation criteria were chosen after the operation and ICU stay length was related to the patient's condition. Due to the use of INVOS 4100 and cooperation with the surgeon the reduction of postoperative ICU stay may lead to a shorter hospital length of stay. Possible economic benefit and decrease of neurological complications such as frequency of stroke and the degree of cognitive dysfunction in off-pump operations using cerebral oxygenation monitoring requires further investigations.
1 Mark DB, Newman MF. Protecting the brain in coronary artery bypass graft surgery. JAMA
2 Van Dijk D, Jansen EW, Hijman R, et al. Cognitive outcome after off-pump and onpump coronary artery bypass graft surgery: a randomized trial. JAMA