Regional myocardial oxygenation during surgical revascularisation

The aim of the study was to assess changes in myocardial oxygenation in patients with ischaemic heart disease during surgical revascularisation. In 20 patients, regional oxygen saturation, oxyhaemoglobin and total haemoglobin concentrations were examined by near-infrared spectroscopy in the myocardium and in a non-ischaemic skeletal muscle, which served as a control. Pre-revascularisation values of all spectroscopy parameters were 40-50% lower in the myocardium than in the control. After successful revascularisation O(2) saturation, oxy-, and total haemoglobin in the myocardium increased by 20, 29, and 18%, respectively (P<0.01). A negative correlation was found between aorta cross-clamping time and the post-operative increase in the myocardial O(2) saturation. In the control muscle and in a patient with incomplete revascularisation the regional O(2) saturation decreased. This preliminary report indicates potential value of the near infrared spectroscopy in an immediate assessment of postoperative changes in myocardial perfusion and oxygenation.