Cerebral NIRS as a marker of superior vena cava oxygen saturation in neonates with congenital heart disease

Abstract

To investigate the correlation between cerebral near-infrared spectroscopy (NIRS) (rSO2c) and superior vena cava venous oxygen saturation (ScvO2) in newborn patients with congenital heart disease (CHD). NIRS is a noninvasive method to monitor hemoglobin oxygen saturation using nonpulsatile oximetry. We retrospectively analyzed perioperative data from 100 newborn patients who underwent cardiac surgery for CHD. rSO2c, ScvO2 from 24 h before to 72 h after surgery were recorded. rSO2c had a fair correlation with ScvO2 (r 0.37; P <0.001). The relationship between rSO2c and ScvO2 did not change when analyzed between patients with cyanotic or acyanotic CHD. During the preoperative period, rSO2c levels overestimated ScvO2; in the first 18 postoperative hours, rSO2c underestimated ScvO2; after that period, they showed very close trends. Hypocapnia caused rSO2c to underestimate ScvO2; in normocapnic patients, rSO2c-ScvO2 average differences were close to zero; in hypercapnic neonates, rSO2c tended to overestimate ScvO2. The best performance of rSO2c as a surrogate of ScvO2 was found in the venous saturation ranges from 40% to 60% (r 0.3, P: 0.03). rSO2c in newborn patients with cyanotic and acyanotic CHD provides a continuous noninvasive information with a fair correlation with ScvO2%: some predictable variables (i.e., time from surgery, carbon dioxide, and venous saturation levels), should guide the operators to adjust rSO2c values in terms of ScvO2. Serial measures of ScvO2 seem recommended to tailor rSO2c information on actual venous saturation percentage.