The Role of Regional Oxygen Saturation Using Near-Infrared Spectroscopy and Blood Lactate Levels as Early Predictors of Outcome After Pediatric Cardiac Surgery

Background The purpose of the study was to evaluate the association between regional oxygen saturation (rSO2) desaturation score (calculated by multiplying the rSO2 < 50% by time in seconds the preoperative baseline value) measured with near-infrared spectroscopy and the peak of lactate with postoperative major morbidities in pediatric patients who undergo cardiac surgery. Methods We retrospectively analyzed the postoperative course of 152 patients between January 2012 and December 2013, for whom we continuously monitored cerebral rSO2 using near-infrared spectroscopy and serial arterial blood lactate levels for at least 48 hours. Results The median age at surgery was 128 days (interquartile range [IQR], 17-537 days). Thirty-nine patients had a single ventricle physiology (26%) and 135 patients (89%) required the use of cardiopulmonary bypass (median time of 130 minutes; IQR, 93-172 minutes). Median postoperative peak lactate level was 3 mmol/L (IQR, 2-5.3 mmol/L); 52 patients (34%) had a postoperative lactate level > 4.6 mmol/L. The median postoperative rSO2 desaturation score was 157 (IQR, 0-2050); 62 patients (41%) had an rSO2 desaturation score > 345. Fifty-seven patients (37%) had postoperative major morbidities. Using a multivariable regression model only rSO2 desaturation score > 345 was independently associated with major morbidities after surgery (odds ratio, 27.26; 95% confidence interval, 10.18-73.00). The proportion of patients with an rSO2 desaturation score > 345 within 240 minutes after surgery was higher than the rate of those who showed a peak of lactate > 4.6 mmol/L (84% vs 59%; P = 0.05). Conclusions The postoperative rSO2 desaturation score has a stronger association with major postoperative morbidities than lactate and it also provides an earlier warning sign of hemodynamic or metabolic compromise.