Objective To investigate different gases and hematocrits on cerebral injury during deep hypothermic circulatory arrest (DHCA) in a piglet model including monitoring by near-infrared spectroscopy (NIRS). Methods Twenty-four piglets were assigned to 4 groups with respect to different blood gas and hematocrit during DHCA. Group A: hematocrit was maintained between 0.25 to 0.30, pH-stat strategy during cooling phases and alpha stat strategy in other phases; group B: hematocrit was maintained between 0.25 to 0.30 and alpha stat strategy; group C: hematocrit was maintained between 0.20 to 0.25, pH-stat strategy during cooling phases and alpha stat strategy in other phases; group D: hematocrit was maintained between 0.20 to 0.25 and alpha stat strategy. Cerebral oxygenations of piglets were monitored continuously by NIRS. The brain was fixed in situ at 6 hours after operation and a histological score for neurological injury was assessed. Results Oxygenated hemoglobin (HbO2) and total hemoglobin (HbT) signals detected by NIRS were significantly lower in group D than those in group A and group B during cooling (Plt;0.05). Oxygenated hemoglobin nadir time was significantly shorter in group A(Plt;0.05). All piglets with oxygenated hemoglobin signal nadir time less than 25 minutes were free from histological evidence of brain injury. Conclusion Combination of pH-stat strategy and higher hematocrit reduces neurological injury after DHCA.
ObjectiveTo evaluate the possibility of monitoring regional tissue oxygen saturation by near-infrared spectroscopy (NIRS) for early predicting adverse events in patients with pulmonary atresia.MethodsTwenty-six patients aged under 3 months who were diagnosed with pulmonary atresia and admitted to cardiovascular intensive care unit in our hospital between January 2016 and May 2017, accepted regional tissue oxygenation (cerebral and splanchnic) by near-infrared spectroscopy. There were 19 males and 7 females at age of 2–89 days. A total of 625 times of heart rate, blood pressure, pulse saturation, regional tissue oxygenation, and 98 serum lactate were retrospectively analyzed. The relationship of the tissue oxygen saturation and clinical adverse events was explored.ResultsThe adverse event by routine monitoring was 69 (11.04%) person-time: isolated hypoxia in 27, hypoxia combined increased lactate in 16, hypotension in 6, hypotension combined increased lactate in 17, isolated increased lactate in 3. A reduction of 12.80% in cranial oxygen predicted the high probability of adverse events, with a sensitivity of 85.30% and a specificity of 87.00%. A reduction of 20.60% in splanchnic oxygen predicted the high probability of adverse event, with a sensitivity of 73.50% and a specificity of 91.2%. On average, the splanchnic oxygenation had fell 3 minutes before a reduction of blood pressure, or 45 minutes before an increase in lactate.ConclusionFor preoperative patients with pulmonary atresia, a fall of 12.80% in cranial oxygen saturations, or of 20.60% in splanchnic oxygen saturation, should attract clinician’s awareness.