Cerebral Oxymeter Changes and Clinical Outcomes at Different Hypothermic Levels During Cardiopulmonary Bypass in Pediatric Patients

Introduction: Cardiopulmonary bypass (CPB) may not provide sufficient tissue perfusion. Hypothermia is used to protect the organs, especially the brain and heart, from this perfusion insufficiency. We investigated the effect of different hypothermic levels on cerebral oxygenation during CPB by using a cerebral oxymeter. Patients and Methods: The study included 30 consecutive pediatric patients with congenital heart disease who were planned to be operated on in the year 2012. The mean age was 41.83 ± 39.96 months (2-156 months), with 19 males. Children were divided into three groups by different hypothermic levels at CPB (32°C, 30°C, and 28°C). The measurements were made five times: before anesthesia induction (baseline values), during cooling (34°C), at the coldest value (first group 32°C, second group 30°C, third group 28°C), during rewarming (34°C), and at the end of rewarming (37°C-38°C). Cerebral-oxygen saturation, arterial-oxygen saturation, arterial carbon dioxide pressure, mean arterial pressure, pH, lactate, base excess, and hematocrit measurements were made for all patients, and mean values were calculated for each group. Results: There were no significant differences between the 32°C, 30°C, and 28°C groups (p> 0.05). When comparing change in cerebral-oxygen saturation values with the other parameters’ changes between the periods, mean arterial pressure, and hematocrit changes showed noteworthy similarities. However, no relationship had been found between the other parameters and cerebral-oxygen saturation. Conclusion: In our study, it was observed that cerebral oxygenation had not changed significantly at different hypothermic degrees of moderate levels during CPB. The highest temperature level of moderate hypothermic degrees (32°C instead of 28°C) was secure enough. This might be more advantageous to avoid the possible negative effects of hypothermia. Close monitoring of the cerebral oxygenation with cerebral oximetry may play an important role in ensuring patients’ safety