Effect of End-Tidal Carbon Dioxide on Cerebral Dynamics in Infants With Ventricular Septal Defect: A Comparison Between Sevoflurane and Intravenous Anesthetics

Abstract

The primary aim was to compare the changes in regional cerebral oxygen saturation (rSO2) and cerebral blood flow velocity (CBFV) during sevoflurane and intravenous anesthesia when the end-tidal carbon dioxide partial pressure (PETCO2) changed in infants undergoing ventricular septal defect (VSD) repair. Prospective, observational study. Tertiary care hospital. Patients younger than 6 months with VSDs. End-tidal carbon dioxide was increased by decreasing tidal volume or respiratory rate. The infants were randomly assigned to receive either sevoflurane (SA group) or midazolam-sufentanil based intravenous anesthesia (IA group). PETCO2 levels of 30 mmHg (T1), 35 mmHg (T2), 40 mmHg (T3), or 45 mmHg (T4) were obtained by adjusting the tidal volume and respiratory rate. There were no significant intergroup differences in rSO2. In the SA group, as PETCO2 increased from T1 to T4, rSO2 increased significantly from 68.8% ± 5.9% to 76.4% ± 6.0% (p < 0.001). CBFV increased linearly, whereas the pulsatility index and resistance index decreased linearly from T1 to T4 (p < 0.001). In the IA group, rSO2 showed a significant increase from 68.6% ± 4.6% to 76.1% ± 6.2% with the change in PETCO2 from T1 to T4 (p < 0.001). CBFV increased linearly, whereas the pulsatility index and resistance index decreased linearly from T1 to T4 (p < 0.001). Cerebrovascular response to different PETCO2 levels was preserved and similar during clinically relevant doses of sevoflurane anesthesia and midazolam-sufentanil based intravenous anesthesia in infants younger than 6 months old undergoing VSD repair.