Cerebral "hyperoxygenation" with inhalational induction of anesthesia in children: a retrospective comparison between vasoparalytic sevoflurane vs. vasoneutral fentanyl.

Background: The higher levels of oxygen in cerebrum may contribute to neuro-apoptosis, analogous to direct tissue injury induced by toxic levels of oxygen. Earlier report highlighted the possibility of cerebral "hyperoxygenation" secondary to inhalational induction of anesthesia with sevoflurane in small number of children.

Objective: The aim of this retrospective review was whether similar cerebral "hyperoxygenation" trends can be seen in larger and retrospective patients' database.

Methods: Data of patients who had undergone cardiac surgeries at Children's Hospital during the two-year period (2010-2011) was retrieved during this retrospective review: (a) stored computer data from INVOS Cerebral/Somatic Oximeter for oximetry numbers and total duration of oximetry monitoring, (b) paper chart perfusion records of the cardiac surgeries for age and sex of the patient, urgency of the surgery, type of induction (inhalational or intravenous), and total duration of cardiopulmonary bypass, (c) general medical records for inpatient setting vs. outpatient setting of the patient, and (d) anesthesia medical records for name of the medications used during induction of anesthesia to segregate the patients who had fentanyl as a lone induction agent and sevoflurane as a lone induction agent, for final statistical calculations and analysis. For the two-year period (2010-2011), data of 358 patients who had cardiac surgeries at Children's Hospital were reviewed. However, after deletions of various patients' data due to various reasons, only 69 patients (0-4 years of age) who had sevoflurane induction were analyzed for final statistical comparisons to 14 patients (0-4 years of age) who had fentanyl induction.

Results: Cerebral and renal "hyperoxygenation" occurred during the first 127 minutes with sevoflurane as compared to fentanyl though the percentage changes from pre-induction values in oximetry during this time did not reach level of significance. However, only cerebral "hyperoxygenation" persisted in the last 127 minutes when patients had been induced with sevoflurane as compared to fentanyl.

Conclusion: Cerebral "hyperoxygenation" occurs with inhalational induction of anesthesia with vasoparalytic sevoflurane in children 0 to 4 years of age when compared to anesthesia induction with vasoneutral fentanyl.