Purpose: Desflurane may be used to replace propofol at the end of anesthesia to facilitate rapid emergence. This study determined the effect of administering desflurane during emergence of anesthesia on middle cerebral artery blood flow velocity (Vmca) in children anesthetized with propofol.Methods: Thirty healthy children aged one to six years scheduled for orchidopexy or hypospadias repair under general anesthesia were enrolled. Anesthesia was maintained with a propofol infusion targeting an estimated serum level of 3 microg x mL(-1), remifentanil 0.2 microg x kg(-1) x min(-1) and a caudal epidural block. Transcranial Doppler sonography was used to measure Vmca at five-minute intervals. In half the patients, propofol was substituted with desflurane 1 MAC, 30 min prior to the end of the surgical procedure. Once steady-state had been achieved recordings of Vmca, heart rate, and mean arterial pressure were resumed. Upon termination of the surgical procedure, the maintenance agent was discontinued and recordings continued at one-minute intervals during emergence of anesthesia.Results: There were no demographic differences between the two groups. Vmca increased from 37.2 +/- 3.1 cm x sec(-1) to 57.7 +/- 4.1 cm x sec(-1) when propofol was changed to desflurane (P < 0.01). Upon emergence of anesthesia, Vmca decreased from 57.8 +/- 4.2 cm x sec(-1) to 37.8 +/- 3.2 cm x sec(-1) in the desflurane group (P < 0.01) but remained unchanged in the propofol group.Conclusion: Desflurane is associated with an increase in cerebral blood flow velocity when used to facilitate rapid emergence following a propofol infusion in children. This may be of clinical significance in patients with intracranial pathology.