Preserved CO2 Reactivity and Increase in Middle Cerebral Arterial Blood Flow Velocity During Laparoscopic Surgery in Children

Abstract

In adult patients, the creation of pneumoperitoneum (PP) by means of carbon dioxide (CO2) insufflation leads to an increase in cerebral blood flow velocity (CBFV), which is thought to be caused by hypercapnia. We evaluated whether PP leads to an increase of CBFV in children, and whether this increase is directly related to PP. The effects of PP on middle cerebral artery blood flow velocity were investigated in 12 children (mean age 3 yr, range 15–63 mo) undergoing laparoscopic herniorrhaphy under general anesthesia with sevoflurane and nitrous oxide/oxygen. CBFV was measured by using transcranial Doppler ultrasonography. During CO2 insufflation, the end-tidal CO2 concentration was kept constant by adjustment of ventilation by increasing minute volume. The CBFV increased significantly at an intraabdominal pressure of 12 mm Hg compared with baseline from 68 ± 11 cm/s to 81 ± 12 cm/s (P < 0.05). CO2 reactivity remained in the normal range (4.0% ± 1.9%/mm Hg) during PP. We conclude that the induction of PP leads to an increase in middle cerebral artery blood flow velocity in young children independent from hypercapnia, whereas CO2 reactivity remains normal.