Transcranial Doppler sonography and internal jugular bulb saturation during hyperventilation in patients with fulminant hepatic failure

Mechanical hyperventilation is often used to postpone or ameliorate intracr anial hypertension in patients with fulminant hepatic failure (FHF), Becaus e such treatment may critically reduce cerebral blood flow (CBF), bedside t echniques to monitor CBF are warranted. In this study, we evaluated the eff icacy of transcranial Doppler (TCD) sonography of the middle cerebral arter y (MCA) and internal jugular bulb saturation (svJO(2)) to determine relativ e changes in CBF during mechanical hyperventilation in 8 patients with FHF (median age, 40 years; range, 20 to 54 years), We found that TCD and svJo(2 ) decreased during hyperventilation in parallel with CBF, determined by the xenon 133 (Xe-133) washout technique. Quantitatively, the TCD method was l ess accurate to determine carbon dioxide (Co-2) reactivity compared with sv Jo(2) and the Xe-133 technique. This indicates a slight change in MCA diame ter during hyperventilation. We conclude that TCD and svJo(2) monitoring ma y give valuable information on relative changes in CBF during hyperventilat ion, However, the TCD method appears less accurate for quantitative estimat ion of Co-2, reactivity in patients with FHF.