Effect of labetalol on cerebral blood flow, oxygen metabolism and autoregulation in healthy humans

Abstract

We have studied the effects of labetalol on cerebral blood flow (CBF) and cerebral oxygen metabolism (CMRO2) in eight healthy volunteers. CBF was measured by single photon emission computerized tomography before and during infusion of labetalol. CMRO2 was calculated as CBF x cerebral arteriovenous oxygen content difference (CaO2-CvO2). CBF autoregulation was tested during infusion of labetalol by changing arterial pressure and estimating relative changes in global CBF from changes in (CaO2-CvO2). CBF before and during infusion of labetalol was 67 and 65 ml/100 g min-1, respectively (P > 0.05). CMRO2 was 2.9 and 2.8 ml/100 g min-1, respectively (P > 0.05). CBF autoregulation was preserved in all subjects. The lower limit of CBF autoregulation was 88 mm Hg (94% of baseline mean arterial pressure). We conclude that labetalol did not influence global or regional CBF, or CMRO2, and CBF autoregulation was preserved.

Cerebral oximetry desaturation during shoulder surgery performed in a sitting position under regional anesthesia

“…6 Below the lower limit of the autoregulatory plateau, cerebral blood flow is reported to be related linearly to cerebral perfusion pressure, 16 and controlled hypotension may induce cerebral hypoperfusion. However, despite frequent hypotension, the low incidence of cerebral desaturation (0.77% of time intervals) suggests that adequate cerebral perfusion was generally maintained.…”

Antihypertensive Therapy Increases Cerebral Blood Flow and Carotid Distensibility in Hypertensive Elderly Subjects

“…[7][8][9][10][11][12][13] However, the effects of these medications on cerebral blood flow during orthostatic stress have not been established, particularly in elderly patients with systolic hypertension.…”

Comparison of effect of Labetalol and fentanyl with only fentanyl for attenuating pressure responses to intubation and skull pin insertion in neurosurgery

“…Labetalol did not influence global or regional cerebral blood flow or cerebral oxygen metabolism and cerebral blood flow and auto regulation is presereved even with dose as high as 1 mg/kg. 20 We used 0.25mg/kg labetalol before 5 minutes of intubation and found HR, SBP, DBP and MAP below baseline at all time including immediately after intubation and pin insertion. In group F HR and MAP was significantly raised but was within higher normal range suggesting that fentanyl also had attenuated pressure response but in labetalol group it was better controlled.…”

“…Moreover this drug targets 5-10 times more specific beta blockade 11,23 and prevent rebound hypertension and tachycardia. 20,10 Researchers used Labetalol and nitroprusside to induce hypotension in major surgeries and showed that nitroprusside significantly increased the heart rate but cardiac output remain unchanged with labetalol administration. 11 The arterial hypertension is due to increase in cardiac output rather than increase in systemic vascular resistance.…”