The Impact of Systemic Vasoconstrictors on the Cerebral Circulation of Anesthetized Patients

Direct comparison of cerebrovascular effects of norepinephrine and dopamine in head-injured patients

“…Patients (seven males, three females) were aged 38 Ϯ 16 yrs. Median admission Glasgow Coma Scale score was 6 (range, [3][4][5][6][7][8][9]. Studies were performed on day 3.3 Ϯ 1.5 after injury.…”

Phenylephrine but not Ephedrine Reduces Frontal Lobe Oxygenation Following Anesthesia-Induced Hypotension

“…Although phenylephrine increases cerebral vascular tone in humans, it can increase [38] or has no influence [39] on cerebral vascular resistance. The use of phenylephrine increases CBF in cardiopulmonary bypass patients [40], healthy subjects [38], and anesthetized patients [41]. However, in other situations, CBF seems unaffected by phenylephrine [6].…”

Carbon dioxide reactivity, pressure autoregulation, and metabolic suppression reactivity after head injury: a transcranial Doppler study

“…Adrenergic agents appear to blunt the hypotensive effect of agents like propofol by causing peripheral vasoconstriction without significant direct cerebrovascular effects, even after head injury. In a TCD ultrasonography study by Strebel,et al,56 conducted in healthy individuals who were anesthetized with propofol, phenylephrine and norepinephrine had no effect on MCA flow velocity despite a 20% increase in MAP. In a cortical contusion injury study by Cherian, et al, 11 early postinjury infusion of phenylephrine increased CBF in the pericontusional area and contralateral hemisphere but only in proportion to the increase in MAP and CPP.…”