Abstract
BackgroundShort-acting vasopressor agents like phenylephrine or ephedrine can be used during carotid endarterectomy (CEA) to achieve adequate blood pressure (BP) to prevent periprocedural stroke by preserving the cerebral perfusion. Previous studies in healthy subjects showed that these vasopressors also affected the frontal lobe cerebral tissue oxygenation (rSO2) with a decrease after administration of phenylephrine. This decrease is unwarranted in patients with jeopardized cerebral perfusion, like CEA patients. The study aimed to evaluate the impact of both phenylephrine and ephedrine on the rSO2 during CEA.MethodsIn this double-blinded randomized controlled trial, 29 patients with symptomatic carotid artery stenosis underwent CEA under volatile general anesthesia in a tertiary referral medical center. Patients were preoperative allocated randomly (1:1) for receiving either phenylephrine (50 µg; n = 14) or ephedrine (5 mg; n = 15) in case intraoperative hypotension occurred, defined as a decreased mean arterial pressure (MAP) ≥ 20% compared to (awake) baseline. Intraoperative MAP was measured by an intra-arterial cannula placed in the radial artery. After administration, the MAP, cardiac output (CO), heart rate (HR), stroke volume, and rSO2 both ipsilateral and contralateral were measured. The timeframe for data analysis was 120 s before, until 600 s after administration.ResultsBoth phenylephrine (70 ± 9 to 101 ± 22 mmHg; p < 0.001; mean ± SD) and ephedrine (75 ± 11 mmHg to 122 ± 22 mmHg; p < 0.001) adequately restored MAP. After administration, HR did not change significantly over time, and CO increased 19% for both phenylephrine and ephedrine. rSO2 ipsilateral and contralateral did not change significantly after administration at 300 and 600 s for either phenylephrine or ephedrine (phenylephrine 73%, 73%, 73% and 73%, 73%, 74%; ephedrine 72%, 73%, 73% and 75%, 74%, 74%).ConclusionsWithin this randomized prospective study, MAP correction by either phenylephrine or ephedrine showed to be equally effective in maintaining rSO2 in patients who underwent CEA.Clinical Trial Registration ClincalTrials.gov, NCT01451294.
Highlights
In most patients scheduled for carotid endarterectomy (CEA), both baroreflex sensitivity (BRS) and cerebral autoregulation (CA) are impaired [1, 2]
This results in blood pressure (BP) fluctuations that cannot be counter-regulated by the brain vasculature [3]
Despite that both vasopressor agents effectively elevate mean arterial pressure (MAP), there is mounting evidence that frontal lobe cerebral tissue oxygenation (rSO2), measured by near-infrared spectroscopy (NIRS), decreases during the administration of phenylephrine while it remains unaffected during ephedrine use [6, 7]
Summary
In most patients scheduled for carotid endarterectomy (CEA), both baroreflex sensitivity (BRS) and cerebral autoregulation (CA) are impaired [1, 2]. Short-acting vasopressors like phenylephrine or a combined vasopressor and positive inotropic agent like ephedrine are administered in relatively large quantities Despite that both vasopressor agents effectively elevate MAP, there is mounting evidence that frontal lobe cerebral tissue oxygenation (rSO2), measured by near-infrared spectroscopy (NIRS), decreases during the administration of phenylephrine while it remains unaffected during ephedrine use [6, 7]. Short-acting vasopressor agents like phenylephrine or ephedrine can be used during carotid endarterectomy (CEA) to achieve adequate blood pressure (BP) to prevent periprocedural stroke by preserving the cerebral perfusion. Previous studies in healthy subjects showed that these vasopressors affected the frontal lobe cerebral tissue oxygenation (rSO2) with a decrease after administration of phenylephrine.
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