Effect of ephedrine and phenylephrine on brain oxygenation and microcirculation in anaesthetised patients with cerebral tumours: study protocol for a randomised controlled trial (original) (raw)
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Anesthesiology, 2020
Background Studies in anesthetized patients suggest that phenylephrine reduces regional cerebral oxygen saturation compared with ephedrine. The present study aimed to quantify the effects of phenylephrine and ephedrine on cerebral blood flow and cerebral metabolic rate of oxygen in brain tumor patients. The authors hypothesized that phenylephrine reduces cerebral metabolic rate of oxygen in selected brain regions compared with ephedrine. Methods In this double-blinded, randomized clinical trial, 24 anesthetized patients with brain tumors were randomly assigned to ephedrine or phenylephrine treatment. Positron emission tomography measurements of cerebral blood flow and cerebral metabolic rate of oxygen in peritumoral and normal contralateral regions were performed before and during vasopressor infusion. The primary endpoint was between-group difference in cerebral metabolic rate of oxygen. Secondary endpoints included changes in cerebral blood flow, oxygen extraction fraction, and re...
Neurocritical Care, 2019
Background 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 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. Methods In 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, de...
Trials, 2013
Background: Intraoperative arterial hypotension can lead to severe complications in patients undergoing carotid endarterectomy, in particular if cerebral auto-regulation is impaired. Short-acting agents, such as phenylephrine or ephedrine, commonly used to correct intra-operative hypotension, have different hemodynamic effects. Recently, it was reported that, in healthy anesthetized subjects with intact cerebral auto-regulation, frontal lobe cerebral tissue oxygenation declined after phenylephrine bolus administration, while it was preserved after ephedrine use (Br J Anaesth 107:209-217, 2011; Neurocrit Care 12:17-23, 2010). However, the effect of both agents in patients undergoing carotid endarterectomy is unknown. The aim of this study is to assess the effect of two routinely used vasopressors (phenylephrine and ephedrine) on the cerebral hemodynamics during carotid endarterectomy. Methods/design: Patients undergoing carotid endarterectomy will be prospectively included and randomized for correction of intraoperative hypotension with either phenylephrine (50 to 100 μg) or ephedrine (5 to 10 mg). If hypotension persists for more than five minutes after treatment, the patient will be classified as a non-responder and escape medication as preferred by the anesthesiologist will be administered. Changes in cerebral hemodynamics will be quantified by changes in transcranial Doppler-derived middle cerebral artery blood velocity and near infra-red spectroscopy-derived frontal lobe cerebral tissue oxygenation, when intra-operative hypotension is treated with phenylephrine or ephedrine in patients who undergo carotid endarterectomy with or without an adequate functioning cerebral auto-regulation. To quantify whether the intra-operative cerebral auto-regulation is impaired or not, a decrease in breathing frequency from the normal 12 breaths per minute to 6 breaths per minute for an episode of three minutes will be performed. Discussion: Phenylephrine and ephedrine are two of the most commonly used short-acting agents to increase blood pressure in clinical anesthesiologic practice. Monitoring of middle cerebral artery blood velocity with transcranial Doppler and frontal lobe cerebral tissue oxygenation with near infra-red spectroscopy are part of the standard of care. Furthermore, there are no reports that the three-minute modification in breathing frequency described in the "intervention"-section is harmful. Therefore, the risks for participating patients are negligible and the burden minimal. Trial registration: Clinical trials.gov: NCT01451294
European journal of anaesthesiology, 2015
Phenylephrine and norepinephrine are two vasopressors commonly used to counteract anaesthesia-induced hypotension. Their dissimilar working mechanisms may differentially affect the macro and microcirculation, and ultimately tissue oxygenation. We investigated the differential effect of phenylephrine and norepinephrine on the heart rate (HR), stroke volume (SV), cardiac index (CI), cerebral tissue oxygenation (SctO2) and peripheral tissue oxygenation (SptO2), and rate-pressure product (RPP). A randomised controlled study. Single-centre, University Medical Centre Groningen, The Netherlands. Sixty normovolaemic patients under balanced propofol/remifentanil anaesthesia. If the mean arterial pressure (MAP) dropped below 80% of the awake-state value, phenylephrine (100 μg + 0.5 μg kg min) or norepinephrine (10 μg + 0.05 μg kg min) was administered in a randomised fashion. MAP, HR, SV, CI, SctO2, SptO2 and rate-pressure product (RPP) analysed from 30 s before drug administration until 240 ...
Medicina (Kaunas, Lithuania), 2010
Hemodynamic effects during cerebral tumor resection surgery under monitoring the depth of anesthesia and during recovery in sevoflurane- or propofol-anesthetized patients have not been previously compared. To compare cerebral hemodynamic changes using transcranial Doppler sonography during sevoflurane or propofol anesthesia under state entropy (SE) monitoring, and during recovery period. In a randomized manner, 130 patients received sevoflurane (group T-S) or propofol (group T-P) to maintain SE at 40-50. Cerebral blood flow velocity (Vmean) in the middle cerebral artery was evaluated at baseline, after tracheal intubation, opening of the dura mater, tumor resection, skin closure, extubation, and two hours after extubation. Cerebrovascular resistance index (RAP), estimated cerebral perfusion pressure (eCPP), and cerebral blood flow index (CBFI) were calculated off-line. During surgery SE was 40.6 (SD, 8.1) in the group T-S and 44.0 (SD, 7.4) in the group T-P. Blood pressure was signi...
Anesthesia & Analgesia, 2002
Using computerized tomography, we measured absolute cerebral blood flow (CBF) and cerebral blood volume (CBV) in tumor, peri-tumor, and contralateral normal regions, at normocapnia and hypocapnia, in 16 rabbits with brain tumors (VX2 carcinoma), under isoflurane or propofol anesthesia. In both anesthetic groups, CBV and CBF were highest in the tumor region and lowest in the contralateral normal tissue. For isoflurane, a significant decrease in both CBV and CBF was observed in all tissue regions with hyperventilation (P Ͻ 0.05), but without accompanying changes in intracranial pressure. However, the percent reduction in regional CBF with hypocapnia was two times larger than that observed in the CBV response (P Ͻ 0.01). In contrast, there were no significant changes in CBV and
Anesthetics and cerebral metabolism
Current Opinion in Anaesthesiology, 2004
Purpose of review This review focuses on the utilization of the effects of general anesthetics on cerebral metabolism as revealed by imaging for therapeutic and preventive purposes, for understanding mechanisms of anesthetic action, and for elucidating mechanisms of cerebral processing in humans. Recent findings General anesthetics suppress cerebral metabolism significantly. This effect has been used for neuroprotection during inadequate cerebral blood flow. With the advent of noninvasive imaging techniques, this suppression has also been used to image and map the sites of anesthetic action in the living human brain. Volatile agents, intravenous anesthetics, and analgesics have all begun to be explored using mostly positron emission tomography. The ability of anesthetics to change global baseline brain metabolism has created the opportunity to examine the relevance of global baseline (resting) brain activity in terms of region-specific cerebral processing. Summary Anesthetics experimentally appear to be useful for neuroprotection, at least during the early post-ischemic period. Identification of the cerebral sites of anesthetic action by in vivo human brain imaging provides new insights into the mechanism of action of these agents. Anesthetic-related manipulation of baseline brain metabolism demonstrates the significant contribution of this global activity to regional cerebral processing.
Critical Care Medicine, 2000
To study the effects of highdose epinephrine, compared with standard-dose epinephrine, on the dynamics of superficial cortical cerebral blood flow as well as global cerebral oxygenation during experimental cardiopulmonary resuscitation. We hypothesized that high-dose epinephrine might be unable to improve cerebral blood flow during cardiopulmonary resuscitation as compared with standarddose epinephrine. Design: Randomized controlled study. Setting: University hospital research laboratory. Subjects: A total of 20 male anesthetized piglets. Interventions: Ventricular fibrillation was induced. A nonintervention interval of 8 mins was followed by open-chest cardiopulmonary resuscitation. The animals were randomized to receive repeated bolus injections of either 20 μ g/kg (standard-dose group, n = 10) or 200 μ g/kg (high-dose group, n = 10) of epinephrine. Measurements and Main Results: Focal cortical cerebral blood flow was measured continuously by using laser Doppler flowmetry. The duration of blood flow increase was significantly shorter in the high-dose group after the second dose of epinephrine. In the high-dose group there was also a consistent tendency for lower peak levels and shorter duration of flow increase in response to repeated bolus doses of epinephrine. Cerebral oxygen extraction ratio was significantly lower in the high-dose group after administration of epinephrine. Conclusions: Repeated bolus doses of epinephrine 200 μ g/kg, as compared with 20 μg/kg, do not improve superficial cortical cerebral blood flow during experimental open-chest cardiopulmonary resuscitation. High-dose epinephrine appears to induce vasoconstriction of cortical cerebral blood vessels resulting in redistribution of blood flow from superficial cortex. This might be one explanation for the failure of highdose epinephrine to improve overall outcome in clinical trials.
IP Innovative Publication Pvt. Ltd., 2017
Introduction: Sevoflurane, and Propofol are widely used for anesthesia during intracranial surgery. All these drugs reduce the cerebral metabolic rate (CMR) for oxygen (CMRO 2). In contrast to their similar effect on cerebral metabolism, they have different effects on cerebral blood flow (CBF). Accordingly, the purpose of our study was to determine the jugular bulb venous blood oxygen saturation (SjO 2) as a measure of the flow metabolism ratio under propofol & sevoflurane anesthesia in patients with intracranial mass lesions. Objectives: To compare the effects of Sevoflurane & Propofol on jugular bulb oxygen saturation with the help of evaluation of arterial and jugular bulb venous blood samples for hemoglobin (Hb), hematocrit, and blood gas analysis using automated blood gas analyzer & Calculation of arterial to jugular bulb venous oxygen content differences (AJDO 2). Materials and Method: The proposed study is being carried out in S.R.N. Hospital associated with M.L.N. Medical College, Allahabad after obtaining clearance from the Ethical Comittee. A total of 40 patients were included in the study, of ASA Grade 1 & 2, who after randomisation were divided into 2 groups of 20 each, receiving Propofol & Sevoflurane respectively. Statistical Test: Data was analysed using unpaired t test with the help of SPSS software. Results: Propofol when compared with Sevoflurane, decreased Jugular Bulb Oxygen saturation (SjO 2) & this difference was statistically significant(49.25±6.57 Vs. 55.60±3.33), decreased PjO2(28.9±2.31 VS 33.15±2.08) & increased AjDO 2 (6.62±1.70 VS 5.75±0.81) to a more significant level(p value < 0.05).Further details will be discussed later in the presentation. Conclusion: In conclusion, brain tumor patients under propofol anesthesia, showed SjO 2 and PjO 2 levels that were significantly lower than those in patients under Sevoflurane anesthesia. Thus in brain tumour patients, in the already compromised brain tissue it is advisable to use Sevoflurane for maintenance of anaesthesia so as to preserve the flow metabolism ratio.