The Effect of Blood Pressure on Cerebral Perfusion During Vascular Surgery
The Effect of Blood Pressure on Cerebral Perfusion and Oxygenation During Vascular Surgery
Studie Overzicht
Toestand
Interventie / Behandeling
Gedetailleerde beschrijving
Background: Induction of anesthesia reduces mean arterial pressure (MAP) and cerebral blood flow is normally considered to be maintained by cerebral autoregulation despite changes in MAP between 60 - 150 mmHg and standard of care during anesthesia is to maintain MAP above 60 mmHg. Vascular surgical patients are often elderly with hypertension and atherosclerotic manifestations that may impair cerebral autoregulation of importance for anesthesia-induced reduction in blood pressure.
Objective: To assess the effect of MAP for preservation of cerebral blood flow and oxygenation during vascular surgery.
Hypothesis: The primary hypothesis is that during general anesthesia in vascular surgical patients, cerebral blood flow velocity and oxygenation is higher with MAP maintained at 80-90 mmHg, compared with a MAP maintained at a minimum of 60 mmHg.
MAP is controlled in both groups using continuous infusion of phenylephrine. Phenylephrine is used as a tool in order to assess the effect of MAP on the cerebral circulation. In both groups, central blood volume is optimized by infusion of lactated Ringer´s solution using a goal directed fluid therapy following induction of anaesthesia and before commencement of phenylephrine infusion.
Trial size: The investigators will include 40 participants (2 x 20) in order to detect or reject a 20% difference in middle cerebral artery velocity with a type I error risk of 5% and a type II error risk of 20% (power at 80%). Interim analysis will be conducted after inclusion of 20 patients (2 x 10). Excluded patients will be replaced.
Studietype
Fase
- Niet toepasbaar
Contacten en locaties
Studie Locaties
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Copenhagen Ø, Denemarken, 2100
- Rigshospitalet, Anæstesi og Operationsklinikken 2043
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Deelname Criteria
Geschiktheidscriteria
Leeftijden die in aanmerking komen voor studie
Accepteert gezonde vrijwilligers
Geslachten die in aanmerking komen voor studie
Beschrijving
Inclusion Criteria:
- Patients undergoing one of the following vascular surgical interventions in general anesthesia: Infra-inguinal bypass, femoro-femoral cross-over bypass or iliofemoral bypass surgery.
- Age > 18 years. Informed consent
Exclusion Criteria:
- Use of monoamine oxidase inhibitors
- Allergy to phenylephrine
- Patients that cannot cooperate during examination
- Dementia defined as Mini-Mental State Examination < 24
- Anesthesia within the last 30 days
- Alcohol consumption at or above 420 grams per week
- Lack of fluency in written and spoken Danish
- Severe hearing and vision impairment
- Neurological disease
Studie plan
Hoe is de studie opgezet?
Ontwerpdetails
- Primair doel: Ondersteunende zorg
- Toewijzing: Gerandomiseerd
- Interventioneel model: Parallelle opdracht
- Masker: Verdrievoudigen
Wapens en interventies
Deelnemersgroep / Arm |
Interventie / Behandeling |
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Experimenteel: MAP maintained at 80 mmHg
During anesthesia MAP is maintained at 80 - 90 mmHg MAP using continuous infusion of phenylephrine.
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Intervention group, MAP is maintained at 80 - 90 mmHg during anesthesia using continuous infusion of phenylephrine.
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Actieve vergelijker: MAP maintained at 60 mmHg
During anesthesia MAP is maintained at minimum of 60 mmHg using continuous infusion of phenylephrine.
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Control group, MAP is maintained at minimum of 60 mmHg during anesthesia using continuous infusion of phenylephrine.
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Wat meet het onderzoek?
Primaire uitkomstmaten
Uitkomstmaat |
Maatregel Beschrijving |
Tijdsspanne |
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Middle cerebral artery blood velocity
Tijdsspanne: During surgery
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Middle cerebral artery blood velocity measured in [cm/s] assessed by transcranial Doppler.
Changes in middle cerebral artery blood velocity reflects changes in cerebral blood flow.
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During surgery
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Secundaire uitkomstmaten
Uitkomstmaat |
Maatregel Beschrijving |
Tijdsspanne |
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Change in serum S100B as compared between subjects in the control- and intervention groups
Tijdsspanne: Blood is sampled 10 min prior to induction of anesthesia and at the end of surgery
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Serum concentrations of S100B, a marker of neuronal injury
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Blood is sampled 10 min prior to induction of anesthesia and at the end of surgery
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Change in serum neuron-specific enolase as compared between subjects in the control- and intervention groups
Tijdsspanne: Blood is sampled 10 min prior to induction of anesthesia and at the end of surgery
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Serum concentrations of neuron-specific enolase, a marker of neuronal injury
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Blood is sampled 10 min prior to induction of anesthesia and at the end of surgery
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Regional cerebral oxygenation as compared between subjects in the control- and intervention groups
Tijdsspanne: During surgery
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Frontal lobe oxygenation measured as the percentage of oxyhemoglobin of total hemoglobin [%] evaluated by near-infrared spectroscopy
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During surgery
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Cardiac output as compared between subjects in the control- and intervention groups
Tijdsspanne: During surgery
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Cardiac output measured in [l/min] evaluated by pulse contour analysis of the arterial blood pressure curve
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During surgery
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Stroke volume as compared between subjects in the control- and intervention groups
Tijdsspanne: During surgery
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Stroke volume measured in [ml/min] evaluated by pulse contour analysis of the arterial blood pressure curve
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During surgery
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Medewerkers en onderzoekers
Sponsor
Onderzoekers
- Hoofdonderzoeker: Niels D. Olesen, MD, Rigshospitalet, Anæstesi og Operationsklinikken 2043, Denmark
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Meer informatie
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