The Effect of Blood Pressure on Cerebral Perfusion During Vascular Surgery
The Effect of Blood Pressure on Cerebral Perfusion and Oxygenation During Vascular Surgery
Aperçu de l'étude
Statut
Les conditions
Intervention / Traitement
Description détaillée
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.
Type d'étude
Phase
- N'est pas applicable
Contacts et emplacements
Lieux d'étude
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Copenhagen Ø, Danemark, 2100
- Rigshospitalet, Anæstesi og Operationsklinikken 2043
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Critères de participation
Critère d'éligibilité
Âges éligibles pour étudier
Accepte les volontaires sains
Sexes éligibles pour l'étude
La description
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
Plan d'étude
Comment l'étude est-elle conçue ?
Détails de conception
- Objectif principal: Soins de soutien
- Répartition: Randomisé
- Modèle interventionnel: Affectation parallèle
- Masquage: Tripler
Armes et Interventions
Groupe de participants / Bras |
Intervention / Traitement |
|---|---|
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Expérimental: 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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Comparateur actif: 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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Que mesure l'étude ?
Principaux critères de jugement
Mesure des résultats |
Description de la mesure |
Délai |
|---|---|---|
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Middle cerebral artery blood velocity
Délai: 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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Mesures de résultats secondaires
Mesure des résultats |
Description de la mesure |
Délai |
|---|---|---|
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Change in serum S100B as compared between subjects in the control- and intervention groups
Délai: 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
Délai: 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
Délai: 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
Délai: 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
Délai: 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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Collaborateurs et enquêteurs
Parrainer
Les enquêteurs
- Chercheur principal: Niels D. Olesen, MD, Rigshospitalet, Anæstesi og Operationsklinikken 2043, Denmark
Dates d'enregistrement des études
Dates principales de l'étude
Début de l'étude (Anticipé)
Achèvement primaire (Anticipé)
Achèvement de l'étude (Anticipé)
Dates d'inscription aux études
Première soumission
Première soumission répondant aux critères de contrôle qualité
Première publication (Estimation)
Mises à jour des dossiers d'étude
Dernière mise à jour publiée (Réel)
Dernière mise à jour soumise répondant aux critères de contrôle qualité
Dernière vérification
Plus d'information
Termes liés à cette étude
Mots clés
Termes MeSH pertinents supplémentaires
Autres numéros d'identification d'étude
- NDOlesen
Informations sur les médicaments et les dispositifs, documents d'étude
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