The Effect of Blood Pressure on Cerebral Perfusion During Vascular Surgery

NCT ID: NCT02531139

Last Updated: 2017-09-28

Basic Information

• Recruitment Status: WITHDRAWN
• Clinical Phase: NA
• Study Classification: INTERVENTIONAL
• Study Start Date: 2017-03-01
• Study Completion Date: 2017-11-30

Brief Summary

Anesthesia reduces blood pressure and cerebral blood flow is normally considered to be maintained despite marked changes in blood pressure. Vascular surgical patients are often elderly, have high blood pressure and atherosclerosis and in these patients cerebral blood flow may decrease if blood pressure is reduced during anesthesia. The purpose of this study is to assess the effect of blood pressure for preservation of cerebral blood flow during anesthesia in vascular surgery. The hypothesis is that in vascular surgical patients, during anesthesia, cerebral blood flow is higher with blood pressure maintained at a higher level than that used in normal clinical practice.

Detailed Description

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.

Conditions

Anesthesia; Peripheral Arterial Diseases

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: PARALLEL
• Primary Study Purpose: SUPPORTIVE_CARE
• Blinding Strategy: TRIPLE

Study Groups

MAP maintained at 80 mmHg

During anesthesia MAP is maintained at 80 - 90 mmHg MAP using continuous infusion of phenylephrine.

Group Type: EXPERIMENTAL

MAP maintained at 80 mmHg

Intervention Type: OTHER

Intervention group, MAP is maintained at 80 - 90 mmHg during anesthesia using continuous infusion of phenylephrine.

MAP maintained at 60 mmHg

During anesthesia MAP is maintained at minimum of 60 mmHg using continuous infusion of phenylephrine.

Group Type: ACTIVE_COMPARATOR

MAP maintained at 60 mmHg

Intervention Type: OTHER

Control group, MAP is maintained at minimum of 60 mmHg during anesthesia using continuous infusion of phenylephrine.

Interventions

MAP maintained at 80 mmHg

Intervention group, MAP is maintained at 80 - 90 mmHg during anesthesia using continuous infusion of phenylephrine.

Intervention Type: OTHER

MAP maintained at 60 mmHg

Control group, MAP is maintained at minimum of 60 mmHg during anesthesia using continuous infusion of phenylephrine.

Intervention Type: OTHER

Eligibility Criteria

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

• Minimum Eligible Age: 19 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: No

Sponsors

Rigshospitalet, Denmark

OTHER

Sponsor Role: lead

Responsible Party

Niels Damkjær Olesen

MD

Responsibility Role: PRINCIPAL_INVESTIGATOR

Principal Investigators

Niels D. Olesen, MD

Role: PRINCIPAL_INVESTIGATOR

Rigshospitalet, Anæstesi og Operationsklinikken 2043, Denmark

Locations

Rigshospitalet, Anæstesi og Operationsklinikken 2043

Copenhagen Ø, , Denmark

Countries

Denmark

Other Identifiers

NDOlesen

Identifier Type: -

Identifier Source: org_study_id