Clinical trial NCT02531139: The Effect of Blood Pressure on Cerebral Perfusion During Vascular Surgery
Official title: The Effect of Blood Pressure on Cerebral Perfusion and Oxygenation During Vascular Surgery
Study type: INTERVENTIONAL
Overall status: WITHDRAWN
Phase: NA
Conditions: Anesthesia
Peripheral Arterial Diseases
Keywords: Cerebrovascular Circulation
Anesthesia
Blood pressure
Peripheral Arterial Diseases
Lead sponsor: Rigshospitalet, Denmark
Sponsor class: OTHER
First posted: 2015-08-24
Enrollment: 0
Sex: ALL
Minimum age (years): 19
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Allocation: RANDOMIZED
Intervention model: PARALLEL
Primary purpose: SUPPORTIVE_CARE

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.

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

Primary outcomes:
measure: Middle cerebral artery blood velocity
timeFrame: During surgery
Secondary outcomes:
measure: Change in serum S100B as compared between subjects in the control- and intervention groups
timeFrame: Blood is sampled 10 min prior to induction of anesthesia and at the end of surgery
measure: Change in serum neuron-specific enolase as compared between subjects in the control- and intervention groups
timeFrame: Blood is sampled 10 min prior to induction of anesthesia and at the end of surgery
measure: Regional cerebral oxygenation as compared between subjects in the control- and intervention groups
timeFrame: During surgery
measure: Cardiac output as compared between subjects in the control- and intervention groups
timeFrame: During surgery
measure: Stroke volume as compared between subjects in the control- and intervention groups
timeFrame: During surgery
Other outcomes:
Locations:
city: Copenhagen Ø
country: Denmark
facility: Rigshospitalet, Anæstesi og Operationsklinikken 2043
Study officials:
affiliation: Rigshospitalet, Anæstesi og Operationsklinikken 2043, Denmark
name: Niels D. Olesen, MD
role: PRINCIPAL_INVESTIGATOR
References: