The Effect of Blood Pressure on Cerebral Perfusion During Vascular Surgery

Anesthesia Clinical Trial

Official title:

The Effect of Blood Pressure on Cerebral Perfusion and Oxygenation During Vascular Surgery

Clinical Trial Details — Status: Withdrawn

Administrative data

• NCT number: NCT02531139
• Other study ID #: NDOlesen
• Status: Withdrawn
• Phase: N/A
• First received: August 14, 2015
• Last updated: September 26, 2017
• Start date: March 1, 2017
• Est. completion date: November 2017

Study information

• Verified date: September 2017
• Source: Rigshospitalet, Denmark
• Contact: n/a
• Is FDA regulated: No
• Study type: Interventional

Clinical Trial 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.

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.

Recruitment information / eligibility

• Status: Withdrawn
• Enrollment: 0
• Est. completion date: November 2017
• Est. primary completion date: November 2017
• Accepts healthy volunteers: No
• Gender: All
• Age group: 19 Years and older

Eligibility

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

Related Conditions & MeSH terms

• Anesthesia
• Peripheral Arterial Disease
• Peripheral Arterial Diseases
• Peripheral Vascular Diseases

Intervention

Other:
• MAP maintained at 80 mmHg
Intervention group, MAP is maintained at 80 - 90 mmHg during anesthesia using continuous infusion of phenylephrine.
• MAP maintained at 60 mmHg
Control group, MAP is maintained at minimum of 60 mmHg during anesthesia using continuous infusion of phenylephrine.

Locations

Country	Name	City	State
Denmark	Rigshospitalet, Anæstesi og Operationsklinikken 2043	Copenhagen Ø

Sponsors (1)

Lead Sponsor	Collaborator
Rigshospitalet, Denmark

Country where clinical trial is conducted

Denmark, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	Middle cerebral artery blood velocity	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.	During surgery
Secondary	Change in serum S100B as compared between subjects in the control- and intervention groups	Serum concentrations of S100B, a marker of neuronal injury	Blood is sampled 10 min prior to induction of anesthesia and at the end of surgery
Secondary	Change in serum neuron-specific enolase as compared between subjects in the control- and intervention groups	Serum concentrations of neuron-specific enolase, a marker of neuronal injury	Blood is sampled 10 min prior to induction of anesthesia and at the end of surgery
Secondary	Regional cerebral oxygenation as compared between subjects in the control- and intervention groups	Frontal lobe oxygenation measured as the percentage of oxyhemoglobin of total hemoglobin [%] evaluated by near-infrared spectroscopy	During surgery
Secondary	Cardiac output as compared between subjects in the control- and intervention groups	Cardiac output measured in [l/min] evaluated by pulse contour analysis of the arterial blood pressure curve	During surgery
Secondary	Stroke volume as compared between subjects in the control- and intervention groups	Stroke volume measured in [ml/min] evaluated by pulse contour analysis of the arterial blood pressure curve	During surgery