Blood Pressure or Cardiac Output - the Influence on Cerebral Perfusion During Cardiopulmonary Bypass

Parameters of Cerebral Perfusion

Sponsors

Lead sponsor: UMC Utrecht

Source UMC Utrecht
Brief Summary

The purpose of this study is to determine whether cerebral blood flow and cerebral tissue oxygenation is most dependent on cardiac output or on mean arterial pressure in patients undergoing cardiac surgery with the use of cardiopulmonary bypass.

Overall Status Completed
Start Date January 2016
Completion Date March 17, 2017
Primary Completion Date March 17, 2017
Phase N/A
Study Type Interventional
Primary Outcome
Measure Time Frame
regional cerebral oxygen saturation During surgery
mean velocity of blood flow of the middle cerebral artery During surgery
Enrollment 15
Condition
Intervention

Intervention type: Other

Intervention name: 50-100ug phenylephrine before CPB

Description: In this intervention we will administer 50-100 μg phenylephrine to the patient before CPB is started. This intervention will take place when the patient shows hypotension (MAP <60mmHg, according to protocol22). Because of the increase in PVR there will be a baroreceptor-reflex-mediated decrease in CO. On-line, we will quantify the percentage decrease in systemic blood flow (i.e. CO) by using the Modelflow algoritm incorporated in a non-invasive beat-to-beat finger blood pressure monitor. This will allow us to obtain a reference for the decrease in CO to use in the next interventions. Our hypothesis is that CO will decrease because of the baroreceptor-reflex. During this intervention NIRS and TCD MCA will be recorded.

Arm group label: Patient for cardiac surgery

Intervention type: Other

Intervention name: 50-100ug phenylephrine during CPB

Description: In this intervention we will induce only 1 component of the changes at intervention (1), being the increase in MAP of approximately 20 mmHg by administrating 50-100 μg phenylephrine. The CPB enables us to maintain a constant CO and thus eliminating the baroreceptor-reflex. During this intervention NIRS and TCD MCA will be recorded.

Arm group label: Patient for cardiac surgery

Intervention type: Other

Intervention name: decreasing CPB flow

Description: With this intervention we will only create a change in CO, which enables us to eliminate the effect of blood pressure. We will modify CPB flow to achieve the CO decrease (in %) measured at intervention (1) meaning: pre-CPB after the bolus of 50-100 μg phenylephrine. In the case of unexpected increase (in %) of CO measured at intervention (1), we will still decrease CPB flow so we will be able to analyse decrease as well as increase in CPB flow. During this intervention NIRS and TCD MCA will be recorded.

Arm group label: Patient for cardiac surgery

Intervention type: Other

Intervention name: Decreasing CPB flow AND 50-100ug phenylephrine

Description: In this intervention we will simulate the 'normal' physiological state when administering phenylephrine. We will modify CPB flow to achieve the percentage change CO as observed during intervention (1) as well as administrate 50-100 μg phenylephrine. We expect to see similar outcomes as in intervention (1). During this intervention NIRS and TCD MCA will be recorded.

Arm group label: Patient for cardiac surgery

Intervention type: Other

Intervention name: Increasing CPB flow

Description: In this last intervention we will create an increase in MAP without using phenylephrine but only by increasing CO. This enables us to eliminate a possible direct α1-adrenergic effect on the cerebral vasculature. MAP will be raised approximately 20 mmHg by increasing CPB flow 20%. During this intervention NIRS and TCD MCA will be recorded.

Arm group label: Patient for cardiac surgery

Eligibility

Criteria:

Inclusion Criteria:

- Undergoing cardiopulmonary bypass for CABG a

- having an appropriate temporal bone window for reliable TCD monitoring

- needing pharmacological intervention because of hypotension before going on CPB.

Exclusion Criteria:

- requiring hypothermia during surgery

- requiring emergency surgery

- contraindication for phenylephrine,

- having known brain pathology (e.g. Cerebral Vascular Accident (CVA) or increased intracranial pressure

- having a history of severe carotid artery stenosis.

Gender: All

Minimum age: 18 Years

Maximum age: N/A

Healthy volunteers: No

Location
facility
UMC Utrecht
Location Countries

Netherlands

Verification Date

June 2017

Responsible Party

Responsible party type: Principal Investigator

Investigator affiliation: UMC Utrecht

Investigator full name: Dr. B. van Zaane

Investigator title: MD PhD

Has Expanded Access No
Number Of Arms 1
Arm Group

Arm group label: Patient for cardiac surgery

Arm group type: Experimental

Description: All patient undergo the 5 different intervention in a randomised matter.

Study Design Info

Allocation: N/A

Intervention model: Single Group Assignment

Primary purpose: Basic Science

Masking: None (Open Label)

Source: ClinicalTrials.gov