The aim of this study is to investigate whether patients on cardio-pulmonary bypass have intact autoregulation or not, and to investigate whether systemic flow or MAP has the greatest effect on cerebral oxygenation.
ID
Source
Brief title
Condition
- Other condition
Synonym
Health condition
Mensen aan een extra-corporeel circuit
Research involving
Sponsors and support
Intervention
Outcome measures
Primary outcome
The relationship between variations in blood pressure and blood flow on the one
hand, and cerebral oxygenation on the other hand.
Secondary outcome
The effect of phenylephrin and vasopressin on cerebral oxygenation
Background summary
This study emphasizes on the influence of changes in systemic flow and systemic
mean arterial blood pressure (MAP) during cardio pulmonary bypass (CPB) on
cerebral oxygenation assessed by transcranial near-infrared spectroscopy
(NIRS). We want to determine whether variations in systemic flow, variations in
MAP or variations in both parameters at the same time have the greatest impact
on the cerebral autoregulation.
Study objective
The aim of this study is to investigate whether patients on cardio-pulmonary
bypass have intact autoregulation or not, and to investigate whether systemic
flow or MAP has the greatest effect on cerebral oxygenation.
Study design
To assess cerebral oxygenation, we use NIRS (near-infrared spectroscopy). We
measure rSO2 per-operatively in patients undergoing thoracic surgery with the
use of CPB (heart-lung machine). When patient is on CPB, we start our
interventions, meaning that we variate CPB-flow at a constant blood pressure
and vice versa.
Intervention
When the patient is on cardiopulmonary bypass, we will modify the systemic
blood pressure and/or systemic blood flow while measuring the cerebral
oxygenation. We have one series of measurements during which the systemic blood
pressure is modified, and one series of measurements during which the systemic
flow is modified. Our measurements will be finished within one hour, this will
not exceed the normal duration of extracorporeal circulation, which is 90-120
minutes. Therefore, we will not prolong the surgical procedure.
Before each intervention, we record a baseline during two minutes. During this
baseline recording, no modifications are made. When the baseline value is
obtained, we perform one of the interventions named below. This process is
repeated until all seven interventions are completed.
During surgery, mean arterial pressure is maintained at approximately 80
mmHg. With our interventions, we induce a raise and a reduction in blood
pressure of approximately 20 mmHg. This is within the normal range during
operations. Systemic flow is regulated by the CPB-operator. Normally CPB-flow
is maintained at 2,6 L/m2. With our interventions, we raise this to 3,1 L/m2
and lower this to 2,1 L/m2. This is also within the normal range.
Our interventions are:
Modifications in blood pressure:
* Increase of the systemic blood pressure by approximately 20 mmHg, using
phenylephrine (an alpha-receptor dependent vasoconstrictor)
* Increase of the systemic blood pressure by approximately 20 mmHg, using
vasopressin (an alpha-receptor independent vasoconstrictor)
* Reduction of the systemic blood pressure by approximately 20 mmHg, using
sodiumnitroprusside
Modifications in blood flow:
* Reduction of the blood flow by 0.5l/m2
* Reduction of the blood flow by 0.5l/m2, while using phenylephrine to maintain
systemic blood pressure
* Increase of the blood flow by 0.5l/m2
* Increase of the blood flow by 0.5l/m2, while maintaining a constant systemic
blood pressure using sodiumnitroprusside
Study burden and risks
The investigated interventions are within the physiological range of
variations. No adverse effects of changes of the hemodynamics within the
proposed limits are known. Anesthesia and surgical technique will be applied
according to standard procedures.
Meibergdreef 9
1105AZ AMSTERDAM
NL
Meibergdreef 9
1105AZ AMSTERDAM
NL
Listed location countries
Age
Inclusion criteria
-patient is older than 18 years
-patient is scheduled to undergo elective cardiac surgery with the use of an cardiopulmonary bypass.
-informed consent
Exclusion criteria
-patient under 18 years old
-patient older than 70 years
-Carotid artery stenosis (examination before surgery with echo-Dopplergraphy)
-emergency operations
-severe COPD
-no informed consent
-SaO2 < 90% at room temperature
-diabetes
-Renal falure
-Brain pathology (CVA) in history
Design
Recruitment
Followed up by the following (possibly more current) registration
No registrations found.
Other (possibly less up-to-date) registrations in this register
No registrations found.
In other registers
| Register | ID |
|---|---|
| CCMO | NL29879.018.09 |