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Influence of Variations in Systemic Blood Flow and Blood Pressure on Cerebral Oxygenation Measured by Cerebral Oximetry

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ClinicalTrials.gov Identifier: NCT01424800
Recruitment Status : Completed
First Posted : August 29, 2011
Last Update Posted : March 6, 2012
Sponsor:
Information provided by (Responsible Party):
University Hospital, Ghent

Tracking Information
First Submitted Date  ICMJE August 22, 2011
First Posted Date  ICMJE August 29, 2011
Last Update Posted Date March 6, 2012
Study Start Date  ICMJE July 2011
Actual Primary Completion Date December 2011   (Final data collection date for primary outcome measure)
Current Primary Outcome Measures  ICMJE
 (submitted: August 26, 2011)
  • Blood flow [ Time Frame: during the entire surgery ]
    Changes in blood flow during cerebral oxygen saturation measured with NIRS, during surgery when the patient is on cardiopulmonary bypass.
  • Blood pressure [ Time Frame: during the entire surgery ]
    Changes in blood pressure during cerebral oxygen saturation measured with NIRS, during surgery when the patient is on cardiopulmonary bypass.
Original Primary Outcome Measures  ICMJE Same as current
Change History Complete list of historical versions of study NCT01424800 on ClinicalTrials.gov Archive Site
Current Secondary Outcome Measures  ICMJE Not Provided
Original Secondary Outcome Measures  ICMJE
 (submitted: August 26, 2011)
Sensitivity of various NIRS devices. [ Time Frame: during the entire surgery ]
Sensitivity of various NIRS devices to detect the physiological changes alterations, during surgery when the patient is on cardiopulmonary bypass.
Current Other Pre-specified Outcome Measures Not Provided
Original Other Pre-specified Outcome Measures Not Provided
 
Descriptive Information
Brief Title  ICMJE Influence of Variations in Systemic Blood Flow and Blood Pressure on Cerebral Oxygenation Measured by Cerebral Oximetry
Official Title  ICMJE Influence of Variations in Systemic Blood Flow and Blood Pressure on Cerebral Oxygenation Measured by Cerebral Oximetry
Brief Summary This study emphasizes on the influence of changes in systemic flow and systemic mean arterial blood pressure (MAP) during cardiopulmonary bypass (CPB) on cerebral oxygenation assessed by near-infrared spectroscopy (NIRS). The aim of the study is to determine whether variations in systemic flow, in MAP, or in both variables at the same time have the greatest impact on the cerebral oxygen saturation.
Detailed Description

Cerebral autoregulation is defined as the whole of regulatory mechanisms that maintains a constant cerebral blood flow (CBF) during changes in cerebral perfusion pressure (CPP). Cerebrovascular resistance adjusts when CPP changes in order to keep CBF constant. In contrast with this concept of pressure-mediated autoregulation, it is suggested that cerebral autoregulation is focused on maintaining homeostasis of the cerebral metabolic rate of oxygen (CMRO2). We assume that both flow and pressure contribute to the regulation of CMRO2.

Assessment of cerebral oxygenation - Cerebral oxygen saturation will be monitored with near-infrared spectroscopy (NIRS). NIRS allows simple, continuous and non-invasive measurement of cerebral oxygen saturation (ScO2)and primarily cerebral venous saturation. Cerebral oxygen saturation will be monitored with a FDA-approved devices: INVOS 5100 (Somanetics Corporation, Troy, MI, USA).

To study the effects of changes in pressure and in flow, we need a condition where we can alter these variables separately and in a controlled manner. Therefore this study will be performed during cardiopulmonary bypass (CPB). Pressure will be varied with the administration of routinely used vasoactive substances, while flow will be varied by altering the pump flow manually. We hypothesize that if we change one parameter (pressure or flow), a compensatory mechanism will preserve the CMRO2 homeostasis, with no change in ScO2. On the other hand, if we change both pressure and flow, we expect a significant effect on cerebral oxygen saturation. With 20 % changes in pressure and/or flow, we expect a change in NIRS values of approximately 5 %. Previous studies showed that this kind of reduction is well tolerated by the brain. This means that the proposed changes are within the normal physiological range, and will have no adverse effects.

Study Type  ICMJE Interventional
Study Phase  ICMJE Not Applicable
Study Design  ICMJE Intervention Model: Single Group Assignment
Masking: None (Open Label)
Primary Purpose: Basic Science
Condition  ICMJE Cerebral Oxygen Saturation
Intervention  ICMJE Device: A disposable NIRS (near-infrared spectroscopy) sensor will be applied on the patient's forehead for continuous registration of the cerebral oxygen saturation.
When the patient is on CPB, pressure and/or flow will be changed while continuously measuring ScO2. Temperature, CO2 , arterial oxygen content, hematocrit and anesthesia will be kept constant during the measurements. First, baseline MAP (mean arterial pressure), baseline ScO2 and baseline central venous oxygen saturation (SvO2) are determined. With the interventions, we will induce a change of 20% in MAP and/or flow. This is within the normal range during operations. Changes in blood pressure will be obtained by the use of vasoactive agents (sodiumnitroprusside for blood pressure decrease and phenylephrine for blood pressure increase). Flow is regulated by manual control of the pump flow. Values of the different variables will be obtained after a 5 min stabilisation period. Flow/pressure interventions will be randomized.
Study Arms  ICMJE Experimental: change in blood pressure and blood flow
34 patients will form the experimental group, in which changes of blood pressure and blood flow will be induced and monitored.
Intervention: Device: A disposable NIRS (near-infrared spectroscopy) sensor will be applied on the patient's forehead for continuous registration of the cerebral oxygen saturation.
Publications * Not Provided

*   Includes publications given by the data provider as well as publications identified by ClinicalTrials.gov Identifier (NCT Number) in Medline.
 
Recruitment Information
Recruitment Status  ICMJE Completed
Actual Enrollment  ICMJE
 (submitted: March 2, 2012)
34
Original Estimated Enrollment  ICMJE
 (submitted: August 26, 2011)
78
Actual Study Completion Date  ICMJE December 2011
Actual Primary Completion Date December 2011   (Final data collection date for primary outcome measure)
Eligibility Criteria  ICMJE

Inclusion Criteria:

  • Age 21-100 years, scheduled for elective cardiac surgery, written informed consent.

Exclusion Criteria:

  • History of cerebrovascular disease or symptomatic carotid artery stenosis.
Sex/Gender  ICMJE
Sexes Eligible for Study: All
Ages  ICMJE 21 Years and older   (Adult, Older Adult)
Accepts Healthy Volunteers  ICMJE No
Contacts  ICMJE Contact information is only displayed when the study is recruiting subjects
Listed Location Countries  ICMJE Belgium
Removed Location Countries  
 
Administrative Information
NCT Number  ICMJE NCT01424800
Other Study ID Numbers  ICMJE 2011/208
Has Data Monitoring Committee No
U.S. FDA-regulated Product Not Provided
IPD Sharing Statement  ICMJE Not Provided
Responsible Party University Hospital, Ghent
Study Sponsor  ICMJE University Hospital, Ghent
Collaborators  ICMJE Not Provided
Investigators  ICMJE
Principal Investigator: Annelies Moerman, MD University Hospital, Ghent
PRS Account University Hospital, Ghent
Verification Date March 2012

ICMJE     Data element required by the International Committee of Medical Journal Editors and the World Health Organization ICTRP