Clinical Trial Details
— Status: Completed
Administrative data
| NCT number |
NCT03969836 |
| Other study ID # |
19.0272 |
| Secondary ID |
|
| Status |
Completed |
| Phase |
|
| First received |
|
| Last updated |
|
| Start date |
January 1, 2019 |
| Est. completion date |
December 31, 2021 |
Study information
| Verified date |
February 2024 |
| Source |
University of Louisville |
| Contact |
n/a |
| Is FDA regulated |
No |
| Health authority |
|
| Study type |
Observational
|
Clinical Trial Summary
Study of Regional Cerebral Oxygenation and Brain Blood Volume changes during Cardiac Surgery
using the NeurOS system
Description:
1. Title of the Research Project： Study of regional Cerebral Oxygenation and Brain Blood
Volume changes during Cardiac Surgery using the NeurOS system (COBBV-CS Trial)
2. Background/Problem Statement: The use of regional cerebral oxygenation (rSO2) monitoring
has grown clinically, even becoming the standard of care in some institutions.
Monitoring of intracranial tissue oxygenation is fundamentally possible because light in
the near infrared spectrum (700-900nm) penetrates bone, muscle, and other tissue.
Oxyhemoglobin and deoxyhemoglobin have distinct peak absorption spectra, but there is an
isobestic wavelength (i.e., wavelength for which the peak absorption of light is similar
for oxyhemoglobin and deoxyhemoglobin, approximately 810nm) for absorption by total
hemoglobin. Determination of rScO2 thus is possible with transmission of just 2
wavelengths of near-infrared spectroscopy (NIRS) to determine the relative
concentrations of oxyhemoglobin versus total hemoglobin. A decrease in rSO2 from
baseline >20% or an absolute rSO2 value <50% often is reported in clinical investigation
as representing a clinically meaningful reduction or "desaturation."
The data is controversial on the benefits of NIRS to prevent or reduce stroke or delirium
after cardiac surgery. However, it must be realized the inherent limitations of monitors
alone to impact clinical outcomes without a standardized intervention algorithm. Although
multiple NIRS monitors are approved in the United States and other countries primarily for
assessing the adequacy of cerebral oxygenation during surgery, their approval is not based on
the indication of detecting and/or lowering the frequency of neurological complications. In
regard to the latter, strokes are believed widely to result primarily from cerebral embolism
and/or cerebral hypoperfusion. Importantly, both etiologies can contribute to cerebral injury
in the same patient insofar as hypoperfusion may delay washout of microembolism and/or
compromise collateral perfusion to the ischemic penumbra. Many strokes, though, occur in
subcortical brain areas or at sites remote from the area of NIRS monitoring, and many occur
in the postoperative period after NIRS monitoring has concluded.
In addition, technological advances with NIRS monitoring have continued and now include the
ability to perform bedside cerebral autoregulation monitoring. Regional cerebral oxygenation
provides a clinically acceptable surrogate of cerebral blood flow (CBF) for clinical
autoregulation monitoring. Monitoring CBF autoregulation with rSO2 has many clinically
attractive features, including the following: It is noninvasive, monitoring requires little
caregiver intervention, and it has sufficient resolution to discriminate the lower
autoregulatory threshold to prevent brain ischemia. On the other hand, simply raising mean
blood pressure targets during CPB, however, may not necessarily be beneficial because for
some individuals this may result in blood pressure above the upper limit of autoregulation,
which potentially could lead to cerebral hyperperfusion, increasing cerebral embolic load
and/or enhancing cerebral edema in the setting of systemic inflammatory response to cardiac
surgery. Individualizing blood pressure during CPB based on physiological endpoints such as
rSO2 monitoring, rather than empiric targets, may provide a means for modifying the risk for
renal injury and major organ morbidity and possibly mortality.
Problem Statement: Disposable rSO2 sensors are costly and is becoming a rate limiting factor
hindering its widespread clinical use. Reusable sensors like NeurOS cerebral oximetry are
only a fraction of cost with similar performances in healthy volunteers. The investigators
will use NeurOS in accordance with its approved labeling and indications by FDA. Cardiac
surgery has significant variations and great clinical importance of cerebral oxygenation
during different stages of surgery. Blood volume changes before, during and after
cardiopulmonary bypass have not been studied previously and could provide critical
information to prevent postoperative cognitive changes. The NeurOS system calculates the sum
of attenuation of two wavelengths to provide brain blood volume index (BVI) continuously.
3. Objectives:
1. To compare the performance of NeurOS with INVOS system during cardiac surgery
2. To study the brain blood volume changes during cardiac surgery, which has never been
studied before.
4. Study Design/Methodology: All cardiac surgical patients are already receiving INVOS
cerebral oximetry monitoring during surgery at Jewish Hospital. Both INVOS and NeurOS pads
will be placed on the same patient. Continuous monitoring of both cerebral oximetry data for
the whole length of cardiac surgery will be recorded and saved in a USB drive for retrieval
and analysis. Key point left and right-side cerebral oximetry data include: Baseline,
Anesthesia Induction, Incision, Initiation cardiopulmonary bypass (CPB), Aortic Clamping,
Coming off CPB and Skin Closure. These key points data will be extracted for comparison
between NeurOS and INVOS in terms of percentage change from the baseline. In addition, a
time-rSO2 graph will be plotted for each patient side by side with NeurOS and INVOS cerebral
oxygenation for trend comparison.
1. . Sample selection and size: 100 consecutive cardiac surgical patients at Jewish
Hospital, Louisville, KY (2 months to recruit)
2. . Describe the proposed intervention: Apply the single use NeurOS cerebral oximetry
sensor adhesive onto patients' forehead who are going to have cardiac surgery in the
operating room before anesthesia induction.
3. . Data collection procedures, instruments used, and methods for data quality control:
Anesthesia providers (attending anesthesiologists, residents and CRNAs) provide routine
anesthesia care for cardiac surgery. NeurOS and INVOS rSO2 reading are automatically
recorded in the VO200-NeurOS Cerebral Oximetry Monitor and the INOVS Monitor
respectively. Significant events (Baseline, Anesthesia Induction, Incision, Initiation
cardiopulmonary bypass (CPB), Aortic Clamping, Coming off CPB and Skin Closure) will be
marked manually by the anesthesia providers in individual systems. Brain blood volume
index will be automatically recorded and retracted from the NeurOS system once surgery
is over. All data will be downloaded from the system into an encrypted USB drive for
storage and analysis. Data quality control will be ensured by the individual system
alarms for poor signals and be corrected by anesthesia providers.
4. . Unit of analysis and observation: Cerebral Oxygenation in percentage of oxyhemoglobin.
Brain blood volume index in the sum of attenuation of two wavelengths.
5. Subject Recruitment Methods: All patients presenting to Jewish Hospital for cardiac
surgery will be contacted for potential recruitment on the day of surgery in the preoperative
area.
6. Informed Consent Process/Complete Waiver Process: Informed consent will be provided to all
participants.
7. Research Procedures:
In all consented patients, baseline cerebral oxygenation and brain blood volume index will be
obtained at room air or baseline oxygen requirement level in NeurOS and INVOS systems. Both
NeurOS and INVOS rSO2 and brain blood volume indexes will be continuously recorded and saved
in the respective system throughout the whole cardiac surgery. General anesthesia will be
induced by using O2 administered via face mask and IV fentanyl 1μg/ kg, propofol 2-3mg/kg and
rocuronium 1mg/kg. Maintenance of anesthesia was achieved with inhaled isoflurane in
air/oxygen mixture and muscle relaxation using intermittent boluses of rocuronium. Fentanyl
will be used as supplemental analgesia. Normocapnic ventilation was maintained. Upon
completion of surgery and weaning from cardio pulmonary bypass, titrated doses of protamine
will be administered to reverse the anticoagulant action of heparin, targeting to achieve
baseline preoperative Activated clotting Time.
After the surgery, all rSO2 and brain blood volume index data are downloaded into an
encrypted USB drive for analysis and storage.
8. Minimizing Risks:
1. All HIPPA related information will be stored in a private computer in a password
protected computer.
2. Cleaning of cables, monitors and reusable equipment are performed after each use.
3. Standard electrical precautions will be followed to prevent electrical shock to
providers and patients.
9. Plan for Analysis of Results:
- Trend graphs of INVOS and NeurOS cerebral oximetry will be plotted together to compare
whether they follow a similar trend. Cerebral oxygenation deviation from the baseline
will be compared through statistical analysis to identify whether NeurOS performs as
well as INVOS at these critical moments during cardiac surgery.
- Trend graphs of NeurOS brain blood volume, arterial blood pressure, central venous
pressure and cerebral oxygenation will be plotted together to identify correlations
among these parameters. Each key point brain blood volume index deviation from the
baseline will be analyzed to identify whether above mentioned critical moments during
cardiac surgery will affect the brain blood volume. Clinical outcomes data will be
collected on 30-day mortality and strokes to identify whether the brain blood volume
index directly affects clinical outcomes.
- Programs to be used for data analysis: Software R
10. Research Materials, Records, and Privacy: Identify the sources of research material
obtained from individually identifiable living human subjects: Prospective noninvasive
data on cerebral oxygenation and brain blood volume during cardiac surgery. Please see
data collection form.
Indicate what information (records, data, etc.) will be recorded and whether use will be made
of existing records or data: Cerebral oxygenation and brain blood volume. They will be
recorded in the medical charts.
Explain why this information is needed to conduct the study: These data are necessary to
identify outcomes for these patients.
Specify how the data will be de-identified (if applicable), who has access to the data, where
the data will be stored and how the researcher will protect both the data with respect to
privacy and confidentiality. Address physical security measures (e.g., locked facility,
limited access); data security (e.g., password-protection, data encryption); safeguards to
protect identifiable research information (e.g., coding or links): Once required information
is collected, HIPPA information will be deleted. All HIPPA related information will be stored
in a private computer in a password protected computer. No links will be provided to the
public.
11. References
1. Lewis C, Parulkar SD, Bebawy J, Sherwani S, Hogue CW. Cerebral Neuromonitoring During
Cardiac Surgery: A Critical Appraisal With an Emphasis on Near-Infrared Spectroscopy. Journal
of Cardiothoracic and Vascular Anesthesia. 2018;32:2313-2322
