Reversing Cerebral Oxygen Desaturations Greater That 10% of Baseline Values Using NIRS in the ICU

NCT ID: NCT01875055

Last Updated: 2019-04-10

Basic Information

• Recruitment Status: COMPLETED
• Clinical Phase: NA
• Total Enrollment: 49 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2013-05-31
• Study Completion Date: 2014-06-30

Brief Summary

Study objectives: The main objective of this study is to determine the feasibility of implementing measures in the intensive care unit (ICU), based on a physiological algorithm, to reverse decreases in cerebral oxygen saturation using, near-infrared spectroscopy (NIRS).

Methods: Randomization of 50 patients is balanced by experimental group; control and intervention, with an allocation sequence based on a block size of ten, generated with a computer random number generator. In the intervention group ICU Staff will use NIRS to follow a physiologically guided strategy to maintain regional oxygen saturation (rSO2) within 90% of baseline values. In the control group ICU Staff will provide standard of care without the use of NIRS.

Detailed Description

Background and Rationale: Cerebral desaturation has previously been shown to be associated with significant morbidity in cardiac surgery postoperatively. As such, previously reported efforts have been aimed at treating intraoperative desaturation events, with early evidence suggesting that this may reduce the incidence of these adverse events. Our previous study, NIRS ICU (B2011:110) has demonstrated that significant cerebral oxygen desaturation [measured using near infrared spectroscopy (NIRS) derived cerebral oximetry] frequently occurs in the intensive care unit (ICU) within the first 24 hours following cardiac surgery. To date, no studies have addressed the early postoperative period (i.e. in the ICU) with respect to treating (and/or preventing) these desaturation events.

Specific Aims and Experimental Design: The specific aim of this pilot prospective interventional trial is to determine the feasibility/efficacy of treating cerebral oxygen desaturation in the ICU following cardiac surgery. Two groups of patients will be studied. Both groups will have cerebral saturation measured continuously both intraoperatively and postoperatively. The control group however, will have these measurements blinded to the intraoperative and postoperative caregivers. The interventional group will have the cerebral oximetry measurements available to the intraoperative and postoperative care team allowing them to intervene when a desaturation event occurs. If a cerebral desaturation occurs, defined as a decline in saturation of 10% from the patient's preoperative baseline, then a previously utilized interventional algorithm, normal cerebral oxygen saturation (NORMOSAT) (B2012:005), will be instituted to reverse the decrease in cerebral saturation, ideally preventing it from becoming a clinically meaningful desaturation (previously defined by others as saturation decline of 25% from the baseline). The algorithm used addresses many of the known causes of desaturation, including low arterial oxygen content (both saturation and hemoglobin) and cardiac output influences on cerebral blood flow. As such, if a desaturation occurs, the patient will first have the partial pressure of oxygen (PaO2) increased by increasing the inspired oxygen content. The partial pressure of carbon dioxide (PaCO2) will also be normalized by adjusting the ventilator settings. The cardiac output will be optimized and the blood pressure will be increased with standard ICU protocols to administer phenylephrine. If remaining low, the patients will be transfused to standard of care hemoglobin levels.

In this pilot trial, a convenience sample of 50 consecutive consenting patients undergoing cardiac surgery employing cardiopulmonary bypass (CPB) will be studied. After obtaining consent, bilateral cerebral oximetry sensors will be placed on the forehead of patients prior to the induction of anesthesia. Baseline (breathing room air) regional cerebral saturation will be recorded. Following this, induction of anesthesia will occur and continuous NIRS measurements will be collected during the surgical procedure with continued monitoring occurring for the first 24 hours (or until discharge) within the ICU. In the control group, conventional anesthesia and ICU standards of care will be carried out throughout the study period. In the interventional group, an algorithm based on the modification of previously defined important physiologic variables will be initiated to reverse the desaturation (beginning when the saturation drops at least 10% from the baseline) that occurs in the operating room (OR) and ICU.

Conditions

Cerebral Ischemia

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: CROSSOVER
• Primary Study Purpose: TREATMENT
• Blinding Strategy: SINGLE

Study Groups

NIRS derived cerebral oximetry

NIRS derived cerebral oximetry device used but data not visable to ICU caregivers

Group Type: EXPERIMENTAL

NIRS derived cerebral oximetry

Intervention Type: DEVICE

NIRS sensors will be placed the forehead of the patient but NIRS derived data will be blinded to the ICU caregivers

NIRS and Algorithm

NIRS derived cerebral oximetry device used and the caregiver in the ICU will see the data in order to guide the use of the interventional algorithm to treat the cerebral desaturation

Group Type: ACTIVE_COMPARATOR

NIRS and Algorithm

Intervention Type: DEVICE

NIRS cerebral oximetry will be used to guide the use of an algorithm based on the modification of previously defined important physiologic variables will be initiated to reverse the desaturation (beginning when the saturation drops at least 10% from the baseline) that occur in the ICU

NIRS derived cerebral oximetry

Intervention Type: DEVICE

NIRS sensors will be placed the forehead of the patient but NIRS derived data will be blinded to the ICU caregivers

Interventions

NIRS and Algorithm

NIRS cerebral oximetry will be used to guide the use of an algorithm based on the modification of previously defined important physiologic variables will be initiated to reverse the desaturation (beginning when the saturation drops at least 10% from the baseline) that occur in the ICU

Intervention Type: DEVICE

NIRS derived cerebral oximetry

NIRS sensors will be placed the forehead of the patient but NIRS derived data will be blinded to the ICU caregivers

Intervention Type: DEVICE

Other Intervention Names

EQUANOX NIRS derived cerebral oximetry; EQUANOX NIRS derived cerebral oximetry

Eligibility Criteria

Inclusion Criteria

• patients undergoing cardiac surgery employing CPB

Exclusion Criteria

• patients having surgeries involving the aorta, or employing deep hypothermic circulatory arrest (DHCA)

• Minimum Eligible Age: 18 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: No

Sponsors

University of Manitoba

OTHER

Sponsor Role: lead

Responsible Party

Responsibility Role: SPONSOR

Principal Investigators

Hillary P Grocott, MD

Role: PRINCIPAL_INVESTIGATOR

Professor Department of Anesthesia and Surgery University of Manitoba

Locations

St. Boniface Hospital

Winnipeg, Manitoba, Canada

Countries

Canada

Other Identifiers

B2012:118

Identifier Type: -

Identifier Source: org_study_id