Cerebral Oxygen Saturation Monitoring In Cardiac Surgery (COSMICS) (COSMICS)

January 26, 2026 updated by: Carlos Galhardo Jr., Instituto Nacional de Cardiologia de Laranjeiras

A Multicenter, Randomized, Controlled Clinical Trial of Cerebral Oxygen Saturation Monitoring In Cardiac Surgery (COSMICS)

Neurological dysfunction continues to be one of the complications of considerable concern in patients undergoing cardiac surgery. It was previously reported in the literature, that cerebral oxygen desaturation during cardiac surgery was associated with an increased incidence of cognitive impairment. This study aims to determine whether continuous monitoring of cerebral oximetry improves the neurocognitive outcome in coronary artery bypass surgery when associated with predetermined intervention protocol to optimize cerebral oxygenation.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

Despite all the progress over the last decades regarding the improvement of the perioperative care of patients with heart disease and the development of new surgical techniques, neurological dysfunction continues to be one of the complications of the greatest concern in patients undergoing cardiac surgery with cardiopulmonary bypass. Brain injury can manifest itself through permanent or temporary injury, contributing to the increase in-hospital mortality, in the length of stay in intensive care, in the length of hospital stay, to a higher incidence of motor dysfunction requiring rehabilitation, and consequently, to reduced quality of life.

Even though the causes of brain injury are multifactorial, perioperative cerebral hypoperfusion, tissue hypoxia, and thromboembolic events are among the main factors related to neurological dysfunction.

Several clinical studies have indicated an association between cerebral desaturation and the increase of neurological complications. Cerebral oximetry monitoring using near-infrared spectroscopy (NIRS) is a non-invasive technique used to estimate regional cerebral oxygen saturation (rSO2) and has been associated with diminishing the incidence of neurological complications.

There is no consensus in the literature about its real benefit, mainly due to the absence of well-designed scientific studies that demonstrate that cerebral desaturation associated with intervention measures to improve rSO2, are related to the prevention of neurological dysfunction in adult cardiac surgery.

The study hypothesis evaluates whether continuous monitoring of cerebral oximetry improves the neurocognitive outcome in coronary artery bypass surgery when associated with early interventions to optimize rSO2.

Study Type

Interventional

Enrollment (Actual)

326

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Brazil
    • Rio de Janeiro
      • Rio de Janeiro, Rio de Janeiro, Brazil
        • Instituto Nacional de Cardiologia
    • Santa Catarina
      • Criciúma, Santa Catarina, Brazil
        • Hospital São José

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

60 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Age 60 or older
  • Elective coronary artery bypass graft surgery using cardiopulmonary bypass
  • Preoperative cognitive assessment by means of Mini-Mental State Examination (MMSE) test, greater than or equal to 24
  • Signed informed consent

Exclusion Criteria:

  • Patients with focal neurologic deficit
  • Carotid artery stenosis greater than 70%
  • Patients with pre-existing cognitive dysfunction
  • Patients with psychotic disorders
  • History of allergy to adhesive part of the electrode
  • History of craniofacial surgery

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Triple

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Active Comparator: Cerebral Oxymetry Monitoring

The following procedures should be performed sequentially in the event of cerebral desaturation after 30 seconds:

  1. The positioning of the head, the presence of facial plethora, and bad position of catheters should be corrected;
  2. In case of arterial hypotension, the causal factors should be assessed and treated;
  3. In the presence of arterial hypoxemia, the causal factors should be assessed and treated to maintain a PaO2 > 150 mmHg;
  4. In the presence of hypercapnia, adjust the ventilation parameters avoiding hyperventilation;
  5. In the presence of anemia, the causal factors should be assessed, and the decision to undergo transfusion should also take into consideration the presence of tissue hypoperfusion;
  6. In cases of SvO2 below 70% and signs of hemodynamic instability, optimize fluid replacement and ventricular global contractility;
  7. Assess the increase of brain consumption of O2, avoiding the superficial level of anesthesia, hyperthermia, and tremors.
Device: Cerebral oximetry monitor (The INVOS® Cerebral/Somatic Oximeter) and protocol-based interventions
In the intervention group, an alarm threshold below 15% of the baseline rSO2 value will be established. Based on the predetermined algorithm the rSO2 will be maintained at or above 85% of the baseline measurements. If the rSO2 reaches levels below 15% of the baseline values or below 50% in absolute value for over 30 seconds, protocol-based interventions will be performed to restore rSO2 to baseline levels.
No Intervention: Control Group
Patients will be treated according to the attending anesthesiologist, without the monitoring of cerebral oximetry, but to maintain a heart rate between 70 - 100 bpm, lactate levels <3 mmol/L and urine output> 0.5mL/Kg/h. In case of arterial hypotension the causal factors should be assessed and treated; in case of SvO2 below 70% and signs of hemodynamic instability, optimize volume replacement and global ventricular contractility through inotropic agents (epinephrine, dobutamine or milrinone); in the presence of anemia (Hb <6 to 7g/dL during CPB or Hb <8g/dL in the pre-CPB or post-CPB period), the causal factors should be assessed and the decision to transfuse should also take into account the presence of hypoperfusion tissue (increased lactate, low SvO2, acidosis); in episodes of bradycardia with hemodynamic instability, atropine may be used.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Preoperative cognitive function
Time Frame: Pre-surgery (within 10 days before)
Mini Mental State Examination (MMSE)
Pre-surgery (within 10 days before)
Postoperative cognitive dysfunction - delayed cognitive recovery
Time Frame: Post-surgery (7 days after surgery)
Mini Mental State Examination (MMSE)
Post-surgery (7 days after surgery)
Postoperative cognitive dysfunction - neurocognitive disorder
Time Frame: Post-surgery (90 days after surgery)
Mini Mental State Examination (MMSE)
Post-surgery (90 days after surgery)
Preoperative cognitive function II
Time Frame: Pre-surgery (within 10 days before)
Montreal Cognitive Assessment (MoCA) test
Pre-surgery (within 10 days before)
Postoperative cognitive dysfunction - delayed cognitive recovery II
Time Frame: Post-surgery (7 days after surgery)
Montreal Cognitive Assessment (MoCA) test
Post-surgery (7 days after surgery)
Postoperative cognitive dysfunction - neurocognitive disorder II
Time Frame: Post-surgery (90 days after surgery)
Montreal Cognitive Assessment (MoCA) test
Post-surgery (90 days after surgery)
Preoperative cognitive function III
Time Frame: Pre-surgery (within 10 days before)
The Telephone Interview for Cognitive Status (TICS)
Pre-surgery (within 10 days before)
Postoperative cognitive dysfunction - delayed cognitive recovery III
Time Frame: Post-surgery (7 days after surgery)
The Telephone Interview for Cognitive Status (TICS)
Post-surgery (7 days after surgery)
Postoperative cognitive dysfunction - neurocognitive disorder III
Time Frame: Post-surgery (90 days after surgery)
The Telephone Interview for Cognitive Status (TICS)
Post-surgery (90 days after surgery)

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Incidence of postoperative delirium
Time Frame: Delirium assessment CAM-ICU preoperatively (baseline) and postoperatively twice a day during the first seven days or until discharge
Delirium will be assessed postoperatively for seven days or until discharge
Delirium assessment CAM-ICU preoperatively (baseline) and postoperatively twice a day during the first seven days or until discharge
Neurological injury type I (stroke)
Time Frame: Post-surgery (until 30 days after surgery)
The incidence of neurological injury type I will be evaluated for 30 days
Post-surgery (until 30 days after surgery)
Duration of mechanical ventilation
Time Frame: Post-surgery (until 30 days after surgery)
The duration of mechanical ventilation will be evaluated
Post-surgery (until 30 days after surgery)
Length of stay at the intensive care unit (ICU)
Time Frame: Post-surgery (until 30 days after surgery)
The length of stay at the intensive care unit (ICU) will be evaluated
Post-surgery (until 30 days after surgery)
Length of stay at the hospital
Time Frame: Post-surgery (until 30 days after surgery)
The length of stay at the hospital will be evaluated
Post-surgery (until 30 days after surgery)
Incidence of mortality resulting from all causes
Time Frame: Post-surgery (until 30 days after surgery)
All causes of mortality will be assessed for 30 days
Post-surgery (until 30 days after surgery)

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Instituto Nacional de Cardiologia de Laranjeiras

Investigators

  • Principal Investigator: Carlos Galhardo, MD, Instituto Nacional de Cardiologia

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

May 19, 2021

Primary Completion (Actual)

August 20, 2024

Study Completion (Actual)

August 20, 2024

Study Registration Dates

First Submitted

February 16, 2021

First Submitted That Met QC Criteria

February 18, 2021

First Posted (Actual)

February 23, 2021

Study Record Updates

Last Update Posted (Actual)

January 28, 2026

Last Update Submitted That Met QC Criteria

January 26, 2026

Last Verified

January 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • COSMICS STUDY

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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