PCO₂ Gap and Lactate as Predictors of POCD After Cardiac Surgery

NCT07843186 | Not Yet Recruiting

• 1 other identifier: FMASU MD309/2025
• Study Type: observational
• Target: 185
• Locations: 0 countries
• Sites: N/A

Brief Summary

This prospective observational study aims to evaluate whether intraoperative venous-to-arterial carbon dioxide partial pressure difference (PCO₂ gap) and arterial lactate levels can serve as early predictors of postoperative cognitive dysfunction (POCD) in elderly patients undergoing elective cardiac surgery with cardiopulmonary bypass. Intraoperative measurements of PCO₂ gap and lactate will be correlated with perioperative cognitive outcomes assessed using the Montreal Cognitive Assessment (MoCA) and postoperative delirium screening using the Confusion Assessment Method for the ICU (CAM-ICU).

Conditions

Postoperative Cognitive Dysfunction (POCD); Cardiac Surgery; Cardiopulmonary Bypass

Keywords

PCO₂ gap; Lactate; Postoperative cognitive dysfunction; CAM-ICU; MoCA

Outcome Measures

Primary Outcomes (1)

• Predictive Value of Intraoperative PCO₂ Gap and Arterial Lactate Levels for Postoperative Cognitive Dysfunction (POCD

  To evaluate whether intraoperative venous-to-arterial carbon dioxide partial pressure difference (PCO₂ gap) and arterial lactate levels predict postoperative cognitive dysfunction in elderly patients undergoing elective cardiac surgery with cardiopulmonary bypass. POCD will be assessed by changes in Montreal Cognitive Assessment (MoCA) scores from the preoperative baseline to 1 month postoperatively.

  Baseline (preoperative) and 1 month postoperatively

Secondary Outcomes (7)

• Early Postoperative Delirium Assessed by the Confusion Assessment Method for the ICU (CAM-ICU)

  Daily during the first 5 postoperative days or until ICU discharge, whichever occurs first

• Determination of Cutoff Values for Intraoperative PCO₂ Gap and Arterial Lactate Levels Predictive of POCD

  1 month postoperative

• Correlation of (CAM - ICU) to MoCA for prediction of cognitive impairmentat 5 days post operative

  CAM-ICU: Daily during the first 5 postoperative days; MoCA: baseline preoperatively and 1 month postoperatively

• Incidence of POCD at 1 month postoperatively, defined by a decline in MoCA scores from baseline in elderly cardiac patient.

  Baseline (preoperative) and 1 month postoperatively

• Duration of Mechanical Ventilation in Relation to Intraoperative PCO₂ Gap and Arterial Lactate Levels

  Measured from the end of surgery until successful extubation (up to 30 days)

Study Arms (1)

Elderly Patients Undergoing Elective Cardiac Surgery with Cardiopulmonary Bypass

Patients aged 65 years or older undergoing elective cardiac surgery with cardiopulmonary bypass. Participants will undergo serial intraoperative measurements of the venous-to-arterial carbon dioxide partial pressure difference (PCO₂ gap) and arterial lactate levels. Postoperative cognitive function will be assessed using the Montreal Cognitive Assessment (MoCA), and postoperative delirium will be screened using the Confusion Assessment Method for the ICU (CAM-ICU).

Eligibility Criteria

• Age: 65 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Older Adult (65+)
• Sampling Method: Non-Probability Sample

Study Population

Elderly patients (65 years or older) undergoing elective cardiac surgery with cardiopulmonary bypass at El-Demerdash Hospital, Ain Shams University, Cairo, Egypt. Eligible participants will undergo routine perioperative management with serial intraoperative PCO₂ gap and arterial lactate measurements and perioperative cognitive assessment according to the study protocol.

You may qualify if:

• Age ≥65 years.
• Undergoing elective cardiac surgery with cardiopulmonary bypass (e.g., coronary artery bypass grafting or valve surgery).
• American Society of Anesthesiologists (ASA) Physical Status III.
• Able to provide written informed consent.

You may not qualify if:

• Refusal or inability to provide written informed consent.
• Pre-existing neurological disorders (e.g., Alzheimer's disease, Parkinson's disease, or stroke with residual neurological deficits).
• Severe psychiatric disorders requiring active treatment.
• History of drug or alcohol abuse.
• Emergency cardiac surgery.
• Significant visual or hearing impairment interfering with cognitive testing.
• Inability to complete preoperative cognitive assessment.
• Preoperative dementia (MoCA score \<20).
• Significant pulmonary disease (e.g., COPD or lung cancer).

Sponsors & Collaborators

• Ain Shams University: lead

MeSH Terms

Conditions

Postoperative Cognitive Complications

Condition Hierarchy (Ancestors)

Postoperative Complications; Pathologic Processes; Pathological Conditions, Signs and Symptoms; Cognitive Dysfunction; Cognition Disorders; Neurocognitive Disorders; Mental Disorders

Central Study Contacts

Mariam Mohamed Hesham, Master

CONTACT

01013933073; Mariamhesham@med.asu.edu.eg

Study Design

• Study Type: observational
• Observational Model: COHORT
• Time Perspective: PROSPECTIVE
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: June 29, 2026
• First Posted: September 25, 2026
• Study Start (Estimated): December 1, 2026
• Primary Completion (Estimated): May 1, 2028
• Study Completion (Estimated): August 1, 2028
• Last Updated: September 25, 2026

Record last verified: 2026-06

Data Sharing

• IPD Sharing: Will not share