Brief description of proposal

Introduction:

Postoperative cognitive dysfunction is a well-recognized complication following cardiac surgery, with reported incidence ranging from 30% to 80% depending on the timing and methods of assessment. POCD can lead to prolonged hospital stay, delayed rehabilitation, increased morbidity, and reduced quality of life. The etiology of POCD is multifactorial, with hypoperfusion, microemboli, systemic inflammatory response, and hypoxia contributing to its development during cardiopulmonary bypass and cardiac surgery.

Cerebral oximetry using near-infrared spectroscopy provides continuous, non-invasive monitoring of regional cerebral oxygen saturation, reflecting the balance between cerebral oxygen supply and demand. It has been proposed that intraoperative monitoring of cerebral oxygenation can help in the early detection of cerebral desaturation episodes, allowing timely interventions to prevent prolonged hypoxia and reduce neurological complications.

Several studies have indicated an association between intraoperative cerebral desaturation and the occurrence of POCD in patients undergoing cardiac surgery . Interventions to maintain cerebral oxygen saturation within 10-20 percent of baseline values during surgery have been shown to decrease the incidence of POCD and improve neurological outcomes.

Despite these findings, the role of cerebral oximetry in predicting and preventing POCD remains under evaluation, with variability in protocols, thresholds for intervention, and methods of cognitive assessment across studies]. Further investigation is warranted to determine whether cerebral oximetry-guided intraoperative management can effectively reduce the incidence and severity of POCD following cardiac surgery.

This study aims to evaluate the role of cerebral oximetry monitoring in cardiac surgery and its association with postoperative cognitive dysfunction in adult patients, contributing to the evidence for optimizing perioperative neurological outcome.

Aim:

To evaluate the role of intraoperative cerebral oximetry in reducing the  incidence of  post operative cognitive dysfunction in patients undergoing cardiac surgeries.

Primary Objective:

• To determine the incidence of Post operative cognitive dysfunction using neurocognitive tests.
• To assess the correlation of intra operative cerebral oximetry  and incidence of Post operative cognitive dysfunction

Secondary Objective:

• To evaluate secondary outcomes 
• Post operative delirium ,
• duration of mechanical ventilation ,
• duration of ICU and hospital stay,

 in relation to intraoperative cerebral desaturation episodes.

Justification: As neurological complications increase the morbidity  in cardiac and vascular surgeries, intra operative cerebral oximetry provides the opportunity to the clinician to use brain as an index organ for the adequacy of perfusion of other vital organs. 

Methodology:

Study Design:  Prospective randomized observational study. 

Place of work: Netaji Subhash Chandra Bose Medical College, Superspeciality Hospital, Jabalpur.

Sample Size:120 based on pilot study

Study Settings:

Cardiothoracic and Vascular Surgery operation theatres and Postoperative ICU.

Study Duration:18 months

Study Population:

Patients undergoing elective cardiac surgery under cardiopulmonary bypass.

Inclusion Criteria:

1) Age >18 years

2)Patients undergoing elective cardiac surgery under CPB.

3)Patients able to complete MoCA Testing

4)ASA III-IV

Exclusion Criteria:

1)Pre-existing cognitive dysfunction or psychiatric illness.

2)Visual or hearing impairment.

3)Emergency surgery.

4)Patient refusal.

Material and Methods: This study will be conducted at Superspeciality hospital,NSCB Medical college,Jabalpur,after approval from our institutional Ethics committee.This study will enroll 120 patients of ASA grade III and IV fulfilling the inclusion criteria undergoing elective Cardiac surgeries .The patients will be randomised into Group A and Group B with the help of computer generated randomized sequence.

GROUP A:Cerebral oximetry

GROUP B:Control 

1)Preoperative assessment

Baseline Montreal Cognitive Assessment will be conducted 1 day before surgery in a quiet environment.

2)Intraoperative Cerebral Oximetry Monitoring

Near-Infrared Spectroscopy cerebral oximeter sensors placed on the bilateral frontal region before induction.

Continuous monitoring of rSO2 throughout surgery including: 

Pre-induction

During CPB

Rewarming

Post-CPB until the end of surgery

Significant desaturation is defined as >20 percent drop from baseline or absolute regional oxygen saturation <50percent

Duration and number of any desaturation episodes will be recorded and treated as per the protocols. Interventions required for desaturation ,head position, FIO2 increase, CO2 adjustment, BP management will be documented.

Apart from standard ASA monitoring parameters, PaCO2, PaO2, hematocrit and MAP will be observed throughout the surgery.

Postoperative Cognitive Assessment: performed on POD-5 , day before discharge and 3 months after discharge in a quiet ,non-stimulating environment.

Delirium will be differentiated from POCD with the help of CAM-ICU Test

Data collection : data collection will be based on MoCA scale and rSO2 values.

Collected data will be analysed using Graphpad Prism version 10.4.2. continuous variables will be expressed as Mean ± SD and compared using Student- t test and Mann Whitney U test. Categorical variables will be analysed using Chi square And Fisher’s exact test, with statistical significance set at p<0.05.