Depth of Anaesthesia and Postoperative Cognitive Decline in Patients Undergoing Heart Surgery

Not Applicable

Completed

• Conditions: Postoperative Cognitive Dysfunction; Postoperative Delirium; Cardiac Bypass Surgery in Adult Patients 65 Years and Older
• Interventions: Other: Targeted intra-operative depth of anaesthesia

• Registration Number: NCT01743456
• Lead Sponsor: King's College Hospital NHS Trust

Brief Summary

Post-Operative Cognitive Decline (POCD) is common after cardiac surgery and associated with increased morbidity and mortality. The pathophysiology of POCD is only poorly understood. Causes include hypoperfusion, microemboli and the systemic inflammatory response, which result in a reduction of cerebral oxygen delivery.

Cerebral oxygenation can be monitored non-invasively by measuring frontal lobe oxygen saturation (rSO2).

The bispectral index (BIS) of the electroencephalogram is widely known to measure depth of anaesthesia, and there is a high correlation between BIS, a dimensionless calculated number between 0 and 100, and clinical criteria of sedation. With BIS below 60 recall is extremely low.

The investigators demonstrated recently that inappropriately high levels of anaesthesia may be associated with poorer long-term outcomes in cognition after non-cardiac surgery (Ballard et al. 2012). Whether optimisation of the depth of anaesthesia and cerebral oxygenation has an effect on postoperative cognitive function in patients undergoing cardiac surgery is unknown.

The investigators hypothesize that the incidence of POCD in elderly patients (\> 65 years old) at 6 weeks is less with mildly deep anaesthesia (BIS 50 +- 10) and optimised rSO2 (interventions when rSO2 drops below 15% of baseline reading) when compared with current practice (BIS blinded anaesthesia, reflecting moderately to highly deep anaesthesia and blinded rSO2 measurements).

Detailed Description

Not available

Study Timeline

• Study First Submitted: 2012-12-04
• Study First Submitted QC: 2012-12-05
• Study First Posted: 2012-12-06
• Status Verified: 2013-01
• Study Start: 2014-01
• Primary Completion: 2016-01
• Study Completion: 2017-01
• Last Update Submitted: 2019-10-21
• Last Update Posted: 2019-10-22

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 88

Inclusion Criteria

• patients undergoing elective coronary artery bypass graft surgery
• patients at 65 years of age and older

Exclusion Criteria

• diseases of the central nervous system including dementia
• inadequate knowledge of English
• a current or past psychiatric illness
• current use of tranquilizers or antidepressants
• severe visual, auditory, or motor handicap

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
Targeted intra-operative depth of anaesthesia	Targeted intra-operative depth of anaesthesia	-

Primary Outcome Measures

Name	Time	Method
Incidence of postoperative cognitive decline after bypass surgery	Six weeks after bypass surgery

Secondary Outcome Measures

Name	Time	Method
Postoperative Delirium	3-5 days postoperatively
Difference in degree of postoperative cognitive decline at 5 days, 6 weeks or 1 year after bypass surgery	5days, 6 weeks or 1 year postoperatively
Incidence of postoperative cognitive decline 5 days and 1 year after bypass surgery	Five days and one year postoperatively
Postoperative central nervous system and myocardial biochemical markers	up to 48 hours postoperatively

Trial Locations

Locations (1)

King's College Hospital NHS Foundation Trust; 🇬🇧 London, Denmark Hill, United Kingdom