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

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ClinicalTrials.gov Identifier: NCT01743456
Recruitment Status : Completed
First Posted : December 6, 2012
Last Update Posted : October 22, 2019
Information provided by (Responsible Party):
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).

Condition or disease Intervention/treatment Phase
Cardiac Bypass Surgery in Adult Patients 65 Years and Older Postoperative Cognitive Dysfunction Postoperative Delirium Other: Targeted intra-operative depth of anaesthesia Not Applicable

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Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 88 participants
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Triple (Participant, Investigator, Outcomes Assessor)
Primary Purpose: Treatment
Official Title: Effect of Depth of Anaesthesia on Postoperative Cognitive Decline in Patients Undergoing Coronary Artery Bypass Graft Surgery - a Prospectively Randomized Controlled Study
Actual Study Start Date : January 2014
Actual Primary Completion Date : January 2016
Actual Study Completion Date : January 2017

Arm Intervention/treatment
No Intervention: Current practice (BIS and rSO2 blinded)
Experimental: Targeted intra-operative depth of anaesthesia Other: Targeted intra-operative depth of anaesthesia
The intervention group receives isoflurane at a concentration that results in a BIS value between 40-60 intra-operatively.

Primary Outcome Measures :
  1. Incidence of postoperative cognitive decline after bypass surgery [ Time Frame: Six weeks after bypass surgery ]

Secondary Outcome Measures :
  1. Incidence of postoperative cognitive decline 5 days and 1 year after bypass surgery [ Time Frame: Five days and one year postoperatively ]
  2. Difference in degree of postoperative cognitive decline at 5 days, 6 weeks or 1 year after bypass surgery [ Time Frame: 5days, 6 weeks or 1 year postoperatively ]
  3. Postoperative Delirium [ Time Frame: 3-5 days postoperatively ]
  4. Postoperative central nervous system and myocardial biochemical markers [ Time Frame: up to 48 hours postoperatively ]

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Ages Eligible for Study:   65 Years and older   (Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No

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

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT01743456

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United Kingdom
King's College Hospital NHS Foundation Trust
London, Denmark Hill, United Kingdom, SE5 9RS
Sponsors and Collaborators
King's College Hospital NHS Trust
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Principal Investigator: David Green, FRCA, MBA King's College Hospital NHS Trust
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Responsible Party: King's College Hospital NHS Trust
ClinicalTrials.gov Identifier: NCT01743456    
Other Study ID Numbers: KHC11-001
First Posted: December 6, 2012    Key Record Dates
Last Update Posted: October 22, 2019
Last Verified: January 2013
Keywords provided by King's College Hospital NHS Trust:
Postoperative cognitive dysfunction
Coronary artery bypass graft surgery
Postoperative cognitive improvement
Postoperative delirium
Additional relevant MeSH terms:
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Postoperative Cognitive Complications
Cognitive Dysfunction
Neurobehavioral Manifestations
Neurologic Manifestations
Nervous System Diseases
Neurocognitive Disorders
Mental Disorders
Cognition Disorders
Postoperative Complications
Pathologic Processes
Central Nervous System Depressants
Physiological Effects of Drugs