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

Postoperative Delirium Clinical Trial

Official title:

Effect of Depth of Anaesthesia on Postoperative Cognitive Decline in Patients Undergoing Coronary Artery Bypass Graft Surgery - a Prospectively Randomized Controlled Study

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT01743456
• Other study ID #: KHC11-001
• Status: Completed
• Phase: N/A
• Start date: January 2014
• Est. completion date: January 2017

Study information

• Verified date: January 2013
• Source: King's College Hospital NHS Trust
• Contact: n/a
• Is FDA regulated: No
• Study type: Interventional

Clinical Trial 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).

Recruitment information / eligibility

• Status: Completed
• Enrollment: 88
• Est. completion date: January 2017
• Est. primary completion date: January 2016
• Accepts healthy volunteers: No
• Gender: All
• Age group: 65 Years and older

Eligibility

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

Related Conditions & MeSH terms

• Cardiac Bypass Surgery in Adult Patients 65 Years and Older
• Cognitive Dysfunction
• Delirium
• Postoperative Cognitive Dysfunction
• Postoperative Delirium

Intervention

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.

Locations

Country	Name	City	State
United Kingdom	King's College Hospital NHS Foundation Trust	London	Denmark Hill

Sponsors (1)

Lead Sponsor	Collaborator
King's College Hospital NHS Trust

Country where clinical trial is conducted

United Kingdom, 

References & Publications (1)

Ballard C, Jones E, Gauge N, Aarsland D, Nilsen OB, Saxby BK, Lowery D, Corbett A, Wesnes K, Katsaiti E, Arden J, Amoako D, Prophet N, Purushothaman B, Green D. Optimised anaesthesia to reduce post operative cognitive decline (POCD) in older patients undergoing elective surgery, a randomised controlled trial. PLoS One. 2012;7(6):e37410. doi: 10.1371/journal.pone.0037410. Epub 2012 Jun 15. Erratum in: PLoS One. 2012;7(9). doi:10.1371/annotation/1cc38e55-23e8-44a5-ac2b-43c7b2a880f9. Amaoko, Derek [corrected to Amoako, Derek]. PLoS One. 2013;8(9). doi:10.1371/annotation/c0569644-bea1-4c38-af9a-75d1168e3142. — View Citation

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	Incidence of postoperative cognitive decline after bypass surgery		Six weeks after bypass surgery
Secondary	Incidence of postoperative cognitive decline 5 days and 1 year after bypass surgery		Five days and one year postoperatively
Secondary	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
Secondary	Postoperative Delirium		3-5 days postoperatively
Secondary	Postoperative central nervous system and myocardial biochemical markers		up to 48 hours postoperatively