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Research and Projects

Cognitive Monitoring in Planned Arthroplasty Surgery Study (CoMPASS)

Theme: ARC - Complex Care
Status: Live

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A South West Anaesthesia Research Matrix (SWARM) Study





SWARM have teamed up with primary care researchers for an exciting study, which aims to help answer one of the most important issues in contemporary anaesthesia; post-operative cognitive decline.

A decline in cognitive function is common and sometimes permanent following major surgery in the elderly and isn’t dependent on whether patients have had a general or spinal anaesthetic. There is uncertainty over which factors cause the change; the operation itself, anaesthesia, emotional stress, medications or a combination of these. It is also unclear whether there would be a similar decline without surgery and who is at risk. Current literature lacks an accurate picture of pre-operative cognitive trajectories and trajectories in older people who don’t have surgery.

More than 2,000 hip and knee replacements are carried out every year in the South West, meaning that patients can be on waiting lists for many months. This provides an opportunity to perform cognitive testing during the pre-operative period and then to follow up with further testing on patients in the short- and long-term post-operative period.  



The South West Anaesthesia Research Matrix (SWARM) provides a workforce of anaesthesia trainees across the South West Peninsula region encompassing six hospitals, all of which perform elective lower limb joint arthroplasty surgery. The trainees will work in collaboration with patients, industry and cognition experts to assess the feasibility of serial remote monitoring of cognition with an online tool (CogTrack™) in elderly patients undergoing planned arthroplasty surgery and matched non-surgical controls.

The long term goal is to follow this feasibility study with a larger multi-centre study to monitor the cognitive trajectory, both pre- and post-operatively of patients undergoing surgery and make comparisons with an appropriate control group.

Ultimately, the aim is to collect cognitive data on a large number of patients over a long period of time. By gaining a more accurate picture of pre-operative cognitive function and comparing with an appropriate control group, we aim to add to the body of evidence, especially regarding those who may be particularly at risk. 

By doing this we will be better placed to develop possible preventative interventions and to advise patients more accurately when discussing the balance of risks and benefits of surgery.



Patient recruitment started in early January 2019. As of December 2019, the primary care arm has recruited their target of 50 patients, and the secondary care arm has recruited 90 patients (target of 100-150).

The study period has been extended from August 2019 to March 2020 to permit follow up of patients with longer than anticipated time on the waiting list between recruitment and surgery.

For more information about this project, visit the SWARM website.