South West Anaesthesia Research Matrix


COMPASS: Cognitive Monitoring in Planned Arthroplasty Surgery - Pilot 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. It is uncertain what causes the change, whether a similar decline might occur without surgery and who is at risk. Current literature lacks an accurate picture of pre-operative cognitive trajectories and trajectory in older people who don’t have surgery. Our aim is 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. Our primary care and anaesthetic trainee research networks will work in collaboration with patients, industry and cognition experts.



Feasibility study testing a prospective observational methodology at two secondary care sites and two primary care sites. Serial cognitive testing will be performed with CogTrack™ on 150 surgical patients and 50 non-surgical controls. The surgical patients will be assessed over a pre-operative period of at least 6 weeks until 6 weeks the surgical episode. The primary outcome measure is feasibility. Secondary outcome measures include CogTrack™ scores and prevalence of factors which may impact on cognition. Patients were involved in refining outcome measures and will contribute throughout.



Feasibility data including number of patients approached, recruited, declining and withdrawing will be collected, as well as information about IT accessibility and completion rates of assessments.  Summary statistics will be conducted on CogTrack™ data for cases and control groups, and plots constructed to demonstrate trajectory of scores over the study period. Mixed Model Repeated Measure analysis will be performed to assess the effects of exposure to arthroplasty and adjust for candidate covariates.



Our aim, in a future multi-centre study, is to track the cognitive trajectories of a large number of operated cases and matched controls over a long time period.  Arthroplasty surgery is performed very commonly, and on an increasingly aging population, aiming to improve functional capacity. Conversely, permanently altered cognition could impact on patients’ quality of life. Clinical research underpins shared decision-making with patients.


Patient recruitment started in early January 2019. As of September 2019, the primary care arm has recruited their target of 50 patients, and the secondary care arm has recruited 72 patients (target of 100-150). The study period has been extended from August 2019 to march 2020 to permit followup of patients with longer than anticipated time on the waiting list between recruitment and surgery. Data collection is now complete and we are now in the analysis and write up phase

Chief Investigator: Johannes Retief

Plymouth Principal Investigator: Gary Minto

Torbay Principal Investigator: Tom Clark


  • British Journal of Anaesthesia Research Forum May 2018 (Andrew Woodgate)
  • RAFT winter meeting February 2018 (Johannes Retief)
  • ​SWARM RTS March 2018 (Johannes Retief)
  • ​South West Society for Academic Primary Care Regional Meeting March 2018 (elevator pitch by Emma Parker)
  • South West Community Clinical Research Forum March 2018 (Gary Minto)