Biomarker Use in Evidence of Neuronal Damage in Response to Anaesthesia and Surgery

The BOUNDARY study is investigating whether the type of anaesthesia given to patients over 65, who are undergoing non-cardiac surgery, influences cognition and proteins found in the blood.

Patients in this study will be randomly allocated to receive either

1) Total Intravenous Anaesthesia (TIVA) or

2) Volatile Anaesthesia.

TIVA is a type of anaesthesia administered via the blood stream. Volatile anaesthesia is administered as a gas that we breathe. To measure for changes in blood based proteins we collect blood samples before surgery, then at 6 and 24 hours post-surgery, and finally once more at the time of discharge from hospital.

To understand any changes in thinking skills, participants enrolled in this study complete memory puzzles prior to surgery and up to 3 months following surgery.

• Complete memory puzzles and quizzes before your surgery and then again three months later

The memory tests will take between an hour and an hour and a half. They involve completing puzzles on paper, simple tasks on a touch screen computer and some questionnaires. At each time point we are happy to come to the your home or to an alternative location that you find convenient.

• Allow us to take some blood samples

While you are in the hospital we take blood just before your surgery, again 6 and 24 hours after your surgery and then once more just before you are discharged. Usually we use the same lines that the nurses use to take bloods which means no additional needles!

• Answer a few brief questions each day you are in the hospital.

One of our research assistants will visit you each day that you are on the ward to ask a few quick questions. These questions help us understand if you are experiencing an episode of delirium. Delirium is a temporary state of confusion that many older adults experience after surgery and anaesthesia.