Correlation of Preoperative Global Olfactory Function With Frailty, Perioperative Neurocognitive Disorders and Mortality

Olfactory function will be evaluated through the Burghart Sniffin' Sticks test which is a validated psychophysical testing method. Sniffin' Sticks test is based on pen-like odor dispensing devices that will be presented to the patients. The extended version of this test will be used and consist of three tests of olfactory function, namely tests for odor threshold, odor discrimination and odor identification.

The Edmonton Frail Scale (EFS) involves nine domains of frailty : functional performance, cognitive function, general health, functional independence, social support, used medications, nutrition, mood and continence. It has been validated with respect to comprehensive geriatric assessment and to other screening tools related to frail state. EFS test is considered most appropriate for use in routine preoperative screening and only requires 5 minutes.

The Clinical Frailty Scale (CFS) uses clinicians' judgement to evaluate frailty. It comprises assessment of specific domains including comorbidity, function, and cognition. Score ranges from 1 (very fit) to 9 (terminally ill).

Patients will undergo a neuropsychological test battery preoperatively and postoperatively. This test consists of a battery of psychometric assessments with the ability to objectively assess specific cognitive domains such as attention, executive function, learning and memory, language, perceptual-motor, or social cognition.