Abstract
With an ageing population, an increasing number of elderly patients are presenting for surgical intervention. Perioperative risk assessment in this population is difficult and commonly used tools often fail to accurately predict risk in this cohort. Accurate risk assessment is important to facilitate patient centred decision making, to identify patients suitable for preoperative optimisation, and to guide perioperative care. Fundamentally, as patients age, their physiological reserves diminish so that they are less equipped to respond to significant external stressors, such as major surgery. Frailty, which can be conceptualised as a state of increased vulnerability as a result of this decline in physiological reserve, offers a potential surrogate of risk, and is becoming an integral component of perioperative risk assessment in older patients. Frailty has been demonstrated to be independently associated with an increased risk of perioperative morbidity and mortality, prolonged hospital admission and a reduction on quality of life.
This thesis aims to determine the prevalence of frailty in an inpatient population and subsequently examine patient outcomes at 90-days follow-up. Secondly, over the subsequent chapters, this thesis aims to determine the relationship between different measures of peri-operative frailty, and post-operative outcomes in patients undergoing major colorectal surgery. Chapter 3 retrospectively reviews post-operative outcomes in patients classified as frail using a radiological surrogate, the Total Psoas Index (TPI) and a clinical frail scale, the modified frailty index (mFI). Chapter 4 prospectively assesses the relationship between three different clinical frailty measures and post-operative outcomes. Chapters 5 and 6 investigate two novel markers of frailty; patient activity levels, as assessed by step count, and patient mitochondrial function; and examines the relationship between these novel markers and post-operative outcomes.