Comparison of Fried’s Frailty Phenotype and American Society of Anaesthesiologists (ASA) classification as predictors of postoperative complications in elective craniotomies - A prospective single center observational study.

As a perioperative physician, a crucial task for every anaesthesiologist is to assess the individualized risk and expected outcome for any patient undergoing surgery. Along with the traditional stack of various risk assessment scores, a recently famous parameter is the frailty index. While more and more studies are being done to assess frailty as a measure of risk stratification, there is still a paucity of literature in this topic with respect to neurosurgical cases involving craniotomy, especially in south-Asian countries.

Frailty is defined as a clinical condition characterized by excessive vulnerability of an individual to endogenous and exogenous stressors. One such exogenous stressor is a major surgical procedure like craniotomy. Frailty can be expected to have an effect on the outcome and thus help individualize perioperative patient counselling and management including incentive spirometry, physiotherapy initiation, nutrition supplementation and social or occupational rehabilitation. For assessing outcome of neurosurgical patients, several tools are in place e.g., ASA physical status, NSQIP calculation, Lee’s Revised cardiac risk index and a few more. Frailty has been validated as a score of risk assessment in general surgical, urologic and cardiac patients.

While the usual scores of assessment of frailty as devised by the national surgical quality improvement program (NSQIP), named modified frailty indices 5 and 11 (mFI-11 and mFI-5) have proven validation, they focus more on the comorbidity status of the patient, whether controlled or uncontrolled, which is essentially similar to the ASA classification. mFI-5 is calculated by presence or absence of 5 co-morbidities, namely Congestive heart failure, diabetes mellitus, Chronic obstructive pulmonary disease or pneumonia, partially or totally dependent health status and hypertension requiring medication. mFI-11 is a 11-score system of assessment, which, along with the 5 factors forming mFI5, involves additional factors including history of Myocardial infarction, percutaneous coronary intervention or coronary artery bypass grafting, peripheral vascular disease, altered sensorium, transient ischemic attacks or cerebrovascular accidents, cerebrovascular accidents with residual neuro-deficit. Fried’s frailty phenotype is a newer index which has been validated as a predictor of postoperative outcome using data from cardiovascular health study and is expected to be equally helpful, and includes measures of current functional status of the patient regardless of their preexisting comorbidities. It has been studied and validated in nonsurgical as well as certain surgical groups including those undergoing urological and cardiothoracic procedures, although less so in craniotomy cases. The effect of frailty on operative outcome has also been studied in spine surgery cases. However there is still a paucity of literature with respect to using this index in craniotomy cases, especially in south-Asian population.

This study seeks to determine comparable reliabilities of Fried’s Frailty Phenotype (FFP) and American Society of Anaesthesiologists (ASA) classification in predicting postoperative outcome in elective craniotomies. It is an attempt to add to the preexisting literature and determine the predictive value of the already established score in the less studied patient population.