Can the 6MWT Can be Used to Identify Reduced Patient Fitness at Surgical Clinic

Overview

The aim of this study is to assess the feasibility of using the 6 minute walk test (6MWT) as a cardiorespiratory fitness (CRF) screening tool. The screening would take place when the patient attends the hospital for their initial surgical outpatient appointment. By screening all potential major intra-abdominal surgery patients for a period of 6 months and recording the distance walked in the 6 minutes (6MWD) the aim is to produce a threshold distance for the patients of Sheffield that would identify those with sufficient CRF what would allow them to proceed to surgery without further investigations or fitness interventions. Having identified the fit it would allow the perioperative team to focus resources on the less fit with the aim of improving CRF and other elements that would lead to reduced postoperative morbidity and mortality. Other primary aims include noting the time to surgery. This data will inform on wither instigation of the early screening test would facilitate enrolment and completion of an exercise programme before surgery. The secondary aim is to assess the relationship between the 6MWD and routine CPET to confirm if those that walk the furthest are in fact the fittest.

This is a prospective observational study that would run for a period of 6 months. The population proceeding to undergo major abdominal surgery is estimated to be 500 patients a year. The primary aim is to invite all patients being considered for major abdominal surgery to participate in a simple screening test of fitness, the 6 minute walk test (6MWT). Potential participants would be identified by the participating surgical teams during their first visit to this institutions Surgical Outpatient Department (SOPD). Upon identification the individual would be provided with information designed to be read on returning to the waiting area from the SOPD clinic room. The study walker, who would be an appropriately trained research nurse or outpatient clinic support worker, would approach the patient to answer questions and provide further information if required. Consent for participation would then be obtained. The participating individual would then be walked the short distance to the testing area and would be offered a seat whilst the 6MWT procedure was explained in more detail. Time would be allowed for questions. The 6MWT would be then conducted as per the American Thoracic Society guidance. Heart rate will be recorded manually both at baseline and at the cessation of the test. Following the 6MWT patients could either depart the hospital or return to the SOPD if it was felt a period of recovery was required. The 6 minute walk distance (6MWD) would be recorded against the patient's participant study identification number. Patient identifiers that would link the patient study number to a particular patient would be stored safely behind lock and key or encryption when electronic. The case report forms will be paper to allow timely collection of data and this information will be collated onto a spreadsheet which will facilitate future analysis. At a later date information will also be collected on date of operation, this will be used to assess the present 'window' of opportunity for enrolling the less fit into an exercise programme. A secondary aim of this study is to investigate the relationship between the 6MWD and the objectively measured anaerobic threshold and peak oxygen consumption that will be obtained when some of these patients undergo cardiopulmonary exercise testing (CPET) as part of their standard pathway to surgery. Reports produced following CPET interpretation are stored as PDFs upon this institutions server, named individuals involved in collecting data for this study will have access to the this server to complete case report forms that require details from the CPET reports. Statistical analysis: Descriptive statistics will be undertaken on the population that participates in the 6MWT, the population will be split into quartiles based on what the investigators know about our non-cardiopulmonary surgery population following analysis of our CPET database. Those deemed significantly less fit occupied the lowest quartile. The aim would be to assess for population normality and produce thresholds for the most fit; the greatest distance walked by 25% of the population with the least fit the lowest 25% of the population. The middle 50% would be less fit. Linear regression analysis will be used to determine the 6MWD threshold that correlates with a level of anaerobic threshold or peak oxygen consumption objectively measured by CPET, deemed acceptable and indicating those individuals for whom no further preoperative interventions are required. During the 12 months of 2017 the investigators undertook 483 preoperative major abdominal surgery cardiopulmonary exercise (CPET) tests. The investigators anticipate collecting 6MWT data on 250 patients and CPET data on at least 240 patients. Hopefully all those who undergo CPET will have consented to undergo a 6MWT whilst in the SOPD during their first visit on their pathway toward surgery.