The thoughtful study on wearable activity monitors by Daskivich et al1 for the first time to date addresses a long-standing paradox. Physicians have known forever that ambulatory status matters and represents a high value toward successful outcomes, with attendant reductions in complications and lengths of stay. Despite that value, we have historically relied on notoriously poor metrics to assess ambulatory status and fitness and done little in the way of structured “prehabilitation” before elective surgery.
Their study of 100 patients undergoing major inpatient operations used activity monitors to quantitate postoperative ambulation. The authors demonstrate that a step count up to 1000 steps on postoperative day 1 is associated with a lower probability of a prolonged length of stay and thus can identify patients at risk for extended lengths of stay.
Management guru Peter Drucker, PhD, famously said, “If you can’t measure it, you can’t improve it.” This article demonstrates that ambulatory status can be measured, thus raising the possibility of improvement. Dr Drucker would be thrilled.
Physicians often think they “know it when they see it.” In other words, their clinical acumen is accurate. Regarding fitness and ambulation, not so! The recently reported results of an international study of more than 1000 patients (1-year follow-up) indicate how poorly subjective preoperative assessment is in identifying patients with “poor fitness.”2 For example, subjective assessment of poor functional capacity had a sensitivity of 19.2% for identifying low maximum oxygen consumption. Duminda N. Wijeysundera, PhD, the lead author, commented: “If your current approach for judging preoperative functional capacity is subjective assessment, you should simply abandon it.”3
It would be a small step to routinely advise and monitor preoperative patients to work up to a baseline step count. Such prehabilitations might ensure attainable postoperative ambulation.
Certainly, there will be those experienced clinicians who regard activity monitors as an infringement on their clinical acumen. Regrettably, throughout time, physicians have resisted new technology as unnecessary or an intrusion. Three hundred years ago, Daniel Fahrenheit proposed a new “temperature sensor” to the esteemed Dutch physician Herman Boerhaave.4 Dr Boerhaave embraced it as a way to make medical diagnosis of body temperature and fever more modern, objective, and scientific. However, many of his colleagues howled that the physician’s touch captured information far richer than any tool: for the next 100 years, many physicians were loath to use the glass tube now known as a thermometer, preferring to simply lay on hands and feel the temperature.
Commercially available wearable activity monitors are now readily available and cheap. While Fitbit, Inc has suffered substantially since its initial public offering valuation in excess of $4 billion, the general principle of ubiquitous wearable computers bodes well for our future ability to measure, track, and understand patient physiological data and behavior both in the hospital and at home. The ability to capture that data, apply machine learning to evolving trends, and alert patients, nurses, and physicians instantaneously is powerful. That alert can come easily via the supercomputer we all carry, the smartphone, which we often erroneously simply refer to as a phone. The technology in your pocket is 120 million times more powerful than that of the 1971 Apollo spacecraft. While Gordon Moore’s law5 may not last to infinity, processing power continues its relentless doubling every 18 to 24 months. More will come of this trend.
What are the implications of ubiquitous high-performance computing? In 2015, an article in The Economist6 predicted by 2020 that 80% of the adult population of the world would have a smartphone in their pocket. This opens up an entirely new world of real-time data acquisition, monitoring, and intervention, and I believe the report by Daskivich et al1 is only the beginning.
On December 6, 2018, Apple rolled out a software upgrade that turns the Apple Watch Series 4 into a personal electrocardiogram.7 In Time Fitzpatrick weighed in on the development.8 While wearables’ fidelity may not yet match medical-grade monitors and devices, “good enough” coupled with around-the-clock capabilities, real-time data capture, storage, and analytics seem likely to provide real value. Once upon a time, not so long ago, a woman went to an obstetrician to get a pregnancy test—no longer. Such “democratization” seems destined to continue and accelerate.
Open Access: This is an open access article distributed under the terms of the CC-BY License. © 2019 Krummel TM. JAMA Network Open.
Published: February 1, 2019. doi:10.1001/jamanetworkopen.2018.7672
Correction: This article was corrected on March 22, 2019, to fix the elocator and doi numbers in reference 1.
Corresponding Author: Thomas M. Krummel, MD, Department of Surgery, School of Medicine, Stanford University, 318 Campus Dr, Room E100D, Mail Code 5428, Stanford, CA 94305 (email@example.com).
Conflict of Interest Disclosures: Dr Krummel reported consulting with a number of early medical technology robotics companies, all of which involved inpatient or operating room devices (none are in wearable computing or perioperative assessment space or in the arena of wearables).