A virtual eye on vital signs

Research and expert perspectives on vital sign monitoring.


Tracking vital signs in non-ICU patients without overtaxing nursing staff continues to be a challenge for hospitals. New continuous monitoring systems have been hitting the market, adding new options for hospitalists trying to strike the optimal balance between monitoring today's often very ill general ward patients and wasting limited time and resources.

The systems, which vary in design and in the indicators they assess, offer a potential alternative on busy medical-surgical floors, where nurses may be unable to check vital signs more than every 4 to 6 hours or even longer, said Eyal Zimlichman, MD, who is deputy director and chief medical officer at Sheba Medical Center in Israel, research associate at Brigham and Women's Hospital in Boston, and advisor to a monitoring system manufacturer.

“We know now, and there's a lot of evidence, that usually when a patient deteriorates we have a window of opportunity of 4 to 8 hours before the deterioration actually happens, where we could identify that the patient is going in the wrong direction and intervene in time to prevent that,” he said. “If we're taking vital signs every 6 hours or every 8 hours, we might miss that window completely.”

Photo by Thinkstock
Photo by Thinkstock

But these devices—still relatively new on hospital floors—are emerging at the same time that hospital clinicians are also striving to avoid alarm fatigue and over-reliance on technology. The non-profit ECRI Institute cited the potentially fatal consequences of missed alarms, in part due to alarm fatigue, among its top 10 list of technology hazards for 2016. Meanwhile, the Choosing Wisely campaign discouraged routine use of telemetry outside of the ICU, saying that it's of limited benefit for patients with a normal electrocardiogram.

Still, some hospitals have come to rely on telemetry, despite its ability to only assess a patient's heart rate and rhythm, as a default way to keep a technological eye on non-ICU patients they're worried about, said Vinay Maheshwari, MD, director of intensive medicine at Christiana Care Health System in Newark, Del.

As of this fall, Dr. Maheshwari said the Christiana Care system was negotiating with a vendor in the hope of trying out the continuous monitoring technology—along with scrutinizing variables like outcomes and alarm fatigue—in intermediate care-level patients starting next year. Some of the vital signs that the system will likely monitor include pulse oximetry, heart rate, respiration rate and continuous blood pressure monitoring, and possibly others such as motion, according to Dr. Maheshwari.

Depending upon their findings, the devices might reduce the need for telemetry in some non-ICU patients, Dr. Maheshwari said. Doctors may sometimes use telemetry “because we don't have anything else,” he said. “In fact what we are looking for is other ways to monitor these patients on a more regular basis.”

Emerging options

While most of these systems have been available for 4 to 5 years, hospital interest has been growing more recently, said Ramya Krishnan, a senior project engineer in the ECRI Institute's health devices evaluation group.

One of the drivers has been worries about the vulnerability of patients on opioids in low-acuity units, where changes in respiration may not be caught overnight or during other long gaps between checks until a patient is found “dead in bed.” Also, hospitals are interested in other potential benefits touted by the technology's developers, including early detection of patient deterioration or sepsis and fall prevention, she said.

At this point, there are a handful of popular systems on the market and they typically track several variables, including blood pressure, temperature, oxygen saturation, and respiration, Ms. Krishnan said. In a recent proprietary report, the institute evaluated 4 such systems: EarlySense All-In-One System, Philips IntelliVue Cableless Measurement with IntelliVue Guardian Software, Sotera Wireless Visi Mobile System, and the Masimo Radius-7 with Root.

“It seems like a lot of hospitals are interested in this technology,” Ms. Krishnan said. “They are talking about it, they're wondering what they want to do. But only a very small percentage is actually implementing them and using them,” she said, noting that it's typically on a pilot basis.

Dr. Zimlichman, who became intrigued by the technology's non-ICU potential roughly a decade ago and now serves on the advisory board for EarlySense, maintains that one of the strengths of these systems is their ability to identify more subtle trends over time, in particular changes in respiration. Even when a nurse is at the bedside, it's difficult to get a precise respiration count because patients are aware and may adjust their breathing accordingly, he said.

Plus, it can be time-consuming to calculate the rate, and a busy nurse might be tempted to estimate, he said. “We call it the missing vital sign.”

Dr. Zimlichman was the lead author on a study, published in 2014 in The American Journal of Medicine, which looked at ICU admissions and other outcomes 9 months before and after a continuous monitoring system was implemented in a 33-bed medical-surgical unit. While there wasn't a significant change in the number of patients who needed to be transferred to the ICU, their condition appeared to be less acute upon transfer, Dr. Zimlichman said.

According to the findings, the mean length of ICU stay after transfer from a medical floor was 4.5 days prior to the implementation of the technology—the researchers studied the EarlySense system—versus 2.45 days during the 9-month intervention period. The rate of code blues also was significantly lower, declining from a rate of 6.3 such events per 1,000 patients to 0.9.

An analysis conducted for the Veterans Health Administration, which has been testing the EarlySense technology in a few facilities, raised some questions about the caliber of the study's findings. The authors noted that some of the outcomes were not blinded and some were not reported, such as the mechanisms used for activating rapid response teams.

One broader concern about relying too much on technological alerts is that nurses might then spend less time with the patient and thus miss more subtle cues that “are not a bunch of numbers,” said Mark Helfand, MD, FACP, a staff physician at the VA Portland Health Care System in Oregon and one of the VA report's authors.

Overall, though, nurses at the 2 VA facilities who were using the EarlySense technology were generally positive regarding its potential as a supplementary vital sign tool, but not as a replacement for the nurse's role, he said.

Dr. Helfand recommended that hospital services considering adding some type of continuous vital sign device start with a subset of patients, such as those who are prone to respiratory difficulties or reliant on percutaneous endoscopic gastronomy tube feeding. “The ability to monitor respiratory rate is very relevant to people who come in with pulmonary problems or people at risk for aspiration,” he said.

Continuous considerations

It's still unclear what role these systems will play, as more research is needed to understand patient outcomes, Ms. Krishnan said. She advises clinicians or administrators who are weighing the investment, even on a pilot basis, to think carefully about what clinical need they are trying to fill.

Which monitoring features are needed will depend on which patient population is being targeted, whether that's patients on pain medication or those who have sepsis or are likely to fall, she said. Each monitoring system claims to address certain patient populations, and it is important to match a new monitoring system to clinical need.

All of these systems “claim to reduce alarm fatigue,” she said. “But they are introducing alarms in a care unit that had no alarms. It's going from 0 to something.”

In some cases, vendors report alarms per bed that total fewer than 10 a day, she said. But those numbers can quickly add up for nurses, who might be caring for 5 or more patients at a time, Ms. Krishnan said. “The risk of introducing alarms in these care areas is that with alarm fatigue comes the risk of missing those alarms,” she said.

Dr. Maheshwari said that once a continuous monitoring system is installed at Christiana Care, numerous variables and touch points will be studied. It will be crucial to set the alarm triggers so that they catch worrisome events without sounding off too frequently, he said. Christiana Care also wants to look at total alarm burden on the clinical staff and how the technology impacts workflow.

It will also be key to see how nurses and other clinicians respond when an alarm sounds. “You still have to have humans that respond in a clinically appropriate manner,” Dr. Maheshwari said.

To what extent will this rapidly evolving technology suppant the need for telemetry in non-ICU patients? When the continuous vital sign technology is implemented at Christiana Care, the plan is to place those patients in the highest-risk units on continuous monitoring, but also still use telemetry for those patients who meet the criteria for arrhythmia monitoring per clinical guidelines, according to Dr. Maheshwari.

When hospitals use telemetry on patients in accordance with clinical guidelines, then continuous vital sign devices shouldn't serve as a substitute, Ms. Krishnan said. “These systems are not meant to replace telemetry but to monitor the patients for whom telemetry is not indicated.”