ECRI Institute’s Health Devices engineering team recently completed an evaluation of wearable and noncontact continuous vital signs monitoring systems – devices that can facilitate the continuous monitoring of low-acuity patients, a practice that has been attracting interest.
Low-Acuity Continuous Monitoring
Spot checks of the patient’s vital signs are routine practice in med/surg units and other low-acuity care areas. Every few hours, a staff member will assess parameters that might include the patient’s pulse rate, noninvasive blood pressure (NIBP), temperature, arterial blood oxygen saturation (SpO2), and respiration rate.
For low-acuity patients, this level of observation typically is sufficient. On rare occasions, however, a patient’s condition will begin to deteriorate during the gap between measurements. The potential to catch such deteriorations before they lead to critical events, such as cardiopulmonary and respiratory arrests, has some hospitals considering continuous measurement of vital signs in low-acuity care areas.
An analysis of the pros and cons of implementing low-acuity continuous monitoring is beyond the scope of this discussion. But for facilities interested in this technology, we describe some of the options and offer guidance for comparing alternatives.
Beyond the Bedside Monitor
Low-acuity continuous monitors are a class of device that fills a niche between two other monitoring technologies: spot-check monitors and higher-acuity, ECG-equipped physiologic monitors. They offer continuous monitoring, which spot-check monitors lack, and they are less expensive than ECG-equipped physiologic monitors.
Some low-acuity continuous monitors are similar in design to traditional physiologic monitors, though smaller and with fewer capabilities. With this “bedside monitor” design, sensors attached to the patient (e.g., noninvasive blood pressure cuff) are physically connected via cables/leads to a display unit situated near the patient’s bed (see the figure).
Other available designs, which are relatively new to the market, provide greater patient mobility or comfort. For instance:
• Wearable monitors consist of small, lightweight display units that are attached to or worn by the patient. Sensors attached to the patient are connected directly to this wearable unit, allowing the patient to move more freely.
• Noncontact (or “unconnected”) monitors can measure certain vital signs (e.g., heart rate, respiratory rate) without any physical connection to the patient. These systems typically use a sensor placed beneath the mattress.
Purchasing Considerations
The ECRI Institute recently tested three wearable and noncontact continuous vital signs monitoring systems. Following are a few of the tips and test findings from the organization’s studies.
Define Your Clinical Needs
Because low-acuity continuous monitoring is not yet considered a standard of care, key actions before deciding whether to invest in the technology are to define your care area’s clinical needs and to identify the monitoring capabilities and performance characteristics that are required to meet those needs. Consultations with clinical staff can be particularly helpful in this regard.
Understand the Impact
Give careful thought to whether obtaining a new monitoring system will require changes to the current clinical workflow and care area infrastructure. For example:
• For a care area that previously used periodic spot checks, a new workflow will be needed to manage patient alarms. Combatting alarm fatigue is a very real patient safety consideration.
• For a facility that intends to integrate its monitoring systems with an existing EMR system, the systems’ compatibility and additional costs for interface development will have to be considered.
In addition, the projected cost of consumables (e.g., disposable sensors) will be an important financial consideration.
Assess Performance
During its evaluations, ECRI Institute examines performance, safety, workflow, and other factors to differentiate the models under consideration. One interesting aspect of the testing for these systems is “the level of physical activity involved,” notes Priyanka Shah, the project lead for ECRI Institute’s study.
“Walking, running, climbing stairs, rolling – we did it all,” reports Shah. “Because these systems can be used on patients who are moving in their beds or who might be ambulatory, we needed to simulate a wide range of movements to see how the systems would respond.”
Patient movement can affect a monitor’s ability to accurately measure patient parameters. A facility will want to avoid systems that display erroneous values during such periods or that sound frequent alarms for nonactionable conditions. ECRI Institute was largely satisfied with how the three systems it tested fared under such circumstances, according to Shah.
Another factor to consider is how the system will react when a patient equipped with a wearable monitor transitions out of, and then back into, the care area. “Will monitoring continue while the patient is outside the care area? And will that data be saved – or lost – when the patient returns to the care area?” The organization discovered differences in how the systems managed these situations.
Other performance factors that ECRI Institute considers include whether the systems’ patient trend displays or early-warning scoring algorithms, if available, are backed by clinical evidence. That is, can claims like “the systems can detect early patient deterioration or ailments like sepsis” be supported?
Key safety factors that ECRI Institute examines relate to alarm fatigue and data security. The organization also assesses workflow considerations, examining activities such as patient association and disassociation, system setup and configuration, and the setting and adjusting of alarm limits based on individual patient needs.
ECRI Institute found that all three of the systems it tested offer acceptable performance, though for different applications – and not without some drawbacks. The systems’ battery life, for example, was not at the level the organization prefers. Differentiating factors that ECRI Institute identified include the ease (or difficulty) of patient setup, the ability (or inability) to detect emergent events and/or predict patient deterioration, and the total cost of ownership.
This article is adapted from ECRI Institute’s “Evaluation Background: Wearable and Noncontact Continuous Vital Signs Monitoring Systems,” Health Devices 2016 Jun 29, and related guidance materials. The source articles – which feature model-specific test results and product ratings, along with additional guidance for purchasing and using this technology – are available online to members of ECRI Institute’s Health Devices System and associated programs; learn more at www.ecri.org/components/HDS.