Toolkits

Mobile Blood Pressure - Technology Overview

Blood pressure measurement is a critical vital sign measured during health care screening, acute care and for chronic conditions.  Increasingly, blood pressure is measured out of the office at home, in pharmacies, schools, ambulances and emergency transport vehicles.  Telehealth platforms encompass multiple solutions for episodic “spot” blood pressure measurement as well as monitoring.  Common applications include home health, remote monitoring, ambulatory blood pressure monitors and units part of a broader package (expensive telehealth software solutions, home hubs, cloud services, etc.). 

The mobile solutions discussed here include consumer-based BP monitors that automatically inflate and measure and record data that can be transmitted via Internet to a software package or personal health record.  The units are relatively inexpensive (<$200) and can be purchased by the consumer without a prescription or physician oversight.  Units were not considered if they required purchase of a larger software package or required leasing.  Each unit is small enough to pack in a backpack or suitcase.

Blood-pressure instruments are standard equipment in telemedicine programs, in both store-and-forward and live video applications. As the technology has advanced from bulb and stethoscope measurements to digital readouts, so have the innovations in remote-monitoring equipment for patient use. There are variations in the basic components based on each manufacturer’s design, discussed in more detail below.

Cuff and Inflation

In the past, blood pressure measurement has relied on the physical measurement of liquid mercury as part of a hand inflated sphygmomanometer in order to measure arterial blood pressure readings.  Now, increasingly for convenience and safety blood pressure measurement has moved to other analog and digital techniques. This review of consumer-based devices includes recent innovations in cuff, inflation mechanism, overall design and software interface.

The cuff of a blood pressure gauge inflates to restrict arterial blood flow with air pressure, and measures the maximum and minimum output pressure (systolic and diastolic) of the heart. Digital home care devices utilize the wrist (radial artery) or the upper arm (brachial artery) to measure blood pressure. Consumer-based devices have long used a hand squeeze bulb to inflate the cuff.  Now, self-inflating models are available and the units that integrate with software are only available with the self-inflating mechanism.  Of the four models identified, two have the inflation pump attached to the cuff and two have a separate station with an air tube attached to the cuff. The blood-pressure cuffs utilize a curved/spring type wrap or a metal loop cinch bar that wraps and attaches with a Velcro wrap.

Display

The newest innovation in mobile blood pressure devices is the use of the iPhone (iPad) and application to display the numerical readings.  Two of the blood pressure devices do not include a built-in display, but instead, utilize the iPhone (iPad) to show the numbers. Mobile blood-pressure devices come with either a display attached to the cuff, or will display readings on the base station or the mobile device itself (laptop, iPhone, etc.). When the cuff inflates and measurements are in progress, an operational indicator shows that the device is functioning correctly. When the reading is complete, the monitor will display the blood pressure and pulse results. Some devices are also designed to detect irregular heart rhythm, and come with a programmable alarm to notify the patient if dangerous physiological changes occur.

The font size of the number displays is variable, which should be considered for patients with poor vision. Also consider if screen glare might cause the user difficulty, as the screens tend to vary in surface reflection. In the future, it would be useful for manufacturers to design units that will recite results out loud for patients with decreased eyesight.

Power Supply

The amount of battery power necessary for mobile blood pressure monitors will vary from vendor to vendor. Some units use conventional AA or AAA batteries, while others have internal rechargeable batteries and a power plug. Factors to consider are the replacement cost of disposable batteries and the stability of the local power source when choosing a device for home care. It seems that each of the units considered has adequate power to measure hundreds of blood pressure measurements before battery replacement is an issue.

Data Storage and Communication

Mobile blood pressure monitors eliminate the need for hand-written logbooks, improve data accuracy, and eliminate falsified readings. These units come with user-friendly software interfaces that need to be installed as separate applications on an iPhone (iPad) or laptop.  Some of these integrate with a personal health record (PHR) such as Microsoft Health Vault.  All of the units discussed include software integration that documents, records, tracks and graphically displays the blood pressure readings.