Noninvasive Blood Pressure Measurement Techniques

Overview

Source: Hamna J. Qureshi and Craig J. Goergen, Weldon School of Biomedical Engineering, Purdue University, West Lafayette, Indiana

Here we will highlight the key similarities and differences of noninvasive blood pressure measurement techniques between humans and rodents and examine the engineering principles that govern blood pressure. The principles that govern current cuff technology to acquire systolic and diastolic pressures will also be discussed.

Commercially available cuffs that connect with mobile devices are typically compact and portable, thereby allowing measurements to be taken virtually anywhere. Noninvasive, portable blood pressure cuffs are especially useful for patients with hypertension and other cardiovascular problems that require careful monitoring and early detection of any changes in blood pressure.

Similarly, noninvasive blood pressure measurement systems are also available for rodents. This technology is used in laboratory settings and is useful for monitoring animal health throughout a study. While radiotelemetry is the gold standard of blood pressure measurement for rodents, this technique is invasive and can lead to animal mortality if done incorrectly. Noninvasive methods, therefore, are convenient for taking measurements in animals as they can provide valuable data without the need for device implantation. A commercially available system will be used to demonstrate how blood pressure can be measured in humans outside of a clinical setting. This technique allows patients to monitor their own blood pressure periodically without having to visit a clinic each time they want these measurements taken.

The methods described here take advantage of blood flow through the tail of the rodent by using pressure sensors and occlusion cuffs. Both mobile blood pressure cuffs for humans and noninvasive tail-cuff methods for rodents take advantage of similar hemodynamic principles to acquire blood pressure measurements that can provide useful data for users, including clinicians, researchers, and patients.

Procedure

1. Wireless Blood Pressure Cuff for Humans

Turn on the cuff and pair it with a mobile device onto which results will be outputted. Pairing can be done via Bluetooth.
Strap the cuff onto the upper arm so that the blood pressure monitor is placed against inner bicep. The Ssrap should be secured tightly on the arm.
Open the application for the cuff on the mobile device. Ensure that the cuff is paired with the mobile device.
Position yourself so that you are seated with your arm rest

Results

A typical graph obtained from taking rodent blood pressure using a noninvasive blood pressure system is shown in Figure 1. There are two curves on the graph: one for the VPR sensor and one for the occlusion cuff. The inflection points of the VPR sensor curve are where systolic and diastolic blood pressures are determined, as depicted in Figure 1. A status is indicated at the bottom of the figure that communicates whether this measurement is deemed acceptable by

Application and Summary

Both commercial cuffs available for at-home use and noninvasive methods for animal research studies take advantage of automated technologies. By tracking changes in blood flow with sensors, algorithms detect the systolic and diastolic pressures and then communicate these results to users. While technologically similar, there are some key differences between the two measurement techniques that should be noted. When taking blood pressures in human subjects, the environment is typically relaxed as the subject is unrestraine