Easy-to-Use Portable Device Quickly Measures Vital Signs

Researchers have developed a 3D-printed, novel hand-held device with sensors that quickly test a patient’s blood pressure, blood oxygen, breathing rate, heart rate, and heartbeat pattern. Updated versions of the prototype could replace hospital vital sign monitors and could gather more data than is typically collected during medical assessment in an ambulance, emergency room, doctor’s office, or patient’s home.

Vital sign monitors in hospitals are relatively bulky, have restrictive mobility, and capture limited information. Engineers and physicians at Johns Hopkins University School of Medicine (Baltimore, MD, USA) have developed the “MouthLab” hand-held device to quickly pick up vital signs from a patient’s lips and fingertip using mouthpiece and thumb pad sensors. The device could help avoid unnecessary ambulance trips and emergency room visits when vital signs are good, and may help detect early signs of medical emergencies, such as heart attacks.


In a new study testing vital signs from 52 volunteers, MouthLab compared well with measurements from standard hospital monitors. The device also takes a basic electrocardiogram (ECG). “We see it as a ‘check-engine’ light for humans,” said first author and lead engineer, Gene Fridman, PhD, assistant professor at Johns Hopkins, “It can be used by people without special training, at home or in the field.” Prof. Fridman is also founder and owner of startup Multisensor Diagnostics, LLC, to which MouthLab technology has been optioned by Johns Hopkins University.

MouthLab consists of a small, flexible mouthpiece (like those used by scuba divers) connected to the hand-held unit. The mouthpiece contains a temperature sensor and blood-volume sensor. The thumb pad on the hand-held unit has a miniaturized pulse oximeter — a smaller version of the finger-gripping device used in hospitals, which uses beams of light to measure blood oxygen levels. Other sensors measure breathing from the nose and mouth.

MouthLab also has 3 electrodes for ECGs — one on the thumb pad, one on the mouthpiece upper lip and one on the lower lip — that work about as well as the chest and ankle electrodes used on basic ECG equipment in many ambulances or clinics.

The ECG signal is the basis for MouthLab’s innovative method for recording blood pressure. When the signal shows the heart is contracting, the device optically measures changes in volume of blood reaching the thumb and upper lip. Unique software converts the blood flow data into systolic and diastolic pressure readings. The study found that MouthLab blood pressure readings effectively match those taken with standard, arm-squeezing cuffs.

Future versions of the device will be developed to detect chemical cues in blood, saliva, and breath that act as markers for serious health conditions. “We envision the detection of a wide range of disorders,” said Prof. Fridman, “from blood glucose levels for diabetics, to kidney failure, to oral, lung and breast cancers.”

“Our final version will be smaller, more ergonomic, more user-friendly and faster. Our goal is to obtain all vital signs in under 10 seconds,” said Prof. Fridman. Currently, MouthLab relays data by Wi-Fi to a nearby laptop or smart device, where graphs display real-time results. The next generation of the device will display its own data readouts. Ultimately, patients will be able to send results to their physicians via cellphone, and physicians will be able use an app to add results to their medical records.

The study, by Fridman GY, et al., was published in the September 2015 issue of the journal Annals of Biomedical Engineering.

Related Links:
Johns Hopkins University School of Medicine
Multisensor Diagnostics