BY JOAN YEA
The medical tricorder of the Star Trek universe, a rapid medical assessment device used to quickly examine the patient’s general health, has long been a real-world inspiration for the development of non-invasive health measurement devices.
The realization of a commercially available, portable rapid medical assessment device hopes to revolutionize the diagnosis and monitoring of various illnesses and conditions.
Recently a group of engineers and physicians at the Johns Hopkins School of Medicine, led by Gene Fridman, an assistant professor of biomedical engineering and otolaryngology—head and neck surgery, have been making progress. They have succeeded in showing the overall accuracy of the vital signs data obtained from the MouthLab, a device reminiscent of Star Trek’s medical tricorder.
A hand-held instrument, the MouthLab quickly takes into account the patient’s condition via the mouthpiece and thumb pad sensors, cataloging the patient’s electrocardiogram and vital signs such as pulse rate, breathing rate, temperature, blood oxygen saturation and blood pressure.
To test the performance of the MouthLab prototype, the researchers compared the vital signs data obtained from the prototype to that from a standard vital signs monitor in a clinical trial involving 52 subjects.
The study, published in the September issue of the Annals of Biomedical Engineering, indicates the accuracy of the vital signs data generated by the MouthLab, a correlation which the researchers attribute to the use of the same technology to measure some of the vital signs.
The MouthLab’s thumb pad sensor for instance is equipped with a smaller version of a pulse oximeter, the standard optical technology utilized to measure blood oxygen saturation.
While the Mouthlab features these existing measurement modalities, the device is novel in its placement of sensors and electrodes, seeking to decrease the possible patient discomfort that can accompany rapid medical assessment. The electrodes of the three-lead electrocardiogram equipped with the MouthLab device, for example, are placed on the patient’s thumb and lip instead of the leg and torso.
The electrocardiogram signals also provide the basis for the MouthLab’s unique method of measuring the patient’s blood pressure. The standard cuff utilized in blood pressure measurements has been noted to be prone to error due to extraneous factors that can affect the systolic blood pressure reading as much as 50 mmHg and the diastolic by as much as 11 mmHg.
In response to these limitations of the standard cuff, the inventors of the MouthLab adjusted the machine so that the blood pressure reading is derived from the electrocardiogram and blood volume measurements from the thumb and upper lip.
Despite the novelty of this measurement approach, the results of the clinical study have illustrated the close correlation between the blood pressure measurements of the MouthLab to those of the standard measurement modality, and the researchers intend to further change the device to improve its accuracy.
They plan to reshape the mouthpiece to better fit the angle of the upper lip and, in case the user incorrectly places the MouthLab in his or her mouth, a blinking LED on the instrument would communicate the low quality of the vital signs measurements.
The designers of the MouthLab envision that the hand unit would enable consumers with no medical training to attain critical data concerning their general health, which would then be streamed to a central cloud storage where the health care provider would readily gain access to the patient’s test results.
MouthLab will provide a way for emergency medical responders to quickly evaluate patients and gain a greater insight into what their medical issue might be. In addition, hospitals may use MouthLab to replace or supplement the bulky hospital equipment they usually use. MouthLab could even be used by doctors in an office or by the average person in their own home.
The inventors of the MouthLab also anticipate the potential of future models to capture biochemical information through detection of chemical cues in the saliva, breath and the mucous membrane of the mouth. The range of information detected by the MouthLab during the rapid medical assessment has the possibility of not only averting unnecessary emergency room visits, but also signaling the onset of a medical emergency, such as a heart attack.