Comparison of Continuous Blood Pressure Measurement Using a Non-invasive Photo Plethysmography-based Monitor With the Gold Standard Sphygmomanometer-based Holter Monitor

HTN is a major risk factor for cerebrovascular morbidity and mortality, yet its identification can be delayed due to lack of overt symptoms, relying on BP measurements for diagnosis. Several BP monitoring techniques are used in clinics and hospitals, and there is also an outpatient method that is used for 24-hour BP monitoring, based on a sphygmomanometer. The general notion is that by using tight BP monitoring in the clinic and during the day, the health system will be able to diagnose hypertension among individuals at an early stage, including high risk patients in the community.

Ambulatory BP monitoring for a period of 24 hours is considered to be better than measurements taken in a clinic setting. First, 24 hours monitoring performed at home can help confirm that hypertension actually does exist, thus ruling out the potential of "white coat syndrome". Second, measurements of BP during sleep also have a predictive value for hypertension in high risk patients. Furthermore, ambulatory BP measurements are a stronger predictor of all-cause and cardiovascular mortality than BP measurements in the clinic. Finally, continuous BP monitoring is beneficial for controlling hypertension in diagnosed and treated patients.

The gold standard ambulatory non-invasive BP monitor that is in broad use today is a sphygmomanometer-based device that includes a cuff, which contracts around the patient's arm and measures BP every 15 to 20 minutes. The cuff is usually uncomfortable for the patients and could prevent them from doing their everyday activities. It can also disrupt the quality of their sleep at night. For these reasons patients are sometimes reluctant to use it. A more comfortable, user- friendly device, which allows a non-invasive, continuous BP measurement will provide a simple, more efficient way for BP monitoring, and will potentially enable to improve the outcome of medical treatment.

A new way for continuous non-invasive BP monitoring is based on the reflective photo plethysmography (PPG) method. A company called "Biobeat" invented a device that measures PPG wave in high temporal resolution that maintains more properties and markings of the original pulse wave than usual PPG-based devices, thereby enabling to provide data on several physiological parameters other than Heart Rate (HR) and blood oxygen saturation, such as: Systolic Blood Pressure (SBP) and its variation, Diastolic Blood Pressure (DBP) and its variation, Pulse Pressure and more. This device can also send and surveillance. The Biobeat device (BB-613) includes either a wearable watch or a patch with a sticker that the patient puts on his/her body. This device may increase the patient's willingness to use it and can also make the measurement more reliable (explanation on the PPG-based sensor and the device itself are provided in the appendixes).

The measurements are transferred via Wi-Fi to the patient's doctor and allows close monitoring.