Apple has been working on a future blood pressure device solution since at least 2018. Since that time, Apple patents have shown us different approaches that their research teams are taking from wrist devices to advanced blood pressure cuffs: 01, 02, 03, 04, 05 and more. Today the US Patent & Trademark Office published a patent application from Apple that relates to systems and methods for obtaining and analyzing non-invasive blood pressure measurement data.

In Apple's patent background they note that various non-invasive blood pressure measurement techniques are commonly used to determine the blood pressure of a user. Auscultation and oscillometry are popular methods of non-invasively measuring blood pressure of a user due to their ease of use and ability to be performed in remote settings such as a user's home. However, non-invasive blood pressure measurement methods, such as these, tend to have lower accuracy and/or greater variability as compared to invasive measurement techniques such as direct intra-arterial sensing.

Apple's invention covers a blood pressure measurement systems for determining one or more blood pressure parameters of a user. Examples of blood pressure parameters can include systolic blood pressure, diastolic blood pressure, mean pressure, blood pressure variability, or other physiological parameters for a user.

The system can include a restriction device that is configured to apply an external pressure cycle to a user to cause restriction of blood flow through one or more blood vessels of the user. In some cases, the external pressure cycle may be referred to as an applied pressure sweep.

The restriction device can be an inflatable cuff, a band that tightens around the limb of a user, or any other suitable device.

The system can also include a pressure sensing device that is configured to detect pressure changes within one or more blood vessels while the external pressure cycle is applied. For example, the pressure changes can be changes to the wave shape of pulse pressure occurring within a user's blood vessel as a result of the external pressure cycle. The system can analyze the detected pressures from the pressure sensing device to determine the one or more blood pressure parameters for the user.

The non-invasive blood pressure measurement system and analysis techniques that may more accurately and repeatably determine one or more blood pressure parameters of a user.

The blood pressure measurement system described includes devices and analysis techniques that may result in more accurate and/or more repeatable non-invasive blood pressure measurements for a user. The system can include using a pressure sensing device that detects pressures within a user's blood vessel while an external pressure cycle is applied to the user to induces changes in flow through the user's blood vessel. In some cases, the pressure sensing device can be configured to detect pressures for the pulse pressure waves that occur within the user's blood vessel and output a signal indicative of the detected pressures for the pulse pressure waves. In this regard, the output pressures include data that corresponds to changes in the blood pressure that occurs during each pulse pressure wave. The output detected pressures can include information related to a minimum pulse pressure, maximum pulse pressure, rates of pressure change, changes in pressure due to valve closure, pulse frequency, and/or other pulse pressure events.

Apple's patent FIG. 1A below shows a block diagram of an example blood pressure management system; FIG. 1B shows an example blood pressure measurement system worn by a user.

Apple's patent FIG. 1C below shows an example blood pressure measurement system worn by a user in the form of an Apple Watch with a custom band;  FIG. 2 is a flowchart of an example process for operating a blood pressure measurement system.

Apple's patent FIG. 5 above is a flowchart showing example operation of determining a blood pressure parameter from blood pressure measurements; and FIG. 6B shows an example set of blood pressure data that is used to determine a blood pressure parameter of a user.

For more details, review Apple's patent application number US 20220400959 A1.

Apple Inventors

• Rob Montgomery: Systems Engineer
• Chinhan Lin: Engineering Manager, Sensing Technology