US 12,220,213 B2
Blood pressure monitoring using a multi-function wrist-worn device
Erno H. Klaassen, Cupertino, CA (US); Wren Nancy Dougherty, San Francisco, CA (US); Richard C. Kimoto, Cupertino, CA (US); Ravi K. Narasimhan, Sunnyvale, CA (US); Thomas J. Sullivan, Cupertino, CA (US); Stephen J. Waydo, Cupertino, CA (US); Todd K. Whitehurst, Cupertino, CA (US); Santiago Quijano, Cupertino, CA (US); Derek Park-Shing Young, Cupertino, CA (US); and Zijing Zeng, Cupertino, CA (US)
Assigned to Apple Inc., Cupertino, CA (US)
Filed by Apple Inc., Cupertino, CA (US)
Filed on Aug. 7, 2020, as Appl. No. 16/987,851.
Application 16/987,851 is a continuation of application No. 15/680,931, filed on Aug. 18, 2017, granted, now 10,772,512.
Application 15/680,931 is a continuation of application No. 15/506,932, abandoned, previously published as PCT/US2015/048836, filed on Sep. 8, 2015.
Claims priority of provisional application 62/047,452, filed on Sep. 8, 2014.
Prior Publication US 2020/0367760 A1, Nov. 26, 2020
Int. Cl. A61B 5/021 (2006.01); A61B 5/00 (2006.01); A61B 5/11 (2006.01); A61B 5/1455 (2006.01); G16H 20/00 (2018.01); G16H 40/67 (2018.01)
CPC A61B 5/021 (2013.01) [A61B 5/11 (2013.01); A61B 5/681 (2013.01); A61B 5/6824 (2013.01); A61B 5/0002 (2013.01); A61B 5/02125 (2013.01); A61B 5/14551 (2013.01); G16H 20/00 (2018.01); G16H 40/67 (2018.01)] 15 Claims
OG exemplary drawing
 
1. A method for obtaining a blood pressure measurement of a subject, the subject having a cardiovascular system including a left ventricle and a wrist covered by skin, the method comprising:
sensing, with an impedance cardiogram (ICG) sensor of a wrist-worn device non-invasively engaging the skin on the wrist of the subject, a first ejection signal indicative of when a first volume of blood is ejected from the left ventricle, wherein the ICG sensor comprises a drive current generator, a first drive current electrode, a second drive current electrode, a voltage sensor, a first sense electrode, and a second sense electrode, wherein the first drive current electrode and the first sense electrode are non-invasively engaged with glabrous skin on an anterior surface of the wrist of the subject, wherein the second drive current electrode and the second sense electrode are contacted by at least two separate fingers of an arm opposite an arm on which the wrist-worn device is worn or non-invasively engaging a skin surface of a sternum of the subject, wherein the drive current generator supplies an alternating current to the first drive current electrode and the second drive current electrode to impart the alternating current into the subject therebetween, wherein voltage sensor is electrically coupled with the first sense electrode and the second sense electrode to measure voltage therebetween for use in determining impedance of the subject therebetween, and wherein each of the first sense electrode and the second sense electrodes is separated from each of the first drive current electrode and the second drive current electrode;
sensing, with a pulse arrival sensor of the wrist-worn device non-invasively engaging the skin on the wrist of the subject, a first pulse arrival signal indicative of when a first pressure pulse generated by an ejection of the first volume of blood from the left ventricle arrives at the wrist;
determining, by the wrist-worn device based on the first ejection signal and the first pulse arrival signal, a first pulse transit time (PTT) for transit of the first pressure pulse from the left ventricle to the wrist;
determining, by the wrist-worn device, a first relative blood pressure value based on the first PTT;
receiving, by the wrist-worn device, a first measured reference absolute blood pressure value associated with the first relative blood pressure value; and
determining, by the wrist-worn device, a first absolute blood pressure value for the first relative blood pressure value based on the first measured reference absolute blood pressure value and the first relative blood pressure value.