Hand-held apparatus for noninvasive measurement of a heart performance metric
Apparatuses, machine-accessible storage media, and methods for noninvasively measuring a heart performance metric, such as left ventricular filling pressure, are described. In an embodiment, the apparatus includes a housing shaped to be grasped by a hand; a tower protruding from a surface of the housing positioned to conform to a finger of the hand when grasping the housing; a tactile sensor disposed on a curved surface of the tower and adapted to measure blood pressure pulsatility in a digital artery of the finger and output pulsatility signals indicative of the blood pressure pulsatility; a graphical user interface for orchestrating a test of the performance metric of the heart and displaying results of the test.
1 . At least one non-transitory machine-accessible storage medium that provides instructions that, when executed by a heart performance measurement apparatus, will cause the heart performance measurement apparatus to perform operations comprising: applying a clamping force, with a strap positioned and oriented to apply pressure to a finger while a housing of the heart performance measurement apparatus is grasped by a hand, to the finger against a curved surface of a tower of the heart performance measurement apparatus protruding from a surface of the housing to flatten a digital artery for applanation tonometry, wherein applying the clamping force comprises adjusting the clamping force by adjusting a strap tightness to identify a clamping force that provides a maximal pulsatility amplitude; monitoring pulsatility signals output from a tactile sensor disposed in or on the curved surface; and generating pulsatility data, based upon the pulsatility signals, from which a performance metric of the heart is determined.
2 . The at least one non-transitory machine-accessible storage medium of claim 1 , further providing instructions that, when executed by the heart performance measurement apparatus, will cause the heart performance measurement apparatus to perform further operations, comprising:
monitoring an expiratory effort with an expiratory subsystem of the heart performance measurement apparatus while monitoring the pulsatility signals;
recording the pulsatility data while the expiratory effort is within a threshold range; and
recording the pulsatility data following cessation of the expiratory effort.
3 . The at least one non-transitory machine-accessible storage medium of claim 2 , further providing instructions that, when executed by the heart performance measurement apparatus, will cause the heart performance measurement apparatus to perform further operations, comprising:
analyzing the pulsatility data recorded during the expiratory effort and recorded following the expiratory effort to determine the performance metric, wherein the performance metric comprises a left ventricular end diastolic pressure (LVEDP) or pulmonary capillary wedge pressure (PCWP); and
displaying a result of the analyzing with a graphical user interface of the heart performance measurement apparatus positioned opposite the tower.
4 . The at least one non-transitory machine-accessible storage medium of claim 3 , further providing instructions that, when executed by the heart performance measurement apparatus, will cause the heart performance measurement apparatus to perform further operations, comprising:
prompting a user to commence an expiration effort after sensing pulsatilty signals;
displaying, with the graphical user interface, an expiratory effort meter that provides real-time feedback for guiding the expiratory effort into the threshold effort range;
prompting the user to cease the expiration effort; and
releasing the clamping force.
5 . The at least one non-transitory machine-accessible storage medium of claim 3 , further providing instructions that, when executed by the heart performance measurement apparatus, will cause the heart performance measurement apparatus to perform further operations, comprising:
displaying, with the graphical user interface, a pulsatility meter in real-time indicating whether the pulsatility signals from the tactile sensor are registering blood pressure pulsatility in the digital artery of the finger.
6 . The at least one non-transitory machine-accessible storage medium of claim 1 , wherein adjusting the clamping force by adjusting a strap tightness comprises operating a motor thereby tightening the strap.