In the most common version of an oscillometric blood pressure monitor, the output from the pressure transducer, Y(t), is split into two parts, and used for separate determinations of the pressure inside the pneumatic ...In the most common version of an oscillometric blood pressure monitor, the output from the pressure transducer, Y(t), is split into two parts, and used for separate determinations of the pressure inside the pneumatic cuff and its fluc-tuating part;the latter is derived by sending Y(t) to a high-pass filter (HPF) and amplifying the fil-tered part to obtain the oscillometric signal O(t). Using a typical HPF-amplifier combination, we show that if p(t), the pulsatile part of the cuff pressure, is defined to be a train of positive-going pulses, O(t) turns out to be rather close but not identical to dp/dt, and to demonstrate that one can easily retrieve p(t) from a record of O(t). This means that, with a small modification, the instrument can provide both p(t) and dp/dt;the practical advantages of this demonstration are pointed out.展开更多
A noninvasive method for monitoring blood pressure, based on the principles established by Riva-Rocci and Korotkoff (K), is described;it furnishes, after a single compression-deflation cycle of the arm-encircling cuff...A noninvasive method for monitoring blood pressure, based on the principles established by Riva-Rocci and Korotkoff (K), is described;it furnishes, after a single compression-deflation cycle of the arm-encircling cuff, values of sys-tolic and diastolic blood pressures as well as the contours of the brachial arterial pulse and the corresponding volume pulse. K-sounds are detected by a single microphone situated in the cubital fossa, and the time-varying cuff pressure P(t) is read by a piezoresistive pressure sensor. The behavior of P(t) during deflation is resolved into two parts, P(t)=p(t)+b(t);p is a train of posi-tive going pulses (arising from arterial pulsa-tions), whereas b is a slowly changing baseline. Noise pulses in the microphone output are re-jected by using the observation that the first few K-sounds are emitted when p is close to a maxi-mum, and the last few when dp/dt is close to a maximum. The performance of the instrument is illustrated by showing how it copes with ambi-ent noise and involuntary manual perturbations of P, and by presenting contours of various pulses.展开更多
文摘In the most common version of an oscillometric blood pressure monitor, the output from the pressure transducer, Y(t), is split into two parts, and used for separate determinations of the pressure inside the pneumatic cuff and its fluc-tuating part;the latter is derived by sending Y(t) to a high-pass filter (HPF) and amplifying the fil-tered part to obtain the oscillometric signal O(t). Using a typical HPF-amplifier combination, we show that if p(t), the pulsatile part of the cuff pressure, is defined to be a train of positive-going pulses, O(t) turns out to be rather close but not identical to dp/dt, and to demonstrate that one can easily retrieve p(t) from a record of O(t). This means that, with a small modification, the instrument can provide both p(t) and dp/dt;the practical advantages of this demonstration are pointed out.
文摘A noninvasive method for monitoring blood pressure, based on the principles established by Riva-Rocci and Korotkoff (K), is described;it furnishes, after a single compression-deflation cycle of the arm-encircling cuff, values of sys-tolic and diastolic blood pressures as well as the contours of the brachial arterial pulse and the corresponding volume pulse. K-sounds are detected by a single microphone situated in the cubital fossa, and the time-varying cuff pressure P(t) is read by a piezoresistive pressure sensor. The behavior of P(t) during deflation is resolved into two parts, P(t)=p(t)+b(t);p is a train of posi-tive going pulses (arising from arterial pulsa-tions), whereas b is a slowly changing baseline. Noise pulses in the microphone output are re-jected by using the observation that the first few K-sounds are emitted when p is close to a maxi-mum, and the last few when dp/dt is close to a maximum. The performance of the instrument is illustrated by showing how it copes with ambi-ent noise and involuntary manual perturbations of P, and by presenting contours of various pulses.
