Korotkoff sounds6/22/2023 (a) raw Korotkoff sounds, (b) square wave indicates detection of Korotkoff sound after rectification, and (c) determination of Korotkoff sounds above the preset thresholdįigure 7. Determination of systolic and diastolic pressure based on Korotkoff sounds and cuff pressure. Korotkoff sounds (top) and the corresponding cuff pressure (bottom)įigure 6. Developed device including sensor implemented inside the cuffįigure 5. Pulse waves before cuff inflation and without a signal filterįigure 4. Sensing module (left) and schematic diagram of sensing module (right)įigure 2. Blood pressure measurements based on Korotkoff sound signals obtained by using the developed PVDF film-based sensor module are accurate and highly correlated with measurements obtained by the traditional auscultatory method.įigure 1. Correlation coefficients for the values obtained by the auscultatory method and from the developed device were 0.982 and 0.980 for systolic and diastolic blood pressure, respectively. The results from 86 out of 90 systolic measurements and 84 out of 90 diastolic measurements indicate that the developed device pass the validation criteria of the international protocol. An algorithm for determining starting and ending points of the Korotkoff sounds was established, and clinical data from subjects were acquired and analyzed to find the relationship between the values obtained by the auscultatory method and from the developed device. PVDF-based sensor pattern was developed to function as a vibration sensor to detect of Korotkoff sounds, and the film's output was connected to an impedance-matching circuit. In this study, we develop a Korotkoff sound based automatic blood pressure measurement device including sensor, hardware, and analysis algorithm. Įxperience has taught us, while it is very easy to name an individual wrongly as hypertensive, it often needs Herculean efforts to remove this medical tag from their neck. So , realise how important it is, to measure the blood pressure properly ! Never be casual. The BP apparatus , though appears as an innocuous machine, the readings that emerge from it determines, how millions of our fellow human beings are going to be labeled ! ( High pressured humans , slaves to anti hypertensive drug marketeers for rest of their life ) . What is the incidence of hypertension due to loose cuff ? How much stiffness is to be applied in the arm for optimal pressure recording ? Loose cuff hypertension (Link to the journal of Cardiovascular engineering ) But this article from a relatively unknown journal from Purdue university, tells us most scientifically, what has been taken for granted by the medical community for so long. There are many articles that describe in detail, how to record blood pressure properly. It is not at all surprising to note, two BP readings rarely match, even if it is recorded by the same person with same machine at the same time ! Failure to hear phase 4 muffling (Aging medico -Auditory insufficiency !). Absent minded recording – Failure to note phase 4 to phase 5 due to inattention.Hasty cuff syndrome, Rapid deflation.It is surprising, such an important tool has a scale of 2mm markings which is prone for parallax errors of light with mercury column undulating. The following fallacies are noted in the measurement of blood pressure. The BP apparatus has to be properly calibrated with the mercury, the tubing, the bladder, inflation balloon etc need to be perfect. (It indeed is !)Įven though BP is considered as a clinical sign, measuring it requires a device called sphygmomanometer. It is such a common thing, both physicians and patients fail to perceive it as an investigation. Blood pressure measurement, probably is the commonest investigation done in our patients in the entire field of medicine.
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