A survey to gauge confidence of Indian clinicians on three primary devices for blood pressure measurement

Concept, hardware development, and clinical trials of a Galinstan based Mercury free sphygmomanometer: Merkfree

The aim of this work is to develop Merkfree-a mercury-free sphygmomanometer that looks, feels, and operates just like a traditional mercury sphygmomanometer (MS). For this we use Galinstan as a substitute for mercury, which is a non-toxic alloy of Gallium, Indium and Tin. Galinstan is nearly half as dense as mercury and sticks to class. To work with the lower density, we designed an enclosure and scale that is nearly double the length of MS. The issue of stickiness with glass was resolved by maintaining a small meniscus of a reducing agent in the measuring tube and tank of Merkfree. Clinical trials to validate the accuracy of Merkfree against MS and oscillometric sphygmomanometer (OS) were conducted over 252 patients. The results show a good correlation of the systolic and diastolic BP measurements from Merkfree with respect to MS and the OS. The mean absolute percentage error is less than 10% for both SBP and DBP. We also found that Merkfree has lower rounding-off errors compared to MS. Merkfree can be a viable alternative to mercury sphygmomanometer that can help achieve the goal of WHO in eliminating mercury from healthcare, while simultaneously making sure that gold standard technique of sphygmomanometry continues to be available to the clinicians.

Auscl-D: a mercury-free digital auscultatory sphygmomanometer

More than quarter of world's population is consumed by hypertension, leading to premature death of thousands of people per year across the globe. One of the major reasons behind hypertension misdiagnosis is inaccurate blood pressure (BP) measurements, which can be attributed to various human or instrumentation errors. Currently used BP measuring sphygmomanometers, suffers from poor reliability, performance deterioration over time or are unable to meet environmental protection protocols. In this article, we propose a low-cost, highly portable, light-weight, easily manufacturable, battery operated, mercury free, auscultation based digital sphygmomanometer - Auscl-D, for easy and accurate BP measurements. The proposed device can be made from easily available components with cheap manufacturing processes available throughout globe, even in remote areas. The device demonstrated to have accuracy comparable to mercury sphygmomanometer, which is the gold-standard for BP measurements. The preliminary clinical trials were conducted at Dayanand Medical College & Hospital (DMCH) (Ludhiana, India), to compare the performance of proposed device with commonly used aneroid sphygmomanometers employing the auscultatory method and validated oscillometric sphygmomanometers from MicroLife. The test results show good agreement for systolic and diastolic BP measurements taken using Auscl-D device compared to the aneroid and oscillometric types. This shows the potential of proposed design to serve as low-cost, highly portable replacement for conventionally used sphygmomanometers, without the toxicity and reliability issues.