Pulse palpation and limited joint mobility examination are better indicators than oscillometric measurement for diagnosing abnormal ankle-brachial index

Background: Peripheral artery disease (PAD) is the least recognized form of atherosclerosis and may even result in amputation if the diagnosis is delayed. Manual pulse palpation is the traditional way to diagnose PAD. Doppler ultrasonographic measurement of ankle-brachial index (ABI) is the gold standard diagnosing method but requires training and is not necessarily available as an outpatient procedure. Using automated oscillometric blood pressure devices has been suggested as an easier method for measuring the ABI. Methods: A single observer palpated the arterial dorsalis pedis, examined hand joints and measured the ABI of one hundred diabetic patients using both Doppler and oscillometric methods. The purpose of this study was to compare the oscillometric method and the manual diagnosing methods to the gold standard method of using a hand held Doppler device for measuring the ABI and detecting PAD. Results: ABI was abnormal in 24 patients (24%) (22 males, 2 females) when measured with the Doppler method. Of these 24 patients, the oscillometric method would have missed 12 giving 12 false negatives. We found that the sensitivity of the oscillometric method was 50.0% and specificity 90.8%. Clinical examination with palpation of ADP combined with limited joint mobility (LJM) scoring would have missed only four cases. Conclusions: Although the oscillometric method is easy and accessible, it is not sensitive enough to be used as the only method in measuring ABI. The simple and inexpensive ADP pulse palpation combined with testing for LMJ was able to find 20 of the 24 (83%) patients with an abnormal ABI measured by Doppler stethoscope.

The Study of Improving Detection Accuracy of Blood Pressure Meter Based on Oscillometric Method

This paper analyses detection errors of blood pressure meter (BPM) based on oscillomatric method with pressure reducing system step by step. The errors of BPM detecting system severely affecting detection accuracy and precision were evaluated. It provided a novel algorithm not only ameliorating these errors but also with shorter detection cycle. In order to release cuff air in linearity, this paper also provide a method to control different valve supplied with different power to maintain a certain deflation rate at 4 mmHg/Step. The experiments of these tests are conducted under PC detecting platform developed specially for this usage. The hardware design of interface of microprocessor and the monitoring program based on C language make this detecting system can be transformed to single chip processor system. The final goal of this research is to bring to a portable wrist BPM product and this call for severe demand for power design. Through detecting 60 subjects with different blood pressure the result is that the maximum experimental standard deviations of systolic, diastolic and mean blood pressure are less than 6 mmHg. Comparing with the congeneric product of wrist BPM with nonuniform specification, this systems specification tallies with overall system accuracy demand defined in EN 1060 3.