دانلود رایگان مقاله محاسبه سرعت موج پالس در داخل بدن با تکنیک افست

Abstract

Pulmonary blood pressure measurements were collected from 5 clinically healthy horses. Pulse wave velocity (PWV) values were calculated using five techniques, four existing (minimum foot-to-foot, F2F; maximum 1st derivative, M1D; maximum 2nd derivative, M2D; and cross correlation, CC) and the new statistical phase offset technique (SPO). The SPO technique was also applied to systolic (SPO-S), diastolic (SPO-D) and full wave (SPO-FW) data. The reliability of each analysis technique was determined using the consistency of calculated PWV values. Using the original data sets, of variable length (2
n
5) due to the effects of respiration, the SPO technique gave the most consistent results (SPO-D, 2.31 0.31 m/s; SPO-S, 2.18 0.30 m/s; and SPO-FW, 2.45 0.35 m/s). The CC technique, was complex to implement but also gave considerable consistency (CC, 2.64 0.36 m/s). The family of techniques utilizing only a single point of comparison all provided less consistent results (M1D, 2.82 0.56 m/s; M2D, 2.90 1.09 m/s; and F2F, 3.42 1.67 m/s). Consistent length data sets were then created (n Z 5) and analyzed. Results were: SPO-S, 2.74 0.34 m/s; SPO-D, 2.67 0.40 m/s; SPO-FW, 2.78 0.36 m/s; F2F, 2.53 0.52 m/s; M1D, 3.39 1.28 m/s; M2D, 3.20 1.90 m/s; and CC, 3.23 0.40 m/s. Comparison of the results indicate that of the techniques included in this study, the new SPO technique provided the greatest reliability for determining PWV values. It was also intuitive to implement. ª 2016 Assoc

Conclusions

Pulse wave velocity (PWV) of the arterial circulation is an important physiological parameter for indicating cardiovascular and pulmonary health. A new statistical phase offset technique for calculating PWV was proposed and compared against existing PWV analysis techniques. One of the major limitations of data collection in this particular study was that blood pressure measurements were being collected from the pulmonary artery and not a systemic artery. Therefore, the blood pressure waveforms were interrupted by respiration every 2e6 cardiac cycles, making collection of consistent, consecutive cardiac cycles unattainable. This presented a challenge when implementing existing characteristic point techniques, as past studies have shown to use the average 10e40 consecutive cardiac cycles in calculating PWV. However, the characteristic point techniques remained inherently simple to implement making them a viable option for PWV calculation if multiple respiratory cycles are combined to increase the length of the data set. Cross correlation and Statistical Phase Offset techniques are both able to be applied to either all or part of the cardiac cycle. This allows them to be used more reliability on variable length data sets than the characteristic point techniques. The cross correlation technique proved to be complex in its implementation, making it difficult to recommend for basic PWV calculations, like those in this study. The SPO technique provided results consistently equal or better than the CC method while remaining intuitive to implement. Based on the results of this study the new proposed SPO technique is a reasonable alternative for PWV analysis and has shown to have considerable advantages for implementation.