Experimental Research About The Relation Between Transesophageal Photoelectric Pulse Wave Of Descending Aorta And Blood Pressure

Objectives The applicability of testing photoelectric pulse wave in descending aorta transesophageally was investigated. The characteristic parameters of descending aorta pulse wave were collected to analyze their correlation with concurrent femoral artery invasive blood pressure and to evaluate the accuracy of calculating artery blood pressure with those characteristic parameters.Methods 1. The chests of ten adult experimental dogs were opened and their esophaguses were incised. Reflective photoelectric sensor was put on the middle part of the esophaguses under straight watching. Then the light was directed at descending aorta to test the photoelectric pulse wave. Meanwhile, the artery blood pressure was monitored by opening the right femoral artery and inserting an arterial duct. Four-channel polygraph was connected to record and store the photoelectric pulse wave and the concurrent femoral artery invasive blood pressure.2. Forty pulse wave of descending aorta were randomly selected, and eight characteristic parameters were picked, namely H, h, h/H, g/H, At, s, H (1+ts/td) and k. Step wise regression analysis method was used to research the correlation efficient between characteristic parameters of descending aorta pulse wave and invasive artery blood pressure, and the characteristic parameters that have good correlation with femoral artery invasive blood pressure was screened.3. The selected characteristic parameters were introduced into regressive equation, and the optimal equation about systolic pressure, diastolic pressure and mean pressure was established.4. In additional to the selected pulse waves,40 pulse waves were randomly chosen, and their characteristic parameters were introduced into a regressive equation to calculate blood pressure. Comparing with concurrent invasive artery blood pressure, the±s of their value differences was obtained, and the accuracy was verified. The correlation efficient was calculated by simple progressive regression analysis. The correlation between descending aorta blood pressure and its concurrent femoral artery invasive blood pressure was investigated.Results 1. In all the experimental dogs, the pulse wave in descending aorta can be obtained transesophageally, among which stable wave took up 93.56%(42100/45000). Pulse wave fluctuated with respiration, holding breath can stabilize the pulse waveform.2. Each stable wave can provide 8 characteristic parameters. K (ratio:90%) and h/H (ratio:80%) had good correlation with systolic pressure; K (ratio:90%), S (ratio:90%) and H (ratio:70%) had good correlation with diastolic pressure; K and H (ratio:90% for both) were in good correlation with mean pressure. The mean multiple correlation coefficients of the selected characteristic parameters of descending aorta pulse wave with systolic pressure, diastolic pressure and mean pressure of femoral artery were 0.871 (0.749 to 0.935),0.900(0.848 to 0.943)and 0.856(0.734 to 0.921), respectively. Those characteristic parameters have good correlation with concurrent invasive blood pressure.3.The selected characteristic parameters were introduced into regressive equation, and the optimal equation about systolic pressure, diastolic pressure and mean pressure can be established in all the experimental dogs. The x±s of the value difference between descending aorta blood pressure and femoral artery invasive blood pressure is small, and the maximal value difference of systolic pressure, diastolic pressure and mean pressure were 1.026±0.573mmHg,0.911±0.605 mmHg, and 0.913±0.747 mmHg, respectively. The mean values of correlation efficients of their systolic pressure, diastolic pressure and mean pressure were 0.860 (0.780 to 0.924),0.832 (0.750 to 0.896), and 0.842 (0.790 to 0.886), respectively. These two values changed with the same trend.Conclusions 1. The pulse wave in descending aorta can be obtained transesophageally with reflective photoelectric sensor, and stable pulse wave can be achieved when eliminating the disturbance from breath.2. Different characteristic parameters of descending aorta pulse wave had specific correlation with systolic pressure, diastolic pressure and mean pressure.3. The optimal equation of systolic pressure, diastolic pressure and mean pressure can be established with the characteristic parameters of photoelectric pulse wave, and the blood pressure of different time points can also be calculated real-timely.4. Transesophageal descending aorta blood pressure had a good correlation with concurrent femoral artery invasive blood pressure, and changed with almost the same pattern.