The Predictive Value Of Preoperative Pulmonary Function Test Parameters For Postoperative Pulmonary Function In Patients With Mitral Stenosis

Objective To analyze the causes and effects of pulmonary function after mitral valve replacement (MVR), discusses predictive value of preoperative pulmonary function test parameters for postoperative pulmonary function in patients with Mitral Stenosis (MS).Methods The patients' history (age; duration of symptoms), preoperative cardiac function (ejection fraction in two- dimensional echocardiograph and clinical evaluation, EF; pulmonary arterial systolic pressure, PASP; mitral valve orifice area, MVA) and pulmonary function test parameters (forced vital capacity, FVC; forced expiratory volume in 1 second, FEV, maximal ventilatory volume, MVV; diffusing capacity of the lung for carbon monoxide, DLCO:TLCO-SB) were collected from 57 consecutive patients with rheumatic mitral stenosis underwent MVR. For eliminating age, height, weight with the influence of pulmonary function test parameters, they were used measured values of predictive values percentage. Postoperative pulmonary function (derived from blood gas analysis and ventilator parameters) were recorded at Oh,2h,6h, after surgery, calculated oxygenation index(01), respiratory index(RI) and PaO2 to PA02. Compared OI, RI and PaO2 to PA02 of Oh,2h,6h after surgery, selected the best suitable pamameter as dependent variable Y. Some preoperative parameters was used as independent variable to make straight line correlation with dependent variable Y, such as X1:age, X2:DOS (duration of symptoms), X3:MVV%pred, X4:FEV,%pred, X5:FVC%pred, X6:TLCO-SB% pred, X7:EF, X8:MVA, X9:PASP, then ran multifactor stepwise gradual regressive analysis for the independent variable of r>0.4.Results Comparisons of OI, RI and retio of PaO2 to PA02 variation after surgery Oh,2h,6h from 57 patients with rheumatic mitral stenosis underwent MVR:it is not statistically significant that contrast OI, RI, Pa02 to PA02 of T2 and T3 with T1 (P> 0.05)。Result of analysis with rectilinear correlation of every index from 57 patients with rheumatic mitral stenosis underwent MVR:X3 (r3=0.43) X4 (r4=0.40), X5(rs=0.41), X6 (r6=0.56), X8 (r8=0.42) are linear relation with Y (P<0.05)The optimal regression equation of pulmonary function was established through multifactor stepwise regression analysis, Y=150.67+2.60X6+27.70X8. The result of analysis of variance is the regression equation is established (P<0.01).The major factors that influence postoperative pulmonary function are X6(diffusion capacity for carbon monoxide of lung, DLCO) and X8 (mitral valve port area, MVA), X6(diffusion capacity for carbon monoxide of lung) and X8(mitral valve port area) both direct correlation with Y(oxygenation index,OI), from the standardized partial regression coefficient, we can see that DLCO (the standardized partial regression coefficient is 0.58)is the most significant influence factor for 01.Conclusion Some of preoperative pulmonary function test parameters, such as DLCO, have important predictive value for postoperative pulmonary function status in patients undergoing MVR. We will predict postoperative pulmonary function status in patients undergoing MVR according Y=150.67+2.60 X6+27.70 X8. It is of great significance to do preoperative pulmonary function test routinely in such patients.