A study in predicting oxygen consumption in older women with diastolic heart failure.

摘要

The purpose of this study was to determine the ability of selected clinical variables to predict functional capacity measured by maximum oxygen consumption (VO_{2 max}) in older women with diastolic heart failure. The clinical predictor variables of interest in this study are the Six-Minute Walk test (6-MW), Body Mass Index (BMI), body weight (WT), E-wave velocity, and E/A wave ratio. The researcher developed a formula that will help health care providers to predict the VO_{2 max} for older women with diastolic heart failure. This formula can be useful for clinicians to use as a diagnostic tool and determine prognosis. A descriptive research design using secondary data analysis was selected to address the research questions.; The sample for this study consisted of 12 women (mean age = 63.3 years, sd = ±5.4) with diastolic heart failure who completed the VO₂ test, the six-minute-walk test (6-MW test), and the Doppler echocardiogram. All of the 12 women from the original study were included in the secondary data analysis. All subjects were considered overweight or obese (mean BMI = 35.8 kg/cm2, sd = ±6.7; fat % = 44.4%, ±4.5).; Linear regression analysis was used to determine which variables provided the best prediction of the dependent variable (VO_{2 max}). The F test was performed to test significance of each model. The overall level of significance was set at the .05 level. Results from the regression analysis were that only the total distance walked during the 6-MW test was found to be a significant and strong predictor, accounting for 60% of the variance in VO_{2 max} for older women with diastolic heart failure ( R2 = .6, F_(1,10) = 14.75, p = .003). The regression equation obtained from the analysis was [Predicted VO_{2 max} = 4.7 + .01*(6-MW distance walked)]. Neither BMI or BW nor E/A ratio or E-wave velocity were significant predictors in this sample. This finding supports the ability of the 6-MW test as an alternative screening and diagnostic tool in the clinical settings.