Magnitude and implications of spontaneous hemodynamic variability in XXXX .

@entity1 @entity2514 @entity120 @entity594
The pulmonary artery (PA) pressure and pulmonary resistance at rest have been noted to vary spontaneously in @entity1 with @entity120 . To evaluate this variation, in 12 @entity1 (8 @entity1 , 4 @entity1 , aged 43 +/- 13 years), hourly measurements were made for 6 consecutive hours of heart rate, systemic and PA pressures, cardiac output, systemic and pulmonary resistance. After these baseline measurements the @entity1 were tested with @entity2514 and @entity594 therapy. Spontaneous variability in pulmonary pressures and resistances occurred in each @entity1 , with the amount of variation (coefficient of variation) in PA pressure averaging 8% and in total pulmonary resistance 13% over the 6 hours. The @entity1 with the most variability in mean PA pressure also had the most variability in cardiac output (r = 0.69, p = 0.02). Variability also correlated with the severity of the disease, as the @entity1 with the highest total pulmonary resistances also had the most variation for that factor (r = 0.91, p less than 0.01). The amount of variability did not correlate, however, with the acute response to either @entity2514 or @entity594 administration. Based on the average coefficients of variation in these 12 @entity1 , estimates were obtained of the percent change needed for an observed change to be attributed to a drug effect with 95% confidence. From these estimates, it was projected that for a single @entity1 , a mean change in pulmonary resistance of 36% or a mean change in PA pressure of 22% would be required in order to attribute the changes to a drug effect.(ABSTRACT TRUNCATED AT 250 WORDS)
