Figure 1. Heart rate variability as a function of trimethaphan dose required for autonomic blockade in Young and Older Women.
The dose of trimethaphan necessary to achieve ganglionic blockade is significantly related to A.) R-R interval (rs=0.079, p=0.62), B.) standard deviation of the R-R interval (rs =0.581, p<0.001), C.) root mean square of the successive differences in R-R interval (RMSSD; rs =0.453, p<0.01), and D.) % R-R interval differences >50ms (pNN50; rs =0.592, p<0.001).