Abstract
It is difficult but important to estimate optimal body fluid level before initiating hemodialysis therapy, since uremic patients usually exhibit volume expansion in the form of hypertension or pulmonary edema. However, at present there are no definite ways of determining their basal body weight, making it impossible to assess how much fluid should be removed in practice. We investigated whether percent increases in body weight and blood pressure could be roughly calculated from parameters routinely obtained in uremic patients, including age, sex, underlying diseases, cardiothoracic ratio and electrocardiographic findings. The 190 patients included in this study were among those started on hemodialysis between 1977 and 1987 at the National Cardiovascular Center Hospital and after stabilization underwent maintenance hemodialysis at other hospitals. Body weight and blood pressure were measured before the initial hemodialysis session, and post-dialysis body weight and pre-dialysis blood pressure were measured at the time of the last dialysis at the National Cardiovascular Center. The percent increase in body weight, from postdialytic body weight at the last dialysis to predialytic body weight at the first dialysis, was correlated with systolic blood pressure before initiating hemodialysis (r=0.33, p<0.0001) and cardiothoracic ratio (r=0.45, p<0.0001), and the percentage increase in systolic blood pressure was correlated with the absolute level of systolic blood pressure before initiating hemodialysis (r=0.44, p<0.0001). They were not correlated with either age or sex. Our results indicate that the amount of fluid excess in uremic patients who must be treated by hemodialysis can be estimated roughly from parameters routinely obtained before hemodialysis. In addition, systolic blood pressure after correcting body fluid volume by hemodialysis also seems estimated from similar parameters.
