THE INCIDENCE OF HYPOVOLEMIC MORBIDITY IN HEMODIALYSIS

While intradialytic hypotension has been linked to intravascular volum e depletion, the pathogenesis of other acute symptoms and their impact on dialysis staff are not well understood. As part of a study to defi ne the association between intradialytic morbidity and intravascular v olume depletion, we monitored those intradialytic nurse interventions (NIs) which required the temporary cessation of ultrafiltration. The d ialysis staff was asked to select for the study 8 ''hypotension-prone' ' and 8 ''stable'' chronic hemodialysis patients based on previous cli nical experience with these patients. Each patient was studied 6 times (total of 93 sessions; 3 sessions could not be performed), and change s in blood volume were calculated from continuously continuously monit ored changes in hematocrit during each session. The rate of decrease i n blood volume was greater (p<0.001) for sessions requiring NI (12.2 /- 5.5%/hr) than for those that did not (5.6+/-3.6%/hr). The incidence of NI due to hypotension only was 22 of 93 sessions (24%), whereas NI for other symptoms (muscle cramps or lightheadedness) occurred in 26 of 93 sessions (28%). In the ''hypotension-prone'' group of patients, 20 of 27 NIs Mere due to hypotension, whereas in the ''stable'' group, 19 of 21 NIs were die to other symptoms. Total NIs were not different between the two groups (56% vs. 47%). We conclude that other symptoms (cramping, lightheadedness, and dizziness) besides hypotension freque ntly require NI. Additionally, many acute intradialytic symptoms requi ring NI appear to be due to intravascular volume depletion and can be identified and corrected by continuous blood volume monitoring during routine hemodialysis.