TOLERANCE OF HEMODIALYSIS - A RANDOMIZED CROSS-OVER TRIAL OF 5-H VERSUS 4-H TREATMENT TIME

Background. Many factors can impair haemodialysis (HD) tolerance. Some such as age and diabetes mellitus are linked to the patient. Others, such as dialysate, machine, and membrane are linked to the treatment c haracteristics. The duration of the HD sessions may represent another factor in tolerance since it influences the rate of ultrafiltration. H owever, its influence has not been studied independently of the type o f membrane or dialysate buffer. Methods. In a randomized crossover stu dy, the incidence of intradialytic symptoms was compared during 4-h an d 5-h HD sessions in 38 patients. The study period was 2 weeks for eac h dialysis time. The influence of age and diabetes was also analysed. Sessions requiring more than 4 litres of ultrafiltration were excluded . Results. During the 5-h period, the incidence of headache, nausea, c hills, back pain and pruritus was significantly greater. On the contra ry, the incidence of hypotension and postdialytic orthostatic hypotens ion was significantly less. We also demonstrated that ultrafiltration rate and orthostatic hypotension were correlated, and that age over 65 years and diabetes influenced HD tolerance. The incidence of hypotens ion was significantly less in patients over 65 receiving 5-h HD treatm ent. Conclusions. Although some symptoms were more frequent during the 5-h HD sessions, the incidence of hypotension and postdialytic orthos tatic hypotension was significantly less. This resulted in an improvem ent in acute haemodynamic HD tolerance, which could also influence lon g-term morbidity and mortality, especially in patients over 65 years.