THE EFFECT OF SODIUM AND ULTRAFILTRATION MODELING ON PLASMA-VOLUME CHANGES AND HEMODYNAMIC STABILITY IN INTENSIVE-CARE PATIENTS RECEIVING HEMODIALYSIS FOR ACUTE-RENAL-FAILURE - A PROSPECTIVE, STRATIFIED, RANDOMIZED, CROSS-OVER STUDY

Background. Haemodynamic stability in intensive care unit (ICU) patien t with acute renal failure (ARF) during intermittent dialytic support has been the focus for several variations to dialysis delivery. Indeed this has been noted by many as a possible cause for prolonged renal d ysfunction created by repeated hypotensive renal insult, as well as a reason for the lower delivered dialysis dose afforded. End-stage renal failure patients supported by intermittent dialysis have benefitted f rom variable sodium dialysate and variable ultrafiltration rate protoc ols. The current study has focused upon the response to these dialysis variations in the ICU ARF patient. Methods. Successive ICU patients w ith defined characteristics of ARF requiring dialytic support were ent ered into a prospective, stratified (by Cleveland Clinic Foundation AR F Acuity Score), randomized, crossover designed study to evaluate haem odynamic effects and need for interaction during dialysis therapy deli vering a fixed dialysis dose based upon urea kinetic analysis. Subject s were supported either by a fixed dialysate sodium (140 meq/dl) and f ixed ultrafiltration rate (Protocol A), or a variable sodium dialysate (160-140 meq/dl) and variable ultrafiltration (50% UF during the firs t third of treatment time, 50% UF over the last two thirds treatment t ime) (Protocol B). After three sessions, the patients were crossed to the other protocol, and if continued, after three sessions returned to the original protocol. Mean arterial pressures, Cardiac output, serum electrolytes, serum albumin, and relative blood volume changes were m easured. Frequency of nursing intervention, quantity and type of volum e replacements as well as presser agent use was standardized, document ed and compared. Results. Ten ARF patients (age: 64.2 +/- 13.7 years), CCF acuity score (13.3 +/- 3.9), APACHE II score (28.7 +/- 4.7). MAP (V-NA: 82.8 +/- 16.9; F-NA: 86.2 +/- 18.9 mmHg), CO, cardiac index, pr esser support interventions required (V-NA: 16%; F-NA: 48.4%, P<0.001) , blood volume changes (Critline) (V-NA: -6.6 +/- 5.2; F-NA: -7.59 +/- 6.7, P<0.05), S. albumin (V-NA: 2.4 +/- 0.6; F-NA: 2.81 +/- 0.9 g/dl, ns) pre/post S.Na (V-NA: 138.7 +/- 5.1/141.7 +/- 2.3; F-NA: 136.6 +/- 5.96/139.1 +/- 3.71 mmol/dl), osmolality, Urea (V-NA: 69.5 +/- 0.6; F -NA: 70.5 +/- 0.6%, ns) and Creatinine (V-NA: 56.6 +/- 0.5; F-NA: 59.6 +/- 0.5%, us) Reduction ratio, dialysis time (V-NA: 4.8 +/- 0.5; F-NA : 4.6 +/- 0.45 h) and achieved UF (V-NA: 2.0 +/- 1.2; F-NA: 1.56 +/- 1 .3 L, P<0.05) were measured. Conclusion Haemodynamic stability was gre ater during Protocol B than during Protocol A in all patients. Signifi cantly less intervention was noted during Protocol B, despite the same dialysis delivery during both Protocols. Relative Blood volume change s were less during Protocol B, despite a greater total ultrafiltration . Variable sodium dialysate coupled with a variable ultrafiltration ra te seems to be the preferred dialysis prescription for ICU ARF patient s undergoing intermittent haemodialysis.