Background:The ultrafiltration volume, a surrogate maker of inter-dialytic weight gain and extraction ratio plays a significant contributory role in the dialysis dose but in very large amount can lead to intradialysis hypotension and its consequences of myocardial ischemia and stunning and further diminution of kidney function. Measures are needed to prescribe the optimal quantity for each session.Method: A thousand six hundred and eighty eight dialysis sessions for 287 participants were studied. Pre and postdialysis blood samples for electrolytes, urea and creatinine, and hematocrit were taken.
Results:The mean age, interdialytic weight gain and ultrafiltration volume were 50.7 ± 11.7 years, 2.23 ± 1.3 kg and 1.3 ± 1.1 L respectively. Greater proportions of participants were males (66.9%), had hypertension associated CKD (44.6%) and were between 35-54 years (44.3%). A greater proportion of the sessions had ultrafiltration volume 1500-1999 mL (23.6%). The ultrafiltration volume was higher in males, was positively related to the inter-dialytic weight gain, fall in interdialytic percentage oxygen saturation and inter-dialytic blood pressure rise but it was negatively correlated with age, predialysis albumin and bicarbonate, blood flow rate, dialysis duration, and dialysis dose (higher in males). Higher ultrafiltration volume was associated with intradialysis hypotension. Dialysis dose was adequate in 15.2% of the sessions. Predictors of the ultrafiltration volume were dialysis frequency, blood flow rate, dialysis duration, predialysis albumin and dialysis dose.
Conclusion:The ultrafiltration volume contributes to the dialysis dose but very high quantity could cause intradialysis hypotension. A carefully prescribed ultrafiltration volume is therefore needed to deliver optimal treatment doses and avoid complications.