How to understand real net ultrafiltration and its association with low blood pressure in critically ill patients with renal replacement therapy

The concept of net ultrafiltration (UFNET) mentioned in the paper by Murugan et al. in a recent issue of Critical Care does not equate to the real UFNET in patients with renal replacement therapy initiation. Furthermore, the baseline blood pressure among the groups had a statistically significant difference. Both of these two factors may affect the final results. Thus, we should be cautious interpreting the conclusions.