Comparison of hemodynamic parameters among continuous, intermittent and hybrid renal replacement therapy in acute kidney injury: a systematic review of randomized clinical trials

Backround: The use of renal replacement therapy (RRT) in acute kidney injury (AKI) patients in the intensive care unit (ICU) is associated with high hemodynamic instability leading to a probable increase in hospital mortality. The aim of this study was to compare hemodynamic parameters among continuous, intermittent and hybrid renal replacement therapy in critical ill patients. Methods: We conducted in accordance with the PRISMA guidelines which was registered at the PROSPERO Database (CRD42018086504). Randomized clinical trials involving patients with AKI in the ICU treated with continuous, intermittent or hybrid RRT were included. We investigated the PubMed, Embase and Cochrane databases. Two reviewers independently performed study selection, evaluation of methodological quality and data extraction. Results: Out of 3442 citations retrieved, 12 randomized clinical trials (RCTs) were included, representing 1419 patients. Most of the studies (n=8) did not report or find differences in hemodynamic parameters across different RTT modalities. However, continuous venovenous hemofiltration (CVVH) was associated with a reduction in heart rate (after 1 and 4 hours) in comparison with intermittent haemodialysis (IHD) patients. CVVH was also associated with an increase in systolic blood pressure (after 0.5 and 2h) when compared with patients treated with IHD. In addition, dobutamine doses were higher in patients submitted to continuous venovenous hemodiafiltration (CVVHDF) compared to patients submitted to IHD. Lower baseline mean arterial pressure (MAP), greater MAP variation on dialysis, higher number of pressors at baseline, and increase in pressor dose during dialysis were associated with shorter survival time; and greater MAP variation on dialysis was negatively correlated with renal recovery. Conclusions: Changes in hemodynamic pattern appear be similar in different dialytic methods used in critical ill patients; however continuous venovenous hemofiltration seems be safer than other renal replacement modalities.