A pilot feasibility study of continuous cardiac output and blood pressure monitoring during intermittent hemodialysis in patients recovering from severe acute kidney injury

Purpose: To detect changes in cardiac output and blood pressure during intermittent hemodialysis (IHD) in patients recovering from severe acute kidney injury (AKI) after transition from continuous renal replacement therapy (CRRT). Material and methods: In this single-center pilot feasibility study, we applied continuous hemodynamic monitoring (ClearSight SystemTM) before and during IHD sessions in patients recovering from severe AKI. We also measured relative blood volume (BV; CRIT-LINE (R) IV) and Net Ultrafiltration Rate (NUF). CI changes were categorized as follows: Increase (>5 %), Stable (-5 % to 5 %), Mild Decrease (-5 % to -15 %), Moderate Decrease (-15 % to -25 %), and Severe Decrease (<-25 %). Results: We enrolled 10 AKI patients. Overall, there were 119 episodes of severe and 286 episodes of moderate reductions in cardiac index (CI). The median time spent with severe and moderate intradialytic reductions in CI was 8.2 min [2.1-115.8] and 49.5 min [21.6-57.5], respectively. Severe CI reductions happened in nine patients out of 10, and in three patients, they lasted more than 2 h. During IHD, mean arterial pressure increased or remained stable in >78 % of measurements, regardless of changes in CI. Overall, CI decreased by -1.14 L/min/ m(2) during a moderate BV decrease (p < 0.001) and by -0.57 L/min/m2 when NUF rate was high (p < 0.001). Conclusions: CI often, repeatedly, and markedly decreased during IHD. Such decreases were not detected by MAP monitoring and were extreme in some patients.