Cumulative Detrimental Effect of Hypotension during Intermittent Hemodialysis on Kidney Recovery in Critically Ill Patients with AKI Requiring Dialysis

Background: Acute kidney injury requiring dialysis (AKI-D) severely affects the mortality and kidney outcomes of critically ill patients. Intermittent hemodialysis (IHD) is commonly implemented throughout the entire period of kidney replacement therapy (KRT) in AKI-D patients, irrespective of initial modality of KRT. There remain concerns about hemodynamic instability during IHD, but the impact of intradialytic hypotension (IDH) during IHD on kidney recovery remains undetermined. Methods: We retrospectively enrolled individuals who were diagnosed with AKI and received IHD at intensive care units of Inha University from January 2018 to February 2024. IDH was defined as having a nadir systolic blood pressure < 90 mmHg, newly starting vasopressors or increasing the dose during IHD sessions, or early termination of dialysis due to hemodynamic instability. We ascertained IDH occurrences and dialysis dependence at discharge in survivors from AKI-D. Results: Of a total of 1,473 patients received kidney replacement therapy due to AKI, 765 patients died, and 276 patients did not undergo IHD. Therefore, 172 patients receiving IHD were included in the main analysis. Median number of IHD sessions were 7.0 (IQR 3-11.5), and the proportion of IDH per patient was approximately 14%. Of these, 67 patients (45.9%) were dialysis-dependent at discharge. Multivariable logistic regression analyses revealed the number of IHD (as a continuous variable) was a significant predictor for dialysis dependence (OR, 1.71; 95% CI, 1.17-2.64). When the number of IHD was categorized (0, 1-2, and ≥3), the risk of dialysis dependence was substantially higher for individuals with the number of IDH ≥3 compared to those without IDH (OR, 10.41; 95% CI, 2.22-58.93). In the per-session analysis, target UFR was the independent risk factor for IDH occurrence. Conclusion: Our study revealed that IHD-related hypotension during hospitalization has the cumulative adverse impact on kidney recovery in AKI-D survivors. To improve kidney outcomes following AKI-D, the prevention for hemodynamic instability during IHD might be crucial.