ABSTRACT
BACKGROUND: Assess the respiratory-related parameters associated with subsequent severe acute kidney injury in mechanically ventilated patients with acute respiratory distress syndrome (ARDS). METHODS: Retrospective cohort, analyzing a large public database-Multiparameter Intelligent Monitoring in Intensive Care-III. Adult patients with at least 48 h of mechanical ventilation (MV), under volume controlled ventilation and an oxygenation index less than 300 mmHg were included. RESULTS: A total of 1,142 patients had complete data and were included in the final analyses. According to a causal directed acyclic graph (DAG) that included respiratory system compliance (Crs), tidal volume (Vt), driving pressure (ΔP), plateau pressure (PPlat), PEEP, PaO2 and PaCO2 as possible exposures related to severe AKI, only Crs and PEEP levels had significant causal association with severe acute kidney injury (AKI) (OR 0.90, 95% CI: 0.84-0.94 for each 5-mL/cmH2O reduction in Crs; OR, 1.05 95% CI: 1.03-1.10 for each 1-cmH2O increase of PEEP). Using mediation analysis, we examined whether any mechanical ventilation, blood gas or hemodynamic parameters could explain the effects of Csr on AKI. Only PEEP mediated the significant but small effect (less than 5%) of Csr on severe AKI. The effects of PEEP, in turn, were not mediated by any other evaluated parameter. Several sensitivity analyses with (I) need of renal replacement therapy (RRT) as an alternative outcome and (II) only patients with Vt <8 mL/kg, confirmed our main findings. In trying to validate our DAG assumptions, we confirmed that only ΔP was associated with mortality but not with severe AKI. CONCLUSIONS: Crs and PEEP are the only respiratory-related variables with a direct causal association in severe AKI. No mechanical ventilator or blood gas parameter mediated the effects of Crs. Approaches reducing Vt and/or ΔP in ARDS can have limited effect on renal protection.
ABSTRACT
BACKGROUND: Cardiorenal syndrome has been recently divided into 5 categories, according to acute or chronic evolution and primary organ dysfunction. Anemia can also accompany this disorder, leading to a more complex situation. This study aims to analyze the renal outcomes of patients, specifically patients with chronic Cardiorenal syndrome, with or without anemia, long-term after heart transplantation. MATERIAL/METHODS: This was a retrospective cohort study on chronic Cardiorenal syndrome patients submitted to heart transplantation. Patients were divided according to presence of anemia and renal dysfunction before heart transplantation. RESULTS: A total of 108 patients (92 males) with the mean age of 45±12 years were included. The etiologies of the heart failure were hypertensive dilated myocardiopathy (66%), ischemic (14%) and Chagasic (12%). Before the heart transplantation, 51 patients had an eGFR less than 60 mL/min. From these, 24 had concomitant anemia. One year after the transplantation, patients with previous isolated renal dysfunction ameliorates eGFR (45±11 vs. 65±26 mL/min, p<0.001), while those patients with previous renal dysfunction and anemia presented no improvement (eGFR 44±14 vs. 47±13 mL/min, p=0.619) 1 year after heart transplantation. Moreover, higher hemoglobin was an independent predictor of eGFR improvement after heart transplantation when associated with previous renal dysfunction (OR 1.8; CI 1.2-3.6, p<0.01 for each hemoglobin increment of 1 g/dL). CONCLUSIONS: Patients with isolated Cardiorenal syndrome presented partial renal function recovery after heart transplantation, while the presence of cardiorenal anemia was a marker of renal function non-recovery 1 year after heart transplantation.