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Background: Circulating extracellular vesicles (EVs) have shown promising results as noninvasive biomarkers for predicting disease outcomes in solid organ transplantation. Because in situ graft cell expression of the tolerogenic molecule HLA-G is associated with acceptance after lung transplantation (LTx), we hypothesized that plasma EV-bound HLA-G (HLA-GEV) levels could predict chronic lung allograft dysfunction (CLAD) development., Methods: We analyzed 78 LTx recipients from the Cohort-for-Lung-Transplantation cohort, all in a stable (STA) state within the first year post-LTx. At 3 y, 41 patients remained STA, and 37 had CLAD (bronchiolitis obliterans syndrome, BOS, [n = 32] or restrictive allograft syndrome [n = 5]). HLA-GEV plasma levels were measured at month 6 (M6) and M12 in 78 patients. CLAD occurrence and graft failure at 3 y post-LTx were assessed according to early HLA-GEV plasma levels., Results: In patients with subsequent BOS, (1) HLA-GEV levels at M12 were significantly lower than those in STA patients (P = 0.013) and (2) also significantly lower than their previous levels at M6 (P = 0.04).A lower incidence of CLAD and BOS and higher graft survival at 3 y were observed in patients with high HLA-GEV plasma levels at M12 (high versus low HLA-GEVs patients [cutoff 21.3 ng/mL]: freedom from CLAD, P = 0.002; freedom from BOS, P < 0.001; and graft survival, P = 0.04, [log-rank]). Furthermore, in multivariate analyses, low HLA-GEV levels at M12 were independently associated with a subsequent risk of CLAD, BOS, and graft failure at 3 y (P = 0.015, P = 0.036, and P = 0.026, respectively [Cox models])., Conclusions: This exploratory study suggests the potential of EV-bound HLA-G plasma levels as a liquid biopsy in predicting CLAD/BOS onset and subsequent graft failure., Competing Interests: The authors declare no conflicts of interest., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Objective: The timely initiation of renal replacement therapy (RRT) for acute kidney injury (AKI) requires sequential decision-making tailored to individuals' evolving characteristics. To learn and validate optimal strategies for RRT initiation, we used reinforcement learning on clinical data from routine care and randomized controlled trials., Materials and Methods: We used the MIMIC-III database for development and AKIKI trials for validation. Participants were adult ICU patients with severe AKI receiving mechanical ventilation or catecholamine infusion. We used a doubly robust estimator to learn when to start RRT after the occurrence of severe AKI for three days in a row. We developed a "crude strategy" maximizing the population-level hospital-free days at day 60 (HFD60) and a "stringent strategy" recommending RRT when there is significant evidence of benefit for an individual. For validation, we evaluated the causal effects of implementing our learned strategies versus following current best practices on HFD60., Results: We included 3748 patients in the development set and 1068 in the validation set. Through external validation, the crude and stringent strategies yielded an average difference of 13.7 [95% CI -5.3 to 35.7] and 14.9 [95% CI -3.2 to 39.2] HFD60, respectively, compared to current best practices. The stringent strategy led to initiating RRT within 3 days in 14% of patients versus 38% under best practices., Discussion: Implementing our strategies could improve the average number of days that ICU patients spend alive and outside the hospital while sparing RRT for many., Conclusion: We developed and validated a practical and interpretable dynamic decision support system for RRT initiation in the ICU., (© The Author(s) 2024. Published by Oxford University Press on behalf of the American Medical Informatics Association. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Purpose: The effect of renal replacement therapy (RRT) in comatose patients with acute kidney injury (AKI) remains unclear. We compared two RRT initiation strategies on the probability of awakening in comatose patients with severe AKI., Methods: We conducted a post hoc analysis of a trial comparing two delayed RRT initiation strategies in patients with severe AKI. Patients were monitored until they had oliguria for more than 72 h and/or blood urea nitrogen higher than 112 mg/dL and then randomized to a delayed strategy (RRT initiated after randomization) or a more-delayed one (RRT initiated if complication occurred or when blood urea nitrogen exceeded 140 mg/dL). We included only comatose patients (Richmond Agitation-Sedation scale [RASS] < - 3), irrespective of sedation, at randomization. A multi-state model was built, defining five mutually exclusive states: death, coma (RASS < - 3), incomplete awakening (RASS [- 3; - 2]), awakening (RASS [- 1; + 1] two consecutive days), and agitation (RASS >  + 1). Primary outcome was the transition from coma to awakening during 28 days after randomization., Results: A total of 168 comatose patients (90 delayed and 78 more-delayed) underwent randomization. The transition intensity from coma to awakening was lower in the more-delayed group (hazard ratio [HR] = 0.36 [0.17-0.78]; p = 0.010). Time spent awake was 10.11 days [8.11-12.15] and 7.63 days [5.57-9.64] in the delayed and the more-delayed groups, respectively. Two sensitivity analyses were performed based on sedation status and sedation practices across centers, yielding comparable results., Conclusion: In comatose patients with severe AKI, a more-delayed RRT initiation strategy resulted in a lower chance of transitioning from coma to awakening., (© 2024. Springer-Verlag GmbH Germany, part of Springer Nature.)

Objectives: Among patients with severe acute kidney injury (AKI) admitted to the ICU in high-income countries, regional practice variations for fluid balance (FB) management, timing, and choice of renal replacement therapy (RRT) modality may be significant., Design: Secondary post hoc analysis of the STandard vs. Accelerated initiation of Renal Replacement Therapy in Acute Kidney Injury (STARRT-AKI) trial (ClinicalTrials.gov number NCT02568722)., Setting: One hundred-fifty-three ICUs in 13 countries., Patients: Altogether 2693 critically ill patients with AKI, of whom 994 were North American, 1143 European, and 556 from Australia and New Zealand (ANZ)., Interventions: None., Measurements and Main Results: Total mean FB to a maximum of 14 days was +7199 mL in North America, +5641 mL in Europe, and +2211 mL in ANZ ( p < 0.001). The median time to RRT initiation among patients allocated to the standard strategy was longest in Europe compared with North America and ANZ ( p < 0.001; p < 0.001). Continuous RRT was the initial RRT modality in 60.8% of patients in North America and 56.8% of patients in Europe, compared with 96.4% of patients in ANZ ( p < 0.001). After adjustment for predefined baseline characteristics, compared with North American and European patients, those in ANZ were more likely to survive to ICU ( p < 0.001) and hospital discharge ( p < 0.001) and to 90 days (for ANZ vs. Europe: risk difference [RD], -11.3%; 95% CI, -17.7% to -4.8%; p < 0.001 and for ANZ vs. North America: RD, -10.3%; 95% CI, -17.5% to -3.1%; p = 0.007)., Conclusions: Among STARRT-AKI trial centers, significant regional practice variation exists regarding FB, timing of initiation of RRT, and initial use of continuous RRT. After adjustment, such practice variation was associated with lower ICU and hospital stay and 90-day mortality among ANZ patients compared with other regions., (Copyright © 2024 The Authors. Published by Wolters Kluwer Health, Inc. on behalf of the Society of Critical Care Medicine.)