Greet De Vlieger

Renal impairment is considered a contra‐indication for lung (LTX) or combined heart‐lung (HLTX) transplantation due to increased mortality. We hypothesized that renal impairment in pulmonary arterial hypertension (PAH) and chronic thromboembolic pulmonary hypertension (CTEPH) is the result of reduced cardiac output and should be partly reversible after LTX. We performed a retrospective analysis in 67 consecutive PAH and CTEPH patients who underwent (H)LTX, to investigate the postoperative evolution of renal function in function of baseline renal function using a mixed model effect test. Furthermore, we assessed potential predictors for postoperative renal dysfunction, renal replacement therapy (RRT) and mortality by multivariate analyses. Median baseline eGFR was 74 mL/min/1.73m². Fourteen patients were classified as KDIGO 3 preoperatively, 38 patients as KDIGO 2. Renal function significantly declined after 1 and 2 years in all patients. In patients with impaired renal function (KDIGO 2 and 3), we observed a significant improvement in eGFR 1 month after (H)LTX (p = 0.02 and p = 0.04, respectively). Baseline renal impairment ≤ 60 mL/min/1.73m² was associated with early RRT but not with further renal function deterioration, long‐term RRT, or mortality. Age was a predictor of renal function decline and mortality. We conclude that renal function evolution can be biphasic after (H)LTX in PAH and CTEPH patients with baseline renal impairment, with initial improvement due to resolution of cardio‐renal syndrome. Mild to moderate renal impairment was not significantly associated with renal deterioration or increased mortality.

Background. Lung transplantations are highly complex procedures, often conducted in frail patients. Through the addition of immunosuppressants, healing can be compromised, primarily leading to the development of bronchopleural fistulas. Although esophageal fistulas (EFs) after lung transplantation remain rare, they are associated with significant morbidity. We aimed to investigate the clinical presentation, diagnostic approaches, and treatment strategies of EF after lung transplantation. Methods. All patients who developed EF after lung transplantation at the University Hospitals Leuven between January 2019 and March 2022 were retrospectively reviewed and the clinical presentations, diagnostic approaches, and treatment strategies were summarized. Results. Among 212 lung transplantation patients, 5 patients (2.4%) developed EF. Three patients were male and median age was 39 y (range, 34–63). Intraoperative circulatory support was required in 3 patients, with 2 needing continued support postoperatively. Bipolar energy devices were consistently used for mediastinal hemostasis. All EFs were right-sided. Median time to diagnosis was 28 d (range, 12–48) and 80% of EFs presented as recurrent respiratory infections or empyema. Diagnosis was made through computed tomography (n = 3) or esophagogastroscopy (n = 2). Surgical repair with muscle flap covering achieved an 80% success rate. All patients achieved complete resolution, with only 1 patient experiencing a fatal outcome during a complicated EF-related recovery. Conclusion. Although EF after lung transplantation remains rare, vigilance is crucial, particularly in cases of right-sided intrathoracic infection. Moreover, caution must be exercised when applying thermal energy in the mediastinal area to prevent EF development and mitigate the risk of major morbidity. Timely diagnosis and surgical intervention can yield favorable outcomes. Export

The ARC predictor is a prediction model for augmented renal clearance (ARC) on the next intensive care unit (ICU) day that showed good performance in a general ICU setting. In this study, we performed a retrospective external validation of the ARC predictor in critically ill coronavirus disease 19 (COVID-19) patients admitted to the ICU of the University Hospitals Leuven from February 2020 to January 2021. All patient-days that had serum creatinine levels available and measured creatinine clearance on the next ICU day were enrolled. The performance of the ARC predictor was evaluated using discrimination, calibration, and decision curves. A total of 120 patients (1064 patient-days) were included, and ARC was found in 57 (47.5%) patients, corresponding to 246 (23.1%) patient-days. The ARC predictor demonstrated good discrimination and calibration (AUROC of 0.86, calibration slope of 1.18, and calibration-in-the-large of 0.14) and a wide clinical-usefulness range. At the default classification threshold of 20% in the original study, the sensitivity and specificity were 72% and 81%, respectively. The ARC predictor is able to accurately predict ARC in critically ill COVID-19 patients. These results support the potential of the ARC predictor to optimize renally cleared drug dosages in this specific ICU population. Investigation of dosing regimen improvement was not included in this study and remains a challenge for future studies.

Traumatic brain injury (TBI) remains a major cause of mortality and morbidity, and almost half of these patients are admitted to the intensive care unit. Of those, 10% develop acute kidney injury (AKI) and 2% even need kidney replacement therapy (KRT). Although clinical trials in patients with TBI who have AKI are lacking, some general principles in this population may apply. The present review is an overview on the epidemiology and pathophysiology of AKI in patients with TBI admitted to the intensive care unit who are at risk for or who have developed AKI. A cornerstone in severe TBI management is preventing secondary brain damage, in which reducing the intracranial pressure (ICP) and optimizing the cerebral perfusion pressure (CPP) remain important therapeutic targets. To treat episodes of elevated ICP, osmolar agents such as mannitol and hypertonic saline are frequently administered. Although we are currently awaiting the results of a prospective randomized controlled trial that compares both agents, it is important to realize that both agents have been associated with an increased risk of developing AKI which is probably higher for mannitol compared with hypertonic saline. For the brain, as well as for the kidney, targeting an adequate perfusion pressure is important. Hemodynamic management based on the combined use of intravascular fluids and vasopressors is ideally guided by hemodynamic monitoring. Hypotonic albumin or crystalloid resuscitation solutions may increase the risk of brain edema, and saline-based solutions are frequently used but have a risk of hyperchloremia, which might jeopardize kidney function. In patients at risk, frequent assessment of serum chloride might be advised. Maintenance of an adequate CPP involves the optimization of circulating blood volume, often combined with vasopressor agents. Whether individualized CPP targets based on cerebrovascular autoregulation monitoring are beneficial need to be further investigated. Interestingly, such individualized perfusion targets are also under investigation in patients as a strategy to mitigate the risk for AKI in patients with chronic hypertension. In the small proportion of patients with TBI who need KRT, continuous techniques are advised based on pathophysiology and expert opinion. The need for KRT is associated with a higher risk of intracranial hypertension, especially if osmolar clearance occurs fast, which can even occur in continuous techniques. Precise ICP and CPP monitoring is mandatory, especially at the initiation of KRT.

Background: Acute kidney injury (AKI) has been reported as a frequent complication of critical COVID-19. We aimed to evaluate the occurrence of AKI and use of kidney replacement therapy (KRT) in critical COVID-19, to assess patient and kidney outcomes and risk factors for AKI and differences in outcome when the diagnosis of AKI is based on urine output (UO) or on serum creatinine (sCr). Methods: Multicenter, retrospective cohort analysis of patients with critical COVID-19 in seven large hospitals in Belgium. AKI was defined according to KDIGO within 21 days after ICU admission. Multivariable logistic regression analysis was used to explore the risk factors for developing AKI and to assess the association between AKI and ICU mortality. Results: Of 1286 patients, 85.1% had AKI, and KRT was used in 9.8%. Older age, obesity, a higher APACHE II score and use of mechanical ventilation at day 1 of ICU stay were associated with an increased risk for AKI. After multivariable adjustment, all AKI stages were associated with ICU mortality. AKI was based on sCr in 40.1% and UO in 81.5% of patients. All AKI stages based on sCr and AKI stage 3 based on UO were associated with ICU mortality. Persistent AKI was present in 88.6% and acute kidney disease (AKD) in 87.6%. Rapid reversal of AKI yielded a better prognosis compared to persistent AKI and AKD. Kidney recovery was observed in 47.4% of surviving AKI patients. Conclusions: Over 80% of critically ill COVID-19 patients had AKI. This was driven by the high occurrence rate of AKI defined by UO criteria. All AKI stages were associated with mortality (NCT04997915).

Background: Clinical decision support systems are implemented in many hospitals to prevent medication errors and associated harm. They are however associated with a high burden of false positive alerts and alert fatigue. The aim of this study was to evaluate a drug–drug interaction (DDI) clinical decision support system in terms of its performance, uptake and user satisfaction and to identify barriers and opportunities for improvement. Methods: A quantitative evaluation and end-user survey were performed in a large teaching hospital. First, very severe DDI alerts generated between 2019 and 2021 were evaluated retrospectively. Data collection comprised alert burden, override rates, the number of alert overrides reviewed by pharmacists and the resulting pharmacist recommendations as well as their acceptance rate. Second, an e-survey was carried out among prescribers to assess satisfaction, usefulness and relevance of DDI alerts as well as reasons for overriding. Results: A total of 38,409 very severe DDI alerts were generated, of which 88.2% were overridden by the prescriber. In 3.2% of reviewed overrides, a recommendation by the pharmacist was provided, of which 79.2% was accepted. False positive alerts were caused by a too broad screening interval and lack of incorporation of patient-specific characteristics, such as QTc values. Co-prescribing of a non-vitamin K oral anticoagulant and a low molecular weight heparin accounted for 49.8% of alerts, of which 92.2% were overridden. In 88 (1.1%) of these overridden alerts, concurrent therapy was still present. Despite the high override rate, the e-survey revealed that the DDI clinical decision support system was found useful by prescribers. Conclusions: Identified barriers were the lack of DDI-specific screening intervals and inclusion of patient-specific characteristics, both leading to a high number of false positive alerts and risk for alert fatigue. Despite these barriers, the added value of the DDI clinical decision support system was recognized by prescribers. Hence, integration of DDI-specific screening intervals and patient-specific characteristics is warranted to improve the performance of the DDI software.