Yadav, Hemang

OBJECTIVE: To identify distinct phenotypes of acute respiratory distress syndrome (ARDS) developing after hematopoietic cell transplantation (HCT), using routinely available clinical data at ICU admission. DESIGN: Multicenter retrospective cohort study using latent class analysis. SETTING: ICUs across three Mayo Clinic campuses (Minnesota, Florida, and Arizona). PATIENTS: A total of 166 adult patients who developed ARDS within 120 days following HCT (96 allogeneic, 70 autologous). INTERVENTION: None. MEASUREMENTS AND MAIN RESULTS: Model selection was based on multiple metrics including Bayesian information criteria, entropy, and Vuong-Lo-Mendell-Rubin Likelihood Ratio testing. A two-class model optimally described the cohort. Class 1 (n = 81) was characterized by worse hypoxemia (P/F ratio 157 vs. 210, p = 0.002), higher Pco 2 (41 vs. 36 mm Hg, p < 0.001), and higher bilirubin (1.4 vs. 0.9 mg/dL, p < 0.001) compared with class 2 (n = 85). Both classes included a mix of transplant types, transcending a simple autologous/allogeneic dichotomy, although class 1 had more allogeneic recipients (70.4% vs. 45.9%, p = 0.001). Although time-from-transplant was not a class-defining variable, class 1 occurred later after transplant (30.0 vs. 11.9 d, p < 0.001) with higher frequency of idiopathic pneumonia syndrome (14.8% vs. 2.4%, p = 0.004). Class 2 had more frequent neutropenia (leukocytes 0.4 vs. 5.9 × 109, p < 0.001) and higher frequency of peri-engraftment respiratory distress syndrome (29.4% vs. 9.9%, p = 0.005). Outcomes were significantly worse for class 1 (90-d mortality: 72.8% vs. 48.2%, p = 0.001). An exploratory parsimonious model had good classification accuracy (0.90) using just six variables: leukocyte count, platelet count, bilirubin, Pco 2, body mass index, and temperature. CONCLUSIONS: ARDS after HCT comprises two distinct phenotypes with distinct clinical characteristics and outcomes. These phenotypes align with recognized post-HCT lung injury syndromes and may reflect different underlying biological processes. This framework provides a foundation for investigating targeted therapeutic approaches.

IMPORTANCE: Propofol is a first-line sedative for adults receiving invasive mechanical ventilation (IMV). However, it can contribute to hemodynamic instability, especially during intubation. The magnitude, timing, risk factors, and variability of sedation-associated mean arterial pressure (MAP) changes remain poorly characterized in ICU settings. OBJECTIVES: To quantify MAP changes following propofol sedation, identify risk factors for hemodynamic instability, and characterize associated interventions. DESIGN: Retrospective cohort study. The primary outcome was MAP change within 2 hours following sedation. Secondary outcomes included vasopressor use and hypotension (MAP ≤ 60 mm Hg). Mixed-effects modeling was used to account for individual patient differences. SETTING AND PARTICIPANTS: Adults (≥ 18 yrs old) who required IMV and received greater than or equal to 6 consecutive hours of propofol infusion, between May 5th, 2018, and July 31st, 2024, in 11 ICUs across the Mayo Clinic, spanning 5 hospitals in 4 states. MAIN OUTCOMES AND MEASURES: The primary outcome was the change in MAP within 2 hours following the initiation of propofol-based sedation. RESULTS: Across 16,418 patients, 25.2% were on vasopressors before sedation initiation. Among the remaining 12,281 patients, 40.3% required vasopressors and 7.7% experienced hypotension within 2 hours of sedation. Propofol-based sedation was associated with a MAP reduction within the first 30 minutes (–6.58 mm Hg; 95% CI, –6.85 to –6.32; p < 0.001). There was substantial interpatient variability in both baseline MAP, and MAP decline after sedation (9.5 and 40.9% between-patient differences, respectively). Higher Sequential Organ Failure Assessment (SOFA) scores (–0.31 mm Hg/point), older age (–0.04 mm Hg/yr), and male sex (–0.47 mm Hg) were associated with lower MAP. Patients with higher illness severity experienced progressively greater MAP decline over time (–0.20 mm Hg/hr/SOFA point; p < 0.001). CONCLUSIONS AND RELEVANCE: Propofol-based sedation was associated with clinically significant hemodynamic effects requiring intervention in the early post-intubation period. The marked interpatient variability in hemodynamic responses highlights the importance of personalized management approaches, including risk stratification based on age, sex, and illness severity.

Abstract Rationale Propofol is one of the first-line sedative-hypnotic agents for critically ill adults requiring mechanical ventilation. Although propofol can elevate triglyceride levels, and the latter is a risk factor for pancreatitis, the association between propofol and acute pancreatitis is unclear. Objectives We sought to determine the clinical impact and potential associations between propofol infusion, hypertriglyceridemia, and acute pancreatitis. Methods This is an observational multicenter study of adults (⩾18 yr old) who were admitted to an intensive care unit, who required mechanical ventilation and received continuous propofol infusion for at least 24 hours. The primary outcomes were the frequency of hypertriglyceridemia (&gt;400 mg/dl) and acute pancreatitis. Further analyses were done to determine the clinical impact of elevated triglyceride levels (i.e., sedation changes) and risk factors for pancreatitis development. Results Of 11,828 patients included, 33.2% (n = 3,922) had triglyceride levels measured, of whom 21.7% (n = 851) had hypertriglyceridemia at 4.5 days (SD = 6.8) after propofol initiation. Of those still requiring sedation, 70.4% (n = 576/818) received alternative sedatives after developing hypertriglyceridemia. Pancreatitis occurred in 1.2% of patients (n = 47/3,922) and was more frequent in those with hypertriglyceridemia (3.2%, 27/851; vs. 0.7%, 20/3,071; P &lt; 0.001). After adjustment for potential confounding variables, each 100 mg/dl increase in triglyceride levels was associated with an 11% increase in risk of pancreatitis. Propofol dose was not associated with pancreatitis development. Conclusions Acute pancreatitis is uncommon in patients receiving propofol infusion, and it occurs over a wide range of triglyceride levels, indicating a multifactorial pathophysiology. Hypertriglyceridemia frequently prompts the use of alternative sedatives. Further study is needed to determine how to best monitor and treat hypertriglyceridemia in critically ill patients receiving propofol infusion.

Abstract Rationale Pulmonary complications contribute significantly to nonrelapse mortality following hematopoietic stem cell transplantation (HCT). Identifying patients at high risk can help enroll such patients into clinical studies to better understand, prevent, and treat posttransplantation respiratory failure syndromes. Objectives To develop and validate a prediction model to identify those at increased risk of acute respiratory failure after HCT. Methods Patients underwent HCT between January 1, 2019, and December 31, 2021, at one of three institutions. Those treated in Rochester, MN, formed the derivation cohort, and those treated in Scottsdale, AZ, or Jacksonville, FL, formed the validation cohort. The primary outcome was the development of acute respiratory distress syndrome (ARDS), with secondary outcomes including the need for invasive mechanical ventilation (IMV) and/or noninvasive ventilation (NIV). Predictors were based on prior case-control studies. Measurements and Main Results Of 2,450 patients undergoing stem cell transplantation, there were 1,718 hospitalizations (888 patients) in the training cohort and 1,005 hospitalizations (470 patients) in the test cohort. A 22-point model was developed, with 11 points from prehospital predictors and 11 points from posttransplantation or early (&lt;24-h) in-hospital predictors. The model performed well in predicting ARDS (C-statistic, 0.905; 95% confidence interval [CI], 0.870–0.941) and the need for IMV and/or NIV (C-statistic, 0.863; 95% CI, 0.828–0.898). The test cohort differed markedly in demographic, medical, and hematologic characteristics. The model also performed well in this setting in predicting ARDS (C-statistic, 0.841; 95% CI, 0.782–0.900) and the need for IMV and/or NIV (C-statistic, 0.872; 95% CI, 0.831–0.914). Conclusions A novel prediction model incorporating data elements from the pretransplantation, posttransplantation, and early in-hospital domains can reliably predict the development of post-HCT acute respiratory failure.

Abstract Rationale Global Lung Function Initiative (GLI) Global spirometry reference equations were recently derived to offer a “race-neutral” interpretation option. The impact of transitioning from the race-specific GLI-2012 to the GLI Global reference equations is unknown. Objectives Describe the direction and magnitude of changes in predicted lung function measurements in a population of diverse race and ethnicity using GLI Global in place of GLI-2012 reference equations. Methods In this multicenter cross-sectional study using a large pulmonary function laboratory database, 109,447 spirometry tests were reanalyzed using GLI Global reference equations and compared with the existing GLI-2012 standard, stratified by self-reported race and ethnicity. Measurements and Main Results Mean FEV1 and FVC percent predicted increased in the White and Northeast Asian groups and decreased in the Black, Southeast Asian, and mixed/other race groups. The prevalence of obstruction increased by 9.7% in the White group, and prevalences of possible restriction increased by 51.1% and 37.1% in the Black and Southeast Asian groups, respectively. Using GLI Global in a population with equal representation of all five race and ethnicity groups altered the interpretation category for 10.2% of spirometry tests. Subjects who self-identified as Black were the only group with a relative increase in the frequency of abnormal spirometry test results (32.9%). Conclusions The use of GLI Global reference equations will significantly impact spirometry interpretation. Although GLI Global offers an innovative approach to transition from race-specific reference equations, it is important to recognize the continued need to place these data within an appropriate clinical context.

Abstract Rationale Acute respiratory distress syndrome (ARDS) is a common complication after hematopoietic stem cell transplantation (HCT) and is a major contributor to nonrelapse mortality. Objectives To better understand pretransplant risk factors for developing ARDS after HCT. Methods This is a single-center observational study comparing risk factors for ARDS development in 164 patients who went on to develop post-HCT ARDS compared with 492 patients who did not. The patients were matched 1 to 3 on age, sex, type of transplant (allogeneic vs. autologous), and underlying disease. Pertinent risk factors were analyzed separately in multivariable conditional logistic regression after adjustment for a priori variables known to be associated with ARDS development. Results Patients with ARDS were more likely to have a lower pretransplant pulmonary function as measured by forced vital capacity (FVC) (odds ratio [OR], 0.54 [0.42–0.70] per liter increase in FVC; P &lt; 0.001), forced expiratory volume in one second (FEV1) (OR, 0.52 [0.38–0.71] per liter increase in FEV1; P &lt; 0.001) and diffusing capacity (OR, 0.92 [0.88–0.96] per ml/min/mm Hg increase in diffusing capacity; P &lt; 0.001). Several laboratory indices were predictive of subsequent ARDS development including elevated AST (aspartate aminotransferase) (OR, 1.01 [1.00–1.01]; P &lt; 0.008), lower serum albumin (OR, 0.44 [0.30–0.66]; P &lt; 0.001), lower pretransplant hemoglobin (OR, 0.82 [0.73–0.92]; P = 0.001), and lower leukocyte count (OR, 0.88 [0.79–0.99]; P &lt; 0.03). Patients who went on to develop ARDS were more likely to have been hospitalized in the year before the transplant (OR, 1.11 [1.04–1.20]; P = 0.003), and required invasive or noninvasive ventilation during that hospitalization. Lastly, patients with ARDS were significantly more likely to have received carboplatin, thalidomide, methotrexate, and cisplatin than the non-ARDS control subjects. Conclusions Several risk factors for developing ARDS after HCT are identifiable at the time of transplantation, well before the development of critical illness and ARDS. The identification of risk factors long before ARDS develops is relatively unique to the HCT population. Further work is needed to develop usable risk prediction tools in this setting.

Abstract Rationale The periengraftment respiratory distress syndrome (PERDS) is an early important cause of morbidity following autologous hematopoietic cell transplantation (HCT). There are few contemporary data describing PERDS. Objectives To determine prevalence, risk factors, and outcomes of PERDS after autologous HCT. Methods This was a historical cohort study of adults undergoing autologous HCT at Mayo Clinic, Rochester, Minnesota, between 2005 and 2016. PERDS was defined as 1) respiratory failure requiring supplemental oxygen within 5 days on either side of the neutrophil engraftment date, 2) new pulmonary opacities on chest imaging, and 3) exclusion of an infectious or cardiac etiology to explain the clinical presentation. Results Of 3,473 patients undergoing autologous HCT, 167 (4.8%) developed PERDS. Radiographic changes preceded engraftment in 77% of cases. In a multivariable regression model, risk factors for PERDS included female sex (odds ratio [OR], 1.73; P = 0.001), the number of preengraftment platelet transfusions (OR, 1.22; P = 0.002), and more rapid engraftment (OR, 0.72 per day longer; P &lt; 0.001). PERDS cases were more likely to be admitted to the intensive care unit (47.3% vs. 9.5%, P &lt; 0.001) and require intubation (20.4% vs. 1.6%, P &lt; 0.001). In an adjusted 100-day death analysis, those diagnosed with PERDS were more likely to die (hazard ratio, 3.1; 95% confidence interval, 1.5–6.2; P = 0.002). Conclusions PERDS is a common complication of autologous HCT and is associated with increased mortality and healthcare use. Radiographic evidence of pulmonary involvement precedes hematopoietic recovery. A larger number of platelet transfusions and more rapid engraftment appear to increase risk for PERDS.