Association of Thoracic Computed Tomographic Measurements and Outcomes in Patients with Hematologic Malignancies Requiring Mechanical Ventilation

Rationale: Patients with hematologic malignancies requiring mechanical ventilation have historically experienced poor outcomes.Objectives: We aimed to determine whether body composition characteristics derived from thoracic computed tomographic (CT) imaging were associated with time to liberation from mechanical ventilation.Methods: We evaluated mechanically ventilated patients with hematological malignancies admitted between 2014 and 2018. We included patients with thoracic CT imaging completed between 1 month before and 48 hours after intensive care unit (ICU) admission. We assessed the association of carinal skeletal muscle cross-sectional area (CSA), subcutaneous fat CSA, and fat index (fat/skeletal muscle ratio) with time to liberation from mechanical ventilation within 28 days. We accounted for the competing event of death within 28 days of mechanical ventilation.Results: One hundred fifty-six patients were included; the mean age was 57 years (standard deviation 14) and 39% were female. Thirty-seven percent had received a hematopoietic stem cell transplant, and the median ratio of arterial oxygen tension/pressure to fraction of inspired oxygen was 134 mm Hg (interquartile range [IQR], 92-205). Median skeletal muscle CSA was 68 cm² (IQR, 54-88) and subcutaneous fat CSA was 38 cm² (IQR, 27-52). Forty-two percent of patients were liberated from mechanical ventilation within 28 days and 56% died in the ICU. Subcutaneous fat CSA (subdistribution hazard ratio [sHR], 0.81; 95% confidence interval [95% CI], -0.68 to 0.97) and fat index (sHR, 0.81; 95% CI, -0.68 to 0.97) were significantly associated with longer time to liberation from mechanical ventilation. Skeletal muscle CSA was not associated with time to liberation from ventilation (sHR, 1.08; 95% CI, -0.94 to 1.23).Conclusions: Body composition measurements based on thoracic CT scans were associated with time to liberation from ventilation. These could represent novel surrogate markers of physical frailty in patients with hematologic malignancies receiving mechanical ventilation.