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Respiratory failure occurs more frequently after thoracic surgery than abdominal surgery. Although the etiology for this complication is frequently attributed to underlying lung disease present in patients undergoing thoracic surgery, this notion is often unfounded because many patients with normal preoperative pulmonary function often require prolonged oxygen supplementation even after minimal resection of lung tissue. Using a murine model of pulmonary resection and peripheral blood samples from patients undergoing resection of the lung or abdominal organs, we demonstrated that lung surgery initiates a proinflammatory loop that results in damage to the remaining lung tissue, noncardiogenic pulmonary edema, hypoxia, and even death. Specifically, we demonstrated that resection of murine lung tissue increased concentrations of the homeostatic cytokine interleukin-7, which led to local and systemic activation of type 2 innate lymphoid cells. This process activated lung-resident eosinophils and facilitated stress-induced eosinophil maturation in the bone marrow in a granulocyte-macrophage colony-stimulating factor–dependent manner, resulting in systemic eosinophilia in both mice and humans. Up-regulation of inducible nitric oxide synthase in lung-resident eosinophils led to tissue nitrosylation, pulmonary edema, hypoxia, and, at times, death. Disrupting this activation cascade at any stage ameliorated deleterious outcomes and improved survival after lung resection in the mouse model. Our data suggest that repurposing US Food and Drug Administration–approved eosinophil-targeting strategies may potentially offer a therapeutic intervention to improve outcomes for patients who require lung resection for benign or malignant etiology. Editor's summary: Respiratory failure frequently occurs after lung resection and may not be fully explained by underlying respiratory disease or the size of the resection. Here, Mei and colleagues used patient samples and mouse models of pneumonectomy to show that lung resection specifically leads to increased percentages of eosinophils through a mechanism involving production of IL-7 by γδ T cells, leading to granulocyte-macrophage colony-stimulating factor production by type 2 innate lymphoid cells, ultimately resulting in increased eosinophil maturation, activation, and production of reactive oxygen species that injure the remaining lung. Targeting different points in this pathway reduced lung damage and improved survival of mice after lung resection, suggesting that perioperative administration of agents that target eosinophils or neutralize nitric oxide synthase could potentially reduce the risk of respiratory failure after lung resection. —Melissa L. Norton [ABSTRACT FROM AUTHOR]