Therapeutic Evaluation of Computed Tomography Findings for Efficacy of Prone Ventilation in Acute Respiratory Distress Syndrome Patients with Abdominal Surgery

Introduction: In Acute Respiratory Distress Syndrome (ARDS), the heterogeneity of lung lesions results in a mismatch between ventilation and perfusion, leading to the development of hypoxia. The study aimed to examine the association between computed tomographic (CT scan) lung findings in patients with ARDS after abdominal surgery and improved hypoxia and mortality after prone ventilation. Material and Methods: A single site, retrospective observational study was performed at the Sapporo Medical University School of Medicine, Sapporo, Hokkaido, Japan, between 1st January 2004 and 31st October 2018. Patients were allocated to one of two groups after CT scanning according to the presence of ground-glass opacity (GGO) or alveolar shadow with predominantly dorsal lung atelectasis (DLA) on lung CT scan images. Also, Patients were divided into a prone ventilation group and a supine ventilation group when the treatment for ARDS was started. Results: We analyzed data for fifty-one patients with ARDS following abdominal surgery. CT scans confirmed GGO in five patients in the Group A and in nine patients in the Group B, and DLA in 17 patients in the Group A and nine patients in the Group B. Both GGO and DLA were present in two patients in the Group A and nine patients in the Group B. Prone ventilation significantly improved patients' impaired ratio of arterial partial pressure of oxygen to fraction of inspired oxygen from 12 h after prone positioning compared with that in the supine position. Weaning from mechanical ventilation occurred significantly earlier in the Group A with DLA vs the Group B with DLA (P < 0.001). Twenty-eight-day mortality was significantly lower for the Group A with DLA vs the Group B with DLA (P = 0.035). Conclusions: These results suggest that prone ventilation could be effective for treating patients with ARDS as showing the DLA.