Do Sik Moon1, Jin Won Huh2, Sang-Bum Hong2, Younsuck Koh2, Chae-Man Lim3. 1. Department of Pulmonology and Critical Care Medicine, Chosun Universitiy Hospital, Gwangju, Republic of Korea. 2. Department of Pulmonary and Critical Care Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea. 3. Department of Pulmonary and Critical Care Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea. Electronic address: cmlim@amc.seoul.kr.
Abstract
PURPOSE: This study aimed to investigate dynamic changes of lung aeration during a spontaneous breathing trial (SBT) in patients with diaphragm dysfunction (DD) and to predict weaning failure using electrical impedance tomography (EIT). MATERIALS AND METHODS: We enrolled 40 adult patients who received mechanical ventilation over 48 h and were eligible for SBT with a T-piece. All patients were screened for DD using ultrasonography before SBT. EIT data, including global inhomogeneity index (an off-site parameter), and temporal skew of aeration (TSA) (an on-site parameter) were collected. RESULTS: Sixteen (40%) patients had DD. During SBT, the tidal impedance variation decreased by 32% from baseline in patients with DD and by 14% in those without DD (p = 0.001). The global inhomogeneity index in the SBT failure group (n = 9) was 0.92 (median), and that of the SBT success group was 0.65 (p = 0.004). The TSA along the vertical axis of the lung was 12.0% and 2.0%, respectively (p = 0.001). With a vertical TSA cutoff of ≥4.35%, SBT failure was predicted with a sensitivity of 88.9% and specificity of 96.9% (area under the curve: 0.955). CONCLUSION: Dynamic inhomogeneity of aeration along the vertical axis of the lung as assessed using TSA predicts SBT failure regardless of DD. TRIAL REGISTRATION: This trial was retrospectively registered at cris.nih.go.kr (identifier: KCT003567; release date February 27, 2019).
PURPOSE: This study aimed to investigate dynamic changes of lung aeration during a spontaneous breathing trial (SBT) in patients with diaphragm dysfunction (DD) and to predict weaning failure using electrical impedance tomography (EIT). MATERIALS AND METHODS: We enrolled 40 adult patients who received mechanical ventilation over 48 h and were eligible for SBT with a T-piece. All patients were screened for DD using ultrasonography before SBT. EIT data, including global inhomogeneity index (an off-site parameter), and temporal skew of aeration (TSA) (an on-site parameter) were collected. RESULTS: Sixteen (40%) patients had DD. During SBT, the tidal impedance variation decreased by 32% from baseline in patients with DD and by 14% in those without DD (p = 0.001). The global inhomogeneity index in the SBT failure group (n = 9) was 0.92 (median), and that of the SBT success group was 0.65 (p = 0.004). The TSA along the vertical axis of the lung was 12.0% and 2.0%, respectively (p = 0.001). With a vertical TSA cutoff of ≥4.35%, SBT failure was predicted with a sensitivity of 88.9% and specificity of 96.9% (area under the curve: 0.955). CONCLUSION: Dynamic inhomogeneity of aeration along the vertical axis of the lung as assessed using TSA predicts SBT failure regardless of DD. TRIAL REGISTRATION: This trial was retrospectively registered at cris.nih.go.kr (identifier: KCT003567; release date February 27, 2019).