Satoko Osuka1, Naozumi Hashimoto2, Koji Sakamoto3, Kenji Wakai4, Kohei Yokoi5, Yoshinori Hasegawa6. 1. Department of Respiratory Medicine, Nagoya University Graduate School of Medicine, Nagoya, Japan. Electronic address: sosuka@med.nagoya-u.ac.jp. 2. Department of Respiratory Medicine, Nagoya University Graduate School of Medicine, Nagoya, Japan. Electronic address: hashinao@med.nagoya-u.ac.jp. 3. Department of Respiratory Medicine, Nagoya University Graduate School of Medicine, Nagoya, Japan. Electronic address: sakakoji@med.nagoya-u.ac.jp. 4. Department of Preventive Medicine, Nagoya University Graduate School of Medicine, Nagoya, Japan. Electronic address: wakai@med.nagoya-u.ac.jp. 5. Department of Thoracic Surgery, Nagoya University Graduate School of Medicine, Nagoya, Japan. Electronic address: k-yokoi@med.nagoya-u.ac.jp. 6. Department of Respiratory Medicine, Nagoya University Graduate School of Medicine, Nagoya, Japan. Electronic address: yhasega@med.nagoya-u.ac.jp.
Abstract
BACKGROUND: Mounting evidence suggests that airway obstruction defined by the lower limit of normal (LLN) of forced expiration volume in 1s (FEV1)/forced vital capacity (FVC) might be an important predictor of mortality in patients with an FEV1/FVC ratio below 0.70. Although better risk stratification for postoperative outcomes in patients with chronic obstructive pulmonary disease (COPD) undergoing thoracic surgery is warranted, whether an FEV1/FVC ratio below 0.70 but above the LLN (i.e., in-between) could identify patients at risk for adverse postoperative outcomes has not been fully evaluated. METHODS: To determine the clinical impact of this "in-between" group of patients with COPD, we evaluated whether classification of the in-between group and the COPD group with FEV1/FVC ratios below 0.70 and below the LLN could provide more accurate risk stratification for postoperative outcomes in COPD patients undergoing thoracic surgery. RESULTS: The criterion of LLN classified 302 patients with an FEV1/FVC ratio below 0.70 into either the in-between group (124 cases) or the COPD group (178 cases). The COPD group showed a 3-fold increase in prolonged oxygen therapy (POT) and a 50% increase in prolonged postoperative stay (PPS), as compared with the in-between group, with an adjusted odds ratio of 3.068 (95% confidence interval: 1.806-5.213) for POT. CONCLUSIONS: Based on the finding that the in-between group could independently identify patients at risk for adverse postoperative outcomes, LLN assessment of the FEV1/FVC ratio might provide more accurate risk stratification in COPD patients undergoing thoracic surgery.
BACKGROUND: Mounting evidence suggests that airway obstruction defined by the lower limit of normal (LLN) of forced expiration volume in 1s (FEV1)/forced vital capacity (FVC) might be an important predictor of mortality in patients with an FEV1/FVC ratio below 0.70. Although better risk stratification for postoperative outcomes in patients with chronic obstructive pulmonary disease (COPD) undergoing thoracic surgery is warranted, whether an FEV1/FVC ratio below 0.70 but above the LLN (i.e., in-between) could identify patients at risk for adverse postoperative outcomes has not been fully evaluated. METHODS: To determine the clinical impact of this "in-between" group of patients with COPD, we evaluated whether classification of the in-between group and the COPD group with FEV1/FVC ratios below 0.70 and below the LLN could provide more accurate risk stratification for postoperative outcomes in COPDpatients undergoing thoracic surgery. RESULTS: The criterion of LLN classified 302 patients with an FEV1/FVC ratio below 0.70 into either the in-between group (124 cases) or the COPD group (178 cases). The COPD group showed a 3-fold increase in prolonged oxygen therapy (POT) and a 50% increase in prolonged postoperative stay (PPS), as compared with the in-between group, with an adjusted odds ratio of 3.068 (95% confidence interval: 1.806-5.213) for POT. CONCLUSIONS: Based on the finding that the in-between group could independently identify patients at risk for adverse postoperative outcomes, LLN assessment of the FEV1/FVC ratio might provide more accurate risk stratification in COPDpatients undergoing thoracic surgery.