Early Identification of Patients Who Will Meet 24-Hour Fluid Output Threshold for Chest Tube Removal After Lung Resection

Improving evidence-based chest tube removal may reduce the length of stay following surgery. Presently, most chest tube removal protocols include a fluid output threshold based on a 24-hour observation period. The purpose of this study was to evaluate if, within a 24-hour time period, fluid output measurements at 6, 8, and 12hours could predict if the total 24-hour fluid output would comply with a predetermined volume threshold considered acceptable for safe chest tube removal. Following lung resection, pleural fluid output data were prospectively recorded by a digital drainage system and analyzed retrospectively. Twenty-four-hour fluid output was calculated from every available 6-, 8-, and 12-hour measurement and compared to set 24-hour output criteria for chest tube removal (ie, 400mL, 250mL, and 20% of whole-body lymphatic flow). Performance of interim fluid outputs in predicting whether 24-hour fluid output criteria were satisfied was measured. From 2015 to 2018, 150 patients had digital pleural fluid drainage data suitable for analysis. Performance of interim fluid output data in identifying which patients would satisfy 24-hour output criteria ranged from 85% (95% confidence interval [CI] = 83–86) to 94% (95% CI = 93–94) for specificity, 75% (95% CI = 73–76) to 92% (95% CI = 90–93) for positive predictive value, and 6% (95% CI = 6–7) to 15% (95% CI = 14–17) for false-positive rate. Potential time saved in duration of drainage using interim fluid output data ranged from 10 to 16hours. Pleural fluid output measured for 6-, 8-, and 12-hour durations can accurately identify patients who will meet 24-hour fluid output threshold for safe chest tube removal.