To avoid the accumulation of blood and fluids in the mediastinum or pleural cavities after cardiac surgery, mediastinal and pleural drains are routinely used. The rate of pneumothorax following chest drain removal is approximately 1.5-13%, resulting in increased patient morbidity and hospital stay. The standard method for the determination of pneumothorax (PNX) in most institutions is to obtain a chest radiography (CXR) following chest tube removal, but the reliability of the supine anteroposterior chest radiography is not utter, with up to 30% of pneumothoraxes misdiagnosis. The delay of ordering, performing and interpreting a CXR post mediastinal tube removal, results in potential delay in patients transfers, with an estimated cost savings of omitting an additional chest radiography, of approximately $10 000 per year.~Lung ultrasound (LUS) is recommended for detection of pneumothorax as per evidence-based guidelines and expert consensus. Lung ultrasound is a safe technique due to minimal radiation, with the potential for immediate results when compared with the standard CXR. LUS has high accuracy for PNX detection, with better pooled sensitivities (78.6%) when compared to CXR (39.8%) and equal specificity (98.4 vs 99.3%). In intensive care units, those results have been reproducible, with LUS having greater sensitivity than CXR for PNX diagnosis (0.87 vs 0.46) and equal specificity, 0.99 vs 1.00. LUS is more accurate and faster than chest radiography.
This is a prospective, single-center, observational, cross-sectional cohort study, comparing nurse-performed bedside lung ultrasound to standard portable CXR, for the detection of pneumothorax in the cardiac surgery patient population, following chest tube removal. This study aims to be conducted at an academic, tertiary adult center cardio-vascular intensive care unit (CVICU at TGH).