Chest ultrasound to detect postoperative pulmonary complications after thoracic surgery: a comparative study

Abstract
Background
Patients who underwent thoracic surgery procedures were usually subjected to daily chest X-rays until discharge, exposing patients to ionizing radiation and requiring patient movement with chest drains, difficult positioning, and time-consuming. Unlike chest ultrasound, which is a good alternative because it is bedside and accurate in the detection of pulmonary complications. We hypothesize that a thoracic surgery resident with a short training program in chest ultrasound can achieve comparable results to a chest X-ray. Our study aims to analyze the agreement between the two techniques.

Results
This is an observational prospective study. Eighty-six adult patients who underwent thoracic surgery were included. Every patient had a chest X-ray and chest ultrasound follow-up on day 0, day 3, and day 5 post-operative. Chest ultrasound examinations were performed by the same resident, and the results were revised by an expert sonographer for the detection of pneumothorax, pleural effusion, pulmonary consolidation, and interstitial pattern. Both diagnostic procedures showed substantial agreement for pneumothorax (K = 0.661). For pleural effusion, they showed moderate agreement (K = 0.448, P < 0.001), and no cases developed an interstitial pattern. Overall, both diagnostic procedures showed perfect agreement (K = 0.838, P < 0.001). The time lag to perform a chest ultrasound was statistically lower than that to perform. chest X-ray, with a median of 7 min versus 80 min, respectively.

Conclusions
Performing chest ultrasound by a thoracic surgery resident is a less time-consuming and easy bedside diagnostic tool. Compared chest ultrasound to the postoperative X-ray showed a perfect diagnostic agreement for pulmonary consolidation and moderate agreement for pleural effusion and pneumothorax.

Trial registration
NCT04118621