Quantification of diaphragm function using ultrasound: evaluation of a novel technique.

A novel method of image analysis for quantifying diaphragmatic motion is described using ultrasound. Nineteen patients scheduled for thoracic surgery were evaluated with ultrasound preoperatively and through their postoperative hospital stay. Diaphragmatic motion was measured using a horizontal on-screen ruler, allowing for quantification and tracking of dynamic diaphragm function. A percentage (73.5%) of all attempted measurements was quantifiable. Preoperative measurements of left and right diaphragm movement were correlated and there was no significant difference between the two. Postoperative diaphragm movement ipsilateral to the incision was statistically significantly less when compared to the contralateral side (p = 0.02 vs. p = 0.19). While not universally feasible in all patients, this method for quantifying diaphragmatic function is the only known imaging technique that can be performed at the bedside. Further evaluation of the impact of diaphragmatic dysfunction on patients undergoing thoracic surgery and its correlation with dyspnea is planned.