Evaluation of Diaphragmatic Paralysis Using Sniff Testing With M-Mode Ultrasonography

SESSION TITLE: Pulmonary Physiology Case Report Posters SESSION TYPE: Affiliate Case Report Poster PRESENTED ON: Tuesday, October 27, 2015 at 01:30 PM - 02:30 PM INTRODUCTION: Establishing a diagnosis of diaphragmatic paralysis is conventionally performed with fluoroscopy to demonstrate abscence of diaphragmatic excursion during voluntary sniffing (“sniff test”). The use of M-mode ultrasonography in the supine patient to establish this diagnosis is a newer modality, as described in the following case. CASE PRESENTATION: A 47 year-old woman from Nepal presented with elevation of the left hemidiaphragm on a chest radiograph obtained following a positive tuberculin skin test. She had mild exertional dyspnea, and no prior medical or surgical history. The patient was placed in supine position and the ultrasound probe was positioned just posterior to the mid-axillary line on either side. The posterior aspect of each hemidiaphragm was identified with 2D ultrasound. The diaphragm was then interrogated in M-mode during tidal breathing followed by a sniff maneuver. While the right hemidiaphragm demonstrated normal downward excursion, the left hemidiaphragm did not move. These findings were confirmed using conventional fluoroscopic sniff testing. The patient underwent measurement of maximal inspiratory pressure, which was low at -27cmH2O, with a restrictive pattern on spirometry. Imaging along the course of the phrenic nerve was normal, and the etiology of the paralysis was presumed to be congenital. DISCUSSION: The use of ultrasonography in the diagnosis of diaphragmatic paralysis offers several advantages over the conventional radiographic technique, including portability, avoidance of radiation, and ease of serial assessment. Additionally, the technique can be performed in the supine position, allowing its use in bedbound patients. Previous publications have described the use of M-mode ultrasonography in healthy patients and B-mode ultrasonography in diaphragmatic paralysis to quantitate diaphragmatic thickening. This case adds to the recent literature on the utility of M-mode ultrasonography during sniff maneuver as a effective modality for the diagnosis of diaphragmatic paralysis. CONCLUSIONS: M-mode ultrasound for the diagnosis of diaphragmatic paralysis is a simple, non-invasive, and reproducible technique that can be used by clinicians at the bedside. Its use in the supine position allows for diverse applications, including potentially in critically ill patients. Reference #1: Boussuges A, et al. Diaphragmatic motion studied by M-mode Ultrasonography. Chest. 2009;132(2):391-400. Reference #2: Summerhill E, et al. Monitoring Recovery from Diaphragmatic Paralysis With Ultrasound. Chest. 2008;133(3):737-743. DISCLOSURE: The following authors have nothing to disclose: Vivek Murthy, Bishoy Zakhary, Melissa Lesko, Jun-Chieh Tsay, Paru Patrawalla No Product/Research Disclosure Information