420 A New Tool for Bilateral Diaphragmatic Paralysis Diagnosis

Background and Aims Bilateral diaphragmatic paralysis (BPD) is a rare cause of unexplained respiratory failure. Although it is a known complication of cardiothoracic surgery, it is often under-recognized and diagnosis is frequently delayed (Billings 2008). We report two children in whom BDP was easily detected using an esophageal probe equipped with sensors for measurement of electrical activity of the diaphragm. Results Case 1: A 3-year-old boy with complex congenital cardiopathy underwent a third surgery for the bidirectional Glenn anastomosis procedure. Extubated few hours after surgery, he developed dyspnea. After reintubation, an esophageal probe equipped with sensors was installed. No electrical activity of the diaphragm could be found, thus evoking the diagnosis of BDP. This diagnosis was confirmed later by a fluoroscopy. Case 2: A 9-month-old girl with atrioventricular canal defect underwent a third surgery for a mitral valve placement. Because of several extubation failures, tracheal fibroscopy, chest tomodensitometry, and an echography of the diaphragm performed by a radiologist did not provide an explanatory diagnosis. Thereafter an esophageal probe equipped with sensors did found electrical activity of the diaphragm, in the absence of blood alkalosis nor profound sedation. The diagnosis of BDP was confirmed by an electromyography of the diaphragm with a phrenic-nerve conduction study. Conclusions Commercially available feeding tubes equipped with sensors permit to record electrical activity of the diaphragm via a ventilator using a standardized method (Sinderby 1997). This measurement allows a rapid diagnosis of bilateral diaphragmatic paralysis at the bedside.