A Case of “Unexplained” Decompression Sickness in a Commercial Diver

While working in the Gulf of Mexico, a 24-year-old male commercial diver developed decompression sickness (DCS) with neurological involvement (Type II DCS). This occurred despite closely adhering to US Navy decompression tables that divers follow upon slowly resurfacing from the ocean depths (so-called unexplained DCS). The patient required therapy in a decompression chamber, and subsequently had complete clinical recovery. He was then referred to “rule out” a right-to-left cardiac shunt. Physical examination, an electrocardiogram, and chest x-ray were all normal. Initial transthoracic echocardiography (TTE) was also normal, having normal cardiac chamber dimensions and function, and normal pulmonary artery pressure calculations. A right antecubital vein intravenous line was placed, and 8 cc of agitated saline using a three-way stop-cock was administered during normal respirations. TTE revealed complete opacification of the right heart chambers. Contrast bubbles appeared within the left heart chambers within two cardiac cycles of its appearance in the right heart (Fig. 1). A transesophageal echocardiogram (TEE) was then performed. At the level of the atrial septum a patent foramen ovale (PFO) was identified with its “slit” ∼10 mm diameter during normal respirations. Agitated saline contrast was injected during normal respirations with contrast visualized to traverse right to left via the PFO (Fig. 2). Based on these findings, the patient was felt to have a clinically