PDEMONSTRATION AND EXPLANATION OF THE BREACH OF THE PULMONARY FILTER WITHTRANSESOPHAGEALBUBBLE CONTRAST ECHOCARDIOGRAPHY.
Paul G. ~arch. Sheldon F. Gottlieb. Keith Van Meter. E. ~mnnethKerut. and Harvey T. Swanson. Jo Ellen Smith Memorial BaroRedical Research Institute and Jc Ellen Smith Medical Center, New Orleans, LA. 70131.

In a companion abstract, a case was presented whereby type II DCS was masked as mental illness. We were interested in understanding the mechanism of the CHS manifestations of the DCS resulting from a breath-hold ascent from 30 feet in cold, fresh water altitude diving. To simulate the cardiovascular/pulmonary mechanics of a breath-hold ascent, bubble contrast transesophageal echocardicgraphy was performed. In the absence of a patent foramen ovals, significant numbers of bubbles were detected in the pulmcnary vein and left atrium during phase IV of the Valsalva maneuver. Blood gas analyses failed to demonstrate significant a-v shunting. The unusual bubble patterns observed may be explained by the cardiovascular and pulmonary vascular dynamics associated with the Valsalva maneuver. It isthought that the overshoot of the blood pressure rebound resulting from the rapid surge of venous return and the subsequent increase in stroke volume results in capillary distension and transmission of otherwise filterable bubbles. Alternatively, one would have to postulate the existence of a subclinical, congenital abncrmal anatomy.