Efficacy of the porcine model for demonstrating pericardial effusion with real-time ultrasound.

Abstract

Ultrasound in emergency medicine (EM) is an invaluable tool for emergent evaluation of pericardial effusion and tamponade. The training in the recognition of such has relied on ultrasonic images or videotapes. OBJECTIVE: To evaluate the efficacy of demonstrating pericardial effusion and tamponade using real-time ultrasound. METHODS: A convenience sample of 10 Yorkshire swine were anesthetized, sedated, intubated, and monitored as per an approved EM training protocol. Using EKG guidance and a subxiphoid approach, an 18-gauge spinal needle was advanced into the pericardium until a current of injury was detected. After a slight withdrawal of the needle, an aliquot of 50-100 mL of normal saline was instilled to produce a pericardial effusion. Ultrasound was used before and after the instillation of fluid into the pericardium. The effusion was confirmed by subsequent pericardiocentesis or by visual inspection on thoracotomy. RESULTS: The instillation saline, detection of effusion, and subsequent confirmation by ultrasound, pericardiocentesis, or visual inspection were successfully performed in 10/10 pigs. Under ultrasound, one pig had a preexisting effusion. Another had much less fluid visualized. On thoracotomy, the saline was found to have leaked into the adjacent lung parenchyma. CONCLUSIONS: We conclude that the porcine model is an adequate model to demonstrate pericardial effusion using real-time ultrasound.