The purpose of this case report is to illustrate the diagnostic difficulties of pericardial tamponade and to suggest that focused cardiac ultrasound be included in the resuscitative care of pediatric shock. Three cases of cardiac tamponade are presented. Each patient had a syncopal episode and presented with altered mental status and hypotension. Muffled heart tones, distended neck veins, and electrocardiogram and chest radiograph abnormalities were not present. Hypotension was not responsive to intravenous volume expansion treatment. Diagnostic delays would have been prevented if focused cardiac ultrasound had been included in the resuscitative care of shock.