This rare, treatable emergency usually follows a penetrating chest injury, or occasionally a blunt one, which causes bleeding into the patient’s pericardial cavity. This prevents his heart filling normally, which: (1) raises his jugular venous pressure, (2) makes his heart sounds faint, (3) causes pulsus paradoxus. Normally, the peripheral pulse becomes stronger on inspiration, because the lower intrathoracic pressure increases the venous return. In pulsus paradoxus the peripheral pulse is stronger on expiration. (4) When there is blood in the pericardial cavity, X–rays show a widening of the heart shadow, especially in the cardiophrenic angle. Screening shows diminished excursion of the borders of the heart. If you can aspirate blood from a patient’s pericardial cavity, you may save his life.
CARDIAC TAMPONADE Insert a needle into the patient’s pericardial cavity from just under his xiphoid. Alternatively, and less satisfactorily, approach it through his fourth left inter costal space 5 cm from the midline, so as to avoid his internal mammary vessels. Refer him for thoracotomy urgently.