[Pericardiocentesis: usefulness in the routine determination of intrapericardial pressure]

The usefulness of routine intrapericardial pressure determination and hemodynamic monitoring during therapeutic (n = 22) or diagnostic (n = 2) pericardiocentesis was analyzed. Hemodynamic data confirmed the presence of cardiac tamponade in all cases, including the 2 patients without clinical suspicion. Prior to fluid evacuation, abnormally elevated levels of intrapericardial (13 +/- 5 mmHg), right atrial (14 +/- 4 mmHg) and pulmonary capillary (16 +/- 3 mmHg) pressures were observed. A significant correlation was found between intrapericardial and right atrial pressures (r = 0.97, p less than 0.05) and also between intrapericardial and pulmonary capillary pressures (r = 0.69, p less than 0.05). The basal cardiac output was low (3 +/- 1 l/min) and increased after the pericardiocentesis in all but one patient. According to the results of pericardiocentesis, patients were classified into three groups. Group I: intrapericardial and right atrial pressures decreased to normal levels. The increment of cardiac output was high (72%) and the procedure was considered successful. Group II: right atrial and intrapericardial pressures remained elevated (7.7 +/- 4 and 7 +/- 2 mmHg, respectively) and the cardiac output increment was less marked (52%), thus indicating incomplete drainage. Group III: intrapericardial pressure decreased to normal levels but right atrial pressure remained elevated. All these patients were found to have associated cardiac disease, most frequently constriction. We conclude that routine determination of intrapericardial pressure: 1) reveals the presence of tamponade in cases without clinical suspicion; 2) indicates the efficacy of drainage; and 3) together with right atrial pressure recording, provides early diagnosis of associated cardiac disease, especially effusive-constrictive pericarditis.