C.5. What hemodynamic changes are frequently associated with opening the pericardial space?
Answer:
When opened, the pericardial space is exposed to atmospheric pressure. For free-flowing pericardial effusions, this will immediately decompress the cardiac chambers, thereby leading to a rapid rise in preload, SV, and CO. This can often be seen on hemodynamic monitoring as a dramatic rise in systemic blood pressure, a reduction in pulmonary artery pressure (PAP) and CVP, and normalization of tachycardia (Figure 12.10). In a patient receiving high doses of vasopressors to maintain perfusion prior to pericardiotomy, this can result in severe hypertension. In patients who have had overly aggressive fluid resuscitation, the sudden release of cardiac constraint can lead to acute pulmonary edema as well as RV dysfunction. For this reason, it is important to be aware of surgical progress to properly anticipate the effects of pericardial opening. Should extremes of hypertension occur, it is effectively treated with rapid weaning of vasopressors, deepening the level of anesthesia, administering analgesia, and titrating short-acting vasodilators until blood pressure is normalized.
Figure 12.10.: Intraoperative Hemodynamics Before and after Pericardial Decompression.
Intraoperative hemodynamics before and after pericardial decompression. Arterial blood pressure (ART), pulmonary artery pressure (PAP), and central venous pressure (CVP) are shown during mediastinal exploration for cardiac tamponade. The moment of pericardial decompression is marked by the asterisk. Note the elevated CVP, PA diastolic pressure, as well as the narrow systemic pulse pressure before decompression, demonstrating extrinsic pericardial pressure on the right atrium (RA) and left atrium (LA) and its effect on decreasing left ventricle (LV) stroke volume. Shortly following pericardial decompression, CVP and PA pressures decrease accompanied by an increase in systemic arterial pressure. Systemic pulse pressure continues to increase, reflecting the recovery of SV and presumably CO.
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