Persistent hypotension following pericardial decompression results from insufficient preload, afterload, and/or contractility. If there is surgical evidence of ongoing hemorrhage, then treating hypovolemia should be a priority. Because this patient has a PAC, a review of CVP and diastolic PAP trends can be helpful in assessing ventricular filling pressures and optimizing fluid resuscitation. Residual clot and regional cardiac tamponade should be evaluated with TEE and careful surgical exploration; in particular, clot located posteriorly within the oblique sinus can continue to compress the LA (Figure 12.3) and might not be immediately apparent on initial surgical exploration.

TEE is invaluable in evaluating myocardial contractility. Ventricular function can be impaired from coronary insufficiency and active ischemia which can persist even after restoring adequate coronary perfusion (ie, "myocardial stunning"). Both conditions can present as cardiogenic shock and manifest wall motion abnormalities on TEE, and should be managed by optimizing myocardial oxygen supply and demand while preserving critical organ perfusion with careful use of inotropic support if required.

A low SVR state can result from vasodilatory medications, including anesthetics and inotropes (eg, milrinone, dobutamine, low-dose epinephrine). Isolated vasoplegia, although not typically associated with this procedure, can occur in the presence of a major surgical inflammatory response, stress-related depletion of endogenous vasopressin, and acquired catecholamine resistance. Norepinephrine is recommended as a first-line agent for treating vasoplegia, although this is largely extrapolated from septic shock study data. If high doses of norepinephrine are required to maintain adequate perfusion pressures, then the addition of vasopressin can be useful to overcome catecholamine resistance, limit catecholamine doses, and possibly reduce the incidence of postoperative renal failure.

References

• Geffroy A, Beloeil H, Bouvier E, et al. Prolonged right ventricular failure after relief of cardiac tamponade. Can J Anaesth. 2004;51:482-485.
• Lambden S, Creagh-Brown BC, Hunt J, et al. Definitions and pathophysiology of vasoplegic shock. Crit Care. 2018;22:174.
• Shaefi S, Mittel A, Klick J, et al. Vasoplegia after cardiovascular procedure—pathophysiology and targeted therapy. J Cardiothorac Vasc Anesth. 2018;32:1013-1022.