Explain Inotropes and Vasopressors

Persisting hemodynamic instability after correction of hypovolemia would necessitate the use of vasoactive agents. Which drug or intervention to use would depend on the type of shock. The clinical effects of available drugs are summarized in table. In cardiogenic shock, characterised by low cardiac output and peripheral vasoconstriction, dobutamine is a good drug to use, as it has inotropic as well as vasodilator effect. Phosphodiesterase inhibitors like milrinone also act in a similar fashion. Pure vasodilators like glyceryl trinitrate and sodium nitroprusside may also help in reducing the peripheral vasoconstriction and thereby, the systemic vascular resistance. Intra-aortic balloon counterpulsation increases coronary blood flow and reduces left ventricular afterload, thus reversing myocardial ischemia and improving cardiac performance. It is useful in patients in whom myocardial revascularization can be accomplished either by surgery or angioplasty and in the postoperative cardiac surgical patient with low cardiac output state. It is less successful in acute myocardial infarction complicated by cardiogenic shock if there is no lesion that can be revscularized.