Texas Heart Institute journal
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The major therapeutic approach to systemic and pulmonary hypertension and vasospasm in cardiac surgery patients involves the use of parenteral agents that reverse systemic vasoconstriction and produce vasodilation. Potential pharmacologic approaches include 1) alpha1-adrenergic receptor blockers, ganglionic blockers, and calcium channel blockers; 2) central alpha2-adrenergic receptor agonists, dopamine1-adrenergic receptor agonists, potassium channel modulators, and vascular cyclic nucleotide stimulators; 3) phosphodiesterase enzyme inhibitors, and 4) angiotensin-converting enzyme inhibitors. Of the currently available intravenous vasoactive therapies, the mainstay agents are the nitrovasodilators and the dihydropyridine-type calcium channel blockers. ⋯ Intravenous dihydropyridine-type calcium channel blockers inhibit mechanical responses of cardiac muscle and vascular smooth muscle by blocking inward calcium currents. Nicardipine is an arterial specific vasodilator. Treatment for vasospasm is usually empiric; pharmacologic options include nitroglycerin, but dihydropyridine calcium channel blockers and phosphodiesterase inhibitors should also be considered.
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Cardiac anesthesiologists have the responsibility to detect myocardial ischemia in a timely manner, which can be a challenging task in the perioperative environment. Transesophageal echocardiography pulmonary artery catheterization, and electrocardiography are the 3 major methods available for monitoring perioperative ischemia. Echocardiography, the newest and most sophisticated method, has been shown to be highly sensitive for detecting ischemia associated with systolic dysfunction. ⋯ Pulmonary artery catheterization can provide information about systolic dysfunction, diastolic dysfunction, and mitral regurgitation, but the sensitivity and safety of catheterization have been questioned. Electrocardiography can be a superb monitoring device as long as clinicians pay adequate attention to lead selection and placement, filter selection, and gain adjustment. The optimal monitoring approach should integrate all 3 available monitoring systems in order to increase the likelihood of detecting both supply- and demand-mediated ischemia.
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Cryptogenic stroke is a diagnosis of exclusion. These are strokes that occur in people who are usually less than 55 years old, without an identifiable cause. Our sensitivity to these events has been heightened because of the new definitions of a transient ischemic attack. ⋯ They also frequently have PFOs; if you close the PFO, the arterial desaturation is alleviated. Fat emboli during orthopedic surgery or air emboli during neurosurgery may also travel through the venous system. If you don't have a PFO, the fat or the air is trapped in the lungs and doesn't cause much of a problem unless it's massive; but if you have a PFO, then the embolus can go from right to left atrium up to the brain, with devastating neurologic consequences.