Critical care clinics
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The contemporary management of acute myocardial infarction continues to evolve rapidly. The ultimate goal of therapy is timely, complete, and sustained myocardial reperfusion. There is a powerful time-dependent effect on mortality, and thus the balance between the time and likelihood of maximal reperfusion is crucial in deciding whether to use primary percutaneous balloon angioplasty or thrombolysis as the initial reperfusion strategy. ⋯ Combination therapy with low-dose fibrinolytics, glycoprotein IIb/IIIa inhibitors, and low molecular weight heparin, with or without subsequent early planned percutaneous coronary interventions, may provide the optimal strategy for maximal coronary reperfusion, but the results of large, randomized mortality trials currently underway need to be analyzed. Risk stratification will continue to play a major role in determining which patients should receive a specific therapy. The care of the patient with an acute myocardial infarction will continue to be a challenge requiring the proper selection from the vast pharmaceutic and interventional options available.
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Echocardiography has become an invaluable tool in the management of critically ill patients. Its safety and portability allow for use at the bedside to provide rapid, detailed information regarding the cardiovascular system. ⋯ Recently, the power of clinical echocardiography has been augmented by the use of Doppler techniques to evaluate cardiovascular hemodynamics. An in-depth understanding of the proper use of echocardiography is a prerequisite for the intensivist.
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The pulmonary artery catheter is an invasive hemodynamic monitor that can provide diagnostic information in situations where history and physical examination are inconclusive. Assisting the physician in therapeutic decisions has added to its clinical value. Understanding the information it provides and making thoughtful therapeutic decisions lie at the core of its use. ⋯ Although instituting a moratorium on its use may be extreme, limiting its use to approved indications seems more appropriate. In the future, ready availability of other less invasive methods such as echocardiography may allow clinicians to become less reliant on the PA catheter. Until then, clinicians would be served best by comprehending the intricacies and the limitations of this sophisticated instrument.
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Mortality rates in patients with cardiogenic shock remain frustratingly high. Its pathophysiology involves a downward spiral in which ischemia causes myocardial dysfunction, which in turn worsens ischemia. Areas of viable but nonfunctional myocardium can contribute to the development of cardiogenic shock. ⋯ The SHOCK multicenter randomized trial has provided important new data that support a strategy of emergent cardiac catheterization and revascularization with angioplasty or coronary surgery when feasible. This strategy can improve survival and represents standard therapy at this time. In hospitals without direct angioplasty capability, stabilization with IABP and thrombolysis followed by transfer to a tertiary care facility may be the best option.
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In summary, patients presenting with a true hypertensive emergency should be diagnosed quickly and promptly started on effective parenteral therapy (typically nitroprusside 0.5 microgram/kg/min or fenoldopam 0.1 microgram/kg/min) in an intensive care unit. Blood pressure should be reduced about 25% gradually over 2 to 3 hours. Oral antihypertensive therapy (often with an immediate-release calcium antagonist) can be instituted after 6 to 12 hours of parenteral therapy, and consideration should be given to secondary causes of hypertension after transfer out of the intensive care unit. Because of advances in antihypertensive therapy and management, "malignant hypertension" should be truly malignant no longer.