Acute Heart Failure: Diagnosis and Monitoring

The critically ill patient in acute heart failure continues to present an exceptional challenge concerning diagnostic procedures, monitoring and treatment. The European Society of Cardiology guidelines was the first to classify patients in acute heart failure into distinct clinical entities. Further management and choice of monitoring relies on this classification. Beside the obligatory monitoring (electrocardiography, respiratory rate, blood pressure, urine output, temperature) further components of a modular monitoring, as well as additional diagnostic procedures, must be implemented according to the acuteness and severity of the patient's condition. Measurement of cardiac output and arterial blood pressure are essential elements in an extended invasive monitoring. The pressure-based monitoring, which uses central venous pressure and pulmonary artery occlusion pressure as a surrogate for cardiac preload, should be replaced by a more volume-oriented monitoring. Moreover, new monitoring strategies should incorporate functional hemodynamic monitoring that evaluates the effects of treatment. Changes in volume and passive leg raising can be used to assess volume responsiveness. Changes in left ventricular output during spontaneous breathing or even positive pressure ventilation may be helpful in differentiating the extent of volume dependency. The greater the increase in tidal volume for the same lung compliance, the greater is the transient decrease in venous return and the subsequent decrease in left ventricular output. Variations in systolic pressure or pulse pressure are reliable measures of preload responsiveness. More clinical validation of these measures must be done before they can become standard measures of monitoring patients in acute heart failure.