Current opinion in critical care
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Curr Opin Crit Care · Jun 2005
ReviewHemodynamic assessment of critically ill patients using echocardiography Doppler.
The evaluation of hemodynamic status in critically ill patients is a leading recommended indication of transesophageal echocardiography in the intensive care unit. Advantages and diagnostic yield of transesophageal echocardiography in this setting are particularly relevant when considering limitations and questioned prognostic impact of pulmonary artery catheterization. ⋯ Transesophageal echocardiography appears well suited for the determination of cardiac index and to track its variations after therapeutic interventions. Although repeated measurements of left ventricular end-diastolic dimension allows to accurately track preload variations, a single determination is not reliable to predict fluid responsiveness in intensive care unit patients. Identification of preload dependence in hemodynamically unstable patients currently tends to rely mainly on dynamic parameters that use cardiopulmonary interactions under mechanical ventilation. Transesophageal echocardiography also allows to adequately assess right ventricular function and left ventricular filling pressure using combined Doppler modalities. Adequate education and training of intensivists and anesthesiologists is crucial to further develop the use of transesophageal echocardiography in the intensive care unit setting. Despite the absence of randomized controlled studies documenting transesophageal echocardiography benefits on patient outcome, present evidence and experience strongly recommend a larger use of echocardiography Doppler for a comprehensive functional hemodynamic assessment of critically ill patients with circulatory failure.
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To summarize the relevant peer-reviewed publications over the past year that addressed issues of when to give (or not give) fluid to the critically ill patient. ⋯ Preload is not preload responsiveness. Functional measures of preload responsiveness exist and are superior to traditional measures of filling pressures in driving resuscitation in critically ill patients.
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Curr Opin Crit Care · Jun 2005
ReviewMonitoring of pulmonary mechanics in acute respiratory distress syndrome to titrate therapy.
This paper reviews recent findings regarding the respiratory mechanics during acute respiratory distress syndrome as a tool for tailoring its ventilatory management. ⋯ The Venegas approach should be the standard analysis of pressure-volume curves. In any patient, the potential for recruitment should be assessed, as a basis for tailoring the most effective mechanical ventilation. Further studies are needed to clarify the potential use of the pressure-volume curve to guide a lung-protective ventilatory strategy.
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Curr Opin Crit Care · Jun 2005
Randomized Controlled Trial Comparative Study Clinical TrialMechanical devices for cardiopulmonary resuscitation.
For over 40 years, manual chest compressions have been the foundation of cardiopulmonary resuscitation and recent studies have clearly reconfirmed the hemodynamic significance of delivering consistent, high-quality, infrequently-interrupted chest compressions. However, there remain multiple inadequacies in the actual delivery of manual chest compressions during cardiopulmonary resuscitation. One potential solution is use of adjunct mechanical devices. ⋯ High quality chest compressions during cardiopulmonary resuscitation are critical elements in effecting successful resuscitation following a cardiac arrest. Recent studies utilizing adjunct mechanical devices have not only revealed significant increases in the effectiveness of chest compressions, including improved hemodynamics in both animal models and human studies, but also improvements in short-term human survival in the clinical setting. It is hoped that these promising findings will eventually be corroborated in terms of improved neurologically intact, long-term patient survival. Clinical trials are currently underway to validate such efficacy.
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Maintenance of adequate tissue oxygenation is an important task in intensive care units. In this context, venous oximetry by obtaining mixed venous oxygen saturation or central venous oxygen saturation has been discussed as useful monitoring parameters. This review discusses the physiology and clinical application of these parameters. ⋯ Early goal directed therapy should be implemented in the initial resuscitation of septic patients. Measurement of central venous oxygen saturation can easily be applied in intensive care unit patients and offers a useful indirect indicator for the adequacy of tissue oxygenation.