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Modalities of fluid management in patients sustaining the acute respiratory distress syndrome (ARDS) are challenging and controversial. Optimal fluid management should provide adequate oxygen delivery to the body, while avoiding inadvertent increase in lung edema which further impairs gas exchange. In ARDS patients, positive fluid balance has been associated with prolonged mechanical ventilation, longer ICU and hospital stay, and higher mortality. Accordingly, a restrictive strategy has been compared to a more liberal approach in randomized controlled trials conducted in various clinical settings. Restrictive strategies included fluid restriction guided by the monitoring of extravascular lung water, pulmonary capillary wedge or central venous pressure, and furosemide targeted to diuresis and/or albumin replacement in hypoproteinemic patients. Overall, restrictive strategies improved oxygenation significantly and reduced duration of mechanical ventilation, but had no significant effect on mortality. Fluid management may require different approaches depending on the time course of ARDS (i.e., early vs. late period). The effects of fluid strategy management according to ARDS phenotypes remain to be evaluated. Since ARDS is frequently associated with sepsis-induced acute circulatory failure, the prediction of fluid responsiveness is crucial in these patients to avoid hemodynamically inefficient-hence respiratory detrimental-fluid administration. Specific hemodynamic indices of fluid responsiveness or mini-fluid challenges should be preferably used. Since the positive airway pressure contributes to positive fluid balance in ventilated ARDS patients, it should be kept as low as possible. As soon as the hemodynamic status is stabilized, correction of cumulated fluid retention may rely on diuretics administration or renal replacement therapy.

Critical care echocardiography (CCE) has specific requirements that cannot be met by consultant cardiologists and support the need for training intensivists in the use of this technique in the intensive care unit (ICU). Hemodynamic monitoring utilizing echography is made in two steps: the first assesses the main mechanisms implicated in the problem (ventricular dysfunction, preload deficit, tamponade), and this can be done by most intensivists with minimal training; the second step evaluates in more detail the precise cause and the various abnormalities presented by the patient’s heart; this step requires more expertise. The training for beginners can easily be achieved with basic courses and a minimal number of assisted and nonassisted echocardiographic examinations. Intensivists who desire to reach competence in advanced CCE must dedicate time to follow an extensive training program to acquire technical and cognitive skills for mastering all aspects of echocardiography in the ICU setting. Competence in advanced CCE should be officially recognized. With accumulated experience, intensivists with competence in advanced CCE will attain expertise and may act as tutors for other physicians in training. Each country should built structured educational programs based on existing international standards.

In contrast to conventional echocardiography performed by cardiologists on a consultative basis, critical care echocardiography is performed and interpreted by the intensivist at the bedside of the patient in the intensive care unit. It assists the frontline intensivist in establishing diagnosis and guiding management of patients with hemodynamic or respiratory failure. Since critical care echocardiography is best performed at the time of organ failure, it should be available on a 24-h basis every day of the year. This emphasizes the need of a dedicated equipment in the modern intensive care unit. Critical care echocardiography requires immediate interpretation since its results must be interpreted in light of the medical history of the patient, the clinical context, ventilator settings and ongoing treatments. A background in intensive care medicine is required to incorporate the obtained information in the medical reasoning and diagnostic work-up. The identification of the leading mechanism for hemodynamic compromise and early recognition of overloaded right ventricle in mechanically ventilated patients with respiratory failure avoid using inefficient or harmful therapeutic interventions. In addition, serial examinations allow monitoring both the efficacy and tolerance of echocardiography-guided therapeutic interventions. Transthoracic and transesophageal approaches can be used for this purpose. The level of competence of the intensivist closely depends on previous personal training and acquired cognitive and technical skills.

The assessment of circulatory failure and shock constitutes the most frequent indication for performing an echocardiographic study in the intensive care unit. In addition to its diagnostic capabilities, echocardiography allows a close monitoring of the effects of the applied therapies.

Four distinct acute aortic diseases that may result in acute aortic syndrome (AAS) should be distinguished: aortic dissection, intramural aortic hematoma (IAH), penetrating aortic ulcer (PAU), and incomplete aortic dissection (corresponding to an aortic wall laceration without dissection of the media). Each of these entities has a clear pathophysiology, but IAH may evolve into a classic aortic dissection, and PAU is frequently associated with intramural hemorrhage and may occasionally constitute the entrance tear of a subsequent aortic dissection. Syncope, hypotension, and shock are warning signs, which are commonly indicative for exsanguination or cardiac tamponade related to the involvement of the ascending aorta. Acute management depends on the nature of the AAS and aortic segment involved: prompt surgery on the ascending aorta and conservative treatment or endovascular repair for the descending aorta. Echocardiography has a pivotal role in the assessment of AAS patients with hypotension or shock. Transesophageal echocardiography (TEE) is preferred since it has greater diagnostic accuracy, though it can be unsafe in nonintubated patients (risk of collapse in the case of tamponade or aortic rupture in the case of acute increases in aortic pressure). Transthoracic echocardiography should be performed first in nonintubated patients since the identification of hemopericardium with potential tamponade, aortic regurgitation, and enlarged ascending aorta allows prompt surgery to be undertaken. In this case, TEE should be performed in the operating room in an anesthetized patient to refine the diagnosis of complicated AAS.associated with intramural hemorrhage and may occasionally constitute the entrance tear of a subsequent aortic dissection. Syncope, hypotension, and shock are warning signs, which are commonly indicative for exsanguination or cardiac tamponade related to the involvement of the ascending aorta. Acute management depends on the nature of the AAS and aortic segment involved: prompt surgery on the ascending aorta and conservative treatment or endovascular repair for the descending aorta. Echocardiography has diagnostic capabilities equivalent. Transesophageal echocardiography (TEE) is preferred, though it can be dangerous in nonintubated patients (risk of collapse in the case of tamponade or aortic rupture in the case of acute increases in aortic pressure). Transthoracic echo should be performed first in nonintubated patients since the identification of hemopericardium with potential tamponade, aortic regurgitation, and enlarged ascending aorta allows prompt surgery to be undertaken. In this case, TEE should be performed in the operating room in an anesthetized patient to refine the diagnosis of complicated AAS.

In the presence of pulmonary edema, the distinction between hydrostatic (often cardiogenic) and permeability (acute respiratory distress syndrome) edema is crucial in the hypoxemic critically-ill patient. Importantly, the absence of relevant left ventricular (LV) systolic dysfunction fails to rule outa hydrostatic pulmonary edema (e.g., acute valvular regurgitation, volume overload, severe diastolic dysfunction, mitral stenosis) and, conversely, acuterespiratory distress syndrome (ARDS) patients may present with a significant LV systolic dysfunction (e.g., septic shock) Consequently, Doppler (with elevated E/A wave ratio and shortened E wave deceleration time) combined with the measurement of mitral annulus motion with tissue Doppler (elevated E/Ea wave ratio). The evaluation of pulmonary vein pulsed-wave Doppler pattern may also help in assessing left cardiac filling pressure. LV loading conditions – hence Doppler velocity profiles – may rapidly fluctuate over time, or as a result of initial therapy. Consequently, echocardiography has a maximal diagnostic value when performed at the time of acute respiratory failure. It accurately document elevated LV filling pressures consistent with hydrostatic pulmonary edema and may help identifying the causative cardiopathy.