Critical care ultrasonography in acute respiratory failure.

Philippe Vignon,Eric Maury,Xavier Repessé,Antoine Vieillard-Baron

doi:10.1186/s13054-016-1400-8

Abstract

Acute respiratory failure (ARF) is a leading indication for performing critical care ultrasonography (CCUS) which, in these patients, combines critical care echocardiography (CCE) and chest ultrasonography. CCE is ideally suited to guide the diagnostic work-up in patients presenting with ARF since it allows the assessment of left ventricular filling pressure and pulmonary artery pressure, and the identification of a potential underlying cardiopathy. In addition, CCE precisely depicts the consequences of pulmonary vascular lesions on right ventricular function and helps in adjusting the ventilator settings in patients sustaining moderate-to-severe acute respiratory distress syndrome. Similarly, CCE helps in identifying patients at high risk of ventilator weaning failure, depicts the mechanisms of weaning pulmonary edema in those patients who fail a spontaneous breathing trial, and guides tailored therapeutic strategy. In all these clinical settings, CCE provides unparalleled information on both the efficacy and tolerance of therapeutic changes. Chest ultrasonography provides further insights into pleural and lung abnormalities associated with ARF, irrespective of its origin. It also allows the assessment of the effects of treatment on lung aeration or pleural effusions. The major limitation of lung ultrasonography is that it is currently based on a qualitative approach in the absence of standardized quantification parameters. CCE combined with chest ultrasonography rapidly provides highly relevant information in patients sustaining ARF. A pragmatic strategy based on the serial use of CCUS for the management of patients presenting with ARF of various origins is detailed in the present manuscript.

Highlights

Acute respiratory failure (ARF) is a leading indication for performing critical care ultrasonography (CCUS), which combines critical care general ultrasonography and critical care echocardiography (CCE) [1]
AVTI S wave/VTI S + VTI D waves expressed as a percentage bVentilated patients cIntensive care unit patients DT deceleration time of pulmonary vein D wave or of mitral E wave, E’ maximal velocity of early diastolic tissue Doppler pulse wave recorded at the level of the mitral annulus, Vp propagation velocity of early diastolic inflow measured in the left ventricular cavity using M-mode color Doppler, VTI
These results suggest that hypertensive pulmonary edema is primarily related to left ventricular (LV) diastolic dysfunction exacerbated by elevated systolic blood pressure [5]

Summary

Background

Acute respiratory failure (ARF) is a leading indication for performing critical care ultrasonography (CCUS), which combines critical care general ultrasonography (thoracic, abdominal, and vascular) and critical care echocardiography (CCE) [1]. Since CPE develops secondary to pulmonary venous congestion, its diagnosis relies on the identification of elevated left ventricular (LV) filling pressures, irrespective of systolic function. Mitral valve disease (stenosis, regurgitation, annular calcification, valvular prosthesis) and constrictive pericarditis invalidate the use of E/E’ to assess LV filling pressure [11]. This approach remains valid in atrial fibrillation [11] (Table 1). Diagnosis of the underlying heart disease In patients with CPE secondary to a decompensated congestive heart failure, CCE allows a comprehensive assessment of the causative cardiomyopathy. TEE more accurately depicts the regurgitant jet which has a clockwise or anticlockwise direction within the left atrium (LA) and may preferably enter left

Atrial fibrillation

Lymphangitis Absent or present Present

Other causes of acute respiratory failure

Findings

Conclusion