Purpose of review: The present review will discuss the usefulness of ultrasound in the ICU in assessing hemodynamic instability in various critical care conditions. We will discuss how to interpret echocardiographic findings in critically ill patients including the physiological consequences of mechanical ventilation.
Recent findings: Most of the studies performed in the ICU used transesophageal echocardiography. However, with improvements in image acquisition with harmonic imaging and new contrast agents, transthoracic echocardiography allows a rapid and accurate diagnosis for almost all patients with unexplained hemodynamic instability. Furthermore, recent studies have shown the usefulness of hand-held echocardiography in a crowded ICU room. One of the major recent advances in echocardiography is the noninvasive assessment of filling pressures using tissue Doppler imaging, including the use of peak mitral flow velocity of the early rapid filling wave and early diastolic velocity of the mitral annulus ratio or peak mitral flow velocity of the early rapid filling wave to early diastolic velocity of the mitral annulus timing relationship. The role of tissue Doppler imaging in the ICU needs to be further explored.
Summary: Echocardiography is now an unavoidable tool in assessing hemodynamic instability in the ICU. Echocardiography is complementary to a pulmonary artery catheter in the management of critical care patients. Echocardiography training is crucial to help its widespread use in all ICUs.