Point of care ultrasound for monitoring and resuscitation in patients with shock

Abstract

Point-of-Care Ultrasound (POCUS), when used by experienced physicians, is a valuable diagnostic tool for the initial minutes of shock management and subsequent monitoring. It enables early diagnosis with high sensitivity (Sn) and specificity (Sp). Published protocols have advanced towards true multi-organ ultrasonographic exploration, with the RUSH (Rapid Ultrasound in Shock) protocol likely being the most well-known nowadays. Although there is no established order, cardiac evaluation, as well as vascular system assessments including intra- and extravascular volume, should be explored. Additionally, there are ultrasonographic evaluations particularly useful for diagnosing and monitoring response/tolerance to volume. Both the identification of B lines and the increase in left ventricular pressures bring us closer to a diagnosis of fluid overload in these patients. Velocity-time integral (VTI) of the left ventricle (LV) outflow tract (LVOT, LVOT_VTI) or right ventricular outflow tract (RVOT, RVOT_VTI) can be indicative of distributive shock if elevated, and help identifying volume responders through leg-raising manoeuvres or crystalloid bolus administration. Several index of the inferior vena cava (IVC) can also be helpful. In addition, different parameters to establish fluid responsiveness are being investigated at the carotid level. Venous congestion parameters have not yet been proven to identify volume responders but can identify patients with poor tolerance. Currently, it is essential that physicians treating critical patients use POCUS to enhance clinical outcomes.

Keywords: Carotid; Inferior vena cava (IVC); Lines; Monitoring, B; POCUS (Point Of Care Ultrasound); Shock; Time integral (VTI); VExUS; Velocity.