The management of critically ill patients becomes more challenging when they are hemodynamically unstable or clinically deteriorating, and the underlying etiology of their condition is unclear. This often occurs shortly after arrival to the emergency department (ED), but it can also occur in other parts of the hospital hours or days after care has been established, with unexpected deterioration of a previously stable patient. In these situations, clinicians are often forced to make treatment decisions before diagnostic tests can be performed. A focused physical examination of the critical organ systems is often inaccurate or misleading. Point-of-care ultrasound (POCUS) can rapidly examine the same organ systems with a higher degree of accuracy.
POCUS, performed and interpreted by the clinician, was introduced into emergency medicine (EM) in the 1980s. In many hospitals, it is now the most commonly used diagnostic tool in the initial evaluation of critically ill patients (Figure 8-1). Clinicians using ultrasound can rapidly detect previously occult findings, such as the etiology of cardiac arrest or shock, causes of shortness of breath, sources of sepsis, and volume status and fluid responsiveness. In unstable patients, the ability to obtain this information immediately at the bedside can be lifesaving.
Ultrasound machine mounted on an articulating arm in an ED critical care bay. This assures that the machine is always available and ready to use.
This chapter describes how to apply and integrate several different types of ultrasound examinations for the diagnosis and management of critically ill patients. The details of how to perform each examination and most of the normal ultrasound findings are detailed in other chapters.
There are a wide variety of ultrasound applications that have great utility in the evaluation and management of critically ill patients. Many clinicians who manage critically ill patients do not appreciate the extent to which POCUS will improve their diagnostic ability and patient care. In the United States, emergency physicians tend to focus on abdominal, cardiac, and shock applications, while intensivists concentrate on cardiac function and hemodynamic parameters.1 In Europe, clinicians tend to have a much better understanding of pulmonary ultrasound and use it extensively for the benefit of critically ill patients. Experienced POCUS clinicians everywhere know that “whole body ultrasonography” improves diagnostic accuracy and patient management, especially for critically ill patients.2
Critically ill patients often present with ill-defined disease entities. A variety of ultrasound applications can help clinicians make management decisions when dealing with common problems encountered in the care of critically ill patients.
Cardiac arrest and peri-arrest states
Evaluation of undifferentiated hypotension
Assessment of volume status and fluid requirements
Evaluation of shortness of breath or respiratory distress
Assessment in the peri-intubation period
Evaluation of extremity vasculature