6: GOAL-DIRECTED ECHOCARDIOGRAPHY IN THE ICU

Introduction

This chapter reviews an important component of critical care ultrasonography (CCUS), which is basic critical care echocardiography (CCE). For purpose of the discussion, the term goal-directed echocardiography (GDE) and basic CCE are used interchangeably. They refer to a limited cardiac ultrasonography examination performed by the intensivist at bedside of the patient with hemodynamic failure in order to establish diagnosis and guide management of the shock state. The examination differs from cardiology-type echocardiography in the intensivist all aspects of the examination. Image acquisition, image interpretation, and application of the results are performed by the bedside clinician who is charge of the case. There is no delay in performance or interpretation of the study, nor is there any problem with clinical disassociation that occurs when the ultrasonographer is not directly involved with management of the case. GDE may be repeated as often as required by the clinical situation in order to track the evolution of disease and response to therapy.

The GDE Examination

The ACCP/SRLF Statement of competence in CCUS defines GDE with transthoracic echocardiography (TTE) as constituting five views:¹ the parasternal long- and short-axis views, the apical four-chamber view, the subcostal long-axis four-chamber view, and the inferior vena cava (IVC) longitudinal view (Case 6-1). Color Doppler may be utilized in order to screen for significant valve dysfunction. The technique of obtaining these key views is reviewed in the chapter on TTE (^ch006 ). It may be difficult to obtain all five views in the critically ill patient, and so it is important to attempt all five in every patient. For example, patients on ventilatory support who are hyperinflated due to PEEP effect or obstructive airway disease may have inadequate parasternal and apical four-chamber views, and yet have a good quality subcostal view. If the IVC is not visible through an anterior sagittal approach, the examiner may need to scan from a lateral approach. A key aspect of GDE is its simplicity. The examination takes a only few minutes to perform, so that the intensivist may perform a rapid evaluation of shock state and immediately integrate the results into other key elements clinical evaluation: the history, the physical examination, and the laboratory analysis. There is no alternative method of assessing cardiac anatomy and function in the intensive care unit (ICU), given clinical reality of the ICU. For the frontline intensivist, mastery of GDE is an essential skill for the evaluation of the patient in shock.