My patient has no blood pressure: is their heart working?

Abstract

How can point-of-care (PoC) ultrasound be used to help the clinician identify cardiogenic and certain non-cardiogenic causes of undifferentiated, non-traumatic hypotension? Hypotension is a common emergency presentation in the emergency department and medical admissions unit. Due to the physiological complexities of this state, the aetiology is often unclear to clinicians at initial presentation. This has clear implications for treatment and outcomes of the patient. Clinical indicators such as vital signs and physical examination are often unreliable in distinguishing causes of hypotension, identifying the correct aetiology in only 25–50% of cases. PoC ultrasound (PoCUS) of the heart can help differentiate between cardiogenic causes such as left ventricular dysfunction, and obstructive causes such as cardiac tamponade, and can point towards other causes such as sepsis and hypovolaemia. Limited cardiac echocardiography or ‘echo in life support’ can be performed as a part of goal-directed protocols for undifferentiated, non-traumatic hypotension. Use of such protocols early can significantly improve the diagnostic accuracy to 80%, thereby reducing the time to diagnosis and the time to initiating appropriate therapies. In this article, we review our approach to PoCUS of the heart in the setting of hypotension.