Perioperative point-of-care ultrasound and echocardiography

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What is the role of point-of-care ultrasound and echocardiography in the perioperative and critical care setting?

Ultrasound is a valuable diagnostic tool capable of providing real-time, rapid evaluation of patients. It is mobile, easy to use, safe, and less expensive than other imaging modalities, making its application pertinent to a variety of clinical environments—perioperative, critical care, emergency department, outpatient clinics, or inpatient wards. Ultrasound is progressively decreasing in cost, becoming more available and easier to use. Time-sensitive decisions can be made at the bedside, reducing the burden on sonographers and delay in patient care. Point-of-care ultrasound (POCUS) and echocardiography may prevent unnecessary tests and consults, surgical delay, and placement of invasive monitors, as well as help determine appropriate levels of postoperative monitoring and patient disposition.

POCUS is a tool that, when combined with history and physical examination, may be used to answer specific clinical questions. These include, but are not limited to, ventricular function, significant structural or valvular cardiac abnormalities, hemodynamic status, and/or severe lung pathology. Formal evaluation of cardiac function/pathology may be further investigated by referral for a diagnostic limited or comprehensive echocardiographic study. POCUS is often performed using transthoracic echocardiography (TTE); however, in the operating room or critical care environment, it may be performed using transesophageal echocardiography (TEE), depending on the physician or provider’s level of training.

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How are POCUS images obtained?

Images result from transmission of ultrasound waves (2–10 mHz) from the TEE/TTE probe through target tissue (heart and great vessels). The time it requires for the wave to be reflected back determines the location of a structure. This can be combined with color flow Doppler to further examine dynamic structures. These high resolution multiplane images and Doppler techniques provide real-time hemodynamic evaluation and assist in the diagnosis of cardiovascular and pulmonary pathology.

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Which ultrasound modes can aid in the POCUS examination?

The diagnostic utility of two-dimensional ultrasound alone can yield significant information, including global and segmental cardiac function, valve restriction or prolapse, pneumothoraxes, pleural effusions, and hemodynamic status. The availability and understanding of color-flow imaging, spectral Doppler, tissue Doppler, and M-mode will further aid in the clinical examination.

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What are some specific pathologies that POCUS can potentially identify?

• Left atrial enlargement

• Left ventricular (LV) hypertrophy, enlargement, and systolic function

• Right ventricular (RV) enlargement and systolic function

• Pericardial effusion

• Intravascular volume status

• Pneumothorax

• Pleural effusion

• Significant aortic and mitral valve pathology

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