key: cord-0772136-xt3zrd5t
authors: Roemer, Sarah; Kaminski, Abigail; Payne, Abby; Tanel, Emily; Perez Moreno, Ana Cristina; Jaglan, Akshar; Khandheria, Bijoy K.
title: Feasibility of Transthoracic Imaging of the Heart in the Prone Position
date: 2020-07-21
journal: J Am Soc Echocardiogr
DOI: 10.1016/j.echo.2020.07.004
sha: e574d87c8ae5368a9f2fe608175bebd3b14139ea
doc_id: 772136
cord_uid: xt3zrd5t

nan

Transthoracic echocardiography (TTE) in the prone position is a non-conventional approach that is not routinely performed for cardiac assessment. The need for prone TTE has increased recently due the needs of the COVID-19 patient population. 1,2 With a few adjustments to the traditional TTE scanning method, we believe we can adequately evaluate myocardial function and detect subclinical impairment while a patient is in the prone position. Due to its feasibility and portability, TTE is the principal imaging modality used to monitor the cardiac function of patients with COVID-19. 3 In this single-center, prospective study, TTE was performed, using a state-of-the-art ultrasound platform, on 24 non-intubated, non-COVID-19-infected patients in both the traditional (left lateral decubitus) and prone positions. This study was designed to test the feasibility and compare quantitative results of traditional versus prone imaging. Ugalde et al.

described a modified prone position as the "swimmer's position." 4 Swimmer's position is accomplished by having the patient lay on his or her stomach with the left arm raised above the head and the right arm resting along the torso. A pillow should be propped under the left arm to slightly elevate the left-sided rib cage, permitting more space for the transducer. If the imager is scanning with their right hand, no system relocation is necessary. If the imager is scanning with their left hand, the system will be located on the patient's right side and placed at the foot of the bed. When connecting the patient to the ultrasound system, electrocardiogram patches can be placed on the patient's back if the chest is not obtainable (Supplemental Video 1).

The following views were attempted in the prone position: parasternal long-axis (PLAX), (Table 1 ).

This study illustrates that RV-focused imaging was feasible in 100% of patients, including a high feasibility rate of analysis of RV systolic parameters such as RVLS (Figure 1 ).

The RV could be easily visualized in the prone population most likely because the heart slides closer to the chest wall, thereby allowing less penetration and better visualization of the ultrasound. The apical 4-chamber view was also visualized in a majority of the patients, providing an idea of the global LV systolic function. However, the other views required for LV GLS assessment were not as easily obtainable, yielding a much lower rate of LV GLS than RVLS. Prone imaging was deemed more challenging if the patient had a more medial window in the traditional position due to the challenge of sliding the probe medially and interference with the exam table while in the prone position. This also explains why the PLAX view was unattainable and the IVC was only analyzed transhepatically. Manuscripts have been published regarding the use of smaller or hand-held ultrasound devices. We believe that similar results are achievable with the exception of longitudinal strain analysis, which is often not available on smaller platform models.

We acknowledge that this is a pilot study based on feasibility of TTE in the prone position and did not include patients infected with COVID-19 or on mechanical ventilation. Now that we know this is achievable, the target population needs to be formally evaluated since COVID-19 infection and mechanical ventilation could impact image quality, heart position, and associated RV abnormalities. During the surge of the pandemic, prone TTE imaging was possible on a small group of patients, but further analysis is warranted. Video 1 Prone TTE imaging demonstration. An example of how to achieve appropriate "swimmer's position" with necessary modifications for a left-handed imager to scan a patient in the prone position. 

Coronavirus disease 2019 (COVID-19): Critical care and airway management issues

Does prone positioning improve oxygenation and reduce mortality in patients with acute respiratory distress syndrome?

ASE Statement on Protection of Patients and Echocardiography Service Providers During the 2019 Novel Coronavirus Outbreak

Transthoracic cardiac ultrasound in prone position: a technique variation description

Clinical characteristics of 138 hospitalized patients with 2019 novel coronavirus-infected pneumonia in Wuhan, China

The authors are grateful to the following from Aurora Cardiovascular and Thoracic Services:Jennifer Pfaff and Susan Nord for editorial preparation of the manuscript and Brian Miller and Brian Schurrer for assistance with the figures.