Transthoracic echo (TTE) in prone patients with COVID-19
In a case series involving 15 patients on prone ventilation, it was found that raising the patient’s left arm and placing a pillow or a folded sheet underneath the mid-thoracic wall to maintain the left hemithorax slightly elevated to allow a comfortable transducer manipulation resulted in successful apical four and five chamber views and related measurements in 14 out of 15 patients who were studied[49]. In another case series involving 8 patients, an alternative method has been proposed for obtaining adequate TTE windows in prone patients. Rather than extending the patient’s left arm above the head, the lower thoracic section of the patient’s air mattress was temporarily deflated, taking advantage of the gravitational effect of the heart and its shift toward the chest wall while obtaining an apical four chamber view\sout. In addition to the traditional apical four chamber view, the apical five chamber view was also obtainable by tilting the probe in this position. These views were adequate to estimate the left ventricular ejection fraction (LVEF), mitral annular plane systolic excursion, mitral valve and annular Doppler velocities, aortic valve Doppler velocity, TAPSE and PASP from the tricuspid regurgitation peak Doppler velocity. Adequate measurements were possible in seven out of eight patients who were included in this case series[50].