Systolic Dysfunction Following Traumatic Brain Injury
I read with interest the article published in a recent issue of Critical Care Medicine by Krishnamoorthy et al (1) that described development of left ventricular systolic dysfunction in a cohort of moderate to severe traumatic brain injury (TBI) patients. The authors used fractional shortening method to estimate left ventricular systolic function (LVSF) from the echocardiographic images obtained from parasternal long axis view. However, the American Society of Echocardiography recommends Simpson’s biplane method for quantitative estimation of left ventricular ejection (LVEF) fraction by 2D echocardiography (2). This method requires obtaining images of the left ventricle in apical four- and two-chamber views. The study authors state that the patients with TBI may develop fluctuations in the intracranial pressure when placed in lateral decubitus position to obtain apical four- or two-chamber views, hence the fractional shortening method was chosen. Fractional shortening is a linear method of estimating LVSF and prone to errors in the presence of regional wall motion abnormalities or if the measurements are not obtained perpendicular to the mid cavity of left ventricle. This could lead to over- or underestimation of LVSF as the authors pointed out in their study limitations (1). However, they reported left ventricular diastolic function variables (Table 2 in ) which should have been measured in apical four-chamber view, which meant that the investigators were able to obtain good quality images in the apical four-chamber view in the study population. Hence, it is plausible that they could have estimated LVSF via Simpson’s method instead of the fractional shortening. I would appreciate if authors could provide values of LVEF as estimated by the Simpson’s method and whether that would lead to any change in the study results and its conclusions.