Usefulness of diaphragmatic ultrasound as a prognosis predictor in a Intermediate Respiratory Care Unit in COVID-19 patients

Abstract

<b>Introduction:</b> During the COVID-19 pandemic several markers have been taken in consideration as potential prognosis factors. Since the role of diaphragmatic dysfunction evaluated by ultrasound has been poorly described both in non-invasive ventilation support and the pandemic we decided to conduct this study. <b>Objective:</b> To determine if diaphragmatic dysfunction detected at the time of&nbsp;Intermediate Respiratory Care Unit (IRCU) admission and defined by a deficit in the excursion and/or thickening fraction is, by itself, a prognosis marker measured as longer lenght of stay in IRCU or the need of intubation in the Intensive Care Unit (ICU). <b>Methods:</b> We recruited 33 consecutive patients at the time of IRCU admission and measured the diaphragmatic excursion by anatomical M-mode and thickening fraction at the moment of non-invasive ventilation support with high-flow nasal cannula (60lpm/100%FiO2). The main outcomes were lenght of stay in IRCU in days, and need for mechanical ventilation (intubation). <b>Results:</b> There no was lineal correlation between excursion and IRCU admission days or ICU admission. Stablishing a 0.250 cutoff for thickening fraction, there was no correlation with ICU admission, but the median values for lenght of stay in IRCU were: 5 (p25 4.5; p75 7) in the dysfunction group and 7 (p25 5; p75 8) in the non dysfunction group. The Mann-Whitney test showed no statistical significance with a p value of 0.100. <b>Conclusions:</b> Despite the lack of statistical significance in the shown data, a trend in the thickening fraction determined by a 0.250 cutoff can be observed. Increasing the sample size could be crucial to achieve significance.