ORIGINAL ARTICLE   Free access

Minerva Anestesiologica 2021 April;87(4):432-8

DOI: 10.23736/S0375-9393.21.15129-6

Copyright © 2021 EDIZIONI MINERVA MEDICA

language: English

Low diaphragm muscle mass predicts adverse outcome in patients hospitalized for COVID-19 pneumonia: an exploratory pilot study

Francesco CORRADI ^{1, 2} ✉, Alessandro ISIRDI ^{1, 2}, Paolo MALACARNE ³, Gregorio SANTORI ⁴, Greta BARBIERI ⁵, Chiara ROMEI ³, Tiziana BOVE ⁶, Luigi VETRUGNO ⁶, Marco FALCONE ⁷, Pietro BERTINI ³, Fabio GUARRACINO ³, Giovanni LANDONI ^{8, 9}, Francesco FORFORI ^{1, 2} UCARE (Ultrasound in Critical care and Anesthesia Research Group) 

¹ Department of Surgical, Medical, Molecular Pathology and Critical Care Medicine, University of Pisa, Pisa, Italy; ² E.O. Ospedali Galliera, Genoa, Italy; ³ University Hospital of Pisa, Pisa, Italy; ⁴ Department of Surgical Sciences and Integrated Diagnostics, University of Genoa, Genoa, Italy; ⁵ Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy; ⁶ Anesthesiology and Intensive Care Clinic, Department of Medicine, University of Udine, Udine, Italy; ⁷ Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy; ⁸ Department of Anesthesiology and Intensive Care, IRCCS San Raffaele Scientific Institute, Milan, Italy; ⁹ School of Medicine, Vita-Salute San Raffaele University, Milan, Italy

BACKGROUND: The aim of this study was to evaluate whether measurement of diaphragm thickness (DT) by ultrasonography may be a clinically useful noninvasive method for identifying patients at risk of adverse outcomes defined as need of invasive mechanical ventilation or death.
METHODS: We prospectively enrolled 77 patients with laboratory-confirmed COVID-19 infection admitted to our intermediate care unit in Pisa between March 5 and March 30, 2020, with follow-up until hospital discharge or death. Logistic regression was used identify variables potentially associated with adverse outcomes and those P<0.10 were entered into a multivariate logistic regression model. Cumulative probability for lack of adverse outcomes in patients with or without low baseline diaphragm muscle mass was calculated with the Kaplan-Meier product-limit estimator.
RESULTS: The main findings of this study are that: 1) patients who developed adverse outcomes had thinner diaphragm than those who did not (2.0 vs. 2.2 mm, P=0.001); and 2) DT and lymphocyte count were independent significant predictors of adverse outcomes, with end-expiratory DT being the strongest (ß=-708; OR=0.492; P=0.018).
CONCLUSIONS: Diaphragmatic ultrasound may be a valid tool to evaluate the risk of respiratory failure. Evaluating the need of mechanical ventilation treatment should be based not only on PaO2/FiO2, but on a more comprehensive assessment including DT because if the lungs become less compliant a thinner diaphragm, albeit free of intrinsic abnormality, may become exhausted, thus contributing to severe respiratory failure.

KEY WORDS: Diaphragm; Respiratory insufficiency; Ultrasonography