Ultrasound Assessment of Diaphragmatic Response to High-Flow Nasal Cannula in COVID-19 Pneumonia

Diaphragmatic dysfunction has emerged as a significant factor in the respiratory complications seen in severely ill COVID-19 patients. High-flow nasal cannula (HFNC) therapy has proven effective in noninvasive respiratory support by alleviating diaphragm dysfunction. This study aimed to assess the diaphragmatic response to HFNC in patients with COVID-19 pneumonia using ultrasound. Conducted retrospectively in a medical-surgical ICU at Sanatorio de Los Arcos in Buenos Aires, Argentina, the study spanned 16 months (January 2021–June 2022). It involved patients diagnosed with COVID-19 pneumonia who were considered suitable candidates for HFNC by their attending physician. Diaphragmatic ultrasound was performed to measure diaphragmatic excursion (DE) before and during HFNC therapy. The study included a total of 10 patients. The results showed a statistically significant decrease in respiratory rate with HFNC usage (p=0.02) and a significant increase in DE (p=0.04). These findings suggest that HFNC can improve respiratory mechanics in COVID-19 pneumonia patients, as evidenced by the enhanced diaphragmatic function observed through ultrasound. The study highlights the potential of HFNC in managing respiratory difficulties in these patients. However, the relatively small sample size means further research is necessary to confirm these promising results and better understand the full impact of HFNC on diaphragmatic mechanics in the context of COVID-19 pneumonia.