Diagnostic Assessment of Respiratory and Hemodynamic Changes Related to Prone Position in COVID-19 Patients.

OBJECTIVE: To study the respiratory patterns and the hemodynamic variations related to postural changes in inpatients with coronavirus disease (COVID-19). METHODS: This report is a prospective study in a cohort of inpatients admitted with COVID-19. We recruited 10 patients admitted to the hospital with moderate or severe COVID-19 who showed improvement in oxygen saturation with prone positioning. We performed cardiorespiratory polygraphy and hemodynamic evaluations by thoracic electrical bioimpedance. RESULTS: We observed a median minimum oxygen saturation of 85.00% (IQR: 7.00) in the supine position versus 91.00% (IQR: 8.00) (P = 0.173) in the prone position. The airflow restriction in the supine position was 2.70% (IQR: 6.55) versus 1.55% (IQR: 2.80) (P = 0.383) in the prone position. A total of 36.4% of patients were classified as having a normo-hemodynamic state in the supine position, whereas 54.5% were classified in this group in the prone position (P = 0.668). A decrease in vascular resistance was observed in the prone position (18.2% of vasoconstriction) compared to the supine position (36.4% of vasoconstriction) (P = 0.871). CONCLUSION: This brief report describes the effects of prone positioning on respiratory and hemodynamic variables in 10 patients with moderate or severe COVID-19.

Diaphragm impairment in patients admitted for severe COVID-19.

Among patients affected by the virus COVID-19, physicians have observed ventilation disorders. It is relevant to assess neurological involvement, including the role of diaphragmatic function. Its possible impairment could be related to the systemic inflammatory response and disease progression that both typify COVID-19 infection. We distinguished two groups (severe group (SG) and mild group (MG)) according to the severity of respiratory symptomatology. We performed neurophysiological and sonography studies to evaluate the diaphragmatic function. Regarding the sonography variables, we identified statistically significant differences in the right mean diaphragmatic thickness along with the expiration, showing 1.56 mm (SEM: 0.11) in the SG vs 1.92 mm (SEM: 0.19) in the MG (p = 0.042). The contractibility of both hemidiaphragms was 15% lower in the severe group, though this difference is not statistically significant. In our examination of the neurophysiological variables, in the amplitude responses, we observed a greater difference between responses from both phrenic nerves as follows: the raw differences in amplitude were 0.40 µV (SEM: 0.14) in the SG vs 0.35 µV (SEM: 0.19) in the MG and the percentage difference was 25.92% (SEM: 7.22) in the SG vs 16.28% (SEM: 4.38%) in the MG. Although diaphragmatic dysfunction is difficult to detect, our combined functional and morphological approach with phrenic electroneurograms and chest ultrasounds could improve diagnostic sensitivity. We suggest that diaphragmatic dysfunction could play a relevant role in respiratory disturbance in hospitalised patients with severe COVID-19.