Right Ventricular Function Across Different Respiratory Support Strategies in Severe Community-Acquired Pneumonia

Background: Right ventricular (RV) dysfunction is increasingly recognized in acute respiratory failure. Hypoxaemia, hypercapnia, acidosis, pulmonary vascular involvement and positive-pressure respiratory support may increase pulmonary vascular resistance (PVR) and RV afterload, thereby impairing RV performance. However, the haemodynamic effects of non-invasive respiratory support strategies in severe community-acquired pneumonia (CAP) outside the ICU remain insufficiently characterized. Objectives: To assess, in patients with severe CAP (Pneumonia Severity Index - PSI - IV and V): (1) the association between oxygenation mode and RV systolic performance (Tricuspid Annular Plane Systolic Excursion - TAPSE, and lateral Tissue Doppler imaging - TDI) and (2) the relationship between oxygenation mode and Length of hospital stay (LOS). Methods: Single-centre prospective observational study with consecutive enrolment of adult patients with severe CAP (PSI IV-V, according to ATS/IDSA - American Thoracic Society/Infectious Diseases Society of America - severity criteria) hospitalized in an internal medicine ward. The initial respiratory support strategy was selected in the emergency setting among NIV-PSV [Pressure Support Ventilation], HFNC, and Venturi Mask according to the patient's gas-exchange and acid-base profile; complete transthoracic echocardiography was then performed on ward admission while patients remained on the initially assigned device and settings, before any ward-driven modification of respiratory settings. The diagnostic etiological work-up comprised blood and sputum samples for cultures and multiplex nasopharyngeal viral/atypical PCR assays. Results: A total of 70 patients were enrolled (NIV = 21, HFNC = 22, Venturi mask = 27). All patients had bilateral multilobar consolidations and pleural effusions. The predominant etiology was viral/atypical bacteria: human metapneumovirus A/B (30%), rhinovirus (30%), HPIV - Human parainfluenza virus − (20%), Mycoplasma pneumoniae (20%). RV systolic parameters significantly varied between oxygenation modalities (p < 0.001). Patients on NIV showed the worst RV performance (TAPSE 1.16 ± 0.19 cm; TDI 6.02 ± 0.73 cm/s), while patients on a Venturi mask had better RV systolic performance (TAPSE 1.74 ± 0.33 cm; TDI 10.12 ± 2.28 cm/s). LOS was considerably longer in NIV and HFNC patients than in Venturi mask patients (28.4 ± 3.0 vs 27.4 ± 2.9 vs 14.7 ± 3.7 days; p < 0.001). In multivariate linear regression analysis, age and pattern of respiratory support (NIV/HFNC vs Venturi) were both independently associated with prolonged LOS. Conclusions: In this cohort, pressure-generating respiratory support modalities were associated with poorer RV systolic indices and longer hospitalization. Because the study specifically evaluated RV systolic function - and not RV failure or RV-pulmonary artery uncoupling - and because echocardiography was performed after respiratory support had already been selected and started, these findings should be interpreted as hypothesis-generating associations that may reflect both underlying disease severity and support-related haemodynamic effects.