Israel Medical Association Journal

Background: At the beginning of the coronavirus disease 2019 (COVID-19) pandemic, many patients presented with acute hypoxemic respiratory failure, requiring ventilatory support. One treatment method was the addition of a reservoir mask to a high flow nasal cannula (HFNC) (dual oxygenation).

Objectives: To evaluate the clinical outcomes of combining reservoir mask on top of a high-flow nasal cannula.

Methods: A retrospective cohort of adult patients who were admitted due to COVID-19 during the first year of the pandemic to Rambam Health Care Campus. The primary endpoint was 30-day mortality. Secondary endpoints were incidence of invasive positive pressure ventilation initiation and admission to the intensive care unit (ICU). Patients who received positive pressure ventilation for reasons other than hypoxemic respiratory failure or who were transferred to another facility while still on HFNC were excluded.

Results: The final analysis included 333 patients; 166 were treated with dual oxygenation and 167 with HFNC only (controls). No significant differences in baseline characteristics were noted between the groups. The dual oxygenation group was slightly older (69.2 ± 14.8 years vs. 65.6 ± 15.5 years, P = 0.034). The 30-day mortality (24.1% vs. 36.5%, P = 0.013), rates of invasive positive pressure ventilation (47% vs. 59.3%, P = 0.024), and ICU admissions (41.6% vs. 52.7%, P = 0.042) were all significantly lower in the dual oxygenation group.

Conclusions: The addition of reservoir masks to HFNC may improve the oxygenation and overall prognosis in patients with severe hypoxemia due to COVID-19.

Background: The identification of the etiology of a pleural effusion can be difficult. Measurement of serum B-type natriuretic peptide (BNP) levels is helpful in the diagnosis of congestive heart failure (CHF) as a cause of respiratory failure, but pleural fluid BNP measurement is still not part of the workup for pleural effusion.

Objectives: To identify the correlation between pleural fluid BNP levels and clinical diagnosis.

Methods: In this cross-sectional study, data from 107 patients admitted to the department of internal medicine between November 2009 and January 2015 were obtained from medical records. Patients underwent a diagnostic thoracocentesis as part of their evaluation. They were grouped according to final diagnosis at discharge and clinical judgment of the attending physician.

Results: Serum BNP levels were significantly higher in the CHF patients compared to patients with non-cardiac causes of pleural effusion (1519.2 and 314.1 respectively, P < 0.0001). Mean pleural fluid BNP was also significantly higher in the CHF patients (1063.2 vs. 208.3, P < 0.0001). Optional cutoff points to distinguish between cardiac and non-cardiac etiology of pleural effusion were 273.4 pg/ml (sensitivity 83.3%, specificity 72.3%, accuracy 76.7%) or 400 pg/ml (sensitivity 78.6%, specificity 86.2%, accuracy 83.0%). A strong correlation was found between serum BNP and pleural fluid BNP levels.

Conclusions: High levels of serum BNP in patients presenting with pleural effusion suggest CHF. In cases with doubt regarding the etiology of pleural effusion, high levels of pleural fluid BNP can support the diagnosis, but are not superior to serum BNP levels.