Vaccination

Some Good News The available data have consistently shown high levels of short-term protection by vaccines against coronavirus disease 2019 (COVID-19). Protection has also been demonstrated with respect to severe outcomes, including hospitalization and death. The duration of protection and the need for further doses remain unclear.

Paradoxical Positioning: Does "Head Up" Always Improve Mechanics and Lung Protection?

OBJECTIVES: Head-elevated body positioning, a default clinical practice, predictably increases end-expiratory transpulmonary pressure and aerated lung volume. In acute respiratory distress syndrome (ARDS), however, the net effect of such vertical inclination on tidal mechanics depends upon whether lung recruitment or overdistension predominates. We hypothesized that in moderate to severe ARDS, bed inclination toward vertical unloads the chest wall but adversely affects overall respiratory system compliance (C rs ). DESIGN: Prospective physiologic study. SETTING: Two medical ICUs in the United States. PATIENTS: Seventeen patients with ARDS, predominantly moderate to severe. INTERVENTION: Patients were ventilated passively by volume control. We measured airway pressures at baseline (noninclined) and following bed inclination toward vertical by an additional 15°. At baseline and following inclination, we manually loaded the chest wall to determine if C rs increased or paradoxically declined, suggestive of end-tidal overdistension. MEASUREMENTS AND MAIN RESULTS: Inclination resulted in a higher plateau pressure (supineΔ: 2.8 ± 3.3 cm H 2 O [ p = 0.01]; proneΔ: 3.3 ± 2.5 cm H 2 O [ p = 0.004]), higher driving pressure (supineΔ: 2.9 ± 3.3 cm H 2 O [ p = 0.01]; proneΔ: 3.3 ± 2.8 cm H 2 O [ p = 0.007]), and lower C rs (supine Δ: 3.4 ± 3.7 mL/cm H 2 O [ p = 0.01]; proneΔ: 3.1 ± 3.2 mL/cm H 2 O [ p = 0.02]). Following inclination, manual loading of the chest wall restored C rs and driving pressure to baseline (preinclination) values. CONCLUSIONS: In advanced ARDS, bed inclination toward vertical adversely affects C rs and therefore affects the numerical values for plateau and driving tidal pressures commonly targeted in lung protective strategies. These changes are fully reversed with manual loading of the chest wall, suggestive of end-tidal overdistension in the upright position. Body inclination should be considered a modifiable determinant of transpulmonary pressure and lung protection, directionally similar to tidal volume and positive end-expiratory pressure.

The US Strategic National Stockpile Ventilators in Coronavirus Disease 2019: A Comparison of Functionality and Analysis Regarding the Emergency Purchase of 200,000 Devices.

BACKGROUND: Early in the coronavirus disease 2019 (COVID-19) pandemic, there was serious concern that the United States would encounter a shortfall of mechanical ventilators. In response, the US government, using the Defense Production Act, ordered the development of 200,000 ventilators from 11 different manufacturers. These ventilators have different capabilities, and whether all are able to support COVID-19 patients is not evident. RESEARCH QUESTION: Evaluate ventilator requirements for affected COVID-19 patients, assess the clinical performance of current US Strategic National Stockpile (SNS) ventilators employed during the pandemic, and finally, compare ordered ventilators' functionality based on COVID-19 patient needs. STUDY DESIGN AND METHODS: Current published literature, publicly available documents, and lay press articles were reviewed by a diverse team of disaster experts. Data were assembled into tabular format, which formed the basis for analysis and future recommendations. RESULTS: COVID-19 patients often develop severe hypoxemic acute respiratory failure and adult respiratory defense syndrome (ARDS), requiring high levels of ventilator support. Current SNS ventilators were unable to fully support all COVID-19 patients, and only approximately half of newly ordered ventilators have the capacity to support the most severely affected patients; ventilators with less capacity for providing high-level support are still of significant value in caring for many patients. INTERPRETATION: Current SNS ventilators and those on order are capable of supporting most but not all COVID-19 patients. Technologic, logistic, and educational challenges encountered from current SNS ventilators are summarized, with potential next-generation SNS ventilator updates offered.