Clinical and Personal Predictors of Helmet-CPAP Use and Failure in Patients Firstly Admitted to Regular Medical Wards with COVID-19-Related Acute Respiratory Distress Syndrome (hCPAP-f Study).

Acute Respiratory Distress Syndrome (ARDS) caused by COVID-19 is substantially different from ARDS caused by other diseases and its treatment is dissimilar and challenging. As many studies showed conflicting results regarding the use of Non-invasive ventilation in COVID-19-associated ARDS, no unquestionable indications by operational guidelines were reported. The aim of this study was to estimate the use and success rate of Helmet (h) Continuous Positive Airway Pressure (CPAP) in COVID-19-associated ARDS in medical regular wards patients and describe the predictive risk factors for its use and failure. In our monocentric retrospective observational study, we included patients admitted for COVID-19 in medical regular wards. hCPAP was delivered when supplemental conventional or high-flow nasal oxygen failed to achieve respiratory targets. The primary outcomes were hCPAP use and failure rate (including the need to use Bilevel (BL) PAP or oro-tracheal intubation (OTI) and death during ventilation). The secondary outcome was the rate of in-hospital death and OTI. We computed a score derived from the factors independently associated with hCPAP failure. Out of 701 patients admitted with COVID-19 symptoms, 295 were diagnosed with ARDS caused by COVID-19 and treated with hCPAP. Factors associated with the need for hCPAP use were the PaO2/FiO2 ratio < 270, IL-6 serum levels over 46 pg/mL, AST > 33 U/L, and LDH > 570 U/L; age > 78 years and neuropsychiatric conditions were associated with lower use of hCPAP. Failure of hCPAP occurred in 125 patients and was associated with male sex, polypharmacotherapy (at least three medications), platelet count < 180 × 109/L, and PaO2/FiO2 ratio < 240. The computed hCPAP-f Score, ranging from 0 to 11.5 points, had an AUC of 0.74 in predicting hCPAP failure (significantly superior to Call Score), and 0.73 for the secondary outcome (non-inferior to IL-6 serum levels). In conclusion, hCPAP was widely used in patients with COVID-19 symptoms admitted to medical regular wards and developing ARDS, with a low OTI rate. A score computed combining male sex, multi-pharmacotherapy, low platelet count, and low PaO2/FiO2 was able to predict hCPAP failure in hospitalized patients with ARDS caused by COVID-19.

Overall contribution of chest wall hyperinflation to breathlessness in asthma.

BACKGROUND: Studies suggest that the increased volume of both abdominal and rib cage compartments of the chest wall contribute to dyspnea during methacholine-induced airway narrowing. MATERIAL: Eight male patients with asthma aged 34 +/- 13 years (mean +/- SD) before and during methacholine challenge. METHODS: The volume of the chest wall (Vcw), volume of the abdomen (Vab), and volume of the rib cage (Vrc) were measured by using a three-dimensional optoelectronic plethysmography. RESULTS: During methacholine challenge, the increase in end-expiratory Vcw (Vcw,ee) [0.55 +/- 0.23 L, p < 0.001] was due to increased Vrc (0.37 +/- 0.20 L, p < 0.01) and, to a lesser extent, Vab (0.18 +/- 0.10 L, p < 0.005). Linear univariate regression analysis showed that changes in dyspnea (Borg scale) with the highest methacholine dose correlated with both DeltaFEV(1) and DeltaVcw,ee. Multiple regression analysis with the Borg score as dependent variable and all other ventilatory indexes as independent variables showed that DeltaVcw,ee and DeltaFEV(1) were the only significant contributors to the Borg score. Taken together Vcw,ee and FEV(1) explained 56% of variance in the Borg score (r(2) = 0.56), although Vcw,ee explained 48% of it. CONCLUSIONS: During methacholine challenge in patients with asthma, the overall increase in Vcw,ee is a better predictor of dyspnea that the reduction in FEV(1).

Inspiratory capacity and decrease in lung hyperinflation with albuterol in COPD.

STUDY OBJECTIVES: Inspiratory capacity (IC) has been proposed as a simple method to assess acute changes in functional residual capacity (FRC) with bronchodilation, assuming that total lung capacity (TLC) is unchanged. This assumption is based on studies using body plethysmography, which may not accurately measure TLC in severely obstructed subjects. The aim of this study is to validate the use of IC measured by optoelectronic plethysmography (OEP) [ICOEP], a noninvasive technique capable of computing changes in absolute lung volumes with great accuracy. MEWTHODS AND MEASUREMENTS: We studied 13 subjects with COPD in clinically stable condition at baseline and after 200 microg of inhaled albuterol. Changes in lung volumes were obtained from changes in chest wall volume (Vcw) measured by OEP and were compared with those measured by standard techniques. RESULTS: Albuterol treatment caused a small but significant increase in FEV(1) and FVC, a significant decrease of Vcw at FRC (VcwFRC), but no changes of Vcw at TLC (VcwTLC) and breathing pattern variables. The reduction of VcwFRC was not correlated with either spirometric or breathing-pattern variables. IC measured with a pneumotachograph was highly correlated with and not significantly different from ICOEP (p < 0.001). CONCLUSIONS: A single dose of inhaled albuterol does not significantly modify VcwTLC in subjects with COPD, thus validating the use of IC to measure changes of FRC in the assessment of reversibility of airway obstruction.