Background: The awake prone positioning strategy for patients with acute respiratory distress syndrome is a safe, simple and cost-effective technique used to improve hypoxaemia. We aimed to evaluate intubation and mortality risk in patients with coronavirus disease 2019 (COVID-19) who underwent awake prone positioning during hospitalisation.Methods: In this retrospective, multicentre observational study conducted between 1 May 2020 and 12 June 2020 in 27 hospitals in Mexico and Ecuador, nonintubated patients with COVID-19 managed with awake prone or awake supine positioning were included to evaluate intubation and mortality risk through logistic regression models; multivariable and centre adjustment, propensity score analyses, and E-values were calculated to limit confounding.Results: 827 nonintubated patients with COVID-19 in the awake prone (n=505) and awake supine (n=322) groups were included for analysis. Fewer patients in the awake prone group required endotracheal intubation (23.6%versus40.4%) or died (19.8%versus37.3%). Awake prone positioning was a protective factor for intubation even after multivariable adjustment (OR 0.35, 95% CI 0.24–0.52; p<0.0001, E=2.12), which prevailed after propensity score analysis (OR 0.41, 95% CI 0.27–0.62; p<0.0001, E=1.86) and mortality (adjusted OR 0.38, 95% CI 0.26–0.55; p<0.0001, E=2.03). The main variables associated with intubation among awake prone patients were increasing age, lower baseline peripheral arterial oxygen saturation/inspiratory oxygen fraction ratio (PaO₂/FIO₂) and management with a nonrebreather mask.Conclusions: Awake prone positioning in hospitalised nonintubated patients with COVID-19 is associated with a lower risk of intubation and mortality.

Determine whether the levels of glycated hemoglobin (HbA1c) measured on admission to the intensive care unit (ICU) are associated with mortality in patients with severe SARS-CoV-2 pneumonia with invasive mechanical ventilation. Cohort study, retrospective, observational. A single center. ICU of a second-level care hospital. Severe SARS-CoV-2 pneumonia confirmed with IMV since admission to the ICU. none. A total of 56 patients with severe pneumonia, confirmed with SARS-CoV-2, all with IMV. The group with HbA1c 500 U/L, OR 3.65 (95% CI 1.18–11.29), HbA1c ≥6.5%, OR 3.12 (95% CI 1.01–9.6), SAH, OR 3.12 (95% CI 1.01–9.5), use of vasopressor, OR 0.2 (95% CI 0.05–0.73), diabetes was not statistically significant. The 28-day probability of survival in patients with severe SARS-CoV-2 pneumonia with IMV in the ICU is lower when the HbA1c level is ≥6.5% on admission.

Purpose: The awake prone position (PP) strategy for patients with acute respiratory distress syndrome (ARDS) is a safe, simple, and cost-effective technique used to improve hypoxemia. We aimed to evaluate the relationship between awake PP (AP) and endotracheal intubation in patients with coronavirus disease (COVID-19). Methods: In this retrospective, multicentre observational study conducted between 1 May and 12 June 2020 in 27 hospitals in Mexico and Ecuador, non-intubated patients with COVID-19 managed with AP or awake supine positioning (AS) were included to evaluate intubation and mortality risk in AP patients through logistic regression models; multivariable adjustment, propensity score analyses, and E-values were calculated to limit confounding. A CART model with cross-validation was also built. This study was registered at https://clinicaltrials.gov/ct2/show/NCT04407468 Results: 827 non-intubated patients with COVID-19 in the AP (n=505) and AS (n=322) groups were included for analysis. Less patients in the AP group required endotracheal intubation (23.6% vs 40.4%) or died (20% vs 37.9%). AP was a protective factor for intubation even after multivariable adjustment (OR=0.39, 95%CI:0.28-0.56, p<0.0001, E-value=2.01), which prevailed after propensity score analysis (OR=0.32, 95%CI:0.21-0.49, p<0.0001, E-value=2.21), and mortality (adjusted OR=0.38, 95%CI:0.25-0.57, p<0.0001, E-value=1.98). The main variables associated with PP failure in AP patients were age, lower SpO ₂ /FiO ₂ , and management with a non-rebreather mask. In the CART model, only two variables were used: SpO ₂ /FiO ₂ (F 97.7, p<0.001) and PP (X2 50.5, p<0.001), with an overall percentage of 75.2%. Conclusion: PP in awake hospitalised patients with COVID-19 is associated with a lower risk of intubation and mortality.

Background: Pulmonary atelectasis is present even before surgery in patients with obesity. No study has reported the prevalence of preoperative atelectasis in obese patients to date. We aimed to estimate the prevalence and extension of preoperative atelectasis in patients with obesity undergoing bariatric surgery and to determine if variation in preoperative SpO2 values in the seated position at room air is explained by the extent of atelectasis coverage in the supine position. Methods: Cross-sectional study in a single center specialized in laparoscopic bariatric surgery. Preoperative chest computed tomographies were reassessed by a senior radiologist to quantify the extent of atelectasis coverage as a percentage of total lung volume. Patients were classified as having atelectasis when the affection was ≥2.5%, to estimate the prevalence of atelectasis. Crude and adjusted prevalence ratios (PR) and odds ratios (OR) were obtained to assess the relative prevalence of atelectasis and percentage coverage, respectively, with increasing obesity category. Inverse probability weighting was used to assess the total, direct (not mediated), and indirect (mediated through atelectasis) effects of BMI on preoperative SpO2, and to quantify the magnitude of mediation (proportion mediated). Results: In 236 patients with a median BMI of 40.3 kg/m ² (IQR: 34.6–46.0, range: 30.0–77.3), the overall prevalence of atelectasis was 32.6% (95%CI: 27.0–38.9) and by BMI category: 30-35 kg/m ² , 12.7% (95%CI: 6.1–24.4); 35-40 kg/m ² , 28.3% (95%CI: 17.2–42.6); 40-45 kg/m ² , 12.3% (95%CI: 5.5–24.3); 45-50 kg/m ² , 48.4% (95%CI: 30.6–66.6); and ≥50 units, 100% (95%CI: 86.7–100). Compared to the 30-35 kg/m ² group, only the categories with BMI ≥45 kg/m ² had significantly higher relative prevalence of atelectasis — 45-50 kg/m ² , aPR=3.52 (95%CI: 1.63–7.61) and ≥50 kg/m ² , aPR=8.0 (95%CI: 4.22–15.2) — and higher odds of greater atelectasis percentage coverage: 45–50 kg/m ² , aOR=7.5 (95%CI: 2.7–20.9) and ≥50 kg/m ² , aOR=91.5 (95%CI: 30.0–279.3). Atelectasis percent alone explained 70.2% of the variation in preoperative SpO2. The proportion of the effect of BMI on preoperative SpO2 values <96% mediated through atelectasis was 81.5% (95%CI: 56.0–100). Conclusions: The prevalence and extension of atelectasis increased with higher BMI, being significantly higher at BMI ≥45 kg/m ² . Preoperative atelectasis mediated the effect of BMI on SpO2 at room air in the seated position. The high prevalence of atelectasis before surgery and their impact on SpO2 could be important factors to consider when deciding ventilation strategies during surgery and for the interpretation of the clinical significance of postoperative atelectasis. Key points: Question: What is the prevalence of preoperative atelectasis in patients undergoing bariatric surgery and are changes in the preoperative peripheral saturation of oxygen (SpO2) at room air in the seated position explained by the extent of atelectasis coverage on chest CT in the supine position? Findings: Preoperative atelectasis were highly prevalent (32.6%, 95%CI: 27.0–38.9) in patients with obesity and a BMI above 45 kg/m ² was associated with a higher relative prevalence and atelectasis percentage coverage, the latter of which alone explained 70.2% of the variation in SpO2, with 81.5% (95%CI: 56.0-100) of the effect of BMI on SpO2 <96% mediated through atelectasis. Meaning: Pulmonary atelectasis are detectable before surgery in obese patients and largely explain decreased preoperative SpO2 values, which could be an important factor to consider when interpreting postoperative atelectasis and for deciding perioperative ventilation strategies.

Background: The role of the ratio between the arterial partial pressure of oxygen and the inspired fraction of oxygen (PaO₂/FiO₂ ratio) during the change in position is not fully established. Methods: This retrospective, single-center cohort study included 98 patients with severe COVID-19 pneumonia. Objective: This study aimed to evaluate the predictive value of the PaO₂/FiO₂ ratio for survival in patients with severe COVID-19 pneumonia between changing from supine to prone positions and vice versa. The PaO₂/FiO₂ ratio was measured preproning (T0), 30 min to 1 hour (T1), and 48 h after prone positioning (T2), and 30 min to 1 h after re-supination (T3). Results: The PaO₂/FiO₂ ratio at T2 and T3 was higher in the survivors than in the non-survivors (T2= 251.5 vs. 208.5, p= 0.032; T3= 182 vs. 108.5, p<0.001). The PaO₂/FiO₂ ratio at T3 was an independent protective factor (Hazard Ratio (HR)= 0.993; 95% Confidence Interval (CI)= 0.989-0.998; p= 0.006) for survival. A threshold of ≤129 for the PaO₂/FiO₂ ratio at T3 predicted non-survival with a sensitivity and specificity of 67.86 and 80.95, respectively (Area Under the Curve (AUC)= 0.782; 95% CI 0.687-0.859). Conclusion: The PaO₂/FiO₂ ratio is a significant protective factor of survival in severe COVID-19 pneumonia within 30 min-1 hour after returning to the supine position (re-supination).