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Few reports have studied lung aeration and perfusion in normal lungs, COVID-19, and ARDS from other causes (NC-ARDS) using dual-energy computed tomography pulmonary angiograms (DE-CTPA). To describe lung aeration and blood-volume distribution using DE-CTPAs of patients with NC-ARDS, COVID-19, and controls with a normal DE-CTPA ("healthy lungs"). We hypothesized that each of these conditions has unique ranges of aeration and pulmonary blood volumes. This retrospective, single-center study of DE-CTPAs included patients with COVID-19, NC-ARDS (Berlin criteria), and controls. Patients with macroscopic pulmonary embolisms were excluded. The outcomes studied were the (1) lung blood-volume in areas with different aeration levels (normal, ground glass opacities [GGO], consolidated lung) and (2) aeration/blood-volume ratios. Included were 20 patients with COVID-19 (10 milds, 10 moderate-severe), six with NC-ARDS, and 12 healthy-controls. Lung aeration was lowest in patients with severe COVID-19 24% (IQR13%–31%) followed by those with NC-ARDS 40%(IQR21%–46%). Blood-volume in GGO was lowest in patients with COVID-19 [moderate-severe:-28.6 (IQR-33.1–23.2); mild: -30.1 (IQR-33.3–23.4)] and highest in normally aerated areas in NC-ARDS -37.4 (IQR-52.5–30.2-) and moderate-severe COVID-19 -33.5(IQR-44.2–28.5). The median aeration/blood-volume ratio was lowest in severe COVID-19 but some values overlapped with those observed among patients with NC-ARDS. Severe COVID-19 disease is associated with low total aerated lung volume and blood-volume in areas with GGO and overall aeration/blood volume ratios, and with high blood volume in normal lung areas. In this hypothesis-generating study, these findings were most pronounced in severe COVID disease. Larger studies are needed to confirm these preliminary findings. [ABSTRACT FROM AUTHOR]

Background: The association between night/after-hours surgery and patients' mortality is unclear.Methods: The protocol of this systematic review was registered in PROSPERO (CRD42019128534). We searched Medline, PubMed, and EMBASE from inception until August 29, 2019 for studies examining an association between timing of surgical procedures (time of anaesthesia induction or surgery start) and mortality (within 30 days or in-hospital) in adult patients. Studies reporting patients' mortality after surgery performed during the weekend only were excluded. All analyses were done using the random-effects model.Results: We included 40 observational studies (36 retrospective and four prospective) that examined a total of 2 957 065 patients. Twenty-eight studies were judged of good quality and 12 of poor quality according to Newcastle-Ottawa score, owing to a lack of adequate comparability between study groups. Primary analysis from adjusted estimates demonstrated as association between night/after-hours surgery and a higher risk of mortality (odds ratio [OR]=1.16; 95% confidence interval [CI], 1.06-1.28; P=0.002; number of studies=18; I2=67%) based on low certainty evidence. Analysis from unadjusted estimates demonstrated a consistent association (OR=1.47; 95% CI, 1.19-1.83; P=0.0005; studies=38, I2=97%; low certainty). The number of centres per study had no credible subgroup effect on the association between the time of surgery and mortality. We were unable to evaluate the subgroup effect of urgency of surgery because of high heterogeneity.Conclusions: Night/after-hours surgery may be associated with a higher risk of mortality. Patients' and surgical characteristics seem not to completely explain this finding. However, the certainty of the evidence was low. [ABSTRACT FROM AUTHOR]