Correlation Between the Ratio of Oxygen Saturation to Fraction of Inspired Oxygen and the Ratio of Partial Pressure of Oxygen to Fraction of Inspired Oxygen in Detection and Risk Stratification of Pediatric Acute Respiratory Distress Syndrome

Respiratory failure (RF) is defined as the acute or chronic impairment of respiratory system function to maintain normal oxygen and CO2 values when breathing room air. ‘Oxygenation failure’ occurs when O2 partial pressure (PaO2) value is lower than the normal predicted values for age and altitude and may be due to ventilation/perfusion mismatch or low oxygen concentration in the inspired air. In contrast, ‘ventilatory failure’ primarily involves CO2 elimination, with arterial CO2 partial pressure (PaCO2) higher than 45 mmHg. The most common causes are exacerbation of chronic obstructive pulmonary disease (COPD), asthma, and neuromuscular fatigue, leading to dyspnoea, tachypnoea, tachycardia, use of accessory muscles of respiration, and altered consciousness. History and arterial blood gas analysis is the easiest way to assess the nature of acute RF and treatment should solve the baseline pathology. In severe cases mechanical ventilation is necessary as a ‘buying time’ therapy. The acute hypoxemic RF arising from widespread diffuse injury to the alveolar-capillary membrane is termed Acute Respiratory Distress Syndrome (ARDS), which is the clinical and radiographic manifestation of acute pulmonary inflammatory states.

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Neutrophil extracellular traps contribute to immunothrombosis in COVID-19 acute respiratory distress syndrome

Blood ◽

10.1182/blood.2020007008 ◽

2020 ◽

Vol 136 (10) ◽

pp. 1169-1179 ◽

Cited By ~ 105

Author(s):

Elizabeth A. Middleton ◽

Xue-Yan He ◽

Frederik Denorme ◽

Robert A. Campbell ◽

David Ng ◽

...

Keyword(s):

Acute Respiratory Distress Syndrome ◽

Respiratory Distress Syndrome ◽

Respiratory Distress ◽

Distress Syndrome ◽

Ex Vivo ◽

Neutrophil Extracellular Traps ◽

Dna Complexes ◽

Platelet Factor ◽

Extracellular Traps ◽

Fraction Of Inspired Oxygen

Abstract COVID-19 affects millions of patients worldwide, with clinical presentation ranging from isolated thrombosis to acute respiratory distress syndrome (ARDS) requiring ventilator support. Neutrophil extracellular traps (NETs) originate from decondensed chromatin released to immobilize pathogens, and they can trigger immunothrombosis. We studied the connection between NETs and COVID-19 severity and progression. We conducted a prospective cohort study of COVID-19 patients (n = 33) and age- and sex-matched controls (n = 17). We measured plasma myeloperoxidase (MPO)-DNA complexes (NETs), platelet factor 4, RANTES, and selected cytokines. Three COVID-19 lung autopsies were examined for NETs and platelet involvement. We assessed NET formation ex vivo in COVID-19 neutrophils and in healthy neutrophils incubated with COVID-19 plasma. We also tested the ability of neonatal NET-inhibitory factor (nNIF) to block NET formation induced by COVID-19 plasma. Plasma MPO-DNA complexes increased in COVID-19, with intubation (P < .0001) and death (P < .0005) as outcome. Illness severity correlated directly with plasma MPO-DNA complexes (P = .0360), whereas Pao2/fraction of inspired oxygen correlated inversely (P = .0340). Soluble and cellular factors triggering NETs were significantly increased in COVID-19, and pulmonary autopsies confirmed NET-containing microthrombi with neutrophil-platelet infiltration. Finally, COVID-19 neutrophils ex vivo displayed excessive NETs at baseline, and COVID-19 plasma triggered NET formation, which was blocked by nNIF. Thus, NETs triggering immunothrombosis may, in part, explain the prothrombotic clinical presentations in COVID-19, and NETs may represent targets for therapeutic intervention.

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Biomarkers of acute respiratory distress syndrome in adults hospitalised for severe SARS-CoV-2 infection in Tenerife Island, Spain

BMC Research Notes ◽

10.1186/s13104-020-05402-w ◽

2020 ◽

Vol 13 (1) ◽

Author(s):

Juan Marco Figueira Gonçalves ◽

José María Hernández Pérez ◽

Marco Acosta Sorensen ◽

Aurelio Luis Wangüemert Pérez ◽

Elena Martín Ruiz de la Rosa ◽

...

Keyword(s):

Acute Respiratory Distress Syndrome ◽

Respiratory Distress Syndrome ◽

Respiratory Distress ◽

Distress Syndrome ◽

Significant Negative Correlation ◽

Protein Levels ◽

Reactive Protein ◽

Infected Adult ◽

Tenerife Island ◽

Fraction Of Inspired Oxygen

Abstract Objective The dramatic spread of SARS-CoV-2 infections calls for reliable, inexpensive tools to quickly identify patients with a poor prognosis. In this study, acute respiratory distress syndrome (ARDS) was assessed within 72 h after admission of each of 153 consecutive, SARS-CoV-2 infected, adult patients to either of two hospitals in Tenerife, Spain, using suitable routine laboratory tests for lymphocyte counts, as well as ferritin, lactate dehydrogenase (LDH), and C-reactive protein levels. Results were correlated with the patients’ respiratory function, defined through their pulse oximetric saturation/fraction of inspired oxygen (SpO2/FiO2) ratio. Results Within 72 h from admission, criteria matched ARDS (SpO2/FiO2 < 235) in 13.1% of cases. We found a significant, negative correlation between SpO2/FiO2 ratios and d-dimer, ferritin, and LDH levels (− 0.31, − 0.32, and − 0.41; p = 0.004, 0.004, and < 0.0001, respectively). In patients with ARDS, the mean LDH was 373 U/L (CI95%: 300.6–445.3), but only 298 U/L (CI95%: 274.7–323.1) when they did not develop the syndrome (p = 0.015). None of the additionally evaluated biomarkers correlated with the SpO2/FiO2 ratios. Serum LDH levels in patients hospitalised for COVID-19 correlate with ARDS, as defined by their SpO2/FiO2 ratio, and might help to predict said complication.

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