Acute respiratory failure, refractory hypoxemia and mechanical ventilation. A review article.

Abstract

Acute respiratory distress syndrome (ARDS) or also known as respiratory distress, is an interruption of homeostasis at the alveolar level that can promote: hypoventilation, deterioration of diffusion, shunt and mismatch between ventilation - perfusion or a combination of both. Refractory hypoxemia is defined as a partial blood oxygen pressure measured by blood gas (PaO2) 60 mmHg or a divided oxygen blood pressure ratio for the oxygen inspiratory fraction, PaO2/FiO2 or (PAFI) 100. Mechanical ventilation is a necessary life support measure in the treatment of severe acute respiratory failure. General Objective: To determine the ventilatory management of patients with acute respiratory failure and refractory hypoxemia. Specific objectives: To evaluate the use of ECMO in refractory hypoxemia 2) To determine the usefulness of non-invasive mechanical ventilation, oxygen therapy and adjuvant therapy. METHODS: a systematic review of the literature according to the PRISMA 2020 declaration was carried out with articles from the last 5 years in the vast majority. Databases such as academic Google, Pubmed, IntechOpen, Mendeley, ScienceDirect, journals: JAMA, BMJ, critical care, NEJM, respiratory care were consulted: randomized studies, multicenter studies, clinical cases, review articles, meta-analysis, systematic review, guidelines, observational, descriptive, retrospective studies and consensus documents on the topics: acute respiratory failure, refractory hypoxemia and mechanical ventilation. RESULTS: Position in a prone position is of great importance during distress, as is support with extracorporeal circulation membrane, neuromuscular block and corticosteroids in the treatment of ARDS. As for the ventilatory strategies in this group of patients, intubation is the first step, via translaringea and connection to invasive mechanical ventilation, after which, we can apply the following strategies to improve oxygenation: Use of low Vt in volume-controlled ventilatory modes, low plateau pressures <30 in controlled modes that minimize barotrauma and low FiO2, to prevent oxygen-free radical-related injuries. Current evidence supports use of tidal volume (Vt) lower 6 ml/kg. DISCUSSION: Mechanical ventilatory management of the critical patient with acute respiratory failure presenting refractory hypoxemia includes evaluating oxygenation by PaO2/FiO2. the primary objective is to achieve adequate airway pressure values, apply low Vt, maintain an adequate plateau pressure and measure the conduction pressure to titrate the PEEP at the lowest possible value. Pronation is vital to improve oxygenation and airway pressures. The results of this research showed that, there is benefit of mechanical ventilation with the use of ECMO in this group of patients, in addition, it was determined that high flow oxygen therapy only decreases hypoxemia before intubation, without altering mortality. Dexamethasone, if it provides benefit, as adjuvant therapy in the treatment of acute respiratory failure, with refractory hypoxemia