Ventilação mecânica protetora nos pacientes com suspeita de infecção pelo vírus influenza

Abstract

Most patients with acute respiratory failure due to influenza require ventilatory support. However, mechanical ventilation itself can exacerbate lung damage and increase mortality. The aim of this study was to evaluate the effects of the protective mechanical ventilation strategy in patients with suspected influenza respiratory infection. This is a study with a retrospective and prospective approach carried out in the intensive care unit and in the emergency room of the HC/UFTM branch EBSERh, in Uberaba - MG. Retrospectively, we identified the mechanical ventilation strategies usually adopted in patients with suspected respiratory infection by influenza during the first seven days of orotracheal intubation, in the years 2015, 2016 and 2017 at HC / UFTM branch EBSERh and evaluated the data of lung necropsies of the patients who died in the medical records analyzed. Prospectively implemented a protective mechanical ventilation protocol independent of sophisticated equipment, based on minimizing collapse and alveolar hyperdistension. Seeking to clarify which mechanical ventilation strategies would be appropriate for suspected cases of influenza, a systematic literature review was carried out in order to answer the question: the protective strategy of mechanical ventilation with a tidal volume limitation and alveolar recruitment maneuver on Severe Acute Respiratory Syndrome (SARS) for Influenza would be able to reduce the duration of mechanical ventilation and increase survival in 28 days in this population? In the retrospective phase, 60 medical records were identified for patients with notification of SARS due to suspected influenza in the years 2015, 2016 and 2017, however, 40 were excluded. Of the 16 cases that died, autopsies were performed on eight individuals. It was possible to verify that the ventilation strategy found during the first 7 days was characterized using high tidal volumes and high values of inspired oxygen fraction. Furthermore, in the autopsy assessments, neutrophilic infiltration was observed in 37.5% of the cases, a finding that may be the result of hyperdistension and collapse caused by large volumes and high inspiratory pressures or also from overlapping bacterial infection. In the prospective phase, four patients underwent the protocol. Initial improvement in oxygenation and respiratory mechanics was observed in all cases. However, our results indicate that the applied mechanical ventilation strategy can be optimized. In the systematic review, the study population consisted of adult individuals diagnosed with severe acute respiratory syndrome due to Influenza, who received a protective strategy for mechanical ventilation with low tidal volumes and / or alveolar recruitment maneuver compared to any other strategy. The searches in the databases resulted in a meeting of a total of 408 references, however, only 1 article met the eligibility criteria. In the literature, the scarcity of articles on the protective ventilation strategy in ARDS secondary to influenza infection does not allow to conclude whether this strategy can reduce the time of mechanical ventilation and/or improving survival in this population. The literature needs more studies that allow robust conclusions.