mechanical ventilation strategy for coronavirus disease 2019 (covid-19)

Conditions: Respiratory Distress Syndrome; Mechanical Ventilation; SARS (Severe Acute Respiratory Syndrome)

Summary: this is a prospective, randomized, single-center, open-label controlled trial, designed to compare the efficacy of two ventilation strategies (low tidal volume and positive end-expiratory pressure (peep) based on the acute respiratory distress syndrome (ards) network low peep-fraction of inspired oxygen inspired oxygen fraction (fio2) table versus low driving pressure and peep guided by electrical impedance tomography (eit) in reducing daily lung injury score in patients with acute respiratory distress syndrome caused by covid-19. the two strategies incorporate different prioritizations of clinical variables. the peep-fio2 table strategy aims to reduce lung overdistension, even if it requires tolerating worse gas exchange. eit-guided strategy prioritizes mechanical stress protection, avoiding alveolar overdistension and collapse.

mechanical ventilatory strategy of the ards network low peep-fio2 table will be followed in the control arm. this strategy consists of at least 12 hours of controlled mechanical ventilation following prespecified peep and fio2 combinations chosen dynamically targeting oxygenation. tidal volume is set at 4-6 ml/kg of predicted body weight (pbw) and plateau pressure is kept below 30 centimeters of water (cmh2o). respiratory rate can be as high as 35 breaths per minute titrated to a potential of hydrogen (ph) 7.30-7.45. as oxygenation improves, patients are transitioned to assisted ventilation and then to pressure support ventilation until they are ready to be liberated from the ventilator. during this phase, no attempt is made to control plateau pressures or tidal volumes. in the intervention arm, minimizing tidal lung strain by keeping driving pressure below 16 cmh2o throughout the mechanical ventilation period will be targeted. the controlled phase will last at least 48 hours. peep will be selected according to a peep titration maneuver with eit at the start of the intervention. this peep level will be kept until extubation. respiratory rate can be as high as 50 breaths per minute targeting a ph of 7.15-7.45.

Eligibility criteria:
inclusion criteria: patients under mechanical ventilation with ards (berlin definition) caused by sars-cov2 infection: * ards diagnosis in less than 24 hours * respiratory system compliance of 0.6 ml/cmh2o/kg of pbw exclusion criteria: * age \< 18 years * active bronchopleural fistula * history of chronic and disabling respirator disease, requiring home oxygen treatment * chronic pulmonary arterial hypertension (pulmonary artery systolic pressure \> 40 mmhg) * huge intrathoracic tumoral mass * electrical impedance tomography monitoring contraindications (as thoracic wounds or burns, electronic implantable devices) * hemodynamic instability (systolic pressure \< 80 mmhg or mean arterial pressure \< 60 mmhg, despite vasopressor drugs; and/or heart rate \< 55bpm) - this patient may be included after recovered from hemodynamic instability * not drained pneumothorax or subcutaneous emphysema or bronchopleural fistula * patients at risk of intracranial hypertension development or post cardiopulmonary resuscitation (first 72 hours) * pregnancy * impossibility of monitoring with eit * not committed to full support or life expectation \< 24 hours * legal responsible or clinical team refusal to participate in the study.