ABSTRACT
Rationale: Defining lung recruitability is needed for safe positive end-expiratory pressure (PEEP) selection in mechanically ventilated patients. However, there is no simple bedside method including both assessment of recruitability and risks of overdistension as well as personalized PEEP titration. Objectives: To describe the range of recruitability using electrical impedance tomography (EIT), effects of PEEP on recruitability, respiratory mechanics and gas exchange, and a method to select optimal EIT-based PEEP. Methods: This is the analysis of patients with coronavirus disease (COVID-19) from an ongoing multicenter prospective physiological study including patients with moderate-severe acute respiratory distress syndrome of different causes. EIT, ventilator data, hemodynamics, and arterial blood gases were obtained during PEEP titration maneuvers. EIT-based optimal PEEP was defined as the crossing point of the overdistension and collapse curves during a decremental PEEP trial. Recruitability was defined as the amount of modifiable collapse when increasing PEEP from 6 to 24 cm H2O (ΔCollapse24-6). Patients were classified as low, medium, or high recruiters on the basis of tertiles of ΔCollapse24-6. Measurements and Main Results: In 108 patients with COVID-19, recruitability varied from 0.3% to 66.9% and was unrelated to acute respiratory distress syndrome severity. Median EIT-based PEEP differed between groups: 10 versus 13.5 versus 15.5 cm H2O for low versus medium versus high recruitability (P < 0.05). This approach assigned a different PEEP level from the highest compliance approach in 81% of patients. The protocol was well tolerated; in four patients, the PEEP level did not reach 24 cm H2O because of hemodynamic instability. Conclusions: Recruitability varies widely among patients with COVID-19. EIT allows personalizing PEEP setting as a compromise between recruitability and overdistension. Clinical trial registered with www.clinicaltrials.gov (NCT04460859).
Subject(s)
COVID-19 , Respiratory Distress Syndrome , Humans , Electric Impedance , Prospective Studies , Lung/diagnostic imaging , Respiratory Distress Syndrome/diagnostic imaging , Respiratory Distress Syndrome/therapy , Tomography, X-Ray Computed/methods , Tomography/methodsSubject(s)
COVID-19/complications , Decompression/methods , Lung Diseases/diagnosis , Lung Diseases/physiopathology , Positive-Pressure Respiration/methods , Respiratory Distress Syndrome/diagnosis , Respiratory Distress Syndrome/therapy , COVID-19/physiopathology , Humans , Male , Middle Aged , Respiratory Distress Syndrome/etiology , Respiratory Distress Syndrome/physiopathology , SARS-CoV-2 , Treatment OutcomeABSTRACT
Despite its life-saving nature, invasive mechanical ventilation does not come without risk, and the avoidance of invasive mechanical ventilation is the primary goal of noninvasive respiratory support. Noninvasive respiratory support in the form of continuous or bi-level positive airway pressure were considered the only viable options to accomplish this for many years. Innovation and research have led to high-flow nasal cannula being added to the list of specialized therapies clinically shown to reduce escalation of care and intubation rates in patients presenting with acute respiratory failure. The amount of research being performed in this clinical space is impressive, to say the least, and it is rapidly evolving. It is the responsibility of the clinicians trained to use these therapies in the management of respiratory failure to understand the currently available evidence, benefits, and risks associated with the type of noninvasive respiratory support being used to treat our patients.