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/methodsABSTRACT
INTRODUCTION: Electrical impedance tomography (EIT) is a noninvasive, radiation-free, bedside tool to monitor ventilation distribution in real time. OBJECTIVE: To evaluate, in pediatric COVID-19 patients, the ventilation distribution using EIT and compare it to thoracic computed tomography (TCT) or chest radiograph results obtained in these patients. METHODS: This was a prospective, observational clinical study including pediatric patients admitted to the intensive care unit of a private hospital. The patients monitored with EIT tested positive for COVID-19 and were submitted to the previously mentioned radiation exams. EIT monitoring lasted 15 min and no sedation was used. RESULTS: Six patients were included in this study. The main differences observed in the EIT were in the right-left distribution and were compatible with the morphological changes found in the TCT or radiograph images due to COVID-19 infection. CONCLUSION: We conclude that EIT is ready to investigate the ventilatory profile present at different lung diseases, including COVID-19, and might postpone or mitigate the need of repeated ionizing radiation exams in the pediatric population, although larger pediatric cohorts comparing to standard radiological imaging are needed.