RESUMO
The treatment of patients with COPD and chronic hypercapnic respiratory failure using noninvasive ventilation (NIV) is well established. A "deventilation syndrome" (DVS) has been described as acute dyspnea after cessation of NIV therapy. A systematic scoping review reporting according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) searching Embase was conducted in September 2021. A final manual search followed in February 2023. Literature synthesis was blinded using Rayyan by three different reviewers. A total of 2,009 studies were screened. Five studies met the eligibility criteria. Four articles presented original data. Three articles examined potential treatment options. Three studies were prospective; none were randomized. A total of 122 patients were included. DVS was defined differently in all studies. Seventy-four patients were identified to suffer from DVS (48 controls). Patients were evaluated by blood gas analysis, transcutaneous TcCO2 measurement, spirometry, whole-body plethysmography, respiratory muscle assessments, diaphragmatic electromyography, ultrasound, 6-min walk test, polysomnography, and questionnaires. Treatment approaches studied were minimization of "patient-ventilator asynchrony" (PVA) and use of pursed- lip breathing ventilation. Pathophysiological mechanisms discussed were PVA, high inspiratory positive airway pressure, hyperinflation, respiratory muscle impairment, and increased respiratory rates. Compared with controls, patients with DVS appeared to suffer from more severe airway obstruction, hyperinflation, and PaCO2 retention; worse exercise test scores; and poorer quality of life. The available evidence does not allow for definite conclusions about pathophysiological mechanisms, ethology, or therapeutic options. Future studies should focus on a consistent definition and possible pathomechanisms.
