Beatriz S Ribeiro1, Agnaldo J Lopes2, Sara L S Menezes3, Fernando S Guimarães4. 1. Rehabilitation Sciences Post Graduation Program, Augusto Motta University Center, Rio de Janeiro, RJ, Brazil. 2. Rehabilitation Sciences Post Graduation Program, Augusto Motta University Center, Rio de Janeiro, RJ, Brazil; Post-graduate Program in Medical Sciences, State University of Rio de Janeiro, Rio de Janeiro, Brazil. 3. Rehabilitation Sciences Post Graduation Program, Augusto Motta University Center, Rio de Janeiro, RJ, Brazil; Physical Therapy Department, Federal University of Rio de Janeiro, RJ, Brazil. 4. Rehabilitation Sciences Post Graduation Program, Augusto Motta University Center, Rio de Janeiro, RJ, Brazil; Physical Therapy Department, Federal University of Rio de Janeiro, RJ, Brazil. Electronic address: fguimaraes_pg@yahoo.com.br.
Abstract
BACKGROUND:Ventilator hyperinflation (VHI) is effective in improving respiratory mechanics, secretion removal, and gas exchange in mechanically ventilated subjects; however, there are no recommendations for the best ventilator settings to perform the technique. OBJECTIVE: To compare six modes of VHI, concerning physiological markers of efficacy and safety criteria to support the selection of optimal settings. METHODS:Thirty mechanically ventilated patients underwent six modes of VHI in a randomized order. The delivered volume, expiratory flow bias criteria, overdistension, patient-ventilator asynchronies and hemodynamic variables were assessed during the interventions. RESULTS:Volume-controlled ventilation with inspiratory flow of 20 lpm (VC-CMV20) and pressure support ventilation (PSV) achieved the best effectiveness scores (P < 0.05). The target peak pressure of 40 cmH2O was associated with a high incidence of overdistension. PSV showed a lower incidence of patient-ventilator asynchronies. CONCLUSIONS: The modes VC-CMV20 and PSV are the most effective for VHI. Alveolar overdistension and patient-ventilator asynchronies must be considered when applying VHI.
RCT Entities:
BACKGROUND: Ventilator hyperinflation (VHI) is effective in improving respiratory mechanics, secretion removal, and gas exchange in mechanically ventilated subjects; however, there are no recommendations for the best ventilator settings to perform the technique. OBJECTIVE: To compare six modes of VHI, concerning physiological markers of efficacy and safety criteria to support the selection of optimal settings. METHODS: Thirty mechanically ventilated patients underwent six modes of VHI in a randomized order. The delivered volume, expiratory flow bias criteria, overdistension, patient-ventilator asynchronies and hemodynamic variables were assessed during the interventions. RESULTS: Volume-controlled ventilation with inspiratory flow of 20 lpm (VC-CMV20) and pressure support ventilation (PSV) achieved the best effectiveness scores (P < 0.05). The target peak pressure of 40 cmH2O was associated with a high incidence of overdistension. PSV showed a lower incidence of patient-ventilator asynchronies. CONCLUSIONS: The modes VC-CMV20 and PSV are the most effective for VHI. Alveolar overdistension and patient-ventilator asynchronies must be considered when applying VHI.