Ventilator Hyperinflation With Increase of Inspiratory Time
Condition: Lung Infection; Mechanical Ventilation
MeSH terms: Respiratory Aspiration
Study type: Interventional

Summary: 
      The investigators hypothesis is that the adjustment of the inspiratory time may optimize the
      distribution of ventilation and increase tidal volume, producing potential therapeutic
      effects on the displacement of secretions and respiratory mechanics. The objective of this
      study was To evaluate the effects of hyperinflation with the ventilator associated with
      increased inspiratory time on respiratory mechanics.
    

Detailed description: 
      A randomized crossover clinical trial was conducted with 38 mechanically ventilated patients
      with pulmonary infection. The order of hyperinflation or control (without changes in
      parameters) was randomized. Hyperinflation was performed for 5 minutes in the controlled
      pressure ventilation mode, with progressive increases of 5cmH2O until reaching a maximum
      pressure of 35cmH2O, maintaining PEEP. After reaching 35cmH2O, the inspiratory time and
      respiratory rate were adjusted so that the inspiratory and expiratory flows reached the
      baseline, respectively. Static compliance (Cest, sr), total resistance (Rsr) and airway
      resistance (Rva), slow pressure drop (ΔP2) and peak expiratory flow (PEF) were assessed
      before (PRÉ), immediately after the maneuver (POSSimed) and after aspiration (POSPasp).
      Two-way ANOVA was used for repeated measurements with Tukey post-test, considering a
      significant p <0.05.
    

Intervention name(s): Ventilator hyperinflation
Intervention type(s): Other
Intervention description(s): The ventilator hyperinflation maneuver with inspiratory time adjustment was performed in the pressure controlled ventilation mode (PCV). The inspiratory pressure was increased gradually every 5 cmH2O until reaching a maximum pressure of 35 cmH2O, according to the tolerance of the patient determined by the absence of cough. PEEP remained unchanged throughout the study. After reaching a maximum pressure of 35 cmH2O (PCV + PEEP level), the inspiratory time was gradually increased until the inspiratory flow reached the baseline. Concomitantly, the respiratory rate was decreased to allow the expiratory flow also to reach the baseline, to avoid self-PEEP. The maneuver was performed for 5 min, followed by tracheal aspiration.
Allocation: Randomized
Intervention model: Crossover Assignment
Intervention model description: The VHI maneuver with inspiratory time adjustment was performed in the pressure controlled ventilation mode (PCV). The inspiratory pressure was increased gradually every 5 cmH2O until reaching a maximum pressure of 35 cmH2O, according to the tolerance of the patient determined by the absence of cough. PEEP remained unchanged throughout the study. The maneuver was performed for 5 min, followed by tracheal aspiration. To perform the control (CTRL), the patients were only positioned and aspirated, without alteration in ventilatory parameters.
Masking: None (Open Label)
Primary purpose: Treatment
Keywords: Physical Therapy Modalities,; Respiration Artificial,; Respiratory Care Units,; Respiratory Mechanics,; Positive-Pressure Respiration