Comparison Between Different Ventilator Hyperinflation Maneuvers

Comparison Between Different Ventilator Hyperinflation Maneuvers

The hyperinflation ventilator was performed in different modalities and ventilatory adjustments, with total pressure of 40cmH2O. The inspiratory volume, inspiratory time, mean airway pressure, inspiratory and expiratory flow, and bias flow were evaluated.

PURPOSE: To compare different ways of applying ventilator hyperinflation. METHODS: A randomized crossover clinical trial was performed with 30 patients (66.5 ± 17.3 years) with hypersecretion. The ventilator hyperinflation was performed in five ventilatory modalities for five minutes, with an interval of 2 hours, the order being determined by randomization: controlled ventilation at volume (VCV) with constant flow of 20 (VCV20) Lpm and 40 Lpm (VCV40), controlled ventilation pressure ventilation (PCV), controlled pressure ventilation associated with inspiratory time adjustment (PCV + Tins) and support pressure ventilation (PSV). In VCV mode, the volume was increased every 50mL, until reaching a maximum pressure of 40cmH2O. In the pressure controlled modes, the inspiratory pressure was increased every 5 cmH2O until the total pressure reached 40 cmH2O. The inspiratory time was adjusted so that the inspiratory flow reached the baseline. The following variables were evaluated: tidal volume, inspiratory time (Tins), mean airway pressure (Pmean), peak inspiratory flow (PIFR) and expiratory flow (PEFR), PIFR / PEFR and Bias Flow (PEFR-PIFR).

Inclusion Criteria:

• Pulmonary infection
• Mechanically ventilated for more than 96 hours through pressure-assisted ventilation (PSV) or pressure-controlled ventilation (PCV)
• Static compliance between 30 and 70 mL/cmH2O
• PEEP between 5 and 8 cmH2O.

Exclusion Criteria:

• Hemodynamic instability
• Non-drained pleural effusion or pneumothorax
• Intracranial hypertension
• Bronchospasm
• Adult respiratory distress syndrome (ARDS)
• Decompensated congestive heart failure