Respiration Disorders, Respiratory Failure
Conditions
Keywords
Respiratory Therapy, Positive Pressure Respiration, Physical Therapy Modalities
Brief summary
Ventilator hyperinflation (VHI) has been shown to be effective in improving respiratory mechanics, secretion removal, and gas exchange in mechanically ventilated patients; however, there are no recommendations on the best ventilator settings to perform the technique. Thus, the aim of this study was to compare six modes of VHI, concerning physiological markers of efficacy and safety criteria, in order to support the optimal VHI settings selection for mechanically ventilated patients. In a randomized, controlled and crossover study, 30 mechanically ventilated patients underwent 6 modes of ventilator hyperinflation. The maximum expansion (tidal volume), expiratory flow bias criteria (inspiratory and expiratory flow patterns), overdistension (alveolar pressure), asynchronies and hemodynamic variables (mean arterial pressure and heart rate) were assessed during the interventions.
Detailed description
Background: Ventilator Hyperinflation (VHI) has been shown to be effective in improving respiratory mechanics, secretion removal, and gas exchange in mechanically ventilated patients; however, there are no recommendations on the best ventilator settings to perform the technique. Thus, the aim of this study was to compare six modes of VHI, concerning physiological markers of efficacy and safety criteria, in order to support the optimal VHI settings selection for mechanically ventilated patients. Methods: In a crossover study, every included mechanically ventilated patient underwent six modes of VHI in a randomized order: Volume Control Continuous Mandatory Ventilation (VC-CMV) with inspiratory flow = 20Lpm (VC-CMV20), VC-CMV with inspiratory flow = 50Lpm (VC-CMV50), Pressure Control Continuous Mandatory Ventilation (PC-CMV) with inspiratory time = 1s. (PC-CMV1), PC-CMV with inspiratory time = 3s. (PC-CMV3), Pressure Support Ventilation (PSV) with cycling off = 10% of peak inspiratory flow (PSV10), and PSV with cycling off = 25% of peak inspiratory flow (PSV25). The maximum expansion (tidal volume), expiratory flow bias criteria (inspiratory and expiratory flow patterns), over-distension (alveolar pressure), asynchronies and hemodynamic variables (mean arterial pressure and heart rate) were assessed during the interventions.
Interventions
OTHERVC-CMV20
Application of a ventilator hyperinflation intervention with Volume Control Continuous Mandatory Ventilation (VC-CMV). The inspiratory flow was set at 20Lpm and the tidal volume was increased in steps of 200mL until the peak airway pressure of 40cmH2O was achieved. After achieving the target pressure, this ventilatory regimen lasted 15 minutes. Positive end expiratory pressure and the inspired oxygen fraction were not modified.
OTHERVC-CMV50
Application of a ventilator hyperinflation intervention with Volume Control Continuous Mandatory Ventilation (VC-CMV). The inspiratory flow was set at 50Lpm and the tidal volume was increased in steps of 200mL until the peak airway pressure of 40cmH2O was achieved. After achieving the target pressure, this ventilatory regimen lasted 15 minutes. Positive end expiratory pressure and the inspired oxygen fraction were not modified.
OTHERPC-CMV1
Application of a ventilator hyperinflation intervention with Pressure Control Continuous Mandatory Ventilation (PC-CMV1). The inspiratory time was set at 1 second and the pressure control was increased until a peak pressure of 40cmH2O was achieved. After achieving the target pressure, this ventilatory regimen lasted 15 minutes. Positive end expiratory pressure and the inspired oxygen fraction were not modified.
OTHERPC-CMV3
Application of a ventilator hyperinflation intervention with Pressure Control Continuous Mandatory Ventilation (PC-CMV1). The inspiratory time was set at 3 seconds and the pressure control was increased until a peak pressure of 40cmH2O was achieved. After achieving the target pressure, this ventilatory regimen lasted 15 minutes. Positive end expiratory pressure and the inspired oxygen fraction were not modified.
OTHERPSV10
Application of a ventilator hyperinflation intervention with Pressure Support Ventilation (PSV). The cycling off was set at 10% of peak inspiratory flow and the pressure support was increased until a peak pressure of 40cmH2O was achieved. After achieving the target pressure, this ventilatory regimen lasted 15 minutes. Positive end expiratory pressure and the inspired oxygen fraction were not modified.
OTHERPSV25
Application of a ventilator hyperinflation intervention with Pressure Support Ventilation (PSV). The cycling off was set at 25% of peak inspiratory flow and the pressure support was increased until a peak pressure of 40cmH2O was achieved. After achieving the target pressure, this ventilatory regimen lasted 15 minutes. Positive end expiratory pressure and the inspired oxygen fraction were not modified.
Sponsors
Universidade Federal do Rio de Janeiro
Centro Universitário Augusto Motta
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
TREATMENT
Masking
SINGLE (Outcomes Assessor)
Eligibility
Sex/Gender
ALL
Age
18 Years to 65 Years
Healthy volunteers
No
Inclusion criteria
* Patients under mechanical ventilation for more than 48h
Exclusion criteria
* mucus hypersecretion (defined as the need for suctioning \< 2-h intervals), * absence of respiratory drive, * atelectasis, * severe bronchospasm, * positive end expiratory pressure \> 10cmH2O, * PaO2-FiO2 relationship \< 150, * mean arterial pressure \< 60mmHg, * inotrope requirement equivalent to \>15 ml/h total of adrenaline and noradrenalin, * intracranial pressure \> 20mmHg
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Peak inspiratory to expiratory flow ratio | Ten minutes after the onset of intervention. | Dichotomous variable, defined as achieving a peak inspiratory flow rate (PIFR) less than 90% of the peak expiratory flow rate (PEFR) |
| Peak expiratory flow higher than 40 Lpm | Ten minutes after the onset of intervention. | Dichotomous variable, defined as achieving a PEFR higher than 40 l/min |
| Difference between peak inspiratory and expiratory flows. | Ten minutes after the onset of intervention. | Dichotomous variable, defined as achieving a difference higher than 17Lpm. |
| Pulmonary expansion | Ten minutes after the onset of intervention. | Percentage of tidal volume above the normal tidal volume (estimated as 6mL/kg). |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Mean arterial pressure | Ten minutes after the onset of intervention. | Mean arterial pressure verified using the multi-parameter monitor. |
| Heart Rate | Ten minutes after the onset of intervention. | Heart rate verified using the multi-parameter monitor. |
Outcome results
None listed