Evaluation of Variable Pressure Support Ventilation in the Therapy of Acute Lung Injury

Evaluation of Variable Pressure Support Ventilation in the Therapy of Acute Lung Injury (EVA-Trial)

Variable pressure support during assisted spontaneous breathing (noisy PSV) has been shown to improve the respiratory function in experimental acute lung injury (ALI). We aimed at comparing the effects of noisy PSV with traditional PSV on the respiratory function of patients suffering from ALI.

Inclusion Criteria:

• age 18 to 75 yrs
• 150 mmHg < PaO2/FIO2 < 300 mmHg
• mechanical ventilation with PSV or BIPAP
• less than 15 days of mechanical ventilation
• at least 20% of minute ventilation originated from spontaneous breathing

Exclusion Criteria:

• BMI > 35
• esophageal disease
• neuromuscular disease
• instable thorax
• pneumothorax
• head trauma
• brain injury
• increased intracranial pressure
• agitation
• increased need for vasoactive drugs
• chronic lung disease
• acute coronary disease
• participation in another clinical trial within the last 4 weeks at enrollment

Interruption criteria:

• acute change of mental status
• SaO2 < 92%
• pHa < 7.30
• respiratory rate > 30 or < 6 /min
• dyspnea
• diaphragm/thorax antagonism
• diaphoresis
• abnormal use of respiratory muscles
• increase of the heart rate above 120% of baseline or absolute value < 60 or > 130 /min
• mean arterial pressure above 120% of baseline or absolute value < 70 or > 110 mmHg