Brief Outline of the Trial

The OSCAR Trial is a multicentre, randomised controlled trial (RCT) comparing conventional positive pressure ventilation with high frequency oscillatory ventilation (HFOV) for adults with acute respiratory distress syndrome (ARDS). The trial is funded by the Health Technology Assessment programme and sponsored by the University of Oxford.

The trial is taking place in12 Adult Intensive Care Units (ICUs) in the NHS in the United Kingdom able to care for Level 3 patients. A total of 802 patients will be recruited over a three year period, recruitment started in November 2007.

Patients are eligible for the trial if they meet the following inclusion criteria:

• Age ≥16 years
• Weight ≥35kg
• Receiving artificial ventilation via an endotracheal or tracheostomy tube
• Have acute hypoxaemic respiratory failure as defined by:
• Lowest recorded PaO2/FiO2 ratio measured between onset of artificial ventilation and time of screening of ≤ 26.7 kPa with apositive end expiratory pressure (PEEP) ≥ 5 cmH20
• Bilateral infiltrates on chest radiograph
• Will not be extubated by tomorrow evening (predicted byattending clinician)
• Have been mechanically ventilated for LESS than 7 consecutive days (≤ 168 hours) at the point of randomisation
• The PaO2/FiO2 ratio ≤26.7kPa is a definition of ARDS agreed at theAmerican-European consensus conference on ARDS in 1994.

Patients in the ICU with acute respiratory distress syndrome are identified and (if meet the inclusion criteria and consent obtained), are randomised to receive either;

Treatment A: Conventional positive pressure ventilation, or
Treatment B: High frequency oscillatory ventilation. 

The primary outcome is mortality at 30 days after randomisation.  An economic analysis is being carried out. 

The control group will be ventilated using conventional positive pressure ventilation using pressure-controlled artificial ventilation. The intervention group will receive high frequency oscillatory ventilation. 

After discharge from the ICU patients are followed up by postal questionnaire.  The first is sent six months after entry to the trial. The questionnaire asks how the patients’ breathing is affecting day-to-day activities, and about general health.   We will also send a questionnaire after 12 months.  We may send up to three more questionnaires, again spaced six month apart.   

The OSCAR Trial Protocol has full details. To request a copy email us: oscar.trial@nda.ox.ac.uk. For a Summary Protocol click here