Objectives: To review the basic physiologic principles that support the role for high-frequency ventilation (HFV) in acutely lung-injured patients, to critically assess clinical trial data in this area, and discuss why a metasummary is not feasible and a large-scale clinical trial is needed.
Data sources: We searched a computerized database (MEDLINE) from 1976 to January 1997 using the text words "high-frequency ventilation" and "acute respiratory distress syndrome" to retrieve all relevant candidate articles.
Study selection: We retrieved all English language clinical studies conducted in tertiary care centers that employed HFV in adult acute respiratory distress syndrome (ARDS) patients.
Data extraction: Only prospective, randomized trials, cohort/case-control studies, and case series evaluating HFV vs. conventional mechanical ventilation in adult ARDS patients were included.
Data synthesis: We independently screened 3,166 articles on ARDS and 494 papers on HFV in our computer search. We checked reference lists and contacted experts in the field of mechanical ventilation in ARDS to ensure that no relevant studies had been missed. Only four articles met our inclusion criteria and were evaluated in detail.
Conclusions: Current clinical studies are statistically under-powered and a metasummary is not feasible because of study quality, as well as lack of similar clinical end points and measures of magnitude of benefit. A large, multicenter trial should be initiated to define the role of HFV in the treatment of adult ARDS.