High-frequency ventilation versus conventional ventilation for treatment of acute lung injury and acute respiratory distress syndrome.

backgroundHigh-frequency ventilation is often used to treat patients with acute lung injury (ALI) or acute respiratory distress syndrome (ARDS) but the effect of this treatment on clinical outcomes has not been well established.

objectivesThe objective of this review is to examine the effect of high-frequency ventilation compared with conventional ventilation as a therapy for ALI or ARDS in children (1 to 17 years old) and adults in order to quantify its effect on patient outcome (mortality, morbidity and other relevant outcomes). SEARCH STRATEGY: We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, issue 4, 2002), MEDLINE (1966 to October Week 5, 2002), EMBASE (1980 to Week 51, 2002), World Wide Web (www.controlled-trials.com, ARDS clinical network), and used Cited Reference Search (Web of Science 1988 to 2002, for specific reference lists of articles). We also contacted authors from each included trial, as well as manufacturers of high-frequency ventilators and other researchers in the field. SELECTION CRITERIA: Randomized controlled clinical trials of children and adults comparing treatment using high-frequency ventilation with conventional ventilation for patients diagnosed with ALI or ARDS. DATA COLLECTION AND ANALYSIS: Two reviewers independently assessed trial quality and extracted data. Study authors were contacted for additional information. MAIN

resultsTwo trials met the inclusion criteria for this review. One trial recruited children (including some children less than one year old) (n = 58) and the other recruited adults (n = 148). Both trials used a high-frequency oscillatory ventilator as the intervention and included variable use of lung-volume recruitment strategies. The intervention groups showed a trend towards lower 30 day mortality (children relative risk (RR) 0.83, 95% confidence interval (CI) 0.43 to 1.62; adults RR 0.72, 95% CI 0.50 to 1.03), although neither study showed a statistically significant difference. Similarly, there was no statistically significant difference between the intervention and control groups for 'Total length of ventilator days' (WMD) -2.00, 95% CI -18.36 to 14.36; and WMD 2.00, 95% CI -6.55 to 10.55 for the child and adult trials respectively). The studies used only proxies to measure long-term quality of life. There was a statistically significant reduction in the risk of requiring supplemental oxygen amongst survivors at 30 days in the paediatric study (RR 0.36, 95% CI 0.14 to 0.93). REVIEWER'S

conclusionsThere is not enough evidence to conclude whether high-frequency ventilation reduces mortality or long-term morbidity in patients with ALI or ARDS; further trials are needed.