Ewan C Goligher1,2,3, Laveena Munshi1,3, Neill K J Adhikari1,4, Maureen O Meade5,6, Carol L Hodgson7, Hannah Wunsch1,4, Elizabeth Uleryk8, Ognjen Gajic9, Marcelo P B Amato10, Niall D Ferguson1,2,11,3,12, Gordon D Rubenfeld1,4, Eddy Fan1,11,12. 1. 1 Interdepartmental Division of Critical Care Medicine. 2. 2 Department of Physiology, and. 3. 3 Division of Respirology, Department of Medicine, University Health Network and Mount Sinai Hospital, Toronto, Ontario, Canada. 4. 4 Department of Critical Care, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada. 5. 5 Department of Medicine and. 6. 6 Department of Epidemiology and Biostatistics, McMaster University, Hamilton, Ontario, Canada. 7. 7 Australian and New Zealand Intensive Care Research Centre, Department of Epidemiology and Preventative Medicine, Monash University, Melbourne, Victoria, Australia. 8. 8 The Hospital for Sick Children, Toronto, Ontario, Canada. 9. 9 Department of Internal Medicine, Division of Pulmonary and Critical Care Medicine, Mayo Clinic College of Medicine, Rochester, Minnesota. 10. 10 Cardio-Pulmonary Department, Pulmonary Division, Heart Institute (Incor), University of São Paulo, São Paulo, Brazil; and. 11. 12 Institute for Health Policy, Management and Evaluation, University of Toronto, Toronto, Ontario, Canada. 12. 11 Department of Medicine, Division of Respirology, University Health Network, Toronto, Ontario, Canada.
Abstract
RATIONALE: By minimizing tidal lung strain and maintaining alveolar recruitment, high-frequency oscillatory ventilation (HFOV) may protect against ventilator-induced lung injury. OBJECTIVES: To summarize the current evidence in support of the use of HFOV in adult patients with acute respiratory distress syndrome. METHODS: We conducted a systematic review and meta-analysis of randomized trials comparing mortality rates with the use of HFOV versus conventional mechanical ventilation for adult patients with acute respiratory distress syndrome. Eligible trials were identified from previously published systematic reviews and an updated literature search. Data on 28-day mortality, oxygenation, adverse events, and use of rescue therapies were collected; effects were pooled using random effects models weighted by inverse variance. Strength of evidence was assessed using Grading of Recommendations Assessment, Development, and Evaluation methodology. RESULTS: Six trials were eligible for inclusion (total n = 1,715 patients). Four trials mandated lung-protective ventilation in the control group and one trial applied a higher positive end-expiratory pressure (PEEP) ventilation strategy in the control group. None of the trials were judged to be at high risk of bias, though all were unblinded. In trials that did not systematically employ any cointerventions with HFOV and that targeted low tidal volumes in the patients randomized to conventional ventilation (primary analysis), HFOV had no significant effect on mortality (three trials; risk ratio [RR], 1.14; 95% confidence interval [CI], 0.88 to 1.48; evidence grade = high). Pooled analysis of all six trials also did not suggest a significant mortality reduction (RR, 0.94; 95% CI, 0.71 to 1.24; evidence grade = low). The single trial that employed a conventional ventilation strategy with both lower tidal volumes and higher PEEP as control reported higher mortality in patients receiving HFOV (RR, 1.41; 95% CI, 1.12 to 1.79). HFOV was not associated with improved oxygenation after 24 hours (five trials; mean increase of 10 mm Hg; 95% CI, -16 to 37 mm Hg). Rates of barotrauma were not different between HFOV and conventional ventilation, although significant benefit or harm could not be excluded (RR, 1.15; 95% CI, 0.61 to 2.17). CONCLUSIONS: Published randomized trials suggest that HFOV is not associated with a mortality benefit, and may even be harmful in comparison to ventilation with low tidal volumes and higher levels of PEEP.
RATIONALE: By minimizing tidal lung strain and maintaining alveolar recruitment, high-frequency oscillatory ventilation (HFOV) may protect against ventilator-induced lung injury. OBJECTIVES: To summarize the current evidence in support of the use of HFOV in adult patients with acute respiratory distress syndrome. METHODS: We conducted a systematic review and meta-analysis of randomized trials comparing mortality rates with the use of HFOV versus conventional mechanical ventilation for adult patients with acute respiratory distress syndrome. Eligible trials were identified from previously published systematic reviews and an updated literature search. Data on 28-day mortality, oxygenation, adverse events, and use of rescue therapies were collected; effects were pooled using random effects models weighted by inverse variance. Strength of evidence was assessed using Grading of Recommendations Assessment, Development, and Evaluation methodology. RESULTS: Six trials were eligible for inclusion (total n = 1,715 patients). Four trials mandated lung-protective ventilation in the control group and one trial applied a higher positive end-expiratory pressure (PEEP) ventilation strategy in the control group. None of the trials were judged to be at high risk of bias, though all were unblinded. In trials that did not systematically employ any cointerventions with HFOV and that targeted low tidal volumes in the patients randomized to conventional ventilation (primary analysis), HFOV had no significant effect on mortality (three trials; risk ratio [RR], 1.14; 95% confidence interval [CI], 0.88 to 1.48; evidence grade = high). Pooled analysis of all six trials also did not suggest a significant mortality reduction (RR, 0.94; 95% CI, 0.71 to 1.24; evidence grade = low). The single trial that employed a conventional ventilation strategy with both lower tidal volumes and higher PEEP as control reported higher mortality in patients receiving HFOV (RR, 1.41; 95% CI, 1.12 to 1.79). HFOV was not associated with improved oxygenation after 24 hours (five trials; mean increase of 10 mm Hg; 95% CI, -16 to 37 mm Hg). Rates of barotrauma were not different between HFOV and conventional ventilation, although significant benefit or harm could not be excluded (RR, 1.15; 95% CI, 0.61 to 2.17). CONCLUSIONS: Published randomized trials suggest that HFOV is not associated with a mortality benefit, and may even be harmful in comparison to ventilation with low tidal volumes and higher levels of PEEP.