ABSTRACT
BACKGROUND: Patients with the acute respiratory distress syndrome (ARDS) require artificial ventilation but this treatment may produce secondary lung damage. High-frequency oscillatory ventilation (HFOV) may reduce this damage. OBJECTIVES: To determine the clinical benefit and cost-effectiveness of HFOV in patients with ARDS compared with standard mechanical ventilation. DESIGN: A parallel, randomised, unblinded clinical trial. SETTING: UK intensive care units. PARTICIPANTS: Mechanically ventilated patients with a partial pressure of oxygen in arterial blood/fractional concentration of inspired oxygen (P : F) ratio of 26.7 kPa (200 mmHg) or less and an expected duration of ventilation of at least 2 days at recruitment. INTERVENTIONS: Treatment arm HFOV using a Novalung R100(®) ventilator (Metran Co. Ltd, Saitama, Japan) ventilator until the start of weaning. Control arm Conventional mechanical ventilation using the devices available in the participating centres. MAIN OUTCOME MEASURES: The primary clinical outcome was all-cause mortality at 30 days after randomisation. The primary health economic outcome was the cost per quality-adjusted life-year (QALY) gained. RESULTS: One hundred and sixty-six of 398 patients (41.7%) randomised to the HFOV group and 163 of 397 patients (41.1%) randomised to the conventional mechanical ventilation group died within 30 days of randomisation (p = 0.85), for an absolute difference of 0.6% [95% confidence interval (CI) -6.1% to 7.5%]. After adjustment for study centre, sex, Acute Physiology and Chronic Health Evaluation II score, and the initial P : F ratio, the odds ratio for survival in the conventional ventilation group was 1.03 (95% CI 0.75 to 1.40; p = 0.87 logistic regression). Survival analysis showed no difference in the probability of survival up to 12 months after randomisation. The average QALY at 1 year in the HFOV group was 0.302 compared to 0.246. This gives an incremental cost-effectiveness ratio (ICER) for the cost to society per QALY of £88,790 and an ICER for the cost to the NHS per QALY of £ 78,260. CONCLUSIONS: The use of HFOV had no effect on 30-day mortality in adult patients undergoing mechanical ventilation for ARDS and no economic advantage. We suggest that further research into avoiding ventilator-induced lung injury should concentrate on ventilatory strategies other than HFOV. TRIAL REGISTRATION: Current Controlled Trials ISRCTN10416500.
Subject(s)
Cost-Benefit Analysis , High-Frequency Ventilation , Hospital Mortality , Quality-Adjusted Life Years , Respiratory Distress Syndrome/therapy , Adult , Aged , Cause of Death , Female , High-Frequency Ventilation/economics , High-Frequency Ventilation/instrumentation , High-Frequency Ventilation/mortality , Humans , Male , Middle Aged , Respiration, Artificial/economics , Respiration, Artificial/instrumentation , Respiration, Artificial/methods , Respiration, Artificial/mortality , Respiratory Distress Syndrome/economics , Respiratory Distress Syndrome/mortality , Severity of Illness Index , State Medicine , Survival Analysis , United KingdomABSTRACT
High-frequency ventilation is the application of mechanical ventilation with a respiratory rate > 100 breaths/min. High-frequency oscillatory ventilation (HFOV) is the form of high-frequency ventilation most widely used in adult critical care. The principles of lung-protective ventilation have matured in parallel with the technology for HFOV. The 2 basic principles of lung-protective ventilation are the use of small tidal volume and maintenance of adequate alveolar recruitment. Research in animal models and humans demonstrate that HFOV can support gas exchange with much smaller tidal volume than can be achieved with conventional ventilation. HFOV also provides more effective lung recruitment than conventional mechanical ventilation. However, at present, evidence is lacking that survival in adults with acute respiratory distress syndrome is improved by HFOV. Although HFOV may improve P(aO(2)) in some patients, this improvement is often transitory. Available evidence does not support that pulmonary inflammation is reduced with HFOV in adult acute respiratory distress syndrome. Heavy sedation and often paralysis are necessary. The promise of HFOV as a lung-protective ventilation strategy remains attractive, but additional clinical trials are needed to determine whether this approach is superior to lung-protective ventilation with conventional mechanical ventilation.
