This is the protocol for a review and there is no abstract. The objectives are as follows:
The objectives of this review are to ascertain whether prone ventilation offers a mortality advantage when compared with traditional supine or semi-recumbent ventilation in patients with severe acute respiratory failure requiring conventional invasive artificial ventilation.
We plan to undertake the following subgroup analyses to explore possible sources of heterogeneity.
Duration of daily ventilation in the prone position (less than 18 hours/day versus 18 hours/day or more). As any benefit from prone ventilation may be a dose (time) related phenomenon, the daily duration of time in that position would appear potentially important.
Duration of supine ventilation prior to randomization. Since ventilatory-induced lung injury is relatively rapid in onset, identification of any randomized trials and outcomes where there was very limited exposure to supine ventilation prior to randomization should be identified.
Outcome according to severity (oxygenation index /PaO2/FIO2 ratio/severity of illness score, e.g. Simplified Acute Physiology Score II (SAPS II)): more severe lung injury benefit from prone ventilation. This may be an important sub-group to explore. SAPS II or similar scores may indirectly reflect the severity of inciting injury and also be relevant.
Tidal volume (size of mechanical breath given to the patient) in relation to body weight has been shown to affect survival and outcomes between high tidal volume (more than 10 ml/kg), moderate tidal volumes (8-10 ml/kg) and low tidal volumes (less than 8 ml/kg) will be explored if the data permit.
We will analyze studies of acute lung injury and ARDS separately from other causes of acute severe hypoxaemic respiratory failure if data allow.
Acute lung injury and ARDS have been further sub-classified into pulmonary and extrapulmonary causes and may behave differently to ventilatory strategies. We will explore differences in outcomes in these subcategories if the collected data allow.