Arnold 1994.

Methods	Multi‐centre RCT in 5 tertiary‐care paediatric ICUs in the United States from July 1990 to January 1994
Participants	70 children (weight < 35 kg, mean age 2.8) with acute diffuse lung injury and impaired oxygenation Excluded: if < 40 weeks post‐conceptual age or former prematurity with residual chronic lung disease, obstructive airway disease, intractable septic or cardiogenic shock, non‐pulmonary terminal diagnosis
Interventions	3100 high‐frequency oscillatory ventilator (SensorMedics). Initial settings of FiO₂: 1.0, frequency of 5 to 10 Hz, mPaw of CV+ (4 to 8) cm H₂O, pressure amplitude of oscillation set for “adequate chest wall movement” or according to transcutaneous PCO₂ sensor, bias gas flow 18 L/min Controls were ventilated with pressure‐limited conventional mechanical ventilation (Servo 900C, Siemens; Veolar, Hamilton Medical). Target blood gas values were the same as for HFO Cross‐over to the alternate ventilator was required if the participant met treatment failure criteria
Outcomes	Duration of mechanical ventilation, 30‐day mortality, supplemental oxygen at 30 days, neurological events. Other clinical and adverse outcomes including barotrauma, hypotension, and treatment failure were also reported.
Notes	Lung‐protective ventilation was not mandated in the control group receiving conventional mechanical ventilation. Participants had ARDS (86%) or pulmonary barotrauma requiring chest tube (14%). 21/62 were < 1 year old. 12 participants excluded from the analysis due to: exclusion from the study within 8 hours of enrolment (n = 6); protocol violations (n = 4); transferred to other institution (n = 2). Open‐lung approach to achieve oxygenation targets used No specific use of lung‐volume recruitment manoeuvres Use of sedation and paralysis was not reported Use of rescue therapies or co‐interventions for ARDS was not reported Partial industry support (SensorMedics)
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Random numbers (email correspondence, J Arnold, 5 June 2003)
Allocation concealment (selection bias)	Low risk	"Randomization was based on a serialized form which included the balanced block design, thus the assignment was blinded to the investigator when a patient was selected to be in the study" (email correspondence, J Arnold, 5 June 2003)
Blinding (performance bias and detection bias) All outcomes	Unclear risk	Blinding of caregivers and family members was not possible due to the nature of the intervention, which increases the risk of performance bias The primary outcome was death, which is less susceptible to detection bias. Radiologists who assessed chest radiographs were blinded to study treatment, which would have reduced detection bias for barotrauma
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Data were available for 58 of 70 randomized participants after author contact
Selective reporting (reporting bias)	Low risk	All primary and secondary outcomes reported
Other bias	Unclear risk	> 10% of participants (30/58) crossed over from assigned ventilator strategy