Environmental or Nasal Cannula Oxygen for Preterm Infants Receiving Oxygen Therapy: a Randomized Cross-over Pilot Study

In preterm infants < 37 weeks' gestation at birth requiring oxygen without ventilatory/CPAP support, will oxygen environment decrease the number of episodes with oxygen saturations less than 85% for ≥ 10 seconds in a 48 hour cross-over period on either intervention compared with nasal cannula oxygen?

The target oxygen saturations (91 to 95%) are based on data from the meta-analysis of randomized controlled trials of oxygen saturation targets which included data on 4911 infants from the SUPPORT, COT, and BOOST II trials.

This study will include preterm infants < 37 weeks' gestation on oxygen therapy via OE or NC with flow rates ≤ 1.0 l/kg/min. There will be three randomization strata [≥ 22+0/7 to ≤ 25+6/7 weeks, ≥ 26+0/7 to ≤ 28+6/7 weeks, ≥ 29+0/7 to ≤ 36+6/7 weeks' gestation]. The purpose of stratification is to ensure an appropriate distribution of risk between study arms. This study will not be powered to detect outcome differences within or between strata.

Following informed consent, randomization, stratified by gestational age at delivery, will be performed using sequentially numbered sealed opaque envelopes. Each envelope will indicate either Treatment group (OE group) or Control group (NC group). The envelope will only be opened after informed consent has been obtained and just before starting the study on each infant.

This will be a single center randomized cross-over pilot study with a 1:1 parallel allocation of infants to oxygen environment or nasal cannula oxygen using stratified permuted block design. Following a 24 hour period on the first intervention and a 15-30 minute washout period, infants will cross-over to a 24 hour period of the second/alternate intervention. Following a further 15-30 minute washout period, infants will cross-over to a 24 hour period on the first intervention. Following another 15-30 minute washout period, infants will cross-over to a 24 hour period on the second/alternate intervention. The effective FiO2 will be calculated for all infants based on their oxygen therapy modality prior to the monitoring period and used to swap between modes.

All infants enrolled in the study will have routine monitoring, uniform target saturation ranges of 91-95% with alarm limits set at 88-95%, and standard care for the duration of the study. Pulse oximetry recordings will be downloaded using ixTrend (iexcellence, Wildau, Germany) software to a secure computer system for later data analysis.

Infants will continue standard treatment as recommended by the treating physician and will act as their own controls.

Primary secondary outcomes are described below. Other safety outcomes include recordings of episodes of bradycardia and circumstances surrounding the event.

Pulse oximetry recordings will be downloaded using ixTrend software to a secure computer system for later data analysis.

Inclusion criteria

• Infant requiring supplemental oxygen therapy via oxygen environment (OE) or nasal cannula (NC) with flow rates ≤ 1.0 liter per kilogram per minute
• Off ventilatory support and/or NCPAP for > 48 hours prior to study entry
• Gestational age < 37 weeks' gestation at birth
• Nursed in incubator for thermoregulation
• Parents/legal guardians have provided consent for enrollment

Exclusion criteria

• A major malformation
• A neuromuscular condition that affects respiration
• Terminal illness or decision to withhold or limit support