Measuring Oxygenation of Newborn Infants in Targeted Oxygen Ranges
Condition: Premature Infant; Hypoxia; Hyperoxia
MeSH terms: Premature Birth; Hypoxia; Hyperoxia
Study type: Interventional

Summary: 
      The investigators aim to measure the effect of targeting premature babies to a slightly
      higher oxygen saturation target range (92-97%) than routinely used, for a brief period, to
      plan a future larger study of the effect of this on clinical outcomes.

      It is still unclear exactly what levels of oxygen premature babies need - both too little or
      too much oxygen in the first weeks after birth may be harmful. Previous studies used
      saturation monitoring (SpO2), where a small probe shines light through the skin and
      calculates how much oxygen is carried in the blood. These studies demonstrated using an SpO2
      range of 91-95% rather than 85-89% was associated with more babies surviving and fewer babies
      suffering from a bowel condition called necrotising enterocolitis (NEC). However, targeting
      oxygen higher increased the number of infants who needed treatment for an eye condition
      called retinopathy of prematurity (ROP).

      It is possible an SpO2 range higher than 91-95% would be associated with even better
      survival. It is also possible that a higher range might not improve survival but could
      increase the need for ROP treatment.

      Infants born at less than 29 weeks gestation, greater than 48 hours of age and receiving
      supplementary oxygen would be eligible for inclusion. The study is at the Royal Infirmary of
      Edinburgh. Total study time is 12 hours for each infant (6 hours at the standard 90-95% range
      used in our unit, and 6 hours at 92-97%). It is a crossover study with infants acting as
      their own controls.

      Based on previous research the investigators are confident these oxygen levels will not be
      dangerously high. To provide an additional measure of oxygen the investigators will also use
      a transcutaneous monitor for the 12 hour study period, which fastens gently to the skin and
      measures oxygen and carbon dioxide levels on the skin surface.
    

Detailed description: 
      This study is a single centre randomised crossover study. Infants born at less than 29 weeks
      gestation, greater than 48 hours of age and receiving supplementary oxygen would be eligible
      for inclusion. The study is at the Royal Infirmary of Edinburgh. Total study time is 12 hours
      for each infant (6 hours at the standard 90-95% range used in our unit, and 6 hours at
      92-97%). It is a crossover study with infants acting as their own controls.

      A complete list of all monitoring that will be carried out is shown below:

        1. SpO2 monitoring

        2. TcPO2 monitoring

        3. Heart rate monitoring (used to validate SpO2 readings as described below)

        4. Arterial gas sampling (only if conducted by the direct care team as part of the routine
           care of the infant will these be recorded. No extra blood samples will be taken as part
           of the study)

      Each infant will be monitored simultaneously with an SpO2 monitor and TcPo2 monitor, with
      data recording starting from the time the transcutaneous monitor finishes calibrating. SpO2
      readings will be downloaded directly from the multiparameter patient monitor. SpO2 will be
      measured using a Siemens Infinity SC7000 multiparameter monitor. This monitor uses Siemens'
      Oxisure pulse oximetry technology and Nellcor Oximax saturation probes and incorporates ECG
      to reduce motion artefact. To reduce the influence of artefact further, data from an infants
      chest leads (recording heart rate) will also be downloaded. If there is a greater than 10
      beats per minute difference between heart rate measured from the pulse oximeter and heart
      rate measured from the chest leads, SpO2 for that time point will be disregarded.

      TcPO2 will be measured using a SenTec Digital Monitoring System with OxiVent sensor. TcPO2 is
      calculated by dynamic fluorescence quenching which measures oxygen molecules present in the
      vicinity of a fluorescent dye incorporated within the sensor surface. The sensor is operated
      at a constant temperature of 43 degrees Celsius. Control of sensor temperature and
      application duration are designed to meet all applicable standards and this monitoring device
      is used routinely in many neonatal units, with transcutaneous monitoring part of the
      monitoring equipment we use in selected infants in our unit and being transported by our
      local neonatal transport team. Temperature is supervised by two independent circuits, as well
      as by the monitor firmware.

      Transcutaneous data will be transferred contemporaneously to a bedside PC via the proprietary
      software V-STATS (with V-CareNeT) version 4.01. We will ensure the time on the monitor is
      synchronised with the time displayed on the electronic patient record system recording SpO2
      and heart rate. V-STATS software can identify any spurious spikes in TcPO2 caused by air
      bubbles and these identified segments of data will be discarded. Artefact has not
      significantly affected readings during the routine use of this monitor previously on our
      neonatal unit and with our neonatal transport team. The site of the transcutaneous probe will
      be rotated on each infant every 2 hours.

      SpO2, TcPO2 and heart rate data will be recorded every second. The time of any arterial
      oxygen samples taken routinely during the study will be recorded from the unit Radiometer
      ABL800 FLEX blood gas analyser.
    

Intervention name(s): Higher target range
Intervention type(s): Other
Intervention description(s): Intervention is using a higher oxygen saturation target range than in routine practice
Other intervention name(s): Using a higher oxygen saturation target range
Allocation: Randomized
Intervention model: Crossover Assignment
Intervention model description: This is a randomised cross-over study of oxygen target ranges in premature infants, with infants acting as their own controls.
Masking: None (Open Label)
Primary purpose: Treatment
Keywords: Neonatology