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Oxygen saturation SpO2 level targeting in neonates

  • Introduction

    Oxygen therapy is one of the most common therapies used in the neonate, especially in the preterm population. Supplemental oxygen has been shown to improve survival and neurodevelopmental outcomes. However, exposure to higher oxygen saturation levels for prolonged periods in neonates is associated with an increased incidence of retinopathy of prematurity (ROP), bronchopulmonary dysplasia (BPD), cerebral palsy, periventricular leukomalacia and necrotizing enterocolitis (NEC). Continuous pulse oximetry allows the clinician to monitor oxygen saturation and titrate oxygen therapy to target levels within a defined range. Evidence for oxygen saturation target ranges in the term neonates is limited. Although term neonates (>1.5kg) are not at risk of ROP, hyperoxia may have harmful effects on cerebral perfusion and exacerbate oxidative stress in the event of hypoxic ischemic injury. 

    Oxygen saturations should be targeted within the range of 91-95%, when receiving oxygen therapy, in both preterm and term neonates.

    Fi02 is one of several determinants of arterial oxygenation provided by supplemental oxygen therapy. Additional factors may include positive end expiratory pressure and mean airway pressure. Both are specific to the mode of respiratory support and oxygen therapy used. This document should be used in conjunction with the appropriate guideline regarding the mode of respiratory support and oxygen delivery the neonate is receiving. To provide medical and nursing staff at the Royal Children’s Hospital with clear parameters within which oxygen saturation (SpO2) levels should be maintained, in the neonate receiving oxygen therapy.

    Definition of Terms

    • Sp02: Peripheral capillary oxygen saturation, is an estimate of arterial oxygen saturation (SaO2).
    • Fi02: fraction of inspired oxygen.
    • Premature Neonate:  Any neonate born before 37 weeks completed gestation
    • Gestational Age:  The number of weeks and days of completed gestation at birth
    • Corrected Age:  Gestational age at birth plus chronological age
    • Hyperoxia:excessive levels of oxygen concentration at tissue and organ level.
    • Cardiac shunt: when the blood flow deviates from the typical flow pattern (right-to left or left-to right shunt). 
    • Bronchopulmonary dysplasia (BPD): Chronic lung disease affecting neonates (primarily premature) resulting from damage to lung tissue due to mechanical ventilation and long term oxygen therapy.
    • Necrotising enterocolitis (NEC): NEC is the most common gastrointestinal emergency in neonates, when segments of bowel tissue dies. Bowel ischemia is an identified risk factor for NEC.
    • Retinopathy of prematurity (ROP): ROP is an eye problem seen in some premature neonates, caused by abnormal development of blood vessels on the surface of the retina. Although treatment is available, severe ROP may lead to visual impairment or blindness. The incidence of ROP has been strongly linked to excessive use of oxygen in premature neonates.

    Assessment

    • Neonates receiving oxygen therapy should have their SpO2 measured continuously by pulse oximetry. Multiple reported cases exist of significant burn and pressure injury due to pulse oximetry. The risk of injury is increased in neonates who are preterm (immature and thinner epidermis and dermis skin layers), hypothermic and have reduced perfusion.
      • Care should be taken to monitor skin beneath the probe site frequently and rotation of probe placement is to be attended to at minimum 2 hourly to prevent burns and pressure injury. 
    • A standardised oxygen saturation target range of 91-95% is applicable to both the pre-term and term population.

    See also:  Nursing Assessment Guideline. &  Pressure Injury Prevention and Management

    Management 

    1. Alarm limits

                                 Alarm limit settings are checked at the start of each nursing shift.

    • Monitoring alarm limits for all neonates receiving oxygen therapy should be set with a lower limit of 89% and an upper limit of 96%.
    • Monitoring alarm mode should be set on the monitor to the appropriate Neonatal mode, either RCH <3kg or RCH <3 months (Note the monitor defaults to RCH paediatric mode).
    • Caution should be taken with frequent alarms at 89%, as the accuracy of continuous pulse oximetry has been shown to be reduced when Sp02 readings are in the range of 85-89%. A reading of 89% may reflect a true arterial saturation as low as <80%.
    • When monitoring pre-ductal (right hand) and post-ductal (either foot) saturations, alarms should be set to alert staff to a difference in SpO2 greater than 10% (normally <10%).
    • Alterations to oxygen saturation targets are a medical order, to be documented in the patient’s EMR.
    • Neonates no longer receiving supplemental oxygen, or receiving it intermittently, may have the upper SpO2 alarm limit adjusted to 100% whilst in room air.

    2. Oxygen titration in response to saturation monitoring

    Preterm neonates commonly experience fleeting desaturations which normally self-correct without interference.

    Accuracy of continuous pulse oximetry is limited as it is based on time-averages over several heartbeats, to reduce the occurrence of false alarms due to erratic movements. This may result in less sensitivity to brief desaturations <30 seconds or marked <70%. Assessment of the patient’s oxygen requirement should be a combination of continuous pulse oximetry with patient assessment.  

    Acute severe or prolonged desaturations should be treated as an emergency- assessing the patient using DRSABC.

    For any neonate with a Sp02 persistently outside the target range, oxygen therapy should be titrated by nursing or medical staff to maintain Sp02 within the target range.

    A significant increase in inspired fraction of oxygen (>10%) required to maintain target saturations should be reviewed by a medical team member.

    Desaturation episodes are to be documented in the patient’s EMR observation flow sheet. Information should include if the patient was apnoeic or not, the lowest recorded heart rate and desaturation, colour change, activity and position prior to event and intervention required.

    Sp02 alone is an inadequate indicator of end-organ perfusion and should be considered in conjunction with patient assessment. 

    Consider underlying pathology and additional factors causing an increase in oxygen requirement. Optimise patient position and comfort, consider analgesic requirement and benefits of skin to skin care.

    Special Considerations

    In the following circumstances, the above oxygen saturation target ranges may not apply:

    Bronchiolitis: Oxygen saturation target of equal to or greater than 90% with supplemental oxygen therapy. See:  Bronchiolitis guideline 

    Cyanotic heart disease and duct dependant cardiac lesions: A target range of 75- 85% is typically recommended for neonates with mixed circulation. Patient specific parameters must be determined by the treating cardiology or primary medical team.

    *Limited evidence is available for a standardised oxygen saturation target range for neonates with cyanotic heart disease. Maintaining saturations >85% may be unachievable in these neonates without causing significant hyperoxia due to cardiac shunting.

    Hyperoxia should be avoided in neonates with duct dependant cardiac lesions to avoid pulmonary over circulation, systemic hypo perfusion and sequelae.

    Persistent pulmonary hypertension of the newborn (PPHN) or *risk of PPHN: Hypoxia should be avoided to reduce pulmonary vasoconstriction and subsequent increased pulmonary vascular resistance, worsening PPHN crisis.

    If pulmonary artery pressure is greater than aortic pressure (systemic blood pressure), post-ductal saturations will decrease due to right-to-left shunting.

    Oxygen saturation target ranges in these neonates may be altered by the treating medical team (may need to be > or equal to 95%). Any deviation from the above guideline should be documented in the patient’s medical notes and a medical order placed in the EMR.

    *Risk factors for PPHN include respiratory distress syndrome (RDS), meconium aspiration syndrome (MAS), sepsis, asphyxia, congenital diaphragmatic hernia (CDH), alveolar capillary dysplasia (ACD) and total anomalous pulmonary venous drainage (TAPVD).

    Links

    Evidence Table

    The evidence table for this guideline can be viewed here.


      Please remember to read the disclaimer.


      The development of this nursing guideline was coordinated by Narelle Miller, CNC, Butterfly Ward, and approved by the Nursing Clinical Effectiveness Committee. Updated June 2023.