Cardiovascular Section

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Contents

1.0 Aim of guideline
2.0 Scope of guideline
3.0 Guideline framework
4.0 Background information
5.0 Guideline Summary
6.0 Details of Guideline
7.0 Appendices
Appendix 1 Pulse oximetry screening pathway for babies born in hospital
Appendix 2 Pulse oximetry screening pathway for babies born in midwifery led units (MLUs) and at home
Appendix 3 Investigations of babies who fail pulse oximetry screening (test positive)
Appendix 4 Parent information leaflet
Appendix 5 Information guidance for health care professionals performing pulse oximetry screening

1.0 Aim of guideline

The purpose of this guideline is to ensure that all newborn babies born in hospital, midwifery led units or at home are screened for critical congenital heart defects through the early recording of pre- and post-ductal oxygen saturations with a hand-held pulse-oximeter.

It also outlines the subsequent management of newborns who fail pulse oximetry screening (test positive).

2.0 Scope of guideline

The guideline applies to all neonates in neonatal units and maternity units covered by Thames Valley & Wessex Neonatal ODN. This includes the following hospitals:

3.0 Guideline framework

This guideline provides guidance on the routine use of pre-discharge pulse oximetry screening in the delivery suite, the postnatal ward and the community to improve the early detection of critical congenital heart disease (CCHD) in asymptomatic newborn babies; and identify babies with non-cardiac respiratory conditions. It is designed to be used by the following staff group:

• Paediatric/Neonatal doctors/ Advanced Neonatal Nurse Practitioner (ANNPs)
• Neonatal nurses
• Midwives
• Nursery nurses
• Community midwives
• Trained Maternity Support Workers (MSW)

4.0 Background information

Cardiovascular malformations are the leading group of congenital malformations with an incidence of 4 to 10 per 1000 live births. They account for 6-10% of all infant mortality. Cardiovascular malformations also account for 20-40% of deaths attributable to all congenital malformations and most of these deaths occur in the first year of life. The term congenital heart disease (CHD) encompasses a variety of lesions with a wide range of clinical importance, ranging from those with no functional or clinical significance, to potentially life threatening lesions. If critical defects are not detected early, they can result in cardiovascular compromise resulting in death or significant long-term effects on neurodevelopment. Critical CHD refers to heart defects that require intervention or lead to death in the first 28 days after birth. Timely recognition of these conditions allows the possibility of early intervention that may influence the natural history of the condition and subsequent outcome.

What is the current screening programme for heart defects in newborn babies?

All babies are currently screened for heart defect antenatally (antenatal ultrasound) and following birth (postnatal clinical examination).

Antenatal ultrasound – between 2014 and 2017 in the UK, less than half (42%) of babies with heart defects that require intervention were identified before birth (2018 NICOR report, table 12a). Between different health regions in the UK there is great variability in the rate of identification – between 33% in the lowest performing regions and 62% in the highest.

Postnatal examination – fails to identify up to 45% of babies with critical congenital heart defects and up to 30% are sent home without diagnosis. Some of these babies will die and many will have a worse outcome as a result of late diagnosis.

What will Pulse Oximetry Screening add?

Routine newborn pulse oximetry screening identifies babies with critical congenital heart defects that would otherwise have been missed by antenatal ultrasound and postnatal examination. Research has consistently shown that when Pulse Oximetry Screening is added to the existing programme the identification rate for critical congenital heart defects increases to between 90 and 95%.

Pulse oximetry screening reduces mortality from critical congenital heart defects and identifies babies with other important conditions, such as respiratory disorders and sepsis. Many countries now recommend pulse oximetry screening, but the UK National Screening Committee is still undecided. Despite the absence of a national recommendation, many neonatal units in the UK have introduced pulse oximetry screening. In 2017, 78 (40%) of the 193 neonatal units in the UK used pulse oximetry screening (an increase from 15 (7%) of 224 neonatal units in 2010).

5.0 Guideline summary

All newborn babies across Thames Valley & Wessex will undergo Pulse Oximetry Screening to identify babies with congenital heart disease; as well as identify babies with non-cardiac causes of low oxygen saturations. Undetected illness including potential infection, breathing difficulties, congenital heart disease and slow adaptation to ex-utero life are among the causes of low saturations. All these conditions merit neonatal review to diagnose, and if needed, to treat the underlying condition.

6.0 Details of the guideline

Measurement of oxygen saturation in newborn babies

Pulse Oximetry Screening is performed by measuring the baby’s pre and post- ductal saturations. The saturation probe is applied to the baby’s right hand (provides a pre-ductal reading) and either foot (provides a post-ductal reading). For best readings tape must be applied to the right hand & either foot to hold the probe in place (see Appendix 5 for further details). It is necessary to wait until a stable good quality waveform is seen. A sustained, good signal both readings of ≥ 95% and difference less than 3% is accepted as normal (test negative) and constitutes no concerns.

Pulse Oximetry Screening for babies born in hospital (Appendix 1 Pulse Oximetry Screening for babies born in Hospital)

• All babies born in hospital should be screened, preferably between 4-12 hours of life before discharge home. Ideally the screening will be conducted prior to the newborn examination and will be performed by a trained professional i.e., Midwifery Support Worker (MSW), midwife, Health Care Assistant (HCA), or SHO/ ANNP who have received the appropriate training.
• Dedicated hand-held saturation monitors with reusable probes should be made available on the postnatal wards, delivery units, and midwife-led birth unit. Each community team should have a monitor available for home births (see separate section for home births).
• Two saturation readings should be taken, a pre-ductal saturation (right arm) and a post- ductal saturation (either foot) – Test one.
• The highest consistent reading attainable in both should be recorded in the neonatal notes and should be available for the newborn examination.
• The following outcomes apply:
  • A Pass (test negative) – both readings 95% or higher and difference less than 3%.
  • A Fail (test positive) – either reading 89% or less, or clinical concerns.
  • A Borderline – either reading 90-94% or difference of 3% or greater.
• For a pass, no further action is required, other than recording the saturations in the medical notes.
• Babies who fail screening (test positive) will be referred to the neonatal/paediatric team for urgent assessment.
• If the result is borderline, and the baby is clinically well, the test should be repeated in 1 to 2 hours by the midwife/HCA – Test two.
• If the result is again borderline, a trained neonatal clinician should examine the baby.
• If this examination is normal, the test should be repeated in 1-2 hours – Test three.
• Anything but a clear pass in Test three requires urgent senior paediatric assessment and investigation.
• Passing the screening does not rule out a congenital heart defect, and an abnormal cardiac examination should always be investigated.
• Oxygen saturations should be checked in any baby where there is a clinical concern regardless of whether or not they have previously passed the test.

Pulse oximetry Screening Pathway for babies born in midwifery led units (MLUs) or at home (Appendix 2 Pulse Oximetry Screening Pathway for babies born in MLU and at home)

• All babies born in Midwifery Led Units should undergo pulse oximetry screening. This can be performed by the attending midwife or maternity support worker (MSW).
• Pulse oximetry screening for babies born at home would usually be undertaken by the attending midwife prior to leaving the home after delivery and not at the Newborn Physical Examination NIPE, that is done at a later stage.
• Each team should have its own portable pulse-oximeter with reusable probes.
• Screening should ideally be performed from 2 hours after birth or sooner if there is clinical concern.
• Two saturation readings should be taken, a pre-ductal saturation (right arm) and a post- ductal saturation (either foot) – Test one.
• The highest, consistent reading attainable in both will be recorded in the neonatal notes and will be available for the newborn examination.
• The following outcomes apply:
  • A Pass (test negative) – both readings 95% or higher and difference of less than 3%.
  • A Fail (test positive) – either reading 89% or less, or baby symptomatic.
  • A Borderline – either reading 90-94% or difference 3% or greater.

• Babies who fail screening (Test positive) should be referred to the neonatal/paediatric team for urgent assessment.
• A borderline result should also be discussed with the on-call neonatal/paediatric registrar, and if both midwife and registrar have no clinical concerns, the test can be repeated in 1 to 2 hours – Test two.
• If the baby does not pass Test two, or the examination is abnormal, or there are other clinical concerns, the baby should be referred to the neonatal registrar for immediate assessment in hospital.
• Oxygen saturations should be checked in any baby where there is a clinical concern regardless of whether or not they have previously passed the test.
• Passing the screening does not rule out a congenital heart defect, and an abnormal cardiac examination should always be investigated.

Note:

The NEWTT2 Deterioration of the Newborn framework of practice was published by BAPM in January 2023 ¹⁰. This framework is designed for use in postnatal care settings including the delivery suite, postnatal ward and transitional care. It describes at risk groups of babies and provides an updated Newborn Early Warning Trigger and Track (NEWTT2). Recommendations for assessment and monitoring are given for all newborns and at risk groups. The pulse oximetry screening guideline should be used in conjunction with the NEWTT2 framework, with the aim of all newborn babies receiving POS as part of their routine postnatal care.

7.0 Appendices

Appendix 1 Pulse oximetry screening pathway for babies born in hospital
Appendix 2 Pulse oximetry screening pathway for babies born in midwifery led units (MLUs) and at home
Appendix 3 Investigations of babies who fail pulse oximetry screening (test positive)
Appendix 4 Parent information leaflet
Appendix 5 Information guidance for health care professionals performing pulse oximetry screening

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