Pulse Oximetry screening for Cardiac malformations in the neonate

Majd Abu-Harb

September 2014

Congenital Cardiac malformations

• 6-10% of all infant deaths

• 74% of all CCM are diagnosed in infancy and most of these present during the neonatal period

• 96% of those who survived infancy will go on to survive into adulthood

Congenital Cardiac malformations

•Many babies are asymptomatic at birth

•More than 50% babies with CM may be missed by neonatal exam*

•Earlier discharge reduces time-window for signs and symptoms to develop

* Wren et al. Arch Dis Child Fetal Neonatal Ed 1999;80:F49-F53

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Current Timing of Diagnosis of Congenital Heart Disease

Modes of presentation in the neonate

• Left heart obstruction

• Right heart obstruction

• Abnormal connections

Modes of presentation

• Left heart obstruction

• Right heart obstruction

• Abnormal connections

Heart failure

Modes of presentation

• Left heart obstruction

• Right heart obstruction

• Abnormal connections

Heart Failure

Cyanosis

• Left heart obstruction

Heart Failure

Coarctation of the Aorta

Right heart obstructive lesions

Cyanosis

Diminished pulmonary blood flow

Cyanosis

Abnormal connections

Problem with mixing

Transposition of the great arteries

Newborn screening

NN check: murmur abnormal pulses

How significant are neonatal murmurs?

Our audit of early neonatal murmurs(2008-9)

• All babies born in Sunderland undergo new born check in hospital even if delivered at home

• All babies with murmurs can be evaluated prior to discharge

• Retrospective - hospital based

• All births over 2 year

• Total births 6874

• Exclusions: prenatal diagnosis

preterm < 35 wks

symptomatic prior to NN examination

admissions to NICU

• 6560 included in the analysis

• Of 6560 babies 70 had murmurs (Prevalence 1%)

• Age of baby when murmur was detected 12-36hrs

• Hospital stay: range 10-96 hrs ( mode 21.5hrs)

• Of those with murmurs 23 had structural CM ( 33%)

Our audit

79

Screening

•Antenatal : Anomaly scan detection rate variable•NN check

•Pulse oximetry:

- Clinically undetectable low oxygen levels present in the

majority of critical CM

- Pulse oximetry may detect babies with Critical CM early,

before they collapse

Measurement of oxygen saturation once in one foot of all babies after 2 hrs and before discharge

The oxygen saturation study

• All babies whose oxygen saturation below 95% had echocardiography

• 2 year birth cohort based at Sunderland April 1999-March 2001

• Total live births: 6166

• 5719 babies eligible for measurement

• 5626 (98.3%) measured

Oxygen saturation study

Total births 6166

( 49 )CHD

Babies with Sat. measured 5625

( 10 )CHD

296 Sat. low

( 12 ) Othersignificant pathology

Oxygen saturation study Babies with Sat. measured 5625

( 10 )CHD

296 Sat. low

( 12 ) Other 10 Respiratory 2 CNS

7Murmur

3No murmur

1 Coarctation2 Transposition

Critical Cardiac malformations

• ~ 1.7/1000 live births• Estimated 1200 new cases per year in England and Wales• May only be recognised when babies collapse

• Hypoplastic Left heart Syndrome (HLHS)• Pulomanry atresia with Intact ventricular septum (PA /IVS)• Interrupted Aortic Arch (IAA)• Transposition of the Great Arteries (TGA)• Those dying or undergoing operation/intervention before 12 weeks of age with the

following– PA with VSD– Coarctaion of the aorta (CoA)– Aortic stenosis (AS)– Total anomalous pulmonary venous connection (TAPVC)

• 2007 -Systematic review ; 8 studies 35 950 patients

Thangaratinam et al . Arch Dis Child Fetal Neonatal Ed 2007,92:F176-F180

“More Larger studies needed to define test accuracy”

• 2011 PulseOx: a test accuracy study

Ewer et al . The Lancet, Volume 378, Issue 9793, pages 785-794, 27 August 2011 20 055 babies screened ( of which 24 cases had Critical CM)

Test positive -18/24 critical cases

- 14 non-critical CM

Accuracy for Critical CM : sensitivity 75% vs 50% antenatal us

False negatives : 6 Critical CM ( 4 of which detected on AN screen )

False positives: 169 (0.8%) of these 6 had significant CM, 40 had other

conditions including pneumonia

•

Oximetry studies

• 2013 -Neonatal screening for critical CM using pulse oximetry

Prudhoe et al Arch Dis Child Fetal Neonatal Ed 2013;98:F346-F350

13 previous studies listed –published birth cohorts 1998-2009

Single centre study (1999-2009)

29 925 babies screened ( of which 27 had Critical CM)

Test positive - 5/27 critical cases

- 5/50 serious cases

“Routine pulse oximetry did not prevent five babies with critical and 15 with

serious anomalies being discharged undiagnosed.

Results from screening over 250 000 babies have now been published, but

this total includes only 49 babies with transposition, and even smaller

number of rarer anomalies”

• 3 more studies have been published since …..

Oximetry studies

What do have oximetry screening (OS) studies in common?

• OS is effective in significant hypoxaemia i.e. most obstructive right heart lesions

• OS is not good at detecting Coarctation of the aorta

• The advantage of detecting non-cardiac serious illnesses

Practical issues

• Antenatal detection rate of CM

• False positive rate and impact on: - admission - workload - parental anxiety

• Timing of screening

• Acceptability and cost-effectiveness

• Wider implementation of OS in the UK?

Birmingham Women’s Hospital data

• 40 month period

• Live births : 25859

• Total admissions 3552 of which 1651 were unexpected - 208/1651 (12.6%) for test +ve OS - Echo was performed in 61/208

- 165/208 had significant clinical condition

17 CM ( 9 critical) 55 pneumonia 30 sepsis 12 PPHNTherefore 1/8 of the unexpected admissions was due to positive OS but less

than third of these had echo performed

Singh A et al . Arch Dis Child Fetal Neonatal Ed 2014;99:F297-F302

Conclusions

Routine pulse oximetry screening:

• is feasible and acceptable to parents and staff

• adds value to existing screening procedures

• is likely to identify cases of Critical CM which would otherwise go undetected

• has the additional advantage of detecting other serious ( non-cardiac ) illnesses

Any questions?