Article Text

Characteristics of children requiring admission to neonatal care and paediatric intensive care before the age of 2 years in England and Wales: a data linkage study
  1. Sarah E Seaton1,
  2. Cheryl Battersby2,
  3. Peter J Davis3,
  4. Alan C Fenton4,
  5. Josie Anderson5,
  6. Tim J van Hasselt1,
  7. Elizabeth Draper1
  1. 1 Department of Population Health Sciences, University of Leicester, Leicester, UK
  2. 2 Neonatal Medicine, School of Public Health, Imperial College London, London, UK
  3. 3 Paediatric Intensive Care Unit, Bristol Royal Hospital for Children, Bristol, Bristol, UK
  4. 4 Newcastle Neonatal Service, Newcastle Upon Tyne Hospitals NHS Foundation Trust, Newcastle Upon Tyne, UK
  5. 5 Bliss Baby Charity, London, UK
  1. Correspondence to Dr Sarah E Seaton, Department of Population Health Sciences, University of Leicester, Leicester, UK; sarah.seaton{at}


Objective To quantify the characteristics of children admitted to neonatal units (NNUs) and paediatric intensive care units (PICUs) before the age of 2 years.

Design A data linkage study of routinely collected data.

Setting National Health Service NNUs and PICUs in England and Wales

Patients Children born from 2013 to 2018.

Interventions None.

Main outcome measure Admission to PICU before the age of 2 years.

Results A total of 384 747 babies were admitted to an NNU and 4.8% (n=18 343) were also admitted to PICU before the age of 2 years. Approximately half of all children admitted to PICU under the age of 2 years born in the same time window (n=18 343/37 549) had previously been cared for in an NNU.

The main reasons for first admission to PICU were cardiac (n=7138) and respiratory conditions (n=5386). Cardiac admissions were primarily from children born at term (n=5146), while respiratory admissions were primarily from children born preterm (<37 weeks’ gestational age, n=3550). A third of children admitted to PICU had more than one admission.

Conclusions Healthcare professionals caring for babies and children in NNU and PICU see some of the same children in the first 2 years of life. While some children are following established care pathways (eg, staged cardiac surgery), the small proportion of children needing NNU care subsequently requiring PICU care account for a large proportion of the total PICU population. These differences may affect perceptions of risk for this group of children between NNU and PICU teams.

  • Intensive Care Units, Paediatric
  • Intensive Care Units, Neonatal
  • Epidemiology

Data availability statement

Data may be obtained from a third party and are not publicly available. Data may be obtained from a third party and are not publicly available. PICANet data may be requested from the data controller, the Healthcare Quality Improvement Partnership (HQIP). A Data Access Request Form can be obtained from

This is an open access article distributed in accordance with the Creative Commons Attribution 4.0 Unported (CC BY 4.0) license, which permits others to copy, redistribute, remix, transform and build upon this work for any purpose, provided the original work is properly cited, a link to the licence is given, and indication of whether changes were made. See:

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What is already known on this topic?

  • Some children, for example, those born very preterm, admitted to a neonatal unit (NNU) following birth are at increased risk of needing further healthcare in early life and beyond.

  • No study has quantified the number or percentage of children who require care in an NNU and a paediatric intensive care unit (PICU) in the first 2 years.

What this study adds?

  • Few children admitted to NNU require PICU admission before two years, but half of PICU admissions before two years have received care in an NNU

  • The main reasons for first PICU admission are cardiac conditions (primarily term born children) and respiratory conditions (primarily emergency admissions from children born preterm)

How this study might affect research, practice or policy

  • The healthcare professionals caring for babies and children in NNUs and PICUs see some of the same children and closer collaboration is essential.


Newborn babies requiring specialist care are admitted to neonatal units (NNUs), with admissions generally taking place shortly after birth and before discharge home. Reasons for admission include prematurity, congenital anomalies, respiratory difficulties and infection, and there has been improved survival of the most vulnerable babies.1–3 Most babies will have short NNU stays, but those with more complex conditions or born extremely preterm can have prolonged stays.4 For babies who reach term-corrected age and continue to require ongoing hospital care, transfer to paediatric care is an option, but this differs across the UK. There are 169 NNUs and 24 paediatric intensive care units (PICUs) across England and Wales. NNUs differ in their surgical and cardiac on-site provision, which may necessitate transfer to PICU in the neonatal period.

PICUs provide care for critically ill children until ~16 years in the UK. Children can be admitted from a variety of healthcare settings (eg, directly from an NNU or an emergency department). Around 40% of admissions to PICU are children aged under 1 year, accounting for ~50% of PICU bed days, but it is unknown how many of these children previously received care in an NNU. There may have been changes in the profile of children,5 6 and there are increasing numbers of children admitted to PICU with technology dependency and complex conditions, potentially following neonatal care.7

In the UK, data for all NNU admissions are available in the National Neonatal Research Database (NNRD). Likewise, all admissions to PICU are collected by the Paediatric Intensive Care Audit Network (PICANet). PICANet collects information about all care received in a PICU setting. These are mainly intensive care days but also a proportion of high-dependency care days provided in the PICU.8 This national data collection provides a unique opportunity to combine both databases to quantify at a population level; the characteristics of children previously cared for in NNU who are also admitted to a PICU. This is vital to share understanding between neonatal and paediatric clinical communities, inform resource needs and focus future research. In this work, we investigate the healthcare needs of children in their first 2 years of life, born from 2013 to 2018, focusing on those admitted to both NNU and PICU.


Population cohort

We used the NNRD and PICANet to create a linked record for each baby in the cohort up to the age of 2 years. We included two cohorts which we used as denominators for this work: (1) all babies born and admitted to an NNU (at least 1 day of intensive care; high dependency care or special care as defined by the British Association of Perinatal Medicine9) in the first week after birth in England or Wales between 1 January 2013 and 31 December 2018 and (2) all children who were born between 1 January 2013 and 31 December 2018 and admitted to PICU aged under 2 years between 2013 and 2020.

Data sources

The NNRD holds data on the demographics, care and outcomes of babies admitted for neonatal care, created from information submitted by hospitals to a national electronic patient record system.10 PICANet holds information about the demographics, care and outcomes of children admitted to PICU, with data entry required within 3 months of the child’s discharge.11

Personal identifiers (NHS number, date of birth, surname, postcode) were provided by the NNRD and PICANet to NHS Digital (now NHS England) for all children born between 1 January 2013 and 31 December 2018. NHS Digital undertook data linkage across the cohorts to inform us of any children common to the NNRD and PICANet prior to the transfer of pseudoanonymised data to the study team. The completion rates of NHS numbers are known to be high in the NNRD and PICANet providing assurance that the linkage was as complete as possible.

Statistical analysis

We investigated the neonatal characteristics of children by whether they were admitted to PICU and NNU or only an NNU. Due to anonymisation of data preventing the use of dates of admission/discharge, we estimated the care pathway of their first PICU admission as follows: (1) admitted to PICU during NNU stay: the child’s NNU stay was greater than the age on PICU admission; (2) directly transferred to PICU from NNU with no return to NNU: their age on admission to PICU was within ±1 day of their age on final discharge from neonatal care; (3) admission to PICU was after NNU: their age on PICU admission was greater than the total stay in NNU.

Information regarding PICU admission was categorised according to reason for the first PICU admission. Admission categories were formed from the four most common primary diagnoses: ‘cardiac’; ‘respiratory’; ‘gastrointestinal’ and ‘neurological’. A fifth category ‘other’ was created for all diagnoses which were not previously captured. We explored characteristics of the children by reason for first admission to PICU. We did this overall and by gestational age to investigate any relationship between prematurity and diagnosis.

We calculated the percentage of children and days of care provided in NNU from children cared for in NNU and PICU. We used the denominator of all care/children in the NNU outlined (1). Similarly, we calculated the percentage of children, admissions and days of care generated in PICU by those children previously cared for in an NNU. When doing this, we used a denominator of children/care in PICU outlined in (2).

To examine the care pathway of children previously cared for in an NNU who have multiple PICU admissions, we explored the reasons for first and subsequent admissions (up to the third admission) in the first 2 years of life using a Sankey diagram, where the width of each connection is relative to the number of admissions attributed to that clinical condition.


Study cohort

In total, over 4 million babies were born from 1 January 2013 to 31 December 2018, of whom 384 747 babies were admitted to an NNU for at least 1 day of specialist neonatal care in the first week of life in England and Wales (figure 1). In total, 37 549 children born in the same time window were admitted to PICU from 1 January 2013 to 31 December 2020 before the age of 2 years.

Figure 1

Flow chart showing the flow of the babies born from 2013 to 2018 and admitted to an NNU and/or PICU in England and Wales. NNU, neonatal unit; PICU, paediatric intensive care unit.

PICU admissions as a proportion of entire cohort of admissions to NNU

The majority of babies admitted to an NNU were not admitted to PICU: 18 343 (4.8%) experienced at least one PICU admission (figure 2A). There were 2769 (0.7%: 2769/384 747) children who experienced at least one PICU admission before returning to NNU to receive ongoing care, 4381 children had their first PICU admission as a direct transfer from NNU and the remainder had their first admission sometime later (figure 1). Information about the children by the source of their first PICU admission is provided in online supplemental table 1.

Figure 2

Percentage of workload contribution in the NNU and PICU for those children who received neonatal care after birth. (A) Percentage of neonatal care accounted for by children who were admitted to a PICU in the first 2 years of life born from 2013 to 2018. (B) Percentage of PICU care provided to children who received neonatal care out of all PICU children/admissions <2 years born from 2013 to 2018.

Extremely preterm babies had the highest proportion of PICU admissions with 13.4% (n=2020/14 547, table 1) admitted to PICU at least once. This risk broadly reduced with increasing gestational age, with 4.7% (9591/202 566, table 1) of babies born at term who required an NNU admission were also admitted to PICU. Babies who received at least 1 day of intensive care in NNU had the highest percentage of PICU admission (11.6%) and for those with a maximum level of care of special care this was 2.2% (table 1).

Table 1

All babies born and admitted to neonatal care broken down by those who received care in NNU and PICU (n=18 343) and those who who received care in NNU only (n=3 66 404)

PICU admissions aged under 2 years of age who have previously been care for in NNU

The largest group of PICU admissions were for cardiac conditions (n=7138), the majority of whom were born at term (n=5146, table 2). These children had the shortest NNU stay, likely reflecting the early transfer to a cardiac centre as part of a planned care pathway. This contrasts with preterm babies with a cardiac condition who had the longest median NNU stay.

Table 2

Characteristics by clinical reason for first admission to PICU (n=18 343) for those children admitted to neonatal care and PICU

The second largest group of PICU admissions (n=5386) were children with respiratory conditions, of which 65.9% were preterm (table 2), with a median age on first PICU admission of 73 days. Respiratory conditions were also the main reason for PICU admission of preterm-born children (online supplemental figure 1) and most of the first admissions were an emergency (84.7%, table 2).

Babies admitted to PICU during their neonatal stay with a readmission to NNU were mainly admitted for cardiovascular (eg, patent ductus arteriosus) or gastrointestinal (eg, necrotising enterocolitis) reasons (online supplemental table 1). Conversely, children admitted to PICU sometime after their neonatal stay were primarily admitted for cardiovascular problems (~80% planned) or respiratory problems (~90% emergency).

Multiple PICU admissions for children previously cared for in NNU

A third of the 18 343 children had more than one PICU admission in the first 2 years of life (table 2). Most second admissions to PICU were for cardiac reasons (n=2822, 45.7% of all second admissions), likely reflecting the planned care pathway for those children undergoing planned staged surgical repairs (figure 3). However, a large proportion of second admissions (n=1800, 29.1% of all second admissions) were for respiratory reasons, including children who had been admitted previously to PICU for other reasons.

Figure 3

Sankey graph to show reasons for repeated admissions to paediatric intensive care unit.

Admissions to PICU of children previously cared for in NNU as a proportion of entire cohort of admissions to PICU under the age of 2 years

There were 37 549 children (55 093 admissions) born between 1 January 2013 and 31 December 2018 admitted to a PICU before the age of 2 years (figure 1). The 18 343 children who had been cared for in NNU accounted for 48.9% of the children in PICU, 55.6% of the PICU admissions and over 60% of all PICU care days for those aged less than 2 years (figure 2B).


Our study has quantified the characteristics and workload of children admitted to both NNU and PICU in the first 2 years of life. Within the general population, only 1% of children aged <1 year are admitted to PICU, but of those admitted to NNU, 4.8% were also admitted to PICU before 2 years. While only a small percentage of babies admitted to NNU required admission to PICU, these children represent approximately half of the children admitted to PICU aged under 2 years. Given approximately 40% of all admissions to PICU are from children aged under 1 year,6 those previously cared for in an NNU represent a large proportion of the overall PICU workload. Therefore, while both specialities see some of the same children at similar time points in early life, each has a very different perspective due to the proportion of workload that these children contribute.

Respiratory and cardiac conditions accounted for nearly 70% of all first PICU admissions from children previously cared for in NNU. The largest group was cardiac conditions who may be following a planned care pathway following the antenatal diagnosis of a cardiac anomaly,12 with 60% of first cardiac PICU admissions being elective. Most of these children were born at term and had short NNU stays. Cardiac conditions were also responsible for nearly half of all second PICU admissions showing that ongoing care needs and admissions may increase due to improved survival of children with complex conditions such as hypoplastic left heart syndrome.13

Respiratory admissions were the second most common reason for PICU admission and in absolute numbers made up a similar number of first PICU admissions to term cardiac babies. These children are likely to have PICU workload implications as most respiratory admissions were emergency admissions, and these are more common in winter when the healthcare service is under increased pressure.14 These children were more likely to have been born preterm and therefore at higher risk of respiratory conditions such as bronchiolitis and were older on admission to PICU. Other work from our group has explored the risk of PICU admission for very preterm-born children further.15

Care pathways within the UK may differ from other countries, demonstrated by the babies who were admitted to PICU during their NNU stay (eg, for necrotising enterocolitis surgery). Therefore, these findings are specific to the UK where some NNUs are unable to provide surgery and may not be generalisable.

Readmission rates to PICU were high across our cohort with one-third of children being readmitted to PICU at least once. This rate of readmission was seen across all diagnostic groups, indicating it was not entirely accounted for by planned multiple admissions for elective surgery (eg, staged cardiac surgery) although cardiac admissions did have the highest rate of PICU readmission. Our population seems similar to medically complex children where PICU readmission rates of 20–30% have been observed.16 17

Across the entire population of children aged <1 year, the percentage admitted to PICU is ~1%.6 Our population of children who had been in NNU had a higher risk of admission to PICU and this persisted even for those receiving lower levels of NNU care, suggesting they are children with increased medical need. While some children transitioning from NNU to PICU follow an established care pathway, these findings suggest increased need for collaboration between and across neonatal and paediatric critical care services to effectively plan for the potentially complex needs of children and their families.

Strengths and limitations

Our work is unique, as while small studies have investigated hospitalisation of children discharged from NNUs in specific populations, such as those born very preterm,18 19 or children admitted to PICU during (but not after) their neonatal stay, to the best of our knowledge, this is the first study to link NNU and PICU data on a population level for individual children. The NNRD and PICANet are national data sources with high levels of ascertainment, completeness and data quality including for personal identifiers, providing potential for high levels of linkage success, although we cannot quantify how many children, if any, were missed.

A limitation of our work is the PICU admissions included some children who received high dependency care, which was still provided in a PICU setting and thus contributed to PICU workload, but this may affect the generalisability of our results internationally. Where we have broken down the admission source, this is an approximation as we do not have exact dates or times of care. While combining this group creates a heterogeneous cohort, together they contribute a large part of the PICU workload provided to young children and we felt it was vital to quantify the whole population. In future work, we will look at different pathways leading to PICU admission and explore healthcare in other settings such as children’s wards via linkage to other data (eg, Hospital Episodes Statistics).

A limitation of our work is that we were not able to present detailed reasons for PICU admission as the population is heterogeneous and the various diagnoses are many and varied. Therefore, we grouped together diagnoses into established categories, for example, ‘respiratory’ within which the most common diagnosis was bronchiolitis. While this is a limitation, we believe it important for this cohort to be considered in its entirety in terms of workload for both neonatal and paediatric communities.

Future work and conclusions

We have focused on the characteristics of children needing care in NNU and PICU. Future work will focus on specific clinical subgroups of children (eg, those born very preterm or congenital anomalies or neurological conditions) to explore risk factors, including child demographics, for PICU admission, with focus on unplanned PICU admissions and their timing, which may cause the most stress for families and unanticipated demand on healthcare services.

The healthcare professionals caring for babies and children in NNUs and PICUs see some of the same children, and therefore, there is a need for close working relationships to ensure smooth transitions for those children who may potentially have ongoing healthcare needs.

Data availability statement

Data may be obtained from a third party and are not publicly available. Data may be obtained from a third party and are not publicly available. PICANet data may be requested from the data controller, the Healthcare Quality Improvement Partnership (HQIP). A Data Access Request Form can be obtained from

Ethics statements

Patient consent for publication

Ethics approval

This study made use of routinely collected data and therefore no participants were actively recruited. Research ethical approval was provided by the East of England committee (reference: 20/EE/0220) and the Confidentiality Advisory Group (20/CAG/0110).


The authors thank all UK Neonatal Collaborative neonatal units that agreed to the inclusion of data in the National Neonatal Research Database from their patients to be used in this work. The UK Neonatal Collaborative lead clinicians of the participating units are: Dr Matthew Babirecki (Airedale General Hospital), Dr Rebecca Kettle (Alder Hey), Dr Anand Kamalanathan (Arrowe Park Hospital), Dr Clare Cane (Barnet Hospital), Dr Kavi Aucharaz (Barnsley District General Hospital), Dr Rathod Poorva (Basildon Hospital), Dr Maninder Bal (Basingstoke & North Hampshire Hospital), Dr L M Wong (Bassetlaw District General Hospital), Dr Anita Mittal (Bedford Hospital), Dr Penny Broggio (Birmingham City Hospital), Dr Pinki Surana (Birmingham Heartlands Hospital), Dr Matt Nash (Birmingham Women's Hospital), Dr Sam Wallis (Bradford Royal Infirmary), Dr Ahmed Hassan (Broomfield Hospital, Chelmsford), Dr Karin Schwarz (Calderdale Royal Hospital), Dr Shu-Ling Chuang (Chelsea & Westminster Hospital), Dr Penelope Young (Chesterfield & North Derbyshire Royal Hospital), Dr Ramona Onita (Colchester General Hospital), Dr Mani Kandasamy (Conquest Hospital), Dr Stephen Brearey (Countess of Chester Hospital), Dr Morris/Dr Siramhatia (Croydon University Hospital), Dr Yee Aung (Cumberland Infirmary), Dr Bharath Gowda (Darent Valley Hospital), Dr Mehdi Garbash (Darlington Memorial Hospital), Dr Alex Allwood (Derriford Hospital), Dr Pauline Adiotomre (Diana Princess of Wales Hospital), Dr Nigel Brooke (Doncaster Royal Infirmary), Dr Claire Hollinsworh (Dorset County Hospital), Dr Toria Klutse (East Surrey Hospital), Dr Sonia Spathis (Epsom General Hospital), Dr Sathish Krishnan (Frimley Park Hospital), Dr Samar Sen (Furness General Hospital), Dr Alaa Ghoneem (George Eliot Hospital), Dr Jennifer Holman (Gloucester Royal Hospital), Dr Daniel Dogar (Good Hope Hospital), Dr Girish Gowda (Great Western Hospital), Dr Karen Turnock (Guy's & St Thomas' Hospital), Dr Sobia Balal (Harrogate District Hospital), Dr Cath Seagrave (Hereford County Hospital), Dr Tristan Bate (Hillingdon Hospital), Dr Hilary Dixon (Hinchingbrooke Hospital), Dr Narendra Aladangady (Homerton Hospital), Dr Hassan Gaili (Hull Royal infirmary), Dr Matthew James (Ipswich Hospital), Dr M Lal (James Cook University Hospital), Dr Oluseun Tayo (James Paget Hospital), Dr Abraham Isaac (Kettering General Hospital), Dr Carolina Zorro (Kings College Hospital), Dr Dhaval Dave (King's Mill Hospital), Dr Jonathan Filkin (Kingston Hospital), Dr Savi Sivashankar (Lancashire Women and Newborn Centre), Dr Hannah Shore (Leeds General Infirmary), Dr Jo Behrsin (Leicester General Hospital), Dr Jo Behrsin (Leicester Royal Infirmary), Dr Michael Grosdenier (Leighton Hospital), Dr Ruchika Gupta (Lincoln County Hospital), Dr Ather Ahmed (Lister Hospital), Dr Alison Bedford Russell (Liverpool Women's Hospital), Dr Jennifer Birch (Luton & Dunstable Hospital), Dr Surendran Chandrasekaran (Macclesfield District General Hospital), Dr Ashok Karupaiah (Manor Hospital), Dr Ghada Ramadan (Medway Maritime Hospital), Dr I Misra (Milton Keynes General Hospital), Dr Chris Knight (Musgrove Park Hospital), Dr Richard Heaver (New Cross Hospital), Dr Mohammad Alam (Newham General Hospital), Dr Prakash Thiagarajan (Nobles Hospital), Dr Muthukumar (Norfolk & Norwich University Hospital), Dr Tiziana Fragapane (North Devon District Hospital), Dr Bivan Saha (North Manchester General Hospital), Dr Cheentan Singh (North Middlesex University Hospital), Dr Nick Barnes (Northampton General Hospital), Dr Sangeeta Tiwary (Northumbria Specialist Emergency Care Hospital), Dr Richard Nicholl (Northwick Park Hospital), Dr Dush Batra (Nottingham City Hospital), Dr Dush Batra (Nottingham University Hospital (QMC)), Dr Victoria Nesbitt (Ormskirk District General Hospital), Dr Amit Gupta (Oxford University Hospitals, John Radcliffe Hospital), Dr Katharine McDevitt (Peterborough City Hospital), Dr Ruchika Gupta (Pilgrim Hospital), Dr David Gibson (Pinderfields General Hospital), Dr Peter Mcewan (Poole General Hospital), Dr Sanath Reddy (Princess Alexandra Hospital), Dr Mark Johnson (Princess Anne Hospital), Dr Aesha Mohammedi (Princess Royal Hospital), Dr Patrica Cowley (Princess Royal Hospital), Dr Rashmi Gandhi (Princess Royal University Hospital), Dr Charlotte Groves (Queen Alexandra Hospital), Dr Lidia Tyszcuzk (Queen Charlotte's Hospital), Dr Shilpa Ramesh (Queen Elizabeth Hospital, Gateshead), Dr Salamatu Jalloh (Queen Elizabeth Hospital, King's Lynn), Dr Julia Croft (Queen Elizabeth Hospital, Woolwich), Dr Bushra Abdul-Malik (Queen Elizabeth the Queen Mother Hospital), Dr Dominic Muogbo (Queen's Hospital, Burton on Trent), Dr Ambalika Das (Queen's Hospital, Romford), Dr Khalid Mannan (Queen's Hospital, Romford), Dr Rajiv Chaudhary (Rosie Maternity Hospital, Addenbrookes), Dr Soma Sengupta (Rotherham District General Hospital), Dr Christos Zipitis (Royal Albert Edward Infirmary), Dr Kemy Naidoo (Royal Berkshire Hospital), Dr Archana Mishra (Royal Bolton Hospital), Dr Chris Warren (Royal Cornwall Hospital), Dr Nigel Ruggins (Royal Derby Hospital), Dr Chrissie Oliver (Royal Devon & Exeter Hospital), Dr Lucinda Winckworth (Royal Hampshire County Hospital), Dr Joanne Fedee (Royal Lancaster Infirmary), Dr Anitha Vayalakkad (Royal Oldham Hospital), Dr Richa Gupta (Royal Preston Hospital), Dr Lee Abbott (Royal Stoke University Hospital), Dr Ben Obi (Royal Surrey County Hospital), Dr Aesha Mohammedi (Royal Sussex County Hospital), Dr Rebecca Winterson (Royal United Hospital), Dr Naveen Athiraman (Royal Victoria Infirmary), Dr Anjali Pektar (Russells Hall Hospital), Dr Jim Baird (Salisbury District Hospital), Dr Adedayo Owoeye (Scarborough General Hospital), Dr Umapathee Majuran (Scunthorpe General Hospital), Dr Richard Lindley (Sheffield Children's Hospital), Dr Vineet Gupta (Southend Hospital), Dr Faith Emery (Southmead Hospital), Dr Donovan Duffy (St George's Hospital), Dr Salim Yasin (St Helier Hospital), Dr Hannah Shore (St James University Hospital), Dr Akinsola Ogundiya (St Mary's Hospital, IOW), Dr Lidia Tyszcuzk (St Mary's Hospital, London), Dr Ngozi Edi-Osagie (St Mary's Hospital, Manchester), Dr Pamela Cairns (St Michael's Hospital), Dr Vennila Ponnusamy (St Peter's Hospital), Dr Victoria Sharp (St Richard's Hospital), Dr Carrie Heal (Stepping Hill Hospital), Dr Sanjay Salgia (Stoke Mandeville Hospital), Dr Imran Ahmed (Sunderland Royal Hospital), Dr Helen Purves (Tameside General Hospital), Dr Porus Bastani (The Jessop Wing, Sheffield), Dr Eleanor Bond (The Royal Free Hospital), Dr Divyen Shah (The Royal London Hospital - Constance Green), Dr Esther Morris (Torbay Hospital), Dr Se-Yeon Park (Tunbridge Wells Hospital), Dr Giles Kendall (University College Hospital), Dr Puneet Nath (University Hospital Coventry), Dr Igor Fierens (University Hospital Lewisham), Dr Mehdi Garbash (University Hospital of North Durham), Dr Hari Kumar (University Hospital of North Tees), Dr Peter Curtis (Victoria Hospital, Blackpool), Dr Delyth Webb (Warrington Hospital), Dr Bird (Warwick Hospital), Dr Sankara Narayanan (Watford General Hospital), Dr Yee Aung (West Cumberland Hospital), Dr Eleanor Hulse (West Middlesex University Hospital), Dr Tayyaba Aamir (West Suffolk Hospital), Dr Angela Yannoulias (Wexham Park Hospital), Dr Caroline Sullivan (Whipps Cross University Hospital), Dr Ros Garr (Whiston Hospital), Dr Wynne Leith (Whittington Hospital), Dr Shaveta Mulla (William Harvey Hospital), Dr Anna Gregory (Worcestershire Royal Hospital), Dr Edward Yates (Worthing Hospital), Dr Abijeet Godhamgaonkar (Wythenshawe Hospital), Dr Megan Eaton (Yeovil District Hospital), Dr Sundeep Sandhu (York District Hospital), Dr Arun Ramachandran (Singleton Hospital), Dr Abby Parish (Princess of Wales Hospital), Dr Anitha James (The Grange University Hospital), Dr Ian Barnard (Glan Clwyd Hospital), Dr Artur Abelian (Wrexham Maelor Hospital), Dr Shakir Saeed (Ysbyty Gwynedd), Dr Nitin Goel (University Hospital of Wales), Dr David Deekollu (Prince Charles Hospital), Dr Prem Pitchaikani (Glangwili General Hospital). The National Neonatal Research Database is a UK Health Research Authority-approved research database; the Chief Investigator for the NNRD is Professor Neena Modi. The NNRD receives no core funding and is resourced through the research it supports. We would like to thank all Paediatric Intensive Care Units in England and Wales who allowed their data to be used in this study. PICANet is commissioned by the Healthcare Quality Improvement Partnership (HQIP) as part of the National Clinical Audit and Patient Outcomes Programme (NCAPOP). HQIP is led by a consortium of the Academy of Medical Royal Colleges, the Royal College of Nursing, and National Voices. Its aim is to promote quality improvement in patient outcomes and, in particular, to increase the impact that clinical audit, outcome review programmes and registries have on healthcare quality in England and Wales. HQIP holds the contract to commission, manage and develop the National Clinical Audit and Patient Outcomes Programme (NCAPOP), comprising around 40 projects covering care provided to people with a wide range of medical, surgical and mental health conditions. The programme is funded by NHS England, the Welsh Government and, with some individual projects, other devolved administrations and crown dependencies Support with the data extraction and linkage was kindly provided by Kayleigh Ougham (NNRD), Lee Norman (PICANet) and NHS Digital. We would like to thank all members of our study advisory group and finally, but importantly, the charities, parents and children who have supported our work.


Supplementary materials

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  • X @DrCBattersby

  • Collaborators On behalf of the United Kingdom Neonatal Collaborative and the Paediatric Critical Care Society Study Group (PCCS-SG).

  • Contributors SES designed the study, obtained the data and undertook analysis under the supervision of ED. SES and CB completed the first draft of the paper. PJD, ACF, TJvH and CB provided clinical interpretation and JA provided the perspective of a charity that supports parents in this area. All authors contributed to the interpretation, revised the manuscript critically and approved the final version for submission. SES is responsible for overall content.

  • Funding SES (Advanced Fellowship: NIHR300579), CB (Advanced Fellowship: NIHR300617) and TJvH (Doctoral Research Fellowship: NIHR301761) are funded by the National Institute for Health Research for this research project.

  • Disclaimer The views expressed in this publication are those of the authors and not necessarily those of the NIHR, NHS or the UK Department of Health and Social Care.

  • Competing interests None declared.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Supplemental material This content has been supplied by the author(s). It has not been vetted by BMJ Publishing Group Limited (BMJ) and may not have been peer-reviewed. Any opinions or recommendations discussed are solely those of the author(s) and are not endorsed by BMJ. BMJ disclaims all liability and responsibility arising from any reliance placed on the content. Where the content includes any translated material, BMJ does not warrant the accuracy and reliability of the translations (including but not limited to local regulations, clinical guidelines, terminology, drug names and drug dosages), and is not responsible for any error and/or omissions arising from translation and adaptation or otherwise.