Article Text

Download PDFPDF
QUESTION 2: Is permissive hypercapnia beneficial to preterm infants?
  1. Murwan Omer1,
  2. Eleanor J Molloy2
  1. 1 Department of Paediatrics, Coombe Women and Infants University Hospital, Dublin, Ireland
  2. 2 Department of Neonatology, Our lady's Children's Hospital, Trinity College, the University of Dublin, Dublin, Ireland
  1. Correspondence to Professor Eleanor Molloy, Consultant Neonatologist & Paediatrician, Discipline of Paediatrics and Child Health, Academic Centre, Tallaght Hospital, Dublin 24, Ireland; Eleanor.molloy{at}

Statistics from

Request Permissions

If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.


A preterm baby girl born at 25 weeks gestation is 1 week old and remains intubated and ventilated. During the ward round, the consultant discusses the ideal target range of pCO2 and the specialist registrar asks about the use of permissive hypercapnia (PHC).

Structured clinical question

In a preterm infant on respiratory support (patient), what is the optimal pCO2 to prevent (intervention) chronic lung disease and periventricular leukomalacia (outcome)?

Search strategy

PubMed database was searched in July 2016 for the following terms: ‘carbon dioxide’ AND ‘Infants’ AND ‘hypercapnia’. The search returned 292 abstracts, 26 were relevant and appropriate for further review. A search of the Cochrane Library using the search terms ‘carbon dioxide’ AND ‘Infants' AND ‘hypercapnia’ was used yielding one result.


Carbon dioxide (CO2) is a by-product of aerobic breathing; it is carried and dissolved in blood and bound to haemoglobin and plasma proteins. The arterial carbon dioxide level (pCO2) represents the balance between CO2 production and elimination.1 Avery et al 2 hypothesised that tolerance of pCO2 above the physiological range may …

View Full Text


  • Contributors This BET article was compiled by MO under the supervision of EJM, who conceptualised the remit and guided the appraisal of the evidence.

  • Competing interests None declared.

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

Linked Articles