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Volume targeting levels and work of breathing in infants with evolving or established bronchopulmonary dysplasia
  1. Katie Hunt1,2,
  2. Theodore Dassios3,
  3. Kamal Ali3,
  4. Anne Greenough1,2,4
  1. 1MRC and Asthma UK Centre in Allergic Mechanisms of Asthma, King’s College London, London, UK
  2. 2Department of Women and Children’s Health, School of Life Course Sciences, Faculty of Life Sciences and Medicine, King’s College London, London, UK
  3. 3Neonatal Intensive Care Unit, King’s College Hospital NHS Foundation Trust, London, UK
  4. 4NIHR Biomedical Research Centre at Guy’s and St Thomas’ NHS Foundation Trust, King’s College London, London, UK
  1. Correspondence to Professor Anne Greenough, NIHR Biomedical Research Centre at Guy’s and St Thoma’s NHS Foundation Trust Kings College London, London SE5 9RS, UK; anne.greenough{at}kcl.ac.uk

Abstract

Objectives To assess the work of breathing at different levels of volume targeting in prematurely born infants with evolving or established bronchopulmonary dysplasia (BPD).

Design Randomised crossover study.

Setting Tertiary neonatal intensive care unit.

Patients Eighteen infants born at <32 weeks gestation who remained ventilated at or beyond 1 week after birth, that is, they had evolving or established BPD.

Interventions Infants received ventilation at volume targeting levels of 4, 5, 6 and 7 mL/kg each for 20 minutes, the levels were delivered in random order. Baseline ventilation (without volume targeting) was delivered for 20 minutes between each epoch of volume-targeting.

Main outcome measures Pressure-time product of the diaphragm (PTPdi), a measure of the work of breathing, at different levels of volume targeting.

Results The 18 infants had a median gestational age of 26 (range 24–30) weeks and were studied at a median of 18 (range 7–60) days. The mean PTPdi was higher at 4 mL/kg than at baseline, 5 mL/kg, 6 mL/kg and 7 mL/kg (all P≤0.001). The mean PTPdi was higher at 5 mL/kg than at 6 mL/kg (P=0.008) and 7 mL/kg (P<0.001) and higher at 6 mL/kg than 7 mL/kg (P=0.003). Only at 7 mL/kg was the PTPdi significantly lower than at baseline (P=0.001).

Conclusions Only a tidal volume target of 7 mL/kg reduced the work of breathing below the baseline and may be more appropriate for infants with evolving or established BPD who remained ventilator dependent at or beyond 7 days of age.

  • volume targeted ventilation
  • bronchopulmonary dysplasia
  • work of breathing

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Footnotes

  • Contributors AG and KA designed the study, KH collected the data, KH, TD and AG were involved in the analysis of the results. All authors were involved in the production of the manuscript and approved the final version.

  • Funding KH was supported by the Charles Wolfson Charitable Trust and by SLE. The research was supported by the National Institute for Health Research (NIHR) Biomedical Research Centre based at Guy’s and St Thoma’s NHS Foundation Trust and King’s College London. The views expressed are those of the authors and not necessarily those of the NHS, the NIHR or the department of health.

  • Competing interests AG has held grants from various ventilator manufacturers. AG has received honoraria for giving lectures and advising various ventilator manufacturers. AG is currently receiving a non-conditional educational grant from SLE.

  • Ethics approval The study received approval from the South-East Coast—Surrey NHS Research Ethics Committee. The study was registered on the ISRCTN database, number 17041826.

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

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