PEDIATRICS Vol. 117 No. 6 June 2006, pp. 2328 (doi:10.1542/peds.2006-0718)
Does Oxygen Concentration Used for Resuscitation Influence Outcome of Asphyxiated Newly Born Infants Treated With Hypothermia?: In Reply
Marianne Thoresen, MD, PhD, FRCPCHDepartment of Clinical Sciences
Child Health at St Michael's Hospital,
University of Bristol,
Bristol BS2 8EG, United Kingdom
Andrew Whitelaw, MD, FRCPCH
Department of Clinical Sciences
Child Health at Southmead Hospital
University of Bristol
Bristol BS10 5NB, United Kingdom
Denis Azzopardi, MD, FRCPCH
Department of Paediatrics
Imperial College
Hammersmith Hospital
London W12 0NN, United Kingdom
Shelley Renowden, FRCR
Department of Neuroradiology
Frenchay Hospital
Bristol BS16 1LE, United Kingdom
A. David Edwards, FMedSci
Mary A. Rutherford, FRCR, FRCPCH
Imaging Sciences Department
Robert Steiner Magnetic Resonance Unit
Department of Paediatrics
Imperial College
London W12 0NN, United Kingdom
Vento et al state that the "Patients and Methods" section in our article1 lacks essential information on resuscitation. They ask how many patients needed intermittent positive-pressure ventilation, what fraction of inspired oxygen was used, and what the arterial oxygen saturation on a minute-to-minute basis was. They then state that our definition of asphyxia was weak, using only an Apgar score of <5 at 5 minutes and a pH level of <7.1. They suggest that use of 100% oxygen in resuscitation could have influenced the results.
We are unable to see the relevance of these comments on our study, which compared MRI brain scans in 3 groups of newborns with hypoxic-ischemic encephalopathy managed at different temperatures. The resuscitation methods used were those recommended in the United Kingdom at the time. Although Vento et al may disagree with them, the methods applied to all the infants studied, and differences between the 3 groups, therefore, cannot be a result of the use of oxygen rather than air.
It is important to point out that our study did not select infants on the basis of birth asphyxia alone. The infants had to have evidence of encephalopathy clinically and by electroencephalography (EEG) as well as evidence of poor Apgar score and/or acidosis at birth. This is well documented, and the encephalopathy criteria were similar to those used for our pilot studies of hypothermia2,3 and in the large Cool Cap randomized, controlled trial.4
Entry criteria were as follows:
- gestational age of
36 weeks (excluding those with metabolic or congenital abnormalities);
- need for resuscitation and an Apgar score of <5 at 5 minutes or cord or first arterial blood pH of <7.1 or base deficit of >16 mmol/L;
- presence of encephalopathy with at least 1 of the following: hypotonia, abnormal reflexes, absent or weak suck, or clinical seizures; and
- amplitude-integrated EEG with either moderate II or severe III abnormality, performed within 24 hours of delivery.
EEG grading in the first 24 hours is the best single predictor of severity of outcome after asphyxia, and this is described and referenced in our article.
Vento et al may be right in claiming that our use of 100% oxygen routinely for resuscitation may seem suboptimal now, but this applied to all our infants and does not invalidate our comparison of brain imaging after different temperature-management regimes.
REFERENCES
- Rutherford MA, Azzopardi D, Whitelaw A, et al. Hypothermia and the distribution of cerebral lesions in neonates with hypoxic-ischemic encephalopathy.
Pediatrics. 2005;116
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–1006
[Abstract/Free Full Text] - Azzopardi D, Robertson NJ, Cowan FM, Rutherford MA, Rampling M, Edwards AD. Pilot study of treatment with whole body hypothermia for neonatal encephalopathy.
Pediatrics. 2000;106
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–694
[Abstract/Free Full Text] - Thoresen M, Whitelaw A. Cardiovascular changes during mild therapeutic hypothermia and rewarming in infants with hypoxic-ischemic encephalopathy.
Pediatrics. 2000;106
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–99
[Abstract/Free Full Text] - Gluckman PD, Wyatt JS, Azzopardi D, et al. Selective head cooling with mild systemic hypothermia after neonatal encephalopathy: multicentre randomised trial. Lancet. 2005;365 :663 –670[Web of Science][Medline]
PEDIATRICS (ISSN 1098-4275). ©2006 by the American Academy of Pediatrics
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- Does Oxygen Concentration Used for Resuscitation Influence Outcome of Asphyxiated Newly Born Infants Treated With Hypothermia?
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Pediatrics 2006 117: 2326-2328.[Extract] [Full Text]
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