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ARTICLES:
Anikó Róka, Kis Tamas Melinda, Barna Vásárhelyi, Tamás Machay, Denis Azzopardi, and Miklós Szabó
Elevated Morphine Concentrations in Neonates Treated With Morphine and Prolonged Hypothermia for Hypoxic Ischemic Encephalopathy
Pediatrics 2008; 121: e844-e849 [Abstract] [Full text] [PDF]
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[Read eLetters] Morphine during hypothermia
Floris Groenendaal   (21 April 2008)

Morphine during hypothermia 21 April 2008
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Floris Groenendaal,
Neonatologist
University Medical Center, Utrecht, Netherlands

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Re: Morphine during hypothermia

F.Groenendaal{at}umcutrecht.nl Floris Groenendaal

Dear Sir,

In their paper Roka et al. (Pediatrics 2008;121;e844-e849) demonstrate changes in morphine concentrations in neonates with hypothermia as a neurprotective treatment after perinatal asphyxia. The authors addressed an important point and they should be applauded for that.

After reading the paper, however, a number of questions remain unanswered,. In both groups, some patients had pH values of >7.25 and Apgar scores >7, which casts doubt on the diagnosis of perinatal asphyxia. In addition, only 4 hypothermia and 3 normothermia infants showed seizures, although 7 and 4 in each group, respectively, had Sarnat 2. By definition neonates with Sarnat 2 demonstrate encephalopathy including seizures.

On page e845 the loading dose of phenobarbital is reported as 20 ìg/kg (1000 times too low), which I consider a typing error. The cumulative dose of morphine is reported as 0.58 mg/kg per h (page e846) which is far too high. The authors write that ‘normothermia treatment was stopped’ (page e846). What do they mean? Finally, it has not been mentioned how many patients in their study had multiple organ failure (affecting clearance of drugs, including morphine) and how many patients received drugs competing for the enzyme UDP- glucuronosyl-transferase (potentially influencing morphine clearance).

In papers dealing with small numbers of patients, details of individual patients are extremely important. Unfortunately, the present paper lacks this accuracy.

Sincerely,

Dr. Floris Groenendaal Department of Neonatology, Wilhelmina Children’s Hospital, University Medical Center Utrecht, Netherlands

Conflict of Interest:

None declared