Dexamethasone treatment and fluid balance in preterm infants at risk for chronic lung disease.
The influence of dexamethasone on diuresis in preterm infants has not been well studied. We examined 15 preterm infants at risk for chronic lung disease with gestational ages ranging from 26 to 29 wk (median 27.6 wk) and birthweights ranging from 700 to 1485 g (median 965 g). Urine output, blood glucose, serum urea, serum creatinine, serum sodium and serum potassium, as well as systolic, diastolic and mean arterial pressure were measured on the day before, and on 4 consecutive days after starting treatment with dexamethasone (0.25 mg kg-1 i.v., twice daily). We found an increase of diuresis of 30 ml kg -1 d-1, 48-96 h after starting dexamethasone treatment. This coincided with a gradual but significant increase of serum urea levels and arterial pressure. During the study period, fluid and protein intake remained constant. Blood glucose and serum creatinine levels did not change. Our findings suggest that the increased urine output following dexamethasone treatment might be caused by two factors: (1) pressure diuresis induced by the increase of arterial pressure and (2) an increase of the osmolar load to the kidney due to an increase of serum urea.


CONCLUSIONS
This study demonstrates that a significant increase of diuresis occurs in preterm infants, 48-96 h after starting dexamethasone. A careful monitoring of fluid balance during the first days of dexamethasone treatment is recommended.
Bos
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AF
Division of Neonatology, Beatrix Children's Hospital, Groningen, The Netherlands. a.f.bos@med.rug.nl
van Asselt
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WA
Okken
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D000893:Anti-Inflammatory Agents / Q000494:pharmacology / Q000627:therapeutic use*; D001786:Blood Glucose / Q000032:analysis; D001794:Blood Pressure / Q000187:drug effects; D002908:Chronic Disease; D003404:Creatinine / Q000097:blood; D003907:Dexamethasone / Q000494:pharmacology / Q000627:therapeutic use*; D004231:Diuresis / Q000187:drug effects*; D004334:Drug Administration Schedule; D006801:Humans; D007230:Infant, Low Birth Weight; D007231:Infant, Newborn; D007234:Infant, Premature; D007235:Infant, Premature, Diseases / Q000517:prevention & control*; D008171:Lung Diseases / Q000517:prevention & control*; D012307:Risk Factors; D014508:Urea / Q000097:blood
D000893:Anti-Inflammatory Agents; D001786:Blood Glucose; D003907:Dexamethasone; D014508:Urea; D003404:Creatinine