Dynamic QT/RR relationship of cardiac conduction in premature infants treated with low-dose doxapram hydrochloride

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Published on: June 16, 2020

Masafumi Miyata1, Tadayoshi Hata, Noriko Kato

  • 1Department of Pediatrics, School of Medicine, Fujita Health University Toyoake, Aichi, Japan. m-miata@jc4.so-net.ne.jp

Journal of Perinatal Medicine
|July 7, 2007
PubMed

Insights

Low-dose doxapram hydrochloride effectively treated apnea of prematurity in infants, significantly reducing breathing pauses. This study found no adverse cardiac effects, supporting its safety for premature newborns.

Area of Science:

  • Neonatal medicine
  • Pediatric cardiology
  • Pharmacology

Background:

  • Doxapram hydrochloride, a respiratory stimulant, has known side effects at high doses, including AV block and QT prolongation.
  • Despite contraindications in Japan for newborns, recent research suggests lower doses may be safe and effective for apnea of prematurity (AOP).
  • Approximately 60% of Japanese neonatologists continue to use doxapram for AOP.

Purpose of the Study:

  • To assess the cardiac safety of low-dose doxapram hydrochloride (0.2 mg/kg/h) in premature infants with idiopathic AOP.
  • To evaluate the impact of low-dose doxapram on cardiac intervals and apnea frequency.

Main Methods:

  • Surface ECG recordings were used to monitor cardiac intervals in fifteen premature very-low-birth-weight infants.
  • Apnea episodes and cardiac parameters were compared before and after administration of low-dose doxapram hydrochloride.
  • Analysis included QT/RR slope to assess myocardial repolarization.

Main Results:

  • Low-dose doxapram hydrochloride administration resulted in a ~90% reduction in apnea frequency.
  • No infants experienced QT prolongation, PR prolongation, arrhythmias, or other conduction disorders.
  • No significant changes were observed in the QT/RR slope, indicating no adverse effects on myocardial depolarization and repolarization.

Conclusions:

  • Low-dose doxapram hydrochloride (0.2 mg/kg/h) is safe for treating apnea of prematurity in very-low-birth-weight infants.
  • The drug effectively reduces apnea frequency without causing cardiac side effects.
  • Findings support the continued use of low-dose doxapram in neonatal care.

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