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Metabolic and respiratory effects of theophylline in the preterm infant
V P Carnielli1, G Verlato, F Benini
1Dipartimento di Pediatria, Via Giustiniani 3, 35128 Padova, Italy. carnielli@child.pedi.unipd.it
Insights
Theophylline increases energy expenditure and carbohydrate use in preterm infants, improving respiratory function without affecting physical activity. This heightened energy demand may impact infant growth.
Area of Science:
- Neonatal Medicine
- Pediatric Pharmacology
- Respiratory Physiology
Background:
- Methylxanthines, including theophylline, are commonly used to manage apnea in preterm infants.
- Understanding the systemic effects of these medications is crucial for optimizing neonatal care.
Purpose of the Study:
- To investigate the impact of theophylline on energy metabolism, physical activity, and lung mechanics in preterm infants.
- To determine if theophylline's effects on these parameters are linked to changes in physical activity.
Main Methods:
- Indirect calorimetry measured energy expenditure and substrate utilization for six hours pre- and post-theophylline administration.
- Video recording assessed physical activity levels in 18 preterm infants.
- Lung mechanics, including respiratory compliance, were evaluated at baseline and 12 and 24 hours post-treatment.
Main Results:
- Theophylline significantly increased energy expenditure by 15 (5) kJ/kg/day and enhanced carbohydrate utilization (6.8 to 8.0 g/kg/day).
- Fat oxidation remained unchanged.
- Respiratory rate increased, transcutaneous CO2 decreased, and static respiratory compliance improved without a concurrent rise in physical activity.
Conclusions:
- A 5 mg/kg theophylline bolus elevates energy expenditure and carbohydrate utilization independently of physical activity, while improving respiratory compliance.
- The observed increase in energy expenditure raises concerns about its potential negative impact on the growth and development of preterm infants.
Background:
Methylxanthines are often administered to preterm infants for the treatment of apnoea.
Aims:
To study the effects of theophylline on energy metabolism, physical activity, and lung mechanics in preterm infants.
Methods:
Indirect calorimetry was performed for six hours before and after administration of a bolus of theophylline (5 mg/kg) in 18 preterm infants while physical activity was recorded with a video camera. Lung mechanics measurements were performed at baseline and 12 and 24 hours after theophylline treatment.
Results:
Theophylline increased mean (SEM) energy expenditure by 15 (5) kJ/kg/day and augmented carbohydrate utilisation from 6.8 to 8.0 g/kg/day, but fat oxidation was unchanged. After theophylline treatment, preterm infants had faster respiration, lower transcutaneous CO2, and improved static respiratory compliance without increased physical activity.
Conclusions:
A bolus of 5 mg/kg theophylline increased energy expenditure independently of physical activity, increased carbohydrate utilisation, and improved respiratory compliance. The increased energy expenditure could be detrimental to the growth of the preterm infant.