Furosemide decreases ventilation in young rabbits

Area of Science:

• Neonatal Physiology
• Pharmacology
• Respiratory Medicine

Background:

• Furosemide is a diuretic commonly used in neonates.
• Its effects on ventilation and acid-base balance in early life require further elucidation.

Purpose of the Study:

• To investigate the effects of furosemide on acid-base status and ventilation in neonatal rabbit pups.
• To determine if furosemide causes metabolic alkalosis and subsequent hypoventilation.

Main Methods:

• Normal rabbit pups were administered furosemide (4 mg/kg/day) or saline for 8-10 days.
• Acid-base status, ventilation, lung compliance, and ventilatory response to CO2 were assessed.
• Potassium chloride (KCl) was injected into alkalotic pups to evaluate ventilatory response.

Main Results:

• Furosemide administration resulted in primary metabolic alkalosis and reduced ventilation in rabbit pups.
• This led to a secondary respiratory acidosis, indicated by increased PaCO2.
• Lung compliance improved with furosemide treatment, while the ventilatory response to CO2 remained unchanged.
• KCl injection in alkalotic pups increased ventilation and decreased pH.

Conclusions:

• Conventional doses of furosemide can induce metabolic alkalosis and hypoventilation in neonatal animals.
• Increased PaCO2 reflects acid-base changes rather than altered lung function.
• Furosemide may improve lung compliance, potentially by reducing lung water.
• These effects could complicate the interpretation of furosemide's benefits in infants with chronic lung disease.