Doxapram: cardiopulmonary effects in the horse.

This research article studies the impact of three doses of a drug called doxapram hydrochloride on the heart and lung functions of horses. It found significant effects on various measures including respiratory rate and blood pressure, with most effects fading rapidly after administering the drug.

Research Methodology

• The study explored the cardiopulmonary effects of three different dosages of doxapram hydrochloride. The doses studied were 0.275 mg/kg, 0.55 mg/kg, and 1.1 mg/kg, all administered intravenously.
• These effects were studied in six adult horses, and this provided the sample size for the investigation.

Key Findings

• Doxapram significantly decreased PaCO2, which is the pressure of carbon dioxide in the arteries, while increasing the respiratory rate. This suggests improved respiratory function after administration.
• Doxapram also significantly increased cardiac output, enforcement indicated enhanced heart functionality.
• Arterial blood pressures – including systolic, mean, and diastolic – were significantly increased following administration.
• There were also significant increases in arterial pH and PaO2, suggesting improved oxygenation following drug administration.
• Following the larger doses of doxapram (0.55 mg/kg and 1.1 mg/kg), heart rate and pulmonary arterial blood pressure increased significantly. These measures did not change significantly after the smallest dose was administered.
• Most measurements, except for heart rate and cardiac output, returned to baseline five minutes after the drug was given.
• Heart rate remained significantly higher for an extended period after administering the larger doses, 10 minutes for the medium dose and 30 minutes for the largest dose.
• Cardiac output remained significantly high for various periods after each dose, with the longest effect observed for the largest dose.

Implications and conclusion

• The significant and varied impacts of doxapram on the cardiopulmonary systems of horses suggest potential uses for therapeutic purposes.
• However, the rapid return to baseline values for most measurements suggests the effects are short-term and the doses might require careful management for sustained therapeutic benefit.