Systemic and pulmonary haemodynamics in normal neonatal foals.

This research investigated how the heart and lung function of newborn horses change during the first two weeks of life. It was found that over time, heart rate, aortic pressure, and cardiac output increased, while pulmonary artery pressure and vascular resistance decreased. These results were consistent with the gradual growth of the newborn horse.

Study Design and Participants

• The study focused on the cardiopulmonary function of newborn horses, specifically foals, from their birth until they were 14 days old.
• The researchers selected 10 full-term, healthy foals for their research to ensure that the findings would not be affected by any health or developmental issues.

Methods

• They continuously recorded systemic and pulmonary haemodynamics – the circulation and transport of blood in the body and lungs respectively – while the foals were lying down.
• The researchers did this using catheters inserted into the aorta and pulmonary artery to monitor the heart function and blood pressure.

Observations and Findings

• The study noted that the average body weight of the foals increased from 45.4 kg at birth to 70.6 kg by the 14th day.
• There was a continuous murmur of patent ductus arteriosus (a normal temporary blood vessel) for 3 to 6 days.
• It was observed that from the first day to the 14th day, the heart rate, mean aortic pressure, cardiac output, cardiac index, and stroke volume progressively increased.
• On the other hand, the mean pulmonary artery pressure and pulmonary vascular resistance decreased, suggesting improved lung function over time.
• The ratio of pulmonary to systemic resistance also gradually decreased, which indicates a balanced development of the heart and lungs.
• The researchers noted that all these changes were gradual except for the pulmonary artery pressure and pulmonary vascular resistance which saw a rapid decrease in the initial 24 hours, again pointing towards improved lung function.

Conclusion and Implications

• The study concluded that the catheters were well tolerated by the foals for several days, implying that this method is feasible for testing cardiovascular function in full-term or premature horse newborns.
• The research provides valuable insights into the progress of cardiopulmonary development in newborn horses, especially the changes that happen during the initial two weeks.