Prolonged perfusion with a membrane oxygenator in awake ponies.

This research study focused on understanding the effects and safety of prolonged extracorporeal membrane oxygenation (PEMO) in adult ponies. The results showed that PEMO, where a significant part of the cardiac output is diverted through an oxygenator for up to 24 hours, can be performed safely with minimal complications.

Research Methods

• Six adult ponies were subjected to prolonged extracorporeal membrane oxygenation (PEMO).
• The oxygenator was placed in vein-to-artery bypass circuit in the ponies.
• A flow rate equal to 46% of control cardiac output was redirected through the PEMO circuit for 10 to 24 hours.

Results and Observations

• Three of the six ponies were perfused for more than 20 hours and did not develop any complications.
• Immediately after the initiation of PEMO, the left ventricular output decreased which increased again between 6 and 24 hours.
• Aortic pressure and left ventricular work were significantly high during PEMO.
• Although there was an initial decrease in pulmonary ventilation and oxygen uptake, they increased during later stages of bypass.
• No significant changes were observed in pulmonary compliance except where there were issues with perfusion techniques.
• Higher glycolysis levels were found in the liver and hyperglycemia occurred, especially in ponies with thrombi caused by catheters.
• Throughout PEMO, marked diuresis, mostly attributed to hyperglycemia, was present.

Conclusion

• The researchers concluded that extracorporeal circulation, which diverts one-half of the cardiac output through a membrane oxygenator, can be carried out safely for up to 24 hours.
• The minimal morphologic changes in the ponies further affirmed the safety of this procedure.