Prolonged perfusion with a membrane oxygenator in awake ponies

Area of Science:

• Cardiovascular Physiology
• Critical Care Medicine
• Medical Device Technology

Background:

• Extracorporeal membrane oxygenation (ECMO) is a life support technology.
• Understanding the physiological effects of prolonged ECMO is crucial for clinical application.
• Previous studies have not extensively evaluated long-term ECMO in large animal models.

Purpose of the Study:

• To evaluate the safety and physiological impact of prolonged extracorporeal membrane oxygenation (PEMO) in adult ponies.
• To assess the feasibility of using a vein-to-artery bypass circuit for extended ECMO duration.
• To identify potential complications and physiological changes associated with PEMO.

Main Methods:

• Six adult ponies underwent prolonged extracorporeal membrane oxygenation (PEMO) using a vein-to-artery bypass circuit.
• A flow rate of 46% of cardiac output was diverted through the PEMO circuit for 10 to 24 hours.
• Physiological parameters including cardiac output, aortic pressure, pulmonary function, and metabolic markers were monitored.

Main Results:

• Three of six ponies tolerated PEMO for at least 20 hours without complications.
• Left ventricular output initially decreased but increased above baseline between 6 and 24 hours.
• Elevated aortic pressure, left ventricular work, hepatic glycolysis, hyperglycemia, and diuresis were observed.
• Pulmonary ventilation and oxygen uptake initially decreased but later increased; pulmonary compliance remained stable unless perfusion issues arose.

Conclusions:

• Extracorporeal circulation diverting up to 50% of cardiac output via a membrane oxygenator is safe for up to 24 hours in ponies.
• Minimal morphological changes suggest the feasibility of PEMO for extended durations.
• Further research is warranted to optimize perfusion techniques and manage metabolic disturbances during PEMO.