The Journal of Thoracic and Cardiovascular Surgery, Vol 69, 539-551, Copyright © 1975 by The American Association for Thoracic Surgery and The Western Thoracic Surgical Association
Prolonged perfusion with a membrane oxygenator in awake ponies
CA Rawlings, GE Bisgard, JH Dufek, DD Buss, JA Will, ML Birnbaum, PS Chopra and DR Kahn
Prolonged extracorporeal membrane oxygenation (PEMO) was performed in 6
adult ponies with the membrane oxygenator in vein-to-artery bypass circuit.
A flow rate equal to 46 per cent of control cardiac output was diverted
through the PEMO circuit of 10 to 24 hours. Three of the 6 ponies were
perfused for at least 20 hours and developed no complications. Immediately
following initiation of PEMO, left ventricular output decreased; however,
in the interval between 6 and 24 hours, left ventricular output was
increased above control levels. Aortic pressure and left ventricular work
were markedly elevated during PEMO. Pulmonary ventilation and oxygen uptake
also decreased initially but were elevated during later stages of bypass.
Pulmonary compliance did not change, except in those studies in which
problems were encountered with perfusion techniques. Hepatic glycolysis and
hyperglycemia occurred and were more severe in ponies with catheter-
produced thrombi. Marked diuresis, which could be attributed only partially
to the hyperglycemia, was present throughout PEMO. Based on the minimal
morphologic changes observed in the ponies, extracorporeal circulation
diverting one half of the cardiac output through a membrane oxygenator can
be safely performed for up to 24 hours.