Minimum acceptable O2 delivery (ḊO2) during extracorporeal membrane oxygenation (ECMO) remains to be defined in a newborn primate model. The right atrium, carotid artery, and femoral artery were cannulated, and the ductus arteriosus, aorta, and pulmonary artery ligated in neonatal baboons (Papio cynocephalus) under a combination of ketamine, diazepam, and pancuronium. The internal jugular vein was also cannulated retrograde to the level of the occipital ridge. We measured hemoglobin, pH, arterial and venous PO2 (both from the pump circuit and from the cerebral venous site), serum lactate and bicarbonate concentrations, and pump flow, and we calculated hemoglobin saturations, (ḊO2), O2 consumption (V̇O2), systemic O2 extraction, and cerebral O2 extraction. Six baboons were studied during each of two phases of the experiment. In the first, flow rates were varied sequentially from 200 to 50 ml·kg-1·min-1 with saturation maximized. In the second, flow was maintained at 200 ml·kg-1·min-1 and saturation was reduced sequentially from 100 to 38%. V̇O2 fell significantly below base-line at a flow rate of 50 ml·kg-1·min-1 and a ḊO2 of 8 ± 2 (SE) ml·kg-1·min-1 in phase 1 and at a ḊO2 of 12 ± 5 in phase 2. Both systemic and cerebral O2 extraction rose significantly at a flow of 100 ml·kg-1·min-1 and a ḊO2 of 17 ± 4 ml·kg-1·min-1 in phase 1, whereas neither rose with decreasing ḊO2 in phase 2. In fact, cerebral extraction fell significantly at ḊO2 of 16 ± 6 ml·kg-1·min-1. These data suggest that flows of 50 ml·kg-1·min-1 may provide adequate ḊO2 for short periods of time but that flows <100 ml·kg-1·min-1 and ḊO2 <17 ml·kg-1·min-1 may be inadequate over longer periods. Also, O2 extracting efficiency is reduced even with maximal flows when hemoglobin saturation is decreased.
|Original language||English (US)|
|Number of pages||7|
|Journal||Journal of Applied Physiology|
|State||Published - Jan 1 1989|
ASJC Scopus subject areas
- Physiology (medical)