The Annals of Thoracic Surgery, Vol 44, 48-52, Copyright © 1987 by The Society of Thoracic Surgeons
Maximal oxygenation of dilute blood cardioplegic solution
WG Hendren, DD O'Keefe, GA Geffin, AG Denenberg, TR Love and WM Daggett
The content of dissolved O2 (the major source of O2 for the myocardium) of
dilute blood cardioplegic solution (dBCS) varied widely when oxygenated at
4 degrees C by surface flow of O2 in a Bentley BCR-3500 cardiotomy
reservoir. We have modified the system to consistently deliver maximally
oxygenated dBCS to the heart. Laboratory studies indicated that bubbling O2
through a 16-gauge intravenous catheter in a central Luer-Lok port of the
cardiotomy reservoir provided contents of dissolved O2 that were
consistently near maximal. We then studied 17 patients in the operating
room. The first 6 patients received dBCS oxygenated with 100% O2 with a
high dissolved O2 content of 3.2 +/- 0.2 ml/dl. However, the pH of the dBCS
became highly alkaline (7.83 +/- 0.11 at 37 degrees C). Therefore, in the
remaining 11 patients, 2% CO2 was added to the O2. The dissolved O2 content
remained high (3.3 +/- 0.1 ml/dl), and the pH was in a more physiological
range (7.35 +/- 0.09 at 37 degrees C). We conclude that consistently
maximal oxygenation of a dBCS at a more physiological pH can be achieved by
this method.