The Annals of Thoracic Surgery, Vol 42, 172-179, Copyright © 1986 by The Society of Thoracic Surgeons
Role played by oxygen in myocardial protection with crystalloid cardioplegic solution
F Oguma, S Imai and S Eguchi
To evaluate the importance of the oxygen dissolved in crystalloid
cardioplegic solution, the protective effects of oxygenated glucose-
insulin-potassium cardioplegic solution (O2-GIK) (oxygen tension greater
than 600 mm Hg) on the isolated working guinea pig heart were compared with
those of deoxygenated (N2-GIK) (oxygen tension less than 10 mm Hg) and
aerated GIK solution (GIK) (oxygen tension = 140 to 160 mm Hg). Hearts were
subjected to 180 minutes of ischemia with intermittent infusions (every 30
minutes) of cold cardioplegic solution, followed by 30 minutes of
normothermic reperfusion. The O2- GIK solution tended to maintain
high-energy phosphates at higher levels during ischemia, and resulted in
the best recovery of cardiac function. Though not as effective as O2-GIK,
GIK solution produced protective effects; N2-GIK solution failed to exert
such effects. These results strongly suggest that the protective effects of
crystalloid cardioplegic solution are due primarily to the oxygen dissolved
in it; anaerobic metabolism or washout of the metabolites plays a minor
part.
