Intramyocardial oxygen monitoring in coronary artery bypass surgery.
OBJECTIVE
In coronary artery bypass surgery various parameters have been used to monitor patients clinical status. Direct monitoring of myocardial oxygenation can be performed by measuring intramyocardial partial oxygen tension pressure (p ti O2). This study was performed to determine the perioperative time course of this parameter in correlation to standard monitoring parameters.


METHODS
Twenty-three patients underwent standard coronary artery bypass grafting (CABG). A special polarographic microprobes was inserted into the myocardium in the distribution zone of the left anterior descending artery which was one of the target vessels of myocardial revascularization. Intramyocardial p ti O2 was monitored intra- and up to 12 hours postoperatively. Values were correlated to hemodynamic, oxygenation and procedure associated parameters.


RESULTS
Myocardial oxygenation during CABG is characterized by a significant decrease of p ti O2 during cross-clamping and a significant increase after removal of the cross-clamp. The postoperative time course of p ti O2 shows a steady increase of p ti O2 in the first 12 postoperative hours investigated. Preoperative ejection fraction as well as cardio-pulmonary bypass time does not seem to have an influence on the postoperative p ti O2 in these patients. Various standard monitoring parameters show complex influence on intramyocardial p ti O2-


CONCLUSIONS
Determination of intramyocardial partial oxygen pressure in patients undergoing bypass surgery shows characteristic changes. Changes in p ti O2 as a direct online parameter of myocardial oxygenation occur immediately after procedures that influence myocardial perfusion and therefore, may help to detect potential complications earlier than standard monitoring parameters in cardiac surgery.
Misfeld
Martin
M
Clinic of Cardiac Surgery, University Clinic Schleswig-Holstein, Campus Luebeck, Luebeck, Germany.
Heinze
Hermann
H
Sievers
Hans-Hinrich
HH
Kraatz
Ernst-Günter
EG
D000368:Aged; D000369:Aged, 80 and over; D001026:Coronary Artery Bypass; D005260:Female; D006439:Hemodynamics; D006801:Humans; D008297:Male; D008875:Middle Aged; D015425:Myocardial Reperfusion; D009206:Myocardium / Q000737:chemistry*; D010100:Oxygen / Q000097:blood*; D019990:Perioperative Care; D011048:Polarography / Q000295:instrumentation; D012680:Sensitivity and Specificity; D013525:Surgical Instruments
D010100:Oxygen