Initial, continuous and intermittent bolus cardioplegia administration: efficacy of potassium-chloride and magnesium-sulfate as minimal additives for minimally-diluted blood cardioplegia.
OBJECTIVE
The most effective delivery of blood cardioplegia (BCP) remains controversial, and a combination of initial continuous and intermittent bolus BCP seems to compensate each demerit. However, a large amount of crystalloid solution is infused into the myocardium in this method, which may nullify the advantages of BCP. We examined the hypothesis that minimally-diluted BCP resolves this issue and provides superior myocardial protective effects.


METHODS
Seventy patients undergoing elective coronary revascularization between 1997-2001 (M:F=55:15, mean age 67.6+/-7.5 years) were randomly allocated into one of 2 groups: Group C (n=35) was given the standard 4:1-diluted blood-crystalloid BCP, and Group M (n=35) was given minimally-diluted BCP supplemented with potassium-chloride and magnesium-sulfate. The BCP temperature was maintained at 30 degrees C. Cardioplegic arrest was induced with 2 minutes of initial antegrade BCP infusion, followed by continuous retrograde BCP infusion. Intermittent antegrade BCP was infused every 30 minutes for 2 minutes.


RESULTS
The time required for achieving cardioplegic arrest was significantly shorter in Group M (47.5+/-16.3 vs 62.5+/-17.6 s, p<0.0001) and the number of patients showing spontaneous heart-beat recovery after aortic unclamping was significantly larger in Group M (28 vs 15, p=0.0029). The number of patients suffering from atrial fibrillation during the postoperative period was significantly smaller in Group M (3 vs 11, p=0.034). The total amount of crystalloid solution infused as cardioplegia was significantly smaller in Group M (62.8+/-22.3 vs 733.6+/-382.6 mL, p<0.0001). Postoperative maximum dopamine dose (3.57+/-2.46 vs 5.44+/-2.23 mg/kg/min, p=0.0014) and peak creatine kinase-MB (19.5+/-8.5 vs 25.8+/-11.9 IU/L, p=0.0128) were significantly lower in Group M. The number of patients showing paradoxical movement of the ventricular septum by early postoperative echocardiography was significantly smaller in Group M (9 vs 24, p<0.0007).


CONCLUSIONS
These results demonstrate that initial continuous and intermittent bolus administration of minimally-diluted BCP supplemented with potassium and magnesium can be a simple, reliable and effective technique of intraoperative myocardial protection.
Hayashi
Y
Y
Unit of Cardiovascular Surgery, National Hospital Organization, Osaka Minami Medical Center, Kawachinagano City, Osaka, Japan.
Ohtani
M
M
Sawa
Y
Y
Hiraishi
T
T
Akedo
H
H
Kobayashi
Y
Y
Nakamura
T
T
Matsuda
H
H
D000368:Aged; D001769:Blood; D002314:Cardioplegic Solutions / Q000008:administration & dosage; D001026:Coronary Artery Bypass; D005260:Female; D006324:Heart Arrest, Induced / Q000379:methods*; D006801:Humans; D008278:Magnesium Sulfate / Q000008:administration & dosage; D008297:Male; D011189:Potassium Chloride / Q000008:administration & dosage
D002314:Cardioplegic Solutions; D011189:Potassium Chloride; D008278:Magnesium Sulfate