title: Initial, continuous and intermittent bolus cardioplegia administration: efficacy of potassium-chloride and magnesium-sulfate as minimal additives for minimally-diluted blood cardioplegia.
abstract: 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.
authors.affiliation: Unit of Cardiovascular Surgery, National Hospital Organization, Osaka Minami Medical Center, Kawachinagano City, Osaka, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Hayashi
authors.forename: M
authors.initials: M
authors.lastname: Ohtani
authors.forename: Y
authors.initials: Y
authors.lastname: Sawa
authors.forename: T
authors.initials: T
authors.lastname: Hiraishi
authors.forename: H
authors.initials: H
authors.lastname: Akedo
authors.forename: Y
authors.initials: Y
authors.lastname: Kobayashi
authors.forename: T
authors.initials: T
authors.lastname: Nakamura
authors.forename: H
authors.initials: H
authors.lastname: Matsuda
mesh_terms: 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
chemical_list: D002314:Cardioplegic Solutions; D011189:Potassium Chloride; D008278:Magnesium Sulfate