title: Coronary bypass grafting using crossclamp fibrillation does not result in reliable reperfusion of the myocardium when the crossclamp is intermittently released: a prospective cohort study.
abstract: BACKGROUND
  Cross-clamp fibrillation is a well established method of performing coronary grafting, but its clinical effect on the myocardium is unknown. We sought to measure these effects clinically using the Khuri Intramyocardial pH monitor.
  
  
  METHODS
  50 episodes of cross-clamping were recorded in 16 patients who underwent CABG with crossclamp-fibrillation. An Intramyocardial pH probe measured the level of acidosis in the anterior and posterior myocardium in real-time. The pH at the start and end of each period of cross-clamping was recorded.
  
  
  RESULTS
  It became very apparent that the pH of some patients recovered quickly while others entirely failed to recover. Thus the patients were split into 2 groups according to whether the pH recovered to above 6.8 after the first crossclamp-release (N = 8 in each group). Initial pH was 7.133 (range 6.974-7.239). After the first period of crossclamping the pH dropped to 6.381 (range 6.034-6.684). The pH in recoverers prior to the second XC application was 6.990 (range 6.808-7.222) compared to only 6.455 (range 6.200-6.737) in patient's whose myocardium did not recover (P < 0.0005). This finding was repeated after the second XC release (mean pH 7.005 vs 6.537) and the third (mean pH 6.736 vs 6.376). However prior to separation from bypass the pH was close to the initial pH in both groups (7.062 vs 7.038).
  
  
  CONCLUSIONS
  Crossclamp fibrillation does not result in reliable reperfusion of the myocardium between periods of crossclamping.
authors.affiliation: Department of Cardiothoracic Surgery, James Cook University Hospital, Middlesbrough, UK. joeldunning@doctors.org.uk
authors.forename: Joel
authors.initials: J
authors.lastname: Dunning
authors.forename: Steven
authors.initials: S
authors.lastname: Hunter
authors.forename: Simon W H
authors.initials: SW
authors.lastname: Kendall
authors.forename: John
authors.initials: J
authors.lastname: Wallis
authors.forename: W Andrew
authors.initials: WA
authors.lastname: Owens
mesh_terms: D000368:Aged; D001026:Coronary Artery Bypass / Q000379:methods*; D003326:Coronary Circulation; D005260:Female; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008297:Male; D016343:Monitoring, Intraoperative; D009206:Myocardium / Q000378:metabolism*