title: Effect of two different bypass techniques on the serum troponin-T levels in newborns and children: does pH-Stat provide better protection?
abstract: BACKGROUND
  Cardiac troponin-T is a sensitive marker of myocardial damage. In a prospective study, the effect of 2 different pH strategies during cardiopulmonary bypass on ischemic myocardial injury and clinical outcome was measured in a pediatric population.
  
  
  RESULTS
  One hundred one patients (31 neonates 13.2+/-8.3 days and 70 children 34.5+/-44.1 months of age) undergoing open-heart surgery were selected to either alpha-stat (n=51) or pH-stat (n=50) acid-based management protocol. Serum troponin-T levels were measured before and 30 minutes after bypass and then 4 and 24 hours postoperatively. Surgical procedure, bypass details, inotropic support requirement, and postoperative recovery were recorded. Baseline troponin-T level was higher in neonates than in children (0.18+/-0.22 versus 0.04+/-0.05 microg/L, P=0.02). Also, a higher baseline level was found in patients with pulmonary hypertension (0.13+/-0.21 versus 0.04+/-0.05 microg/L, P=0.04). Cyanotic children showed a higher peak troponin-T level (3.76+/-3.11 versus 1.67+/-1.33 microg/L, P=0.04). Peak troponin levels showed a correlation with the length of circulatory arrest and aortic cross-clamp time. Postoperative levels remained high at 24 hours in patients requiring inotropic support. Peak troponin-T levels were significantly lower in the pH-stat group in patients with pulmonary hypertension (P=0.03) and in cases where circulatory arrest (P=0.01) or inotropic support (P=0.01) was necessary during operation than in those with alpha-stat technique. Postoperative ventilation time and length of intensive care unit stay were also significantly longer with alpha-stat than with pH-stat technique (P=0.005 and P=0.006, respectively).
  
  
  CONCLUSIONS
  Cardiac troponin-T sensitively reflects myocardial damage in children. Our results suggest that pH-stat acid-based management protocol may provide better protection against ischemic myocardial damage than alpha-stat technique.
authors.affiliation: Yorkshire Heart Centre, Leeds Teaching Hospitals, Calverley St, Leeds LS1 3EX, UK.
authors.forename: Zsolt L
authors.initials: ZL
authors.lastname: Nagy
authors.forename: Mike
authors.initials: M
authors.lastname: Collins
authors.forename: Tracy
authors.initials: T
authors.lastname: Sharpe
authors.forename: Saeed
authors.initials: S
authors.lastname: Mirsadraee
authors.forename: Rafael R
authors.initials: RR
authors.lastname: Guerrero
authors.forename: John
authors.initials: J
authors.lastname: Gibbs
authors.forename: Kevin G
authors.initials: KG
authors.lastname: Watterson
mesh_terms: D000136:Acid-Base Equilibrium; D015415:Biomarkers / Q000097:blood; D002304:Cardiac Pacing, Artificial; D002315:Cardiopulmonary Bypass / Q000009:adverse effects / Q000379:methods* / Q000401:mortality; D002648:Child; D002675:Child, Preschool; D005260:Female; D006324:Heart Arrest, Induced / Q000379:methods; D006330:Heart Defects, Congenital / Q000601:surgery*; D017052:Hospital Mortality; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007223:Infant; D007231:Infant, Newborn; D007902:Length of Stay; D008297:Male; D015999:Multivariate Analysis; D017202:Myocardial Ischemia / Q000209:etiology / Q000517:prevention & control; D009206:Myocardium / Q000378:metabolism; D011446:Prospective Studies; D015427:Reperfusion Injury / Q000209:etiology / Q000517:prevention & control; D016896:Treatment Outcome; D020107:Troponin T / Q000097:blood*
chemical_list: D015415:Biomarkers; D020107:Troponin T