title: Influence of external cardiac pacing on cerebral oxygenation measured by near-infrared spectroscopy in children after cardiac surgery.
abstract: BACKGROUND
  The brain of children in the early period after repair of congenital heart defects with cardiopulmonary bypass (CPB) may be more vulnerable to hemodynamic changes because of impaired cerebral autoregulation. During postoperative testing of the external temporary safety pacer, we performed desynchronizing ventricular pacing (VVI) while monitoring cerebral oxygenation using near-infrared spectroscopy (NIRS).
  
  
  METHODS
  We prospectively investigated 11 children (6 girls, 5 boys). Mean age was 6.1 months (+/-3.8 months) and mean weight: 5.3 kg (+/-1.5 kg). We performed measurements at four study steps: baseline I, VVI pacing, baseline II and atrial pacing (AOO) to exclude effects of higher heart rate. We continuously measured the effects on hemodynamic and respiratory parameters as well as on cerebral tissue oxygenation index (TOI). Hemoglobin difference (HbD) was calculated as a parameter for cerebral blood flow (CBF).
  
  
  RESULTS
  Ventricular pacing leads to a significant decrease in arterial blood pressure and central venous saturation accompanied by an immediate and significant decrease in TOI (63.3% +/- 7.6% to 61.5% +/- 8.4% [P < 0.05]) and HbD (0.51 +/- 1.8 micromol.l(-1) to -2.9 +/- 4.7 micromol.l(-1) [P < 0.05]).
  
  
  CONCLUSIONS
  Cardiac desynchronization after CPB seems to reduce CBF and cerebral oxygenation in children.
authors.affiliation: Department of Congenital Heart Disease/Pediatric Cardiology, Deutsches Herzzentrum Berlin, Augustenburger Platz 1, Berlin, Germany. thilofleck@web.de
authors.forename: Thilo
authors.initials: T
authors.lastname: Fleck
authors.forename: Stefan
authors.initials: S
authors.lastname: Schubert
authors.forename: Matthias
authors.initials: M
authors.lastname: Redlin
authors.forename: Brigitte
authors.initials: B
authors.lastname: Stiller
authors.forename: Peter
authors.initials: P
authors.lastname: Ewert
authors.forename: Felix
authors.initials: F
authors.lastname: Berger
authors.forename: Nicole
authors.initials: N
authors.lastname: Nagdyman
mesh_terms: D000768:Anesthesia, General; D001784:Blood Gas Analysis; D001923:Brain Chemistry / Q000502:physiology*; D002304:Cardiac Pacing, Artificial; D006348:Cardiac Surgical Procedures; D002560:Cerebrovascular Circulation; D005260:Female; D006439:Hemodynamics / Q000187:drug effects; D006454:Hemoglobins / Q000378:metabolism; D006801:Humans; D007223:Infant; D008297:Male; D010100:Oxygen / Q000097:blood; D010101:Oxygen Consumption / Q000502:physiology*; D011446:Prospective Studies; D019265:Spectroscopy, Near-Infrared
chemical_list: D006454:Hemoglobins; D010100:Oxygen