title: The effects of cardiopulmonary bypass on remifentanil kinetics in children undergoing atrial septal defect repair.
abstract: Cardiopulmonary bypass (CPB) can greatly influence the pharmacokinetics of opioids. This study investigated the pharmacokinetic profile of remifentanil in 12 pediatric patients undergoing CPB for repair of an atrial septal defect. All patients received remifentanil (5 microg/kg) over 1 min into a peripheral vein both before the onset of CPB and after the discontinuation of CPB. Arterial blood samples were obtained at defined time periods, and remifentanil concentration was determined using high-performance liquid chromatography ultraviolet detection. The pharmacokinetic profiles both before and after bypass were determined in all 12 patients. There was no change in the volume of distribution at steady state, the volume of the central compartment, or the alpha- and beta-elimination half-life. Although the clearance values increased 20% in the postbypass period (from 38.7 +/- 9.6 to 46.8 +/- 14 mL x kg(-1) x min(-1), there was no meaningful change in the coefficient of variation (from 25% to 30%).
  
  
  CONCLUSIONS
  After cardiopulmonary bypass the clearance of remifentanil increases in children. However, the relative lack of change in the coefficient of variation suggests that remifentanil should be a predictable drug in the postcardiopulmonary bypass period.
authors.affiliation: Department of Anesthesiology, University of Pittsburgh, School of Medicine, Children's Hospital of Pittsburgh, Pennsylvania 15213-2583, USA.
authors.forename: P J
authors.initials: PJ
authors.lastname: Davis
authors.forename: A S
authors.initials: AS
authors.lastname: Wilson
authors.forename: R D
authors.initials: RD
authors.lastname: Siewers
authors.forename: F A
authors.initials: FA
authors.lastname: Pigula
authors.forename: I S
authors.initials: IS
authors.lastname: Landsman
mesh_terms: D000293:Adolescent; D000701:Analgesics, Opioid / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics* / Q000627:therapeutic use; D018685:Anesthetics, Inhalation / Q000008:administration & dosage; D018686:Anesthetics, Intravenous / Q000008:administration & dosage; D019540:Area Under Curve; D002315:Cardiopulmonary Bypass; D002648:Child; D002675:Child, Preschool; D002851:Chromatography, High Pressure Liquid; D017558:Elective Surgical Procedures; D005500:Follow-Up Studies; D006207:Half-Life; D006344:Heart Septal Defects, Atrial / Q000601:surgery*; D006454:Hemoglobins / Q000032:analysis; D006801:Humans; D007223:Infant; D007262:Infusions, Intravenous; D008657:Metabolic Clearance Rate; D010880:Piperidines / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics* / Q000627:therapeutic use; D012044:Regression Analysis; D000077208:Remifentanil
chemical_list: D000701:Analgesics, Opioid; D018685:Anesthetics, Inhalation; D018686:Anesthetics, Intravenous; D006454:Hemoglobins; D010880:Piperidines; D000077208:Remifentanil