title: Dopamine clearance in critically ill patients.
abstract: OBJECTIVE
  To examine the validity of the low-dose "renal" dopamine regimen in critically ill patients by investigating the steady-state clearance of dopamine.
  
  
  METHODS
  A prospective clinical study.
  
  
  METHODS
  Teaching hospital intensive care unit.
  
  
  METHODS
  48 haemodynamically stable patients receiving a dopamine infusion.
  
  
  METHODS
  Sampling of arterial blood and dopamine infusates.
  
  
  RESULTS
  Plasma and infusate dopamine levels were measured by liquid chromatography with electrochemical detection. Steady-state clearance was determined by dividing the actual infusion rate by the steady-state plasma concentration. Dopamine clearance for the whole group was 46.4 +/- 35.9 ml/kg per min (mean +/- SD), which is significantly lower than 70 +/- 15.2 ml/kg per min reported for elective surgical patients (p = 0.01). Twelve patients with renal dysfunction had significantly lower dopamine clearances (36 +/- 16.6 ml/kg per min) than the remaining 36 patients (61 +/- 38.5 ml/kg per min, p = 0.022). There was a very poor correlation between plasma dopamine level and infusion rate for the group as a whole (r = 0.47), and this worsened (r = 0.31) when only those patients on a "renal" dose of 2-5 microg/kg per min were considered (n = 30).
  
  
  CONCLUSIONS
  Plasma dopamine clearance is lower in critically ill patients and there is a large interindividual variation. It is therefore impossible to predict the plasma level from the infusion rate. Consequently, the concept of a selective renovascular low-dose dopamine infusion is invalid in critically ill patients.
authors.affiliation: Magill Department of Anaesthesia, Chelsea and Westminster Hospital, London, UK.
authors.forename: R N
authors.initials: RN
authors.lastname: Juste
authors.forename: L
authors.initials: L
authors.lastname: Moran
authors.forename: J
authors.initials: J
authors.lastname: Hooper
authors.forename: N
authors.initials: N
authors.lastname: Soni
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002316:Cardiotonic Agents / Q000008:administration & dosage* / Q000097:blood / Q000493:pharmacokinetics*; D016638:Critical Illness; D004298:Dopamine / Q000008:administration & dosage* / Q000097:blood / Q000493:pharmacokinetics*; D004305:Dose-Response Relationship, Drug; D016903:Drug Monitoring; D006801:Humans; D007262:Infusions, Intravenous; D007674:Kidney Diseases / Q000188:drug therapy* / Q000378:metabolism*; D008657:Metabolic Clearance Rate; D008875:Middle Aged; D011446:Prospective Studies; D015203:Reproducibility of Results
chemical_list: D002316:Cardiotonic Agents; D004298:Dopamine