title: The effect of varying continuous propofol infusions on plasma cyclic guanosine 3',5'-monophosphate concentrations in anesthetized children.
abstract: BACKGROUND
  The glutamate-nitric oxide-cyclic guanosine 3',5'-monophosphate (cGMP) pathway is potentially an effective target for general anesthetics. Plasma cGMP concentrations are reduced after an increase in predicted plasma propofol concentrations during sedation in healthy adult volunteers. We hypothesized that an increase in measured plasma propofol concentration leads to a reduction in plasma cGMP in anesthetized children.
  
  
  METHODS
  Eighteen healthy children aged 46.8 (+/-19.6) mo, requiring general anesthesia for lower body surgical procedures were enrolled. After inhaled induction, tracheal intubation and initiation of intermittent positive pressure ventilation, caudal epidural analgesia was performed. Anesthesia was maintained using a continuous propofol infusion adapted from a previously published regimen to achieve predicted propofol plasma concentration of 6, 3, and 1.5 microg/mL after 30, 50, and 70 min, respectively. Samples for propofol and cGMP plasma concentrations were collected and analyzed using high-performance liquid chromatography and an enzyme immunoassay system.
  
  
  RESULTS
  The plasma cGMP concentrations varied significantly (median [range]) 19.2 [11.8-23.5], 21.3 [14.6-30.8], and 24.9 [15.7-37.8] nmol/L among each predicted plasma propofol concentration, P < 0.0001. The correlation coefficient (r) was -0.62.
  
  
  CONCLUSIONS
  This study demonstrates that an increase in plasma propofol concentration leads to a decrease in plasma cGMP in healthy children, and could serve as a biochemical marker for depth of propofol anesthesia in children.
authors: Department of Anaesthesia and Laboratory Medicine, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada. t.engelhardt@nhs.net
authors: Thomas
authors: T
authors: Engelhardt
authors: Man K
authors: MK
authors: Chan
authors: Alan J
authors: AJ
authors: McCheyne
authors: Cengiz
authors: C
authors: Karsli
authors: Igor
authors: I
authors: Luginbuehl
authors: Bruno
authors: B
authors: Bissonnette
mesh_terms: D018686:Anesthetics, Intravenous / Q000008:administration & dosage* / Q000097:blood; D015415:Biomarkers / Q000097:blood; D002675:Child, Preschool; D002851:Chromatography, High Pressure Liquid; D003243:Consciousness / Q000187:drug effects*; D006152:Cyclic GMP / Q000097:blood*; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D015536:Down-Regulation; D004569:Electroencephalography; D006801:Humans; D007124:Immunoenzyme Techniques; D015742:Propofol / Q000008:administration & dosage* / Q000097:blood; D011446:Prospective Studies; D015398:Signal Transduction / Q000187:drug effects*; D013514:Surgical Procedures, Operative
chemical_list: D018686:Anesthetics, Intravenous; D015415:Biomarkers; D006152:Cyclic GMP; D015742:Propofol