title: Clonidine premedication prevents preoperative hypokalemia.
abstract: OBJECTIVE
  To test the hypothesis that clonidine premedication could prevent an increase of plasma epinephrine occurring as a result of anxiety, and a decrease of the serum potassium (K+) levels before the induction of anesthesia.
  
  
  METHODS
  Randomized, double-blinded study.
  
  
  METHODS
  University Hospital of Seoul.
  
  
  METHODS
  44 ASA physical status I and II patients, aged 20 to 50 years, scheduled for knee, ear, or nose surgery.
  
  
  METHODS
  44 patients were randomly allocated into one of two groups: 22 patients (clonidine group) received clonidine 300 microg orally at 120 minutes before the induction of anesthesia. The other 22 patients (control group) received a placebo.
  
  
  RESULTS
  Anxiety level, serum K+, and plasma epinephrine were measured at an outpatient clinic, and immediately before the induction of anesthesia. There were no differences between groups in degree of anxiety experienced, serum K+, or plasma epinephrine levels as measured at the out-patient clinic. Immediately before the induction of anesthesia, the serum K+ levels of the clonidine group were higher than those of the control group (3.89 +/- 0.26 mEq/L vs. 3.50 +/- 0.36 mEq/L), and anxiety and plasma epinephrine levels of clonidine group were lower than those of the control group (p < 0.05). The frequency of hypokalemia (K+ < or = 3.5 mEq/L) of the clonidine group immediately before the induction of anesthesia was significantly lower than that of the control group (0% vs. 50%).
  
  
  CONCLUSIONS
  Clonidine premedication was effective in preventing hypokalemic episodes occurring before the induction of anesthesia.
authors.affiliation: Department of Anesthesiology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea.
authors.forename: Tae S
authors.initials: TS
authors.lastname: Hahm
authors.forename: Hyun S
authors.initials: HS
authors.lastname: Cho
authors.forename: Kook H
authors.initials: KH
authors.lastname: Lee
authors.forename: Ik S
authors.initials: IS
authors.lastname: Chung
authors.forename: Ji A
authors.initials: JA
authors.lastname: Kim
authors.forename: Myung H
authors.initials: MH
authors.lastname: Kim
mesh_terms: D000316:Adrenergic alpha-Agonists / Q000008:administration & dosage*; D000328:Adult; D000768:Anesthesia, General; D001007:Anxiety / Q000097:blood / Q000517:prevention & control*; D003000:Clonidine / Q000008:administration & dosage*; D004311:Double-Blind Method; D004837:Epinephrine / Q000097:blood; D005260:Female; D006801:Humans; D007008:Hypokalemia / Q000517:prevention & control*; D008297:Male; D008875:Middle Aged; D011188:Potassium / Q000097:blood; D011229:Preanesthetic Medication; D013514:Surgical Procedures, Operative / Q000523:psychology; D013565:Sympatholytics / Q000008:administration & dosage*
chemical_list: D000316:Adrenergic alpha-Agonists; D013565:Sympatholytics; D003000:Clonidine; D011188:Potassium; D004837:Epinephrine