title: The effect of intravenous labetalol administration on hemodynamic responses during desflurane inhalation.
abstract: BACKGROUND
  Inspired concentrations of desflurane ≥ 1 minimum alveolar anesthetic concentration (MAC) have been related to sympathetic stimulation such as hypertension and tachycardia. The current study examined whether labetalol, an α(1) and β-adrenergic antagonist would blunt these hemodynamic responses.
  
  
  METHODS
  Fifty-four ASA physical status I patients, aged 20-60 years, were enrolled in this study. The patients were randomly divided into 2 groups. The breathing circuit was primed with an end-tidal desflurane concentration of 1.2 MAC in 6 L/min O(2). Normal saline 5 ml or labetalol 0.3 mg/kg was injected into groups S and L respectively. After 5 minutes, anesthesia was induced with intravenous etomidate 0.2 mg/kg and vecuronium 0.1 mg/kg. Each patient inhaled desflurane through a tight fitting facemask. Heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP) and end-tidal concentration of desflurane (et-des) were measured at 5 minutes after saline or labetalol injection (baseline) and every 1 minute for 5 minutes after desflurane inhalation and for 2 minutes after intubation.
  
  
  RESULTS
  In the saline injection group (group S), desflurane inhalation increased heart rate and blood pressure, while labetalol 0.3 mg/kg attenuated the heart rate and blood pressure increase in group L. After tracheal intubation, heart rate and blood pressure were significantly lower in group L than in group S.
  
  
  CONCLUSIONS
  These results demonstrate that administration of intravenous labetalol is effective in attenuating tracheal intubation and desflurane-induced hemodynamic responses.
authors.affiliation: Department of Anesthesiology and Pain Medicine, College of Medicine, Yeungnam University, Daegu, Korea.
authors.forename: Hyun-Seok
authors.initials: HS
authors.lastname: Do
authors.forename: Sae Yeon
authors.initials: SY
authors.lastname: Kim
authors.forename: Su-Jeong
authors.initials: SJ
authors.lastname: Heo
authors.forename: Sang-Jin
authors.initials: SJ
authors.lastname: Park