title: Comparative prophylactic and therapeutic effects of intravenous labetalol 0.4 mg/kg and nicardipine 20 μg/kg on hypertensive responses to endotracheal intubation in patients undergoing elective surgeries with general anesthesia: a prospective, randomized, double-blind study.
abstract: BACKGROUND
  Laryngoscopy and tracheal intubation (LTI) after induction of general anesthesia often cause hypertension and tachycardia. Labetalol and nicardipine have been used to prevent and treat acute cardiovascular responses to LTI.
  
  
  OBJECTIVE
  The goal of this study was to compare the preventive and therapeutic effects of labetalol 0.4 mg/kg IV and nicardipine 20 μg/kg IV on hypertensive responses to LTI during induction of general anesthesia.
  
  
  METHODS
  Patients undergoing general anesthesia were randomly allocated to 4 groups. In part I (prevention), 80 patients were randomized to receive either 0.4 mg/kg of labetalol (n = 40) or 20 μg/kg of nicardipine (n = 40) 4 minutes before LTI. In part II (treatment), patients were randomized to receive 0.4 mg/kg of labetalol (n = 40) or 20 μg/kg of nicardipine (n = 40) after LTI if hypertension occurred. The number of additional study drug doses required by patients with hypertension (parts I and II) and time to return to normotension (part II) were recorded. Mean arterial pressure and heart rate were monitored, and rate-pressure product was calculated. Adverse events were also monitored.
  
  
  RESULTS
  A total of 130 patients (72 patients in part I and 58 patients in part II) were included in the analysis. In parts I and II, the number of patients who required additional doses of the study drug because of persistent hypertension was lower in the nicardipine groups than in the labetalol groups (P < 0.05). Mean arterial pressure was lower and heart rate was significantly higher over time in the nicardipine groups compared with the labetalol groups (P < 0.05) in parts I and II. In part II, time to return to normotension was shorter in the nicardipine treatment group than in the labetalol treatment group (61 [21] vs 130 [46] seconds; P = 0.01). No statistical differences were observed in the incidence of adverse events except for tachycardia in part I (2 cases in the labetalol prevention group vs 18 cases in the nicardipine prevention group; P = 0.01).
  
  
  CONCLUSIONS
  Patients who received nicardipine were less likely to require additional doses for either the prevention or treatment of hypertensive responses to LTI and responded to the study drug more rapidly than patients who received labetalol for the treatment of hypertensive responses to LTI. However, labetalol was associated with a lower incidence of tachycardia and less of an increase in rate-pressure product when used for the prevention of hypertension during LTI.
authors.affiliation: Department of Anesthesiology and Pain Medicine, Seoul National University Bundang Hospital, Seongnam-si, Gyeonggi-do, South Korea.
authors.forename: Jung-Hee
authors.initials: JH
authors.lastname: Ryu
authors.forename: Christian C
authors.initials: CC
authors.lastname: Apfel
authors.forename: Rachel
authors.initials: R
authors.lastname: Whelan
authors.forename: Young-Tae
authors.initials: YT
authors.lastname: Jeon
authors.forename: Jung-Won
authors.initials: JW
authors.lastname: Hwang
authors.forename: Sang-Hwan
authors.initials: SH
authors.lastname: Do
authors.forename: Young-Jin
authors.initials: YJ
authors.lastname: Ro
authors.forename: Chong-Soo
authors.initials: CS
authors.lastname: Kim
mesh_terms: D000328:Adult; D000768:Anesthesia, General; D000959:Antihypertensive Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D004334:Drug Administration Schedule; D017558:Elective Surgical Procedures / Q000379:methods*; D005260:Female; D006801:Humans; D006973:Hypertension / Q000188:drug therapy / Q000209:etiology / Q000517:prevention & control*; D007275:Injections, Intravenous; D007442:Intubation, Intratracheal / Q000009:adverse effects*; D007741:Labetalol / Q000008:administration & dosage / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D009529:Nicardipine / Q000008:administration & dosage / Q000627:therapeutic use*; D011446:Prospective Studies; D013997:Time Factors; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D000959:Antihypertensive Agents; D009529:Nicardipine; D007741:Labetalol