title: Comparison of the effect of continuous intravenous infusion and two bolus injections of remifentanil on haemodynamic responses during anaesthesia induction: a prospective randomised single-centre study.
abstract: Remifentanil is an effective drug for protecting against adverse haemodynamic responses to tracheal intubation. We compared the haemodynamic responses during anaesthesia induction between continuous intravenous (IV) infusion and two bolus injections of remifentanil.
  
  
  
  This prospective, randomised, open-label, single-centre study included patients with American Society of Anesthesiologists physical status I-II, scheduled to undergo elective surgery under general anaesthesia. Patients were randomised into two groups based on remifentanil administration type: the continuous IV infusion group (Group C) receiving a 0.3-μg/kg/min remifentanil infusion for 5 min followed by a 0.1-μg/kg/min remifentanil infusion, and the IV bolus group (Group B) receiving a combination of two bolus injections of remifentanil (first bolus of 0.4 μg/kg and second bolus of 0.6 μg/kg after 3 min) and 0.1 μg/kg/min remifentanil. General anaesthesia was induced with 1 mg/kg propofol and 0.6 mg/kg rocuronium 3 min after remifentanil infusion (Group C) or immediately after the first bolus of remifentanil (Group B). Tracheal intubation was performed 4 min after the injection of propofol and rocuronium. Heart rate and non-invasive blood pressure were recorded at 1-min intervals from baseline (i.e., before induction) to 5 min after tracheal intubation.
  
  
  
  A total of 107 patients were enrolled (Group C, 55; Group B, 52). Normotensive patients with no history of antihypertensive medication use were assigned to the normotensive subgroup (41 each in both groups), while those with hypertension but without a history of antihypertensive medication use were assigned to the untreated hypertensive subgroup (Group C vs. B, n = 7 vs. 4). Finally, patients with a history of antihypertensive medication use were assigned to the treated hypertensive subgroup (7 each in both Groups C and B). No differences in heart rate and blood pressure were observed between Groups C and B within each subgroup.
  
  
  
  Haemodynamic responses during anaesthesia induction were similar between continuous infusion and two bolus injections of remifentanil within both normotensive and hypertensive patients with or without medication.
  
  
  
  The trial was retrospectively registered with Japanese Clinical Trial Registry "UMIN-CTR" on 20 October 2016 and was given a trial ID number UMIN000024495 .
authors.affiliation: Department of Anesthesiology, Miyazaki Medical College, University of Miyazaki, Miyazaki, 889-1692, Japan. mmctm2@yahoo.co.jp.
authors.forename: Toyoaki
authors.initials: T
authors.lastname: Maruta
authors.affiliation: Department of Anesthesiology, Miyazaki Medical Association Hospital, Miyazaki, 880-0834, Japan.
authors.forename: Yoshihumi
authors.initials: Y
authors.lastname: Kodama
authors.affiliation: Department of Internal Medicine, Koga General Hospital, Miyazaki, 880-0041, Japan.
authors.forename: Ishie
authors.initials: I
authors.lastname: Tanaka
authors.affiliation: Department of Anesthesiology, Miyazaki Medical College, University of Miyazaki, Miyazaki, 889-1692, Japan.
authors.forename: Tetsuro
authors.initials: T
authors.lastname: Shirasaka
authors.affiliation: Department of Anesthesiology, Miyazaki Medical College, University of Miyazaki, Miyazaki, 889-1692, Japan.
authors.forename: Isao
authors.initials: I
authors.lastname: Tsuneyoshi
mesh_terms: D000328:Adult; D000368:Aged; D000732:Androstanols / Q000008:administration & dosage; D000768:Anesthesia, General / Q000379:methods; D018686:Anesthetics, Intravenous / Q000008:administration & dosage* / Q000494:pharmacology; D001794:Blood Pressure / Q000187:drug effects; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006439:Hemodynamics / Q000187:drug effects*; D006801:Humans; D007262:Infusions, Intravenous; D007275:Injections, Intravenous; D007442:Intubation, Intratracheal; D008297:Male; D008875:Middle Aged; D010880:Piperidines / Q000008:administration & dosage* / Q000494:pharmacology; D015742:Propofol / Q000008:administration & dosage; D011446:Prospective Studies; D000077208:Remifentanil; D000077123:Rocuronium
chemical_list: D000732:Androstanols; D018686:Anesthetics, Intravenous; D010880:Piperidines; D000077208:Remifentanil; D000077123:Rocuronium; D015742:Propofol
keywords: Anaesthesia induction; Intubation; Laryngoscopy; Prospective study; Remifentanil