title: [Remifentanil: does the infusion regimen make a difference in the prevention of hemodynamic responses to tracheal intubation?].
abstract: OBJECTIVE
  High doses of opioids decrease the hemodynamic response to tracheal intubation. However, the slow recovery profile of traditional opioids may limit the use of high doses. Remifentanil has a fast time of onset and is short acting, which differentiates it from the other drugs in this class. The primary objective of this study was to verify the hypothesis that there is no need to initiate the administration of remifentanil before the induction with propofol.
  
  
  METHODS
  Thirty patients, divided in two groups, who received total intravenous anesthesia, were evaluated. In Group 1, the infusion of remifentanil (0.3 microg.kg-1.min-1) was initiated two minutes before induction, and in Group 2, at the same time of the induction. Systolic, diastolic, and mean arterial blood pressure (SBP, DBP, MAP), heart rate (HR), concentration of propofol (CEF-prop) and remifentanil (CEF-remi) in the effector area in three moments: baseline (M0), after losing verbal contact (M1), and after tracheal intubation (M2) were evaluated.
  
  
  RESULTS
  There were significant reductions in blood pressure in both groups at M1 and M2. CEF-remi was greater in Group 1, at M1, and greater in Group 2, at M2 (p < 0.05). There was a significant statistical correlation between the vascular overload index (VOI) and the variation of the systolic pressure after the loss of verbal contact in Group 1 (r = -0.80; p < 0.01) and in Group 2 after tracheal intubation (r = -0.60; p < 0.01).
  
  
  CONCLUSIONS
  Remifentanil administered two minutes before induction with propofol did not offer additional cardiovascular protection to tracheal intubation. This suggests that it is not necessary to start the infusion of remifentanil two minutes before anesthetic induction.
authors.affiliation: Hospital de Clínicas de Porto Alegre.
authors.forename: Fernando Squeff
authors.initials: FS
authors.lastname: Nora
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Klipel
authors.forename: Gustavo
authors.initials: G
authors.lastname: Ayala
authors.forename: Getúlio Rodrigues de
authors.initials: GR
authors.lastname: Oliveira Filho