Hemodynamics During Induction of General Anesthesia With Medium or Low Remifentanil Doses.
Condition: Hemodynamic Instability; Anesthesia, General; Anesthesia, Intravenous
Study type: Interventional
Phase: Phase 4

Summary: 
      In this trial the investigators want to examine if there is any difference in hemodynamic
      stability during induction when comparing two low and a medium remifentanil dose and keeping
      propofol induction dose at about 2.0 mg/kg.
    

Detailed description: 
      Typically, one or more adjuvant medications is administered during induction of general
      anesthesia. When anesthetic drugs are combined, the hypnotic effects are often synergistic.
      Propofol is associated with hypotension and bradycardia and used together with remifentanil
      or sedative agents it may give synergistic or additive sedative and hemodynamic effects.

      Remifentanil is infused at 0.05-0.3 microg/kg/min during induction of anesthesia. Some use a
      loading dose of 0.5-1.0 microg/kg before starting the continuous infusion. The onset of
      action of remifentanil is within one to two minutes and it reaches rapidly a steady state
      effect site concentration after a bolus dose.

      Kazmaier (2000) showed that a high-dose remifentanil anesthesia (2 microg/kg/min) reduced
      cardiac index (-25%), stroke volume (-14%) and mean arterial blood pressure (-39%) in a
      similar manner as propofol/remifentanil (propofol target 2 microg/ml and remifentanil 0.5
      microg/kg/min), but systemic vascular resistance index decreased (-14%) in
      propofol/remifentanil combination. Fairfield et al have earlier (1991) showed that propofol
      2.5 mg/kg induction without opioid reduces cardiac output (-15%) stroke volume (-5 %), mean
      arterial pressure (-33%) and systemic vascular resistance (-11%) and a slight reduction i
      heart rate. Guarracino (2003) suggests the reduction in cardiac index during induction with
      propofol/remifentanil with a low propofol target (1.2 microg/ml) may be due to decreased
      heart rate. Zaballos (2009) have shown that remifentanil depresses sinus node and
      atrioventricular (AV) -nodal function in comparison with propofol alone in a closed chest
      porcine model. Hayashi (2016) states that even in a low remifentanil effect site
      concentration (3.5 nanog/ml) it may reduce heart rate significantly when combined with
      propofol bolus 30-50 mg.
    

Intervention name(s): Remifentanil R2; Remifentanil R4; Remifentanil R8
Intervention type(s): Drug; Drug; Drug
Intervention description(s): 0,7 microg/kg; 1,1 microg/kg; 1,7 microg/kg
Other intervention name(s): Ultiva; Ultiva; Ultiva
Intervention MeSH terms: Remifentanil
Allocation: Randomized
Intervention model: Parallel Assignment
Intervention model description: Randomized, controlled, double blind.
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Primary purpose: Basic Science
Keywords: Cardiac Output (CO); Systolic Blood Pressure (SBP); Systemic Vascular Resistance (SVR); Heart Rate (HR); Stroke Volume (SV); Lithium Dilutional Cardiac Output (LiDCO); Minimal Invasive Hemodynamic Monitor; Remifentanil