Anesthesia, General, Anesthesia, Intravenous, Hemodynamic Instability
Conditions
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
Brief 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.
Interventions
DRUGRemifentanil R2
0,7 microg/kg
DRUGRemifentanil R4
1,1 microg/kg
DRUGRemifentanil R8
1,7 microg/kg
Sponsors
Helse Fonna
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
BASIC_SCIENCE
Masking
QUADRUPLE (Subject, Caregiver, Investigator, Outcomes Assessor)
Masking description
Randomization made by a person not involved in trial in other ways. Allocation masked in sealed envelopes, stored in a locked cash box only opened by two drug preparing nurses not involved in patient care. Syringe labelled with patient identification (ID) (eg 03Remi). Patient, Care Provider and Investigator blinded for actual concentration of drug. Allocation break after data data wash and processing.
Intervention model description
Randomized, controlled, double blind.
Eligibility
Sex/Gender
FEMALE
Age
18 Years to 50 Years
Healthy volunteers
No
Inclusion criteria
* Gynecological procedure * Age 18-50 years * General anesthesia planned * Systolic blood pressure \< 150 mmHg, HR \< 100 beats/min
Exclusion criteria
* Pre-existing hypertension * Diabetes * Ischemic heart disease or cerebrovascular disease * Heart valve disease * Verified cardiac arrhythmia other than extrasystoles * Verified anaemia with hemoglobin level below 9.0 gr/dl. * Kidney or hepatic disease * Hypersensitivity for propofol, soya, eggs or peanuts * Pregnancy * Poor health state * Illicit substance use * BMI \<20 or \>35 kg/m2
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Systolic Blood Pressure (SBP) | First 7,5 minutes from start of induction | Change in systolic blood pressure during induction |
| Heart Rate (HR) | First 7,5 minutes from start of induction | Change in heart rate during induction |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Stroke Volume (SV) | First 7,5 minutes from start of induction | Change in stroke volume during induction |
| Cardiac Output (CO) | First 7,5 minutes from a start of induction | Change in cardiac output during induction |
| Systemic Vascular Resistance (SVR) | First 7,5 minutes from start of induction | Change in systemic vascular resistance during induction |
Countries
Norway
Outcome results
None listed