Impact of Propofol Reduction in Anesthesia Induction

Study Overview
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Brief Summary
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Objective: Determine if, by reducing the dose of propofol and increasing the time elapsed between fentanyl and propofol administration, hemodynamic response is improved. Methods: Patients were randomized into time groups (2 and 1 minute) and each subdivided into dose groups (1, 1.5 and 2 mg kg-1) obtaining six time-dose groups. After receiving 2 μg kg-1 of fentanyl, propofol was administered after the predetermined time. Time to hypnosis (BIS<60) and hemodynamic parameters at pre-induction, pre-intubation and postintubation were registered.

Detailed Description
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A minimum of 162 patients were required, considering an expected Mean Difference of 5 with expected Standard Deviation of 22, confidence level of 95% and power of 80%. Estimating a possible loss of 15%, it was raised to 192. Consecutive identification numbers were assigned and the sample was randomized in six groups of 32 patients according to time and dose of propofol. Pre-oxygenation was performed until the expired oxygen fraction exceeded 80% and 2 µg/kg of intravenous fentanyl were administered. Depending on the study group, 1 or 2 minutes were allowed to pass and 1, 1.5 or 2 mg/kg of propofol were supplied (prior administration of intravenous lidocaine 0.5 mg/kg). The time in which the BIS dropped below 60 was recorded. If it did not reach that level after two minutes or when it exceeded it but then rose above 60 again, an extra dose of propofol of 0.5 mg/kg was administered. Muscle relaxation was performed with rocuronium 0.6 mg/kg. The patient was manually ventilated until endotracheal intubation was performed by the same experienced anaesthesiologist and connected to mechanical ventilation. Data were collected manually. Statistical analysis was performed using SPSS ver. 22. Inferential statistics were performed using t-test for quantitative variables, chi-square for qualitative and ANOVA for qualitative and quantitative comparisons. Non-parametric statistical tests were used when necessary. Confidence intervals were estimated at a level of 95% and a P value of <.05 was considered statistically significant.

Official Title
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Impact of Propofol Dose Reduction in Relation to the Time Since Administration of Fentanyl During Anesthesia Induction

Conditions
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Propofol Adverse Reaction, Anesthesia

Intervention / Treatment
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* Drug: Propofol Injection


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Adults who required general anesthesia General anesthesia with endotracheal intubation (no supraglottic devices) Signed informed consent Non-cardiac surgery Same anesthesiologist Exclusion Criteria: Hemodynamic instability (systolic BP < 90 mmHg with clinical signs of low cardiac output: impaired consciousness, diuresis <0.5 ml/kg/h, central venous saturation <60% with normal arterial saturation or lactate >3 mmol/l) Increased risk of bronchoaspiration (absence of fasting, stomach retention, intestinal obstruction, pregnancy, etc.) Suspected difficult airway Known allergy to anesthetic drugs

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Supportive Care
Allocation: Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: 2 time groups, divided into 3 dose groups
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: 2 minute - 2 mg/kg group<br>2 mcg/kg of fentanyl administrated intravenously. wait for 2 minutes to inject 2 mg/kg of propofol | Drug: Propofol Injection<br>* 1, 1.5 or 2 mg/kg of propofol according to the subgroup<br>|
| Active Comparator: 2 minute - 1,5 mg/kg group<br>2 mcg/kg of fentanyl administrated intravenously. wait for 2 minutes to inject 1,5 mg/kg of propofol | Drug: Propofol Injection<br>* 1, 1.5 or 2 mg/kg of propofol according to the subgroup<br>|
| Active Comparator: 2 minute - 1 mg/kg group<br>2 mcg/kg of fentanyl administrated intravenously. wait for 2 minutes to inject 1 mg/kg of propofol | Drug: Propofol Injection<br>* 1, 1.5 or 2 mg/kg of propofol according to the subgroup<br>|
| Active Comparator: 1 minute - 2 mg/kg group<br>2 mcg/kg of fentanyl administrated intravenously. wait for 1 minute to inject 2 mg/kg of propofol | Drug: Propofol Injection<br>* 1, 1.5 or 2 mg/kg of propofol according to the subgroup<br>|
| Active Comparator: 1 minute - 1,5 mg/kg group<br>2 mcg/kg of fentanyl administrated intravenously. wait for 1 minute to inject 1,5 mg/kg of propofol | Drug: Propofol Injection<br>* 1, 1.5 or 2 mg/kg of propofol according to the subgroup<br>|
| Active Comparator: 1 minute - 1 mg/kg group<br>2 mcg/kg of fentanyl administrated intravenously. wait for 1 minute to inject 1 mg/kg of propofol | Drug: Propofol Injection<br>* 1, 1.5 or 2 mg/kg of propofol according to the subgroup<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Systolic Blood Pressure Variation | Non-invasive systolic blood pressure change (%) at baseline, pre-intubation and postintubation. Positive results mean percentage reduction in SBP between the studied moments. Negative results mean percentage increase in SBP between the studied moments. | Baseline before fentanyl administration, pre-intubation after propofol and bispectral index<60 and postintubation 15 seconds after endotracheal tube positioned | 
| Heart Rate Variation | Heart rate change (%) registered at baseline, pre-intubation and postintubation. Positive results mean percentage reduction in HR between the studied moments. Negative results mean percentage increase in HR between the studied moments. | Baseline before fentanyl administration, pre-intubation after propofol and bispectral index<60 and postintubation 15 seconds after endotracheal tube positioned | 
| Systolic Blood Pressure Variation in Elderly (>55y) | Non-invasive SBP change (%) in patients > 55 years at baseline, pre-intubation and postintubation. Positive results mean percentage reduction in SBP between the studied moments. Negative results mean percentage increase in SBP between the studied moments. | Baseline before fentanyl administration, pre-intubation after propofol and bispectral index<60 and postintubation 15 seconds after endotracheal tube positioned | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Time to Hypnosis | Bispectral index (BIS)<60 meaning general anesthesia, BIS>60 meaning mild/moderate sedation. We measure the time until patient reachs hypnosis | After administration of propofol, time is measured in seconds until BIS values are less than 60 | 
| Number of Patients Who Needed Vasoactive Drug | Patients who suffered SPB reduction > 30% or SPB < 90mmHg, receive vasoactive drugs | 1 minute after intubation | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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propofol synergy, fentanyl, anesthesia induction