Evaluation of Influencing Variables in Awakening Concentration and Concentration at Body Movements of Propofol TCI (Targeted Controlled Infusion) Targeted at the Effector Site

Study Overview
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Brief Summary
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Age has been related to awakening propofol concentration at effector site of TCI, but not to the loss of consciousness concentration, neither to the concentration of body movements during surgery, that can be interpreted as a sign of light anesthesia and lead to awareness. This study aims to determinate the incidence and the propofol TCI concentration at the effector site, in patients undergoing general anaesthesia without NBDs, of any patients body movements, defined as any spontaneous movements (but no reflex movements) during surgery.

Detailed Description
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Target-Controlled-Infusion (TCI), estimating the effect-size concentration (Ce) of propofol and its elimination time with a computerized system, provides the anaesthesiologist useful information to guide anaesthesia. Although the correlation between propofol at the effector site at loss of consciousness (Ce LOC) and age is still debated with contrasting results, the correlation between propofol at the effector site at return of consciousness (Ce ROC) and age is well established, and some authors suggested that, due also for age-related changes in both pharmacokinetics and pharmacodynamics of propofol, its dosage should be reduced in elderly patients. Lowering propofol dosage however, can lead to an higher incidence of awareness during general anaesthesia, even if anaesthesia management is guided by consciousness monitors. Awareness during anaesthesia has recently been defined not as a binary phenomenon, but as a graded spectra of states and, during general anaesthesia without using neuromuscular blocking drugs (NBDs), body movement on the operating table can be taken as an indication of increasing probability of consciousness or 'light' anaesthesia. Hence, this study aims to evaluate the impact of age on the concentration at the effector site of propofol-remifentanil anaesthesia administered with TCI pump and without NBDs. Concnetration at the effector site of Propofol at the return of consciousness (CeP ROC) and at any clinical sign of superficialization such as body movements (CeP BM) will be considered.

Official Title
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Evaluation of Influencing Variables in Awakening Concentration and Concentration at Body Movements of Propofol TCI (Targeted Controlled Infusion) Targeted at the Effector Site

Conditions
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Awareness, Anesthesia

Intervention / Treatment
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* Drug: We do not modify the normale general anesthesia delivery. We note the concentration of propofol at the effector site of body movementsand awakening


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients undergoing general anesthesia with propofol and remifentanil delivered with TCI infusion pump Exclusion Criteria: neurological or psychiatric or cerebrovascular diseases renal insufficiency patients unable to understand the information contained in the informed consent form, patients with intraoperative hemodynamic instability or patients who was delivered curare agents during anaesthesia

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 90 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Patients without body movements<br>Patient who, under general anesthesia without curare agents, during surgery has no body movements | Drug: We do not modify the normale general anesthesia delivery. We note the concentration of propofol at the effector site of body movementsand awakening<br>* Propofol in our hospital is routinely delivered by Targeted Controlled Infusion (TCI) pumps. We note the concentration of propofol at the effector site of body movements and awakening<br>|
| Patients with body movements<br>Patient who, under general anesthesia without curare agents, during surgery has any body movements that are no reflexes movements | Drug: We do not modify the normale general anesthesia delivery. We note the concentration of propofol at the effector site of body movementsand awakening<br>* Propofol in our hospital is routinely delivered by Targeted Controlled Infusion (TCI) pumps. We note the concentration of propofol at the effector site of body movements and awakening<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Incidence of body movements in patients undergoing surgery without curare agents | We will note if patients have spontaneous movements during surgery, and calculate the incidence of the phenomenon. | During surgery | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Concentration of propofol at body movements | We will note the concentration at the effector site of propofol TCI during body movements and compare them to pre-operative and demographical variables (age, weight, height, American Society of Anaesthesiologist physical status classification system (ASA), number of previous general anaesthesia, years of schooling, Sort Portable Mental Status Questionnaire score) and intra-operative variables ( concentration at the effector site of remifentanil at ventilator maladjustment (CeR VM), mean Ce propofol and remifentanil target during maintenance, and maximum, mean and minimum State Entropy (SE) and Response Entropy (RE) values during maintenance). | Patients will be subjected to Sort Portable Mental Status Questionnaire (SPMSQ) before surgery. Other variables are collected during surgery | 
| Concentration of propofol at return of consciousness | We will note the concentration at the effector site of propofol TCI at awakening and compare them to pre-operative and demographical variables (age, weight, height, American Society of Anaesthesiologist physical status classification system (ASA), number of previous general anaesthesia, years of schooling, Sort Portable Mental Status Questionnaire score) and intra-operative variables ( concentration at the effector site of remifentanil at ventilator maladjustement (CeR VM), mean Ce propofol and remifentanil target during maintenance, and maximum, mean and minimum SE and RE Entropy values during maintenance). | Patients will be subjected to Sort Portable Mental Status Questionnaire (SPMSQ) before surgery. Other variables are collected during surgery |