Awareness in Old Aged Patients During Laryngoscopy and Intubation Using Isolated Forearm Technique

Study Overview
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Brief Summary
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Awareness during general anesthesia - that has an incidence between 0.1% and 0.9% of cases and may be more in elderly - remains a concern for anesthesiologists. Awareness experiences range from isolated auditory perceptions to reports of a patient being fully awake, immobilized, and in pain. The isolated forearm technique allows assessment of consciousness of the external world (connected consciousness) through a verbal command to move the hand (of a tourniquet-isolated arm) during intended general anesthesia.

Detailed Description
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Objective: To compare inhalational induction versus intravenous induction regarding awareness during laryngoscopy and intubation in elderly patients undergoing day case elective surgery.

Official Title
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Detection of Responsiveness and Awareness in Old Aged Patients During Laryngoscopy and Intubation Using Isolated Forearm Technique

Conditions
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Awareness, Anesthesia, Recall Phenomenon, Inhalation; Gas

Intervention / Treatment
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* Drug: Sevoflurane
* Drug: TIVA


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: 50 American society of anesthesiologists- Physical status (ASA-PS) I and II patients, aged 60 to 80 years, 70-80 kg, both sexes, with intact hearing, undergoing elective day case surgery were included in the study. Exclusion Criteria: Uncooperative patients, Language barrier problems, Psychological disorders, Suspected difficult intubation, History of awareness under anesthesia, History of substance abuse, The inability to have tourniquet on arm for the IFT (e.g., lymphedema or operative site) Neuromuscular disorders. Advanced renal, hepatic, cardiac, respiratory or neurological dysfunction If rapid sequence induction was indicated (not suitable for inhalation induction).

Ages Eligible for Study
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Minimum Age: 60 Years
Maximum Age: 80 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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Design Details

Primary Purpose: Diagnostic
Allocation: Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: Interventions: Patients were randomized into either Group A (who received inhalational induction) and Group B (who received total intravenous induction followed by maintenance infusion). Main outcome measure: IFT response was recorded at laryngoscopy and intubation to identify awareness at this stressful timepoint.
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Group A<br>In group A: The researcher, who supervised the anesthesia, explained the concept of the study to all patients before induction, and then a tourniquet was placed around the dominant arm of the patients after placing a cotton bandage; to be inflated to 200mmHg or 40 mmHg above the systolic blood pressure of the patient; immediately before administration of the muscle relaxant later on. Patients received inhalation induction using sevoflurane 8% and fentanyl 2 µg/kg was administered intravenously. After loss of consciousness, and BIS value of 50 or less, the tourniquet cuff was inflated then atracurium 0.5 mg/kg was given intravenously and sevoflurane reduced to 2%, then laryngoscopy and intubation were done when action of neuromuscular blocker (NMB) was confirmed by the disappearance of T3,T4. During this time, mask assisted ventilation with 100% oxygen was used to achieve normocapnia | Drug: Sevoflurane<br>* IFT response, hemodynamics and BIS value were recorded during intubation period. Then the data acquisition was stopped and the isolated forearm cuff deflated. IFT values were noted by two independent observers<br>* Other names: Inhalational induction;|
| Active Comparator: Group B<br>In group B: The researcher, who supervised the anesthesia, explained the concept of the study to all patients before induction, and then a tourniquet was placed around the dominant arm of the patients after placing a cotton bandage; to be inflated to 200mmHg or 40 mmHg above the systolic blood pressure of the patient; immediately before administration of the muscle relaxant later on. In group B: propofol 1.5 mg/kg and fentanyl 2 µg/kg were administered intravenously. After loss of consciousness, and BIS value of 50 or less, the tourniquet cuff was inflated and then atracurium 0.5 mg/kg was given intravenously. Propofol infusion 6 mg/kg/hr was started, until action of neuromuscular blocker (NMB) was confirmed by disappearance of T3,T4, then laryngoscopy and intubation were done. The used dosing regimen is according to previous guidelines [8] [9].No inhalational agent was used. Mask assisted ventilation was used to achieve normocapnia. | Drug: TIVA<br>* IFT response, hemodynamics and BIS value were recorded during intubation period. Then the data acquisition was stopped and the isolated forearm cuff deflated. IFT values were noted by two independent observers<br>* Other names: Total Intravenous induction;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| IFT response was recorded at laryngoscopy and intubation | Score is from zero to 5 Increasing score means increasing risk of awareness especially if >3 The primary outcome was IFT response was recorded at laryngoscopy and intubation to identify awareness at this stressful timepoint. | 10 minutes | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Bispectral index monitor (BIS) | Value from 100 to zero. 100 means fully awake We aim to be with in 40-60 intraoperatively to decrease risk of awareness BIS values were recorded at the following timings: Baseline After induction and muscle relaxation, During laryngoscopy, After successful intubation After 20 minutes from skin incision After 40 minutes from skin incision | 40 minutes | 
| Modified Brice questionnaire | 2 hours and 24 hours after the end of anesthesia, patients were interviewed regarding the experience of dreaming or recall (of the induction period) | 24 hours | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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TIVA, Isoflurane, old age