Muscle Relaxants and Laryngeal Local Anesthetics for Laryngeal Mask Airway Insertion Decreasing Propofol in Elderly

Study Overview
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Brief Summary
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Laryngeal mask airway (LMA) is currently the most widely used supraglottic airway device with advantages of simple and fast placement, reduced anesthesia drug use, more stable hemodynamics, and less throat discomfort after anesthesia compared to endotracheal intubation. Some studies claimed the use of muscle relaxants or local anesthetics (sprays or lubricants containing local anesthetics) for the throat before LMA placement can reduce the dosage of induction agents and postoperative throat complications. In modern society, more and more elderly people undergo elective surgery with the need of general anesthesia. However, they are the more vulnerable population with tendency of greater hemodynamic changes with more induction agent usage. Propofol is one of the most used induction agents which may lead to a drop in blood pressure. The objective of this study is to observe whether the dose of propofol and the changes in hemodynamics can be reduced by using muscle relaxants or laryngeal local anesthetics in elderly who receiving general anesthesia with LMA insertion.

Official Title
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The Impact of Using Muscle Relaxants and Laryngeal Local Anesthetics for Laryngeal Mask Airway (LMA) Insertion on Hemodynamics and Induction Anesthetics Dosage in Elderly

Conditions
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Anesthesia, General

Intervention / Treatment
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* Drug: 10% lidocaine spray
* Drug: Placebo of lidocaine spray
* Drug: Cisatracurium
* Drug: Placebo of cisatracurium
* Drug: Propofol


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: American Society of Anesthesiologists (ASA) physical status I-III Age: over 65 years Elective orthopedic surgery undergo general anesthesia in supine position Exclusion Criteria: Anticipated difficult airway (Mallampati score 3-4), limited mouth opening, intra-oral and pharyngeal pathology Risk of pulmonary aspiration of gastric contents (full stomach) Obesity (Body mass index > 35) Significant lung abnormalities (low lung compliance, high airway resistance, impaired oxygenation) Loosening teeth Allergic to Cisatracurium or Lidocaine Failure in successful LMA insertion after second attempts

Ages Eligible for Study
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Minimum Age: 65 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: Other
Allocation: Randomized
Intervention Model: Factorial Assignment
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: 10% lidocaine spray and cisatracurium group<br>The subjects received laryngeal local anesthetics (10% lidocaine spray), intravenous cisatracurium 0.12 mg/kg, and propofol before laryngeal mask airway placement. The predetermined dosage of propofol for the first subject is 1 mg/kg. | Drug: 10% lidocaine spray<br>* 10% lidocaine spray 3 puff for the throat before induction<br>Drug: Cisatracurium<br>* Intravenous cisatracurium 0.12 mg/kg during induction<br>Drug: Propofol<br>* The dosage of intravenous propofol for the first subjects was predetermined for each arm, and the dosage for the subsequent subjects would be determined according to the response of the previous subjects using the Dixon's up-and-down method with a step size of 0.25 mg/kg. If the subjects had no movement and stable hemodynamic status during and after the laryngeal mask airway (LMA) placement, the predetermined dosage of propofol for the subsequent subject would be decreased by 0.25 mg/kg. On the other hand, if the subjects had obvious movement, failure to LMA placement, and significant hemodynamic changes, the predetermined dosage of propofol for the subsequent subject would be increased by 0.25 mg/kg.<br>|
| Experimental: 10% lidocaine spray and placebo of cisatracurium group<br>The subjects received laryngeal local anesthetics (10% lidocaine spray), intravenous normal saline as a substitute for cisatracurium, and propofol before laryngeal mask airway placement. The predetermined dosage of propofol for the first subject is 1.25 mg/kg. | Drug: 10% lidocaine spray<br>* 10% lidocaine spray 3 puff for the throat before induction<br>Drug: Placebo of cisatracurium<br>* Intravenous normal saline during induction<br>Drug: Propofol<br>* The dosage of intravenous propofol for the first subjects was predetermined for each arm, and the dosage for the subsequent subjects would be determined according to the response of the previous subjects using the Dixon's up-and-down method with a step size of 0.25 mg/kg. If the subjects had no movement and stable hemodynamic status during and after the laryngeal mask airway (LMA) placement, the predetermined dosage of propofol for the subsequent subject would be decreased by 0.25 mg/kg. On the other hand, if the subjects had obvious movement, failure to LMA placement, and significant hemodynamic changes, the predetermined dosage of propofol for the subsequent subject would be increased by 0.25 mg/kg.<br>|
| Experimental: Placebo of lidocaine spray and cisatracurium group<br>The subjects received normal saline spray as a substitute for laryngeal local anesthetics (10% lidocaine spray), intravenous cisatracurium 0.12 mg/kg, and propofol before laryngeal mask airway placement. The predetermined dosage of propofol for the first subject is 1 mg/kg. | Drug: Placebo of lidocaine spray<br>* Normal saline spray 3 puff for the throat before induction<br>Drug: Cisatracurium<br>* Intravenous cisatracurium 0.12 mg/kg during induction<br>Drug: Propofol<br>* The dosage of intravenous propofol for the first subjects was predetermined for each arm, and the dosage for the subsequent subjects would be determined according to the response of the previous subjects using the Dixon's up-and-down method with a step size of 0.25 mg/kg. If the subjects had no movement and stable hemodynamic status during and after the laryngeal mask airway (LMA) placement, the predetermined dosage of propofol for the subsequent subject would be decreased by 0.25 mg/kg. On the other hand, if the subjects had obvious movement, failure to LMA placement, and significant hemodynamic changes, the predetermined dosage of propofol for the subsequent subject would be increased by 0.25 mg/kg.<br>|
| Placebo Comparator: Placebo group<br>The subjects received normal saline spray as a substitute for laryngeal local anesthetics (10% lidocaine spray), intravenous normal saline as a substitute for cisatracurium, and propofol before laryngeal mask airway placement. The predetermined dosage of propofol for the first subject is 2 mg/kg. | Drug: Placebo of lidocaine spray<br>* Normal saline spray 3 puff for the throat before induction<br>Drug: Placebo of cisatracurium<br>* Intravenous normal saline during induction<br>Drug: Propofol<br>* The dosage of intravenous propofol for the first subjects was predetermined for each arm, and the dosage for the subsequent subjects would be determined according to the response of the previous subjects using the Dixon's up-and-down method with a step size of 0.25 mg/kg. If the subjects had no movement and stable hemodynamic status during and after the laryngeal mask airway (LMA) placement, the predetermined dosage of propofol for the subsequent subject would be decreased by 0.25 mg/kg. On the other hand, if the subjects had obvious movement, failure to LMA placement, and significant hemodynamic changes, the predetermined dosage of propofol for the subsequent subject would be increased by 0.25 mg/kg.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Propofol requirement | The minimal propofol requirement dose was defined as the median effective dose (ED50) of movement or increased mean arterial pressure (MAP) to no movement or stable MAP. The ED50 is the average of the crossover midpoints found during conducting the Dixon's up-and-down method. | one minute after propofol infusion | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Non-invasive blood pressure (NIBP) | Using the non-invasive blood pressure machine to collect the systolic blood pressure, diastolic blood pressure, and mean arterial pressure | 0 minute, 1 minute, 2 minute, 3 minute, 4 minute, 5 minute, 10 minute after LMA placement | 
| Heart rate (HR) | Using the electrocardiogram monitor to collect the real-time heart rate | 0 minute, 1 minute, 2 minute, 3 minute, 4 minute, 5 minute, 10 minute after LMA placement | 
| Oxygen saturation (SpO2) | Using the pulse oximeter to collect the real-time oxygen saturation | 0 minute, 1 minute, 2 minute, 3 minute, 4 minute, 5 minute, 10 minute after LMA placement | 
| Peak pressure (P peak) of the airway | One of the monitoring parameter demonstrated on the mechanical ventilator | 0 minute after LMA placement | 
| Mean pressure (P mean) of the airway | One of the monitoring parameter demonstrated on the mechanical ventilator | 0 minute after LMA placement | 
| Ease of jaw opening | A factor for evaluating the condition of LMA insertion | Procedure (At the same time of LMA placement) | 
| Ease of LMA insertion | A factor for evaluating the condition of LMA insertion | Procedure (At the same time of LMA placement) | 
| Coughing or gagging | Symptoms which suggest non-optimal condition of LMA insertion | Within 1 minute after LMA placement | 
| Hiccups | Symptoms which suggest non-optimal condition of LMA insertion | Within 1 minute after LMA placement | 
| Head or body movement | Symptoms which suggest non-optimal condition of LMA insertion | Within 1 minute after LMA placement | 
| Laryngospasm | Laryngospasm is defined as airway obstruction with assumption that LMA is correctly placed, which is also a factor for evaluating the condition of LMA insertion | Within 1 minute after LMA placement | 
| Attempts for LMA insertion | The number of attempts for LMA insertion | Procedure (At the same time of LMA placement) | 
| Complications | Including sore throat, dysphagia, dysphonia | One hour after LMA removal | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Muscle relaxants, Laryngeal local anesthetics, Laryngeal mask airway, Laryngeal Masks, LMA, Propofol, Elderly, Aged