ED50 of Cis-atracurium for Laryngeal Mask Incubation in General Anesthesia

Study Overview
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Brief Summary
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The muscle relaxants can improve the conditions of laryngeal mask incubation and reduce the related complications (such as laryngeal spasm and postoperative throat pain) The dosages of muscle relaxants used in various researches vary greatly. We are planning use the most classical method for determining the ED50 or half effective concentration of cis-atracurium using sequential method, which is also called  up and down method and  ladder method.

Detailed Description
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The concordance of the current research is that muscle relaxants can improve the conditions of laryngeal mask incubation and reduce the related complications (such as laryngeal spasm and postoperative throat pain ) of laryngeal mask incubation. It is necessary to use muscle relaxants in laryngeal mask incubation under non-special circumstances. However, the dosages of muscle relaxants used in various researches vary greatly of normal endotracheal intubation. Previous studies have shown that the amount of muscle relaxant required for laryngeal mask intubation is smaller than that required for endotracheal intubation. Although the dosage of muscle relaxant required for tracheal intubation can ensure the smooth insertion of laryngeal mask airway, laryngeal mask airway is mostly used for short surgery, which is prone to postoperative muscle relaxation residue and prolongs the recovery. We planning use the most classical method for determining the ED50 or half effective concentration of cis-atracurium using sequential method, which is also called  up and down method and  ladder method.

Official Title
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ED50 of Cis-atracurium for Laryngeal Mask Incubation in General Anesthesia During Urology Surgery

Conditions
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Urologic Diseases

Intervention / Treatment
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* Drug: Cis-atracurium


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: ASA Ⅱ Ⅲlevel; BMI18.5-30； Those who intend to undergo short urological surgery ( operation time < 1h ); Age 25 75 years Estimated amount of bleeding < 5ml / kg. Exclusion Criteria: Neuromuscular diseases or metabolic diseases; Preoperative complicated with water and electrolytes disorders ( such as hypokalemia and hypocalcemia ); Serious hepatic and renal insufficiency and serious heart and lung diseases; Predictable difficult airway; Take drugs ( such as aminoglycoside, polymyxin, phenytoin sodium, carbamazepine, etc. ) that affect the nerve-muscle transmission function or the efficacy of muscle relaxants before surgery; Muscle relaxation drug allergy; Previous history of alcoholism or drug abuse.

Ages Eligible for Study
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Minimum Age: 25 Years
Maximum Age: 75 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 |
| --- | --- |
| 0.15mg/ kg group<br>Administration method of cis-atracurium: the dose of the first patient is 0.15 mg / kg, and the ratio between adjacent doses is 1.5. If the laryngeal mask insertion condition of this patient is satisfactory, the next patient will use the lower dose. If the laryngeal mask insertion condition of this patient is not satisfactory, the next patient will use a higher dose. Starting from the first case of dissatisfaction, the number of observation units is counted. Dissatisfaction - satisfaction occurs at 7 exchange points and then the test ends. | Drug: Cis-atracurium<br>* Different concentration of cis-atracurium<br>* Other names: muscle relaxants;|
| 0.1mg/ kg group<br>Administration method of cis-atracurium: the dose of the first patient is 0.15 mg / kg, and the ratio between adjacent doses is 1.5. 0.15/1.5=0.1 ( If the laryngeal mask insertion condition of this patient is satisfactory, the next patient will use the lower dose. If the laryngeal mask insertion condition of this patient is not satisfactory, the next patient will use a higher dose. Starting from the first case of dissatisfaction, the number of observation units is counted. Dissatisfaction - satisfaction occurs at 7 exchange points and then the test ends.) | Drug: Cis-atracurium<br>* Different concentration of cis-atracurium<br>* Other names: muscle relaxants;|
| 0.07mg/ kg group<br>Administration method of cis-atracurium: the dose of the first patient is 0.15 mg / kg, and the ratio between adjacent doses is 1.5. 0.1/1.5=0.0667 ( If the laryngeal mask insertion condition of this patient is satisfactory, the next patient will use the lower dose. If the laryngeal mask insertion condition of this patient is not satisfactory, the next patient will use a higher dose. Starting from the first case of dissatisfaction, the number of observation units is counted. Dissatisfaction - satisfaction occurs at 7 exchange points and then the test ends.) | Drug: Cis-atracurium<br>* Different concentration of cis-atracurium<br>* Other names: muscle relaxants;|
| 0.05mg/ kg group<br>Administration method of cis-atracurium: the dose of the first patient is 0.15 mg / kg, and the ratio between adjacent doses is 1.5. 0.07/1.5=0.0466( If the laryngeal mask insertion condition of this patient is satisfactory, the next patient will use the lower dose. If the laryngeal mask insertion condition of this patient is not satisfactory, the next patient will use a higher dose. Starting from the first case of dissatisfaction, the number of observation units is counted. Dissatisfaction - satisfaction occurs at 7 exchange points and then the test ends.) | Drug: Cis-atracurium<br>* Different concentration of cis-atracurium<br>* Other names: muscle relaxants;|
| 0.03mg/ kg group<br>Administration method of cis-atracurium: the dose of the first patient is 0.15 mg / kg, and the ratio between adjacent doses is 1.5. 0.05/1.5=0.0333 ( If the laryngeal mask insertion condition of this patient is satisfactory, the next patient will use the lower dose. If the laryngeal mask insertion condition of this patient is not satisfactory, the next patient will use a higher dose. Starting from the first case of dissatisfaction, the number of observation units is counted. Dissatisfaction - satisfaction occurs at 7 exchange points and then the test ends.) | Drug: Cis-atracurium<br>* Different concentration of cis-atracurium<br>* Other names: muscle relaxants;|
| 0.02mg/ kg group<br>Administration method of cis-atracurium: the dose of the first patient is 0.15 mg / kg, and the ratio between adjacent doses is 1.5. 0.03/1.5=0.02( If the laryngeal mask insertion condition of this patient is satisfactory, the next patient will use the lower dose. If the laryngeal mask insertion condition of this patient is not satisfactory, the next patient will use a higher dose. Starting from the first case of dissatisfaction, the number of observation units is counted. Dissatisfaction - satisfaction occurs at 7 exchange points and then the test ends.) | Drug: Cis-atracurium<br>* Different concentration of cis-atracurium<br>* Other names: muscle relaxants;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Laryngeal mask insertion conditions(satisfactory/unsatisfactory) | The evaluation criteria of laryngeal mask insertion conditions are based on siva lingam's six-point three-level table, which is evaluated from the following six aspects: the degree of mouth opening, difficulty in laryngeal mask insertion, cough, retch, laryngeal spasm, and body movement. Each item is divided into 3, 2 and 1 points according to the degree of severity, with a full score of 18 points, 16 points and above being satisfactory, and 16 points and below being unsatisfactory. | through study completion, an average of 1 day |