IRCT20110513006465N3 IRCT 2021-06-15 Iran University of Medical Sciences Comparison of the use of laryngeal mask with and without muscle relaxant in anesthesia of children one to four years old. Comparative study of using laryngeal mask (LMA) with and without muscle relaxant in anesthesia of children one to four years old undergoing upper extremity reconstructive surgery in Hazrat Fatemeh Hospital. 2021-06-22 anticipated 70 Complete https://irct.ir/trial/54389 interventional Randomization: Randomized, Blinding: Double blinded, Placebo: Used, Assignment: Parallel, Purpose: Treatment, Randomization description: In this study, we use the block randomization method so that after selecting patients according to the inclusion and exclusion criteria by selecting numbers from the table of random numbers and adapting to the blocks, patients are divided into study groups, Blinding description: The patient and the person evaluating the goals are unaware of the type of intervention being assigned. 3 Children's diseases. Intervention 1: Intervention group: In one group of patients, the neuromuscular relaxant drug Atracurium made by Caspian Pharmaceutical Company at a dose of 0.5 mg / kg is used as an intervention during induction of anesthesia. The drug is drawn in a 5 cc syringe and labeled A. Intervention 2: Control group: In the other group, instead of using a neuromuscular relaxant, normal saline is used. The drug is drawn in a 5 cc syringe and labeled B. Undecided - It is not yet known if there will be a plan to make this available Justification or reason for indecision in sharing IPD is There is no more information.