Comparison of Sevoflurane and Propofol for Laryngeal Mask Airway Insertion in Children

INTRODUCTION: The major responsibility of an anaesthesiologist is to provide adequate ventilation for the patient by providing unobstructed airway. An anaesthetic technique is safe only when diligent efforts are devoted to maintain an intact functional airway. To maintain airway in an anaesthetized or unconscious patient we have supraglottic devices like anatomical face mask, laryngeal mask airway, cuffed oropharyngeal airway and combitube. Laryngeal mask airway was invented by Dr. ARCHIE BRAIN, United Kingdom in 1981. The LMA is an ingenious supraglottic airway device that is designed to provide and maintain a seal around the laryngeal inlet for spontaneous ventilation and allow controlled ventilation at modest levels of positive pressure. In controlled ventilation peak inflation pressure should not exceed 25cm H2O. An outstanding feature of LMA is that it provides a rapid clear airway in vast majority of patients and it is both faster and easier to insert than a tracheal tube. LMA can be used for pediatric and adult patients undergoing daycare surgeries. Successful insertion of LMA requires sufficient depth of anaesthesia and depression of airway reflexes to avoid gagging, coughing and laryngeal spasm. Propofol is the induction agent most commonly used for insertion of LMA. Sevoflurane is a recently introduced volatile anaesthetic agent which allows rapid smooth inhalational induction with excellent recovery. This study was being conducted to compare Sevoflurane and Propofol for insertion of laryngeal mask airway in children. This study was carried out in Dept. of Anaesthesiology, Stanley medical college, Chennai. AIM OF THE STUDY: The aim of the study is to compare the conditions of Laryngeal Mask Airway insertion in children after induction of anaesthesia with either inhalation of sevoflurane or intravenous propofol. The time taken for induction, time taken for jaw relaxation, time to LMA insertion, hemodynamic parameters, complications during induction and LMA insertion are compared. MATERIALS AND METHODS: Sixty patients of ASA physical status 1&2 undergoing elective minor surgical procedures below umbilicus lasting less than 60 mins. were included in the study. Patients belonged to age group of 4 – 12 of both sexes. It was a prospective randomized controlled study. The study was approved by institutional ethical committee and parent provided written informed consent before induction. Inclusion Criteria: 1. ASA I and II physical status. 2. No predicted airway difficulty. 3. Elective minor surgical procedures below umbilicus lasting less than 60 min. Exclusion Criteria: 1. Patients at risk of aspiration – upper GI surgery, gastroesophageal disease, not fasted. 2. Patients who require high positive pressure ventilation – eg. Pulmonary fibrosis. 3. Known allergy to any anaesthetic. MATERIALS: 1. Classic Laryngeal mask airways of appropriate size, 2. Propofol 1%, 3. Sevoflurane, 4. Fentanyl and glycopyrrolate, 5. Appropriate size oral airways, 6. 2,5 and 10 ml syringes, 7. Lubricant jelly. Preparation of the Patient: Informed consent from the parent obtained. All patients were fasted as per NPO guidelines. Premedication: Syp. Triclofos 60 mg/kg po given 45 min before shifting the child to operating room. METHODS: 1. Basal heart rate, blood pressure and oxygen saturation were recorded. 2. Intravenous access established. 3. Inj. Glycopyrrolate 10μg/kg and Inj. Fentanyl citrate 2 μg/kg i.v. given on table. 4. Preoxygenation with 100% O2 done for 3 min. SUMMARY: We assessed the conditions for insertion of LMA in two groups of patient receiving either inhalational sevoflurane or intravenous propofol and the following observations were made. • There were no significant differences between the two groups in demographic data. • The time to induction is less with sevoflurane compared to propofol in this study, though statistically not significant. • The time to jaw relaxation and the time to LMA insertion is less with propofol, with statistical significance. • The insertion is more successful by 1st attempt in the propofol group. But this is not statistically significant. • There are few cases who had movements during induction in propofol group and few cases had transient apnea during induction in sevoflurane group. • There is no significant difference between both groups in the incidence of coughing, gagging and laryngospasm. • There is significant difference in pulse rate in both groups. The pulse rates in propofol group decreased from baseline but within acceptable limits. In Sevoflurane group pulse rate increased from baseline during induction and LMA insertion, within acceptable limits. • The decrease in mean arterial pressure is observed in both groups and is not statistically significant. CONCLUSION: In conclusion, Propofol and Sevoflurane are equally effective for LMA insertion in children. However, Propofol has a faster insertion time due to early onset of jaw relaxation compared to sevoflurane and high success rate in 1st attempt for LMA insertion whereas Sevoflurane has better hemodynamic stability and less side effects compared to propofol