The Optimal Time to Put Laryngeal Mask Airway in the Mouth Under General Anesthesia

Study Overview
=================
Brief Summary
-----------------
Laryngeal mask airway (LMA) is routinely used for some patients who have surgery under general anesthesia. LMA is placed in the mouth and allow the anesthesia to be given without having to put a breathing tube in the throat. Previous studies have focused on the effect of different anesthesia medicines on optimal condition for LMA use. The objective of the present study is to find the optimal time for LMA insertion.

Detailed Description
-----------------
This is a randomized, controlled, blinded trial. Midazolam, 2 mg and fentanyl 1.0 µg/kg, would be given prior to induction with propofol, 2.5 mg/kg. The investigator who does the induction of general anesthesia will also be responsible for the timekeeping. For this reason, it is not possible for this investigator to be blinded to randomization. The induction would conclude after loss of eyelash reflex (LER). At that point insertion of the LMA (#4 for females, #5 for males) will occur 0, 60 and 90 seconds after LER. The LMA will be lubricated with a water soluble gel and will be inserted with a deflated cuff according to the technique described by Brain. The investigator who inserts the LMA (Inv1) will be in the operating room and blinded to randomization groups by not seeing the induction of general anesthesia. This investigator will insert the LMA only when called by the investigator who induces general anesthesia (Inv2). Inv1 will also grade ease of LMA insertion. The primary outcome is Jaw opening at the time of LMA insertion, defined as full 1, partial 2, and nil 3. Secondary outcomes include: Insertion of LMA (easy, difficult, impossible) Coughing or gagging (none, some, significant) Head or body movement (none, some, significant) Laryngospasm or airway obstruction (none, partial, total)

Official Title
-----------------
The Optimal Time of Insertion of Laryngeal Mask Airway With Propofol Induction

Conditions
-----------------
General Anesthesia

Intervention / Treatment
-----------------
* Procedure: Insertion of Laryngeal Mask Airway


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: subjects 18 years or older ASA status 1-3 Exclusion Criteria: high risk of aspiration anticipated difficult airway use of sedative drugs patient refusal

Ages Eligible for Study
-----------------
Minimum Age: 18 Years
Maximum Age: 65 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------

Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Other: 0 sec, 60 sec, 90 sec<br>LMA will be inserted at 0, 60, and 90 seconds after eyelash reflex disappears | Procedure: Insertion of Laryngeal Mask Airway<br>* The LMA will be inserted at 0 sec, 60 sec. and 90 sec. after induction of general anesthesia<br>* Other names: Laryngeal Mask Airway;|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Ease of Mouth opening |  | From Induction of general anesthesia to satisfactory LMA insertion |