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

This study has been completed.
Information provided by (Responsible Party):
Tufts Medical Center Identifier:
First received: September 3, 2009
Last updated: December 3, 2013
Last verified: December 2013
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.

Condition Intervention
General Anesthesia Procedure: Insertion of Laryngeal Mask Airway

Study Type: Interventional
Study Design: Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single (Outcomes Assessor)
Primary Purpose: Treatment
Official Title: The Optimal Time of Insertion of Laryngeal Mask Airway With Propofol Induction

Resource links provided by NLM:

Further study details as provided by Tufts Medical Center:

Primary Outcome Measures:
  • Ease of Mouth opening [ Time Frame: From Induction of general anesthesia to satisfactory LMA insertion ]

Enrollment: 198
Study Start Date: September 2009
Study Completion Date: December 2013
Primary Completion Date: December 2013 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
0 sec, 60 sec, 90 sec
LMA will be inserted at 0, 60, and 90 seconds after eyelash reflex disappears
Procedure: Insertion of Laryngeal Mask Airway
The LMA will be inserted at 0 sec, 60 sec. and 90 sec. after induction of general anesthesia
Other Name: Laryngeal Mask Airway

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:

  1. Insertion of LMA (easy, difficult, impossible)
  2. Coughing or gagging (none, some, significant)
  3. Head or body movement (none, some, significant)
  4. Laryngospasm or airway obstruction (none, partial, total)

Ages Eligible for Study:   18 Years to 65 Years   (Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No

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
  Contacts and Locations
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Please refer to this study by its identifier: NCT00972491

United States, Massachusetts
Tufts Medical Center
Boston, Massachusetts, United States, 02111
Sponsors and Collaborators
Tufts Medical Center
Principal Investigator: Pei-shan Zhao, MD,PhD Tufts Medical Center
  More Information

Responsible Party: Tufts Medical Center Identifier: NCT00972491     History of Changes
Other Study ID Numbers: IRB-8910
Study First Received: September 3, 2009
Last Updated: December 3, 2013 processed this record on September 21, 2017