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Evaluation of Functional Dimensions of Macintosh Laryngoscope Blade During Direct Laryngoscopy in Patients With Normal Mouth Opening

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Know the risks and potential benefits of clinical studies and talk to your health care provider before participating. Read our disclaimer for details. Identifier: NCT02639897
Recruitment Status : Recruiting
First Posted : December 28, 2015
Last Update Posted : October 30, 2020
Information provided by (Responsible Party):
Dr Nitin Sethi, Sir Ganga Ram Hospital

Brief Summary:

Direct laryngoscopy and intubation is an essential initial aspect of airway access during general anesthesia. To perform the procedure effectively, it requires adequate mouth opening, head and neck movement, and a normal temporo-mandibular joint mobility. Any issue with the above three results in a compromised upper airway at the outset and the condition is known as anticipated difficult airway, i.e. an airway that is difficult to access with conventional laryngoscopy and intubation methods. To overcome the difficulty, either one has to resort to newer advanced technique and equipment or the available conventional technique needs to be refined and modified to suit the requirement. While the former requires extraordinary expertise and finances, an option difficult to achieve in developing countries; the latter warrants focused interest to develop alternative approach with the same set of equipments.

Since submucous fibrosis and the associated restricted mouth opening have taken the proposition of an epidemic owing to widespread use of betel nut and tobacco; these patients, when requiring surgery, are difficult candidates for GA and airway control. The fact that, when they arrive as pre-surgical candidates, they have variable degree of mouth opening restriction, which if approached with a strategy, may be amenable to conventional control of airway. If investigators paint all the patients with mouth restriction as difficult airway, it will result in uncalled surgical, economic, health system and psychological burden. Therefore, it is prudent to undertake research relating to refinement of airway access techniques with the easily available, cheap and user- friendly equipment (conventional laryngoscope), such that a proportion of above stated burden can be reduced.

In view of the above, investigators plan to undertake a study to enhance our working knowledge with a conventional laryngoscope (Macintosh) to facilitate ways to control the airway difficulty secondary to mouth opening restriction. Investigators believe that the prospective knowledge thus generated would help us identify whether there is a feasibility of conventional airway management or an alternative advanced access technique is needed in the first place. This will prevent undue cancellations, delayed surgeries, and patient morbidity.

Condition or disease Intervention/treatment
Submucous Fibrosis Other: Direct Laryngoscopy

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Study Type : Observational
Estimated Enrollment : 100 participants
Observational Model: Cohort
Time Perspective: Prospective
Official Title: Evaluation of Functional Dimensions of Macintosh Blade During Laryngoscopy in Patients With Normal Mouth Opening: Development of a Feasibility Model for Facilitation of Laryngoscopy in Cases of Mouth Opening Restriction Due to Submucous Fibrosis
Study Start Date : October 2016
Estimated Primary Completion Date : June 2022
Estimated Study Completion Date : July 2022

Intervention Details:
  • Other: Direct Laryngoscopy
    Tracheal intubation with direct laryngoscopy using Macintosh laryngoscope blade

Primary Outcome Measures :
  1. Macintosh Blade Length Measurement (in centimeters) [ Time Frame: 0 to 5-minutes ]
    Length of Macintosh blade size 3 and 4 as such (static) and during active direct laryngoscopy (active).

  2. Macintosh Blade Width Measurement (in centimeters) [ Time Frame: 0 to 5-minutes ]
    Width of Macintosh blade size 3 and 4 as such (static) and during active direct laryngoscopy (active).

  3. Inter-incisor Angle on Macintosh Blade Contact Point (in degrees) [ Time Frame: 0 to 5-minutes ]
    The angle formed by the line between the two contact points, viz. a point formed by upper incisor contact of upper flange curve (convex) of the Macintosh laryngoscope blade, and a point of contact between the lower incisor contact with lower flange curve (concave curve) of the Macintosh laryngoscope blade. The line formed by joining these two contact points with the baseline of the laryngoscope will form an angle. This angle will be noted as functional separation of eugnathic, retrognathic or prognathic maxilo-mandibular orientation

Secondary Outcome Measures :
  1. Upper Airway Measurements (in centimeters) [ Time Frame: 0 to 5-minutes ]
    Mento-hyoid, mento-thyroid distance, and the length of sub-mandibular triangle perpendicular

  2. Correlation Assessment [ Time Frame: 0 to 5-minutes ]
    The functional laryngoscope length will be tested for correlation with the linear neck (Mento-hyoid distance, menlo-thyroid distance ) and mandibular distances (perpendicular to sub-mandibular triangle) and the most consistent one will be taken

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Ages Eligible for Study:   20 Years to 65 Years   (Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No
Sampling Method:   Non-Probability Sample
Study Population
Patients scheduled for surgery under general anaesthesia with airway control by direct laryngoscopy and tracheal intubation

Inclusion Criteria:

  1. Consenting adults
  2. Both gender
  3. Age: 20-65 years
  4. Normal preoperative upper airway evaluation and without the presence of anticipated airway access difficulty
  5. Patients scheduled for surgery under general anaesthesia with airway control by direct laryngoscopy and tracheal intubation

Exclusion Criteria:

  1. Patient refusal
  2. Anticipated airway access difficulty
  3. Edentulous patients
  4. Patients with dental problem (missing tooth, overlap, cosmetic treatment)
  5. Vulnerable Patients: High risk situation, major surgery, extremes of age, obstetric patients
  6. Previously difficult airway

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT02639897

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Contact: Nitin Sethi, DNB 00919717494498
Contact: Amitabh Dutta, MD 00919810848064

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Sir Ganga Ram Hospital Recruiting
New Delhi, India, 110060
Contact: Amitabh Dutta, MD    +919810848064   
Contact: Nitin Sethi, DNB    +919717494498   
Principal Investigator: Amitabh Dutta, MD         
Principal Investigator: Ameya Pappu, MBBS         
Principal Investigator: Nitin Sethi, DNB         
Sub-Investigator: Prabhat Choudhary, MD         
Sub-Investigator: Manish Gupta, MD         
Sub-Investigator: Savitar Malhotra, MD         
Sub-Investigator: Bhuwan C Panday, MD         
Sub-Investigator: Shvet Mahajan, DA, DNB         
Sub-Investigator: Jayashree Sood, MD, FFARCS         
Sponsors and Collaborators
Sir Ganga Ram Hospital
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Study Director: Amitabh Dutta, MD Sir Ganga Ram Hospital, New Delhi, INDIA
Study Chair: Ameya Pappu, MBBS Sir Ganga Ram Hospital, New Delhi, INDIA
Principal Investigator: Nitin Sethi, DNB Sir Ganga Ram Hospital, New Delhi, INDIA
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Responsible Party: Dr Nitin Sethi, Consultant, Sir Ganga Ram Hospital Identifier: NCT02639897    
Other Study ID Numbers: EC/10/15/901
First Posted: December 28, 2015    Key Record Dates
Last Update Posted: October 30, 2020
Last Verified: October 2020
Additional relevant MeSH terms:
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Pathologic Processes