Comparison of Intubation Rate of Macintosh Size 2 and 3 Blades in Asian Female: a Randomised Controlled Trial

Direct laryngoscope is a standard equipment for endotracheal intubation. To identify the differences between Macintosh size 3 and 2 blades, we will analysis the data collected from airway and intubation condition.

Study Overview

• Status: Completed
• Conditions: Intubation;Difficult
• Intervention / Treatment: Device: Macintosh size 2 blade; Device: Macintosh size 3 blade

Detailed Description

Selection the most appropriate size of laryngoscope blade size could not only increased intubation successful rate at the first time but also decrease the incidence of tissue trauma. Laryngoscope blade used in daily practice is usually Macintosh 3. However, compared with Caucasian people, Asian people are smaller and thinner especially in women. This study aims to confirm that the Macintosh 2 blade is not inferior to size 3 blade in laryngeal view and intubation rate.

Female patients without known difficult airway will be enrolled and allocated into Macintosh blade size 2 and size 3 groups. The age, body weight, body height, Mallampati classification, mouth opening, thyromental distance, neck circumference, intubation time, Cormack-Lehane grade, intubation difficulty scale scores and associated teeth or tissue traumas will be recorded.

• Study Type: Interventional
• Enrollment (Actual): 90
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Taiwan
  • Taipei, Taiwan
    • Mackay Memorial Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 20 years to 70 years (ADULT, OLDER_ADULT)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: Female

Description

Inclusion Criteria:

• with American Society of Anesthesiologists (ASA) physical status classification 1, 2, or 3
• undergo elective surgery
• receive endotracheal intubation

Exclusion Criteria:

• with known difficult airway (i.e. pathology of the neck, upper airway or alimentary tracts)
• with risks of pulmonary aspiration (i.e. emergent operation, pregnancy or inadequate nil per os)
• with previous difficult intubation history
• intubation attempts more than three times
• patient refusal

Study Plan

How is the study designed?

Design Details

• Primary Purpose: PREVENTION
• Allocation: RANDOMIZED
• Interventional Model: PARALLEL
• Masking: DOUBLE

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
EXPERIMENTAL: Macintosh 2 group; Using Macintosh size 2 blade for direct laryngoscope intubation according to randomization	Device: Macintosh size 2 blade; intubate with Macintosh size 2 blade
ACTIVE_COMPARATOR: Macintosh 3 group; Using Macintosh size 3 blade for direct laryngoscope intubation according to randomization	Device: Macintosh size 3 blade; intubate with Macintosh size 3 blade

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Intubation time	Time from laryngoscope insertion to the first adequate lung insufflation	0-10 minutes during induction
Cormack-Lehane grade	Classification of glottis view during intubation	0-10 minutes during induction
Intubation difficulty scale scores	Scoring system to assess the difficulty of intubation in each patient	0-10 minutes during induction
Tissue trauma	Any tissue trauma event related to intubation	0-10 minutes during induction
Teeth trauma	Any dental damage event related to intubation	0-10 minutes during induction

Collaborators and Investigators

• Sponsor: Mackay Memorial Hospital
• Investigators: Study Director: Nuan-Yen Su, MS, Mackay Memorial hospital, department of anesthesiology, attending physician

Publications and helpful links

General Publications

• Mellick LB, Edholm T, Corbett SW. Pediatric laryngoscope blade size selection using facial landmarks. Pediatr Emerg Care. 2006 Apr;22(4):226-9. doi: 10.1097/01.pec.0000210171.17892.7a.
• Ashfaque M, Mason J, Al-Shaikh B, Adegoke K. A comparison of the Laryngopharyngeal Examination blade and the English Macintosh laryngoscope blade using an intubating manikin: a prospective randomized crossover study. Eur J Anaesthesiol. 2009 Nov;26(11):917-22. doi: 10.1097/EJA.0b013e32832c7848.
• Asai T, Matsumoto S, Fujise K, Johmura S, Shingu K. Comparison of two Macintosh laryngoscope blades in 300 patients. Br J Anaesth. 2003 Apr;90(4):457-60. doi: 10.1093/bja/aeg086.
• Watanabe S, Suga A, Asakura N, Takeshima R, Kimura T, Taguchi N, Kumagai M. Determination of the distance between the laryngoscope blade and the upper incisors during direct laryngoscopy: comparisons of a curved, an angulated straight, and two straight blades. Anesth Analg. 1994 Oct;79(4):638-41. doi: 10.1213/00000539-199410000-00004.

Study record dates

Study Major Dates

• Study Start (ACTUAL): June 1, 2011
• Primary Completion (ACTUAL): May 31, 2012
• Study Completion (ACTUAL): May 31, 2012

Study Registration Dates

• First Submitted: September 22, 2020
• First Submitted That Met QC Criteria: September 22, 2020
• First Posted (ACTUAL): September 28, 2020

Study Record Updates

• Last Update Posted (ACTUAL): September 28, 2020
• Last Update Submitted That Met QC Criteria: September 22, 2020
• Last Verified: September 1, 2020

More Information

Terms related to this study

• Keywords: Macintosh blade; Intubation rate; Asian women; intubation difficulty scale
• Additional Relevant MeSH Terms: Dermatologic Agents; Keratolytic Agents; Pyrithione zinc
• Other Study ID Numbers: 11MMHIS107

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No