Intubation; Difficult
Conditions
Brief summary
The purpose of this prospective open labeled randomized study was to compare the laryngoscopic glottis view as well as ease of intubation between the two blades in routine intubations in non-difficult airways.
Detailed description
One hundred and fifty patients with predicted non difficult airway were randomly assigned into two groups. After induction of anaesthesia laryngoscopy was performed with respective blades and trachea intubated. Parameters monitored were: glottis view obtained during laryngoscopy (Cormack Lehane grade), ease of intubation, intubation attempts, total duration of laryngoscopy in seconds and encountered complications.
Interventions
OTHERMiller group
Miller blade was used for laryngoscopy
OTHERMacintosh group
Macintosh blade was used for laryngoscopy
Sponsors
Tata Main Hospital
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
18 Years to 70 Years
Healthy volunteers
Yes
Inclusion criteria
* All ASA I & II grade patients undergoing elective surgery requiring general anesthesia with oral endotracheal intubation
Exclusion criteria
* Patients with anticipated difficult airway * Cervical spine disorders * Anesthesia requiring rapid sequence induction
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Ease of Intubation or Degree of Difficulty With Intubation | 60 seconds | Degree of difficulty with intubation Grade 1 Intubation easy Grade 2 Intubation requiring an increased anterior lifting force/optimal external laryngeal manipulation (OELM)/assistance to pull the right corner of the mouth upwards to augment space Grade 3 Intubation requiring more than one attempt or bougie guided intubation Grade 4 failure to intubate with the assigned laryngoscope |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Cormack Lehane Grading | 60 seconds | Grade 1 Full view of glottis Grade 2 Only posterior commissure visible Grade 3 Only epiglottis visible Grade 4 No glottis structure visible |
| Number of Intubation Attempts | 180 seconds | An intubation attempt is defined as intubation activities occurring during a single continuous laryngoscopy maneuver. Thus, even if several attempts were made to place an endotracheal tube during the course of a single laryngoscopy, this would be counted as a single intubation attempt. |
| Total Laryngoscopy Duration in Seconds | 180 seconds | The duration of intubation was defined as the time taken from placement of the laryngoscope in the mouth to the time taken to remove the laryngoscope from the mouth following intubation. |
Participant flow
Participants by arm
| Arm | Count |
|---|---|
| Miller Group In Miller group, no 3 Miller blade was used for laryngoscopy by paraglossal technique. While intubating, the endotracheal tube (ETT) was directed underneath the laryngoscope blade without allowing it to go lateral to the blade. The curvature of the ETT automatically brings the tip towards the vocal cords as it was advanced. After successful endotracheal intubation, the ETT was attached to the circuit and anaesthesia continued as per plan.
Miller group: Miller blade was used for laryngoscopy | 75 |
| Macintosh Group In Macintosh group, the curved blade was introduced to lift the base of the epiglottis to visualize larynx and then trachea intubated conventionally.After successful endotracheal intubation, the ETT was attached to the circuit and anaesthesia continued as per plan.
Macintosh group: Macintosh blade was used for laryngoscopy | 75 |
| Total | 150 |
Baseline characteristics
| Characteristic | Macintosh Group | Miller Group | Total |
|---|---|---|---|
| Age, Categorical <=18 years | 0 Participants | 0 Participants | 0 Participants |
| Age, Categorical >=65 years | 0 Participants | 0 Participants | 0 Participants |
| Age, Categorical Between 18 and 65 years | 75 Participants | 75 Participants | 150 Participants |
| Age, Continuous | 48.2 years STANDARD_DEVIATION 14 | 44.8 years STANDARD_DEVIATION 13.1 | 47.6 years STANDARD_DEVIATION 13.7 |
| Region of Enrollment India | 75 participants | 75 participants | 150 participants |
| Sex: Female, Male Female | 47 Participants | 46 Participants | 93 Participants |
| Sex: Female, Male Male | 28 Participants | 29 Participants | 57 Participants |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk |
|---|---|---|
| deaths Total, all-cause mortality | — / — | — / — |
| other Total, other adverse events | 0 / 75 | 0 / 75 |
| serious Total, serious adverse events | 0 / 75 | 0 / 75 |
Outcome results
Primary
Ease of Intubation or Degree of Difficulty With Intubation
Degree of difficulty with intubation Grade 1 Intubation easy Grade 2 Intubation requiring an increased anterior lifting force/optimal external laryngeal manipulation (OELM)/assistance to pull the right corner of the mouth upwards to augment space Grade 3 Intubation requiring more than one attempt or bougie guided intubation Grade 4 failure to intubate with the assigned laryngoscope
Time frame: 60 seconds
| Arm | Measure | Group | Value (NUMBER) |
|---|---|---|---|
| Miller Group | Ease of Intubation or Degree of Difficulty With Intubation | Grade 1 | 52 participants |
| Miller Group | Ease of Intubation or Degree of Difficulty With Intubation | Grade 2 | 23 participants |
| Miller Group | Ease of Intubation or Degree of Difficulty With Intubation | Grade 3 | 0 participants |
| Miller Group | Ease of Intubation or Degree of Difficulty With Intubation | Grade 4 | 0 participants |
| Macintosh Group | Ease of Intubation or Degree of Difficulty With Intubation | Grade 4 | 0 participants |
| Macintosh Group | Ease of Intubation or Degree of Difficulty With Intubation | Grade 1 | 54 participants |
| Macintosh Group | Ease of Intubation or Degree of Difficulty With Intubation | Grade 3 | 5 participants |
| Macintosh Group | Ease of Intubation or Degree of Difficulty With Intubation | Grade 2 | 16 participants |
Secondary
Cormack Lehane Grading
Grade 1 Full view of glottis Grade 2 Only posterior commissure visible Grade 3 Only epiglottis visible Grade 4 No glottis structure visible
Time frame: 60 seconds
| Arm | Measure | Group | Value (NUMBER) |
|---|---|---|---|
| Miller Group | Cormack Lehane Grading | Grade 1 | 69 participants |
| Miller Group | Cormack Lehane Grading | Grade 2 | 6 participants |
| Miller Group | Cormack Lehane Grading | Grade 3 | 0 participants |
| Miller Group | Cormack Lehane Grading | Grade 4 | 0 participants |
| Macintosh Group | Cormack Lehane Grading | Grade 4 | 0 participants |
| Macintosh Group | Cormack Lehane Grading | Grade 1 | 51 participants |
| Macintosh Group | Cormack Lehane Grading | Grade 3 | 6 participants |
| Macintosh Group | Cormack Lehane Grading | Grade 2 | 18 participants |
Secondary
Number of Intubation Attempts
An intubation attempt is defined as intubation activities occurring during a single continuous laryngoscopy maneuver. Thus, even if several attempts were made to place an endotracheal tube during the course of a single laryngoscopy, this would be counted as a single intubation attempt.
Time frame: 180 seconds
| Arm | Measure | Group | Value (NUMBER) |
|---|---|---|---|
| Miller Group | Number of Intubation Attempts | Single Attempt | 75 participants |
| Miller Group | Number of Intubation Attempts | Second attempt | 0 participants |
| Macintosh Group | Number of Intubation Attempts | Single Attempt | 74 participants |
| Macintosh Group | Number of Intubation Attempts | Second attempt | 1 participants |
Secondary
Total Laryngoscopy Duration in Seconds
The duration of intubation was defined as the time taken from placement of the laryngoscope in the mouth to the time taken to remove the laryngoscope from the mouth following intubation.
Time frame: 180 seconds
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Miller Group | Total Laryngoscopy Duration in Seconds | 23 Seconds | Standard Deviation 7 |
| Macintosh Group | Total Laryngoscopy Duration in Seconds | 20.5 Seconds | Standard Deviation 7.7 |