Miller Straight Blade vs Macintosh Blade

Study Overview
=================
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.

Official Title
-----------------
Miller Straight Blade With Paraglossal Technique Compared to the Macintosh Blade in Respect to Visualization of Larynx and Ease of Intubation

Conditions
-----------------
Intubation; Difficult

Intervention / Treatment
-----------------
* Other: Miller group
* Other: Macintosh group


Participation Criteria
=================
Eligibility Criteria
-----------------
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

Ages Eligible for Study
-----------------
Minimum Age: 18 Years
Maximum Age: 70 Years

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

Accepts Healthy Volunteers
-----------------
Accepts Healthy Volunteers

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

Design Details

Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Miller group<br>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. | Other: Miller group<br>* Miller blade was used for laryngoscopy<br>|
| Other: Macintosh group<br>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. | Other: Macintosh group<br>* Macintosh blade was used for laryngoscopy<br>|

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

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| 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 | 60 seconds | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| 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 | 60 seconds | 
| 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. | 180 seconds | 
| 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. | 180 seconds |