Force and Pressure Distribution Using Macintosh and GlideScope Laryngoscopes in Normal Airway: an in Vivo Study

• Sponsor: Campus Bio-Medico University (Other)
• Overall Status: Completed
• CT.gov ID: NCT01685320
• Collaborator: (none)
• Enrollment: 30
• Location: 1
• Arms: 2
• Duration (Months): 11
• Patients Per Site Per Month: 2.7

Study Details

Study Description

Brief Summary

Forces applied on soft upper tissues by different laryngoscope blades during direct laryngoscopy and intubation are considered to be major stimuli to cause serious damages to the patients. The aim of this study is to compare the force and pressure applied to soft tissue in order to achieve the same glottis view comparing direct laryngoscopy and videolaryngoscopy in vivo.

Condition or Disease	Intervention/Treatment	Phase
Tracheal Intubation; Laryngoscopy	Procedure: Forces applied by laryngoscope	N/A

Detailed Description

Forces applied on soft upper tissues by different laryngoscope blades during direct laryngoscopy and intubation are considered to be major stimuli to cause serious damages to the patients, such as local injures to incisors, larynx and spinal column, or hemodynamic changes in heart rate and/or blood pressure due to autonomic nervous system stimulation.

In order to reduce risk of such injures, indirect videolaryngoscopy provides the advantage of an easier laryngeal visualization with less need for the mouth-pharyngeal-laryngeal axes alignment, thereby reducing the detrimental effects above mentioned.

The aim of this study is to measure the minimal force exertion to achieve not only glottis view but also a successful intubation, comparing GlideScope and Macintosh laryngoscope, in patients with normal airway conditions. Furthermore, The investigators measured the following parameters: pressure distribution upon the blade; time required to visualize the glottis; time required to complete oro-tracheal intubation.

Study Design

• Study Type: Interventional
• Actual Enrollment: 30 participants
• Allocation: Randomized
• Intervention Model: Parallel Assignment
• Masking: Single (Participant)
• Primary Purpose: Prevention
• Official Title: Force and Pressure Distribution Using Macintosh and GlideScope Laryngoscopes in Normal Airway: an in Vivo Study
• Study Start Date: Jan 1, 2011
• Actual Primary Completion Date: Oct 1, 2011
• Actual Study Completion Date: Dec 1, 2011

Arms and Interventions

Arm	Intervention/Treatment
Active Comparator: Direct laryngoscope Includes cases in which the forces applied by Macintosh direct laryngoscope onto soft tissue of the pharynx during glottis visualization and intubation were measured.	Procedure: Forces applied by laryngoscope; Force and pressure distribution applied by direct or indirect laryngoscope during glottis visualization and intubation were measured using film pressure transducers.
Active Comparator: Indirect laryngoscope Includes cases in which the forces applied by GlideScope indirect laryngoscope onto soft tissue of the pharynx during glottis visualization and intubation were measured.	Procedure: Forces applied by laryngoscope; Force and pressure distribution applied by direct or indirect laryngoscope during glottis visualization and intubation were measured using film pressure transducers.

Outcome Measures

Primary Outcome Measures

1. Force Applied and Pressure Distribution Upon the Blade of Laryngoscopes During Tracheal Intubation. [Force measurement is referred to an average of 45 seconds in patients scheduled to undergo elective surgery under general anaesthesia]

   The pressure distribution exerted upon the tissues by the blade was measured (in Newton)through pressure film transducers put on the blade of both direct and indirect laryngoscopes, in order to compare the two devices.

Secondary Outcome Measures

1. Time Required to Visualize the Glottis and Complete Oro-tracheal Intubation [On average 20 seconds]

   Since the time needed for laryngoscopy and intubation could represent one of the major contributors to the stress response during these procedures, times to achieve the glottis visualization and to perform the entire intubation were recorded.

Eligibility Criteria

Criteria

• Ages Eligible for Study: 18 Years to 65 Years
• Sexes Eligible for Study: All
• Accepts Healthy Volunteers: No

Inclusion Criteria:

• Patients classified as American Society of Anesthesiologists physical status (ASA-PS) class 1 or 2

• Patients whose intubation was associated with a Cormack-Lehane grade 1

Exclusion Criteria:

• younger than 18 yrs

• older than 65 yrs

• body-mass index (BMI) between 18 and 30

• predicted difficult intubation according to SIAARTI (Italian Society Anaesthesia, Analgesia, Resuscitation and Intensive Care)

Contacts and Locations

Locations

	Site	City	State	Country	Postal Code
1	University Hospital Campus BioMedico	Rome		Italy	00128

Sponsors and Collaborators

• Campus Bio-Medico University

Investigators

• Principal Investigator: Massimiliano Carassiti, Professor, Campus BioMedico

Study Documents (Full-Text)

None provided.

More Information

Publications

None provided.

• Responsible Party: Massimiliano Carassiti, Professor, Campus Bio-Medico University
• ClinicalTrials.gov Identifier: NCT01685320
• Other Study ID Numbers: PressureCara
• First Posted: Sep 14, 2012
• Last Update Posted: Feb 11, 2021
• Last Verified: Jan 1, 2021

• Keywords provided by Massimiliano Carassiti, Professor, Campus Bio-Medico University: Force; Pressure; Intubation; laryngoscopy

Study Results

Participant Flow

Recruitment Details	Date of recruitment period: January-October 2011. Type of location: Dept. of Anaesthesia, University School of Medicine Campus Bio-Medico, Rome, Italy.
Pre-assignment Detail	After written consent, thirty adult patients scheduled for elective surgery under general anaesthesia (age between 18 and 65 years, body-mass index between 18 and 30, classified as ASA-PS class 1 or 2), were included in this study. Subjects likely to be difficult to intubate, according to the SIAARTI Recommendations, were excluded.

Arm/Group Title	Direct Laryngoscope	Indirect Laryngoscope
Arm/Group Description	Includes cases in which the forces applied by McIntosh direct laryngoscope onto soft tissue of the pharynx during glottis visualization and intubation were measured using film pressure transducers.	Includes cases in which the forces applied by GlideScope indirect laryngoscope onto soft tissue of the pharynx during glottis visualization and intubation were measured using film pressure transducers.
Period Title: Overall Study
STARTED	15	15
COMPLETED	15	15
NOT COMPLETED	0	0

Baseline Characteristics

Arm/Group Title	Direct Laryngoscope	Indirect Laryngoscope	Total
Arm/Group Description	Includes cases in which the forces applied by McIntosh direct laryngoscope onto soft tissue of the pharynx during glottis visualization and intubation were measured using film pressure transducers.	Includes cases in which the forces applied by GlideScope indirect laryngoscope onto soft tissue of the pharynx during glottis visualization and intubation were measured using film pressure transducers.	Total of all reporting groups
Overall Participants	15	15	30
Age (Count of Participants)
<=18 years	0 0%	0 0%	0 0%
Between 18 and 65 years	15 100%	15 100%	30 100%
>=65 years	0 0%	0 0%	0 0%
Age (years) [Mean (Standard Deviation) ]
Mean (Standard Deviation) [years]	41 (12)	44 (11)	42.5 (12)
Sex: Female, Male (Count of Participants)
Female	7 46.7%	7 46.7%	14 46.7%
Male	8 53.3%	8 53.3%	16 53.3%
Region of Enrollment (participants) [Number]
Italy	15 100%	15 100%	30 100%

Outcome Measures

1. Primary Outcome

Title	Force Applied and Pressure Distribution Upon the Blade of Laryngoscopes During Tracheal Intubation.
Description	The pressure distribution exerted upon the tissues by the blade was measured (in Newton)through pressure film transducers put on the blade of both direct and indirect laryngoscopes, in order to compare the two devices.
Time Frame	Force measurement is referred to an average of 45 seconds in patients scheduled to undergo elective surgery under general anaesthesia

Outcome Measure Data

Analysis Population Description

We have utilized our previous in vitro study on manikin (Carassiti et al. Br J Anaesth 2012; 108: 146-151) as basis for the calculus of sample size in this research, considering 95% confidence interval (2-sided), power of 80%, ratio of sample size (Group B/Group A) = 1.

Arm/Group Title	Direct Laryngoscope	Indirect Laryngoscope
Arm/Group Description	Includes cases in which the forces applied by McIntosh direct laryngoscope onto soft tissue of the pharynx during glottis visualization and intubation were measured using film pressure transducers.	Includes cases in which the forces applied by GlideScope indirect laryngoscope onto soft tissue of the pharynx during glottis visualization and intubation were measured using film pressure transducers.
Measure Participants	15	15
Measurements during glottis visualization	16 (6)	10 (3)
Measurements during intubation	40 (14)	8 (4)

2. Secondary Outcome

Title	Time Required to Visualize the Glottis and Complete Oro-tracheal Intubation
Description	Since the time needed for laryngoscopy and intubation could represent one of the major contributors to the stress response during these procedures, times to achieve the glottis visualization and to perform the entire intubation were recorded.
Time Frame	On average 20 seconds

Outcome Measure Data

Analysis Population Description

We have utilized our previous in vitro study on manikin (Carassiti et al. Br J Anaesth 2012; 108: 146-151) as basis for the calculus of sample size in this research, considering 95% confidence interval (2-sided), power of 80%, ratio of sample size (Group B/Group A) = 1.

Arm/Group Title	Direct Laryngoscope	Indirect Laryngoscope
Arm/Group Description	Includes cases in which the forces applied by McIntosh direct laryngoscope onto soft tissue of the pharynx during glottis visualization and intubation were measured using film pressure transducers.	Includes cases in which the forces applied by GlideScope indirect laryngoscope onto soft tissue of the pharynx during glottis visualization and intubation were measured using film pressure transducers.
Measure Participants	15	15
Time measured during glottis visualization	13 (1)	7 (1)
Time measured during intubation	22 (3)	20 (1)

Adverse Events

Adverse Event Reporting Description	Serious and/or other non-serious adverse events were not collected/assessed
Arm/Group Title	Direct Laryngoscope		Indirect Laryngoscope
Arm/Group Description	Includes cases in which the forces applied by McIntosh direct laryngoscope onto soft tissue of the pharynx during glottis visualization and intubation were measured using film pressure transducers.		Includes cases in which the forces applied by GlideScope indirect laryngoscope onto soft tissue of the pharynx during glottis visualization and intubation were measured using film pressure transducers.
All Cause Mortality
	Direct Laryngoscope		Indirect Laryngoscope
	Affected / at Risk (%)	# Events	Affected / at Risk (%)	# Events
Total	/ (NaN)		/ (NaN)
Serious Adverse Events
	Direct Laryngoscope		Indirect Laryngoscope
	Affected / at Risk (%)	# Events	Affected / at Risk (%)	# Events
Total	0/15 (0%)		0/15 (0%)
Other (Not Including Serious) Adverse Events
	Direct Laryngoscope		Indirect Laryngoscope
	Affected / at Risk (%)	# Events	Affected / at Risk (%)	# Events
Total	0/15 (0%)		0/15 (0%)

Limitations/Caveats

Patients studied were classified with "normal airways", while difficult intubations were not considered. We excluded patients with CL grade 2 or greater. We employed only the Macintosh size 3 blade to avoid additional variables.

More Information

Certain Agreements

All Principal Investigators ARE employed by the organization sponsoring the study.

There is NOT an agreement between Principal Investigators and the Sponsor (or its agents) that restricts the PI's rights to discuss or publish trial results after the trial is completed.