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Measurement of Forces Applied Using a Macintosh Direct Laryngoscope Compared to GlideScope Video Laryngoscope

Measurement of Forces Applied Using a Macintosh Direct Laryngoscope Compared to GlideScope Video Laryngoscope

Status
Completed
Phases
NA
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT00992628
Enrollment
70
Registered
2009-10-09
Start date
2010-07-31
Completion date
2011-04-30
Last updated
2011-04-15

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Endotracheal Intubation, Laryngoscopy

Keywords

GlideScope Video Laryngoscope, Macintosh Direct Laryngoscope, Intubation, Applied Forces, Elective surgery where endotracheal intubation required

Brief summary

Patients undergoing surgery or intensive care management often require a tube to be inserted into the trachea allowing lung ventilation. Usually a laryngoscope is used to allow visualisation of the larynx and facilitate intubation. During direct laryngoscopy, the blade of the laryngoscope is inserted into the patient's mouth and the structures pulled upwards out of the line of vision. If visualisation is difficult, users often exert excess force on the tissues to obtain an adequate view. Generally the applied force is evaluated by the patient's stress response such as increased heart rate, blood pressure or plasma cortisol levels. These changes, while important, may be confounded by a variety of patient factors, as well as anaesthesia. An increased force may also be associated with tissue trauma, dental damage, and prolonged attempts. The investigators' objective is to compare the force exerted on patient's tissues by the Macintosh laryngoscope and GlideScope video-laryngoscope. Video-laryngoscopes may be associated with the application of reduced force to the soft tissues of patients during intubation. While this is a common contention, it has not been proven. The GlideScope has a micro camera in the distal portion of the blade meaning a direct line of vision is not required. An adequate view can therefore be obtained with less displacement of tongue tissue. If the force exerted by the video laryngoscope is less, this would have beneficial implications by reducing stress response, neck movement, and trauma.

Interventions

DEVICEMacintosh (direct vision) laryngoscope

Macintosh (direct vision) laryngoscope

DEVICEGlideScope videolaryngoscope (indirect vision)

GlideScope videolaryngoscope (indirect vision)

Sponsors

University Health Network, Toronto
Lead SponsorOTHER

Study design

Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
PREVENTION
Masking
SINGLE (Outcomes Assessor)

Eligibility

Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No

Inclusion criteria

* age \> 18years * ASA 1-2 * elective surgery * endotracheal intubation required (with non-depolarising muscle relaxant) * signed informed consent

Exclusion criteria

* lack of informed consent * endotracheal intubation not required * ASA 3-5 * symptomatic gastro-oesophageal reflux * rapid sequence intubation * other method of intubation indicated eg fibreoptic, awake tracheostomy * cervical spine instability * unstable hypertension * coronary artery disease * cerebral disease * COPD/asthma * oral/pharyngeal/laryngeal carcinoma * loose teeth/poor dentition * Macintosh laryngoscope \>size 3 required

Design outcomes

Primary

MeasureTime frame
Forces generated during the intubation process using both laryngoscopes including peak and mean forces.5-15minutes

Countries

Canada

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Feb 4, 2026