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

University Health Network, Toronto logo

University Health Network, Toronto

Status

Completed

Conditions

Endotracheal Intubation
Laryngoscopy

Treatments

Device: Macintosh (direct vision) laryngoscope
Device: GlideScope videolaryngoscope (indirect vision)

Study type

Interventional

Funder types

Other

Identifiers

NCT00992628
UHN REB 09-0262-B

Details and patient eligibility

About

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.

Enrollment

70 estimated patients

Sex

All

Ages

18+ years old

Volunteers

No Healthy Volunteers

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

Trial design

Primary purpose

Prevention

Allocation

Randomized

Interventional model

Parallel Assignment

Masking

Single Blind

70 participants in 2 patient groups

Macintosh (direct vision) laryngoscope
Active Comparator group
Description:
Macintosh (direct vision) laryngoscope
Treatment:
Device: Macintosh (direct vision) laryngoscope
GlideScope videolaryngoscope (indirect vision)
Active Comparator group
Description:
GlideScope videolaryngoscope (indirect vision)
Treatment:
Device: GlideScope videolaryngoscope (indirect vision)

Trial contacts and locations

2

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Data sourced from clinicaltrials.gov

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