Evidence map›Paper›PMID 24739996›Full record

Trial reportAnesthesiology2014

Intubation biomechanics: laryngoscope force and cervical spine motion during intubation with Macintosh and Airtraq laryngoscopes.

Bradley J Hindman, Brandon G Santoni, Christian M Puttlitz, Robert P From, Michael M Todd

Open access · bronzeAbstract readComparative StudyRandomized Controlled Trial
PubMed Full text at PMC Publisher
In one paragraph

Trial report in Anesthesiology, 2014. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 30 papers, 5 of them syntheses that pooled it.

0numbers the graph read from it
0cells of the map it votes in
30citing papers in PubMed, 5 pooled it
7.1field-weighted citation impact, top 3% of its field
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

30 citing papers in PubMed, 5 syntheses or guidelines pooled it, 79 citations in OpenAlex.

  1. Pooled it
  2. Pooled it
  3. Pooled it
  4. Pooled it
  5. Pooled it
  6. Trial
  7. Trial
  8. Trial
  9. Trial
  10. Trial
  11. Trial
  12. Effects on hemodynamics of SEEKAmerican journal of translational research · 2026
    Article
  13. Review
  14. Article
  15. Article
  16. Article
  17. Article
  18. Comparison of the Efficacy of Macintosh Laryngoscope Versus Airtraq Videolaryngoscope for Visualization of Laryngeal Structures at the End of Thyroidectomy: A Randomized Control Study.Indian journal of otolaryngology and head and neck surgery : official publication of the Association of Otolaryngologists of India · 2023
    Article
  19. Article
  20. Article
4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

5 authors at 1 institution in 3 countries.

Bradley J HindmanFrom the Department of Anesthesia, University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, Iowa (B.J.H., R.P.F., M.M.T.); Foundation for Orthopaedic Research and Education, Tampa, Florida (B.G.S.); and Department of Mechanical Engineering, School of Biomedical Engineering, Orthopaedic Bioengineering Research Laboratory, Colorado State University, Fort Collins, Colorado (C.M.P.).
Brandon G Santoni
Christian M Puttlitz
Robert P From
Michael M Todd
University of Iowa · US

Funding

Intubation Mechanics of the Stable and Unstable Cervical SpineR01EB012048 · NIBIB · COLORADO STATE UNIVERSITY · PI HINDMAN, BRADLEY JAY, PUTTLITZ, CHRISTIAN · 2011 to 2014
$1.3M
NIBIB NIH HHS 1R01EB012048-01A1NIBIB NIH HHS R01 EB012048
6 · The paper itself

Abstract

introductionLaryngoscopy and endotracheal intubation in the presence of cervical spine instability may put patients at risk of cervical cord injury. Nevertheless, the biomechanics of intubation (cervical spine motion as a function of applied force) have not been characterized. This study characterized and compared the relationship between laryngoscope force and cervical spine motion using two laryngoscopes hypothesized to differ in force.

methodsFourteen adults undergoing elective surgery were intubated twice (Macintosh, Airtraq). During each intubation, laryngoscope force, cervical spine motion, and glottic view were recorded. Force and motion were referenced to a preintubation baseline (stage 1) and were characterized at three stages: stage 2 (laryngoscope introduction); stage 3 (best glottic view); and stage 4 (endotracheal tube in trachea).

resultsMaximal force and motion occurred at stage 3 and differed between the Macintosh and Airtraq: (1) force: 48.8 ± 15.8 versus 10.4 ± 2.8 N, respectively, P = 0.0001; (2) occiput-C5 extension: 29.5 ± 8.5 versus 19.1 ± 8.7 degrees, respectively, P = 0.0023. Between stages 2 and 3, the motion/force ratio differed between Macintosh and Airtraq: 0.5 ± 0.2 versus 2.0 ± 1.4 degrees/N, respectively; P = 0.0006. DISCUSSION: The relationship between laryngoscope force and cervical spine motion is: (1) nonlinear and (2) differs between laryngoscopes. Differences between laryngoscopes in motion/force relationships are likely due to: (1) laryngoscope-specific cervical extension needed for intubation, (2) laryngoscope-specific airway displacement/deformation needed for intubation, and (3) cervical spine and airway tissue viscoelastic properties. Cervical spine motion during endotracheal intubation is not directly proportional to force. Low-force laryngoscopes cannot be assumed to result in proportionally low cervical spine motion.

Indexed as

LaryngoscopesAdultAgedAnesthesia, GeneralBiomechanical PhenomenaCervical VertebraeDeglutition DisordersFemaleGlottisHeadHumansIntubation, IntratrachealLaryngoscopyMaleMiddle AgedMotion

Identifiers

PMID24739996
PMCPMC4110170
OpenAlexW1964620034

What OpenQuestion holds

Textmetadata
LicenceTDM
Read underepoch 390

Registered trials

None linked

Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.