Intubation biomechanics: laryngoscope force and cervical spine motion during intubation with Macintosh and Airtraq laryngoscopes.
Anesthesiology
; 121(2): 260-71, 2014 Aug.
Article
em En
| MEDLINE
| ID: mdl-24739996
ABSTRACT
INTRODUCTION:
Laryngoscopy 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.METHODS:
Fourteen 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).RESULTS:
Maximal 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.
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Base de dados:
MEDLINE
Assunto principal:
Coluna Vertebral
/
Laringoscópios
/
Intubação Intratraqueal
/
Laringoscopia
Tipo de estudo:
Clinical_trials
/
Etiology_studies
Limite:
Adult
/
Aged
/
Female
/
Humans
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Male
/
Middle aged
Idioma:
En
Ano de publicação:
2014
Tipo de documento:
Article