title: Upper limb muscular activity and perceived workload during laryngoscopy: comparison of Glidescope(R) and Macintosh laryngoscopy in manikin: an observational study.
abstract: BACKGROUND
  The interaction between operators and their working environment during laryngoscopy is poorly understood. Numerous studies have focused on the forces applied to the patient's airway during laryngoscopy, but only a few authors have addressed operator muscle activity and workload. We tested whether different devices (Glidescope(®) and Macintosh) use different muscles and how these differences affect the perceived workload.
  
  
  METHODS
  Ten staff anaesthetists performed three intubations with each device on a manikin. Surface electromyography was recorded for eight single muscles of the left upper limb. The NASA Task Load Index (TLX) was administered after each experimental session to evaluate perceived workload.
  
  
  RESULTS
  A consistent reduction in muscular activation occurred with Glidescope(®) compared with Macintosh for all muscles tested (mean effect size d=3.28), and significant differences for the upper trapezius (P=0.002), anterior deltoid (P=0.001), posterior deltoid (P=0.000), and brachioradialis (P=0.001) were observed. The overall NASA-TLX workload score was significantly lower for Glidescope(®) than for Macintosh (P=0.006), and the factors of physical demand (P=0.008) and effort (P=0.006) decreased significantly.
  
  
  CONCLUSIONS
  Greater muscular activity and workload were observed with the Macintosh laryngoscope. Augmented vision and related postural adjustments related to using the Glidescope(®) may reduce activation of the operator's muscles and task workload.
authors.affiliation: Department of Neuroanaesthesia and Intensive Care and.
authors.forename: D
authors.initials: D
authors.lastname: Caldiroli
authors.forename: F
authors.initials: F
authors.lastname: Molteni
authors.forename: A
authors.initials: A
authors.lastname: Sommariva
authors.forename: S
authors.initials: S
authors.lastname: Frittoli
authors.forename: E
authors.initials: E
authors.lastname: Guanziroli
authors.forename: P
authors.initials: P
authors.lastname: Cortellazzi
authors.forename: E F
authors.initials: EF
authors.lastname: Orena
mesh_terms: D000328:Adult; D000776:Anesthesiology; D003625:Data Collection; D003627:Data Interpretation, Statistical; D004576:Electromyography; D005260:Female; D006801:Humans; D020704:Laryngoscopes; D007828:Laryngoscopy; D008297:Male; D008348:Manikins; D008606:Mental Processes / Q000502:physiology; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000502:physiology*; D005082:Physical Exertion / Q000502:physiology*; D010820:Physicians; D011597:Psychomotor Performance / Q000502:physiology; D018401:Sample Size; D034941:Upper Extremity / Q000502:physiology*
keywords: electromyography; intubation, tracheal; laryngoscopy; muscle fatigue, workload