title: Airway injury during emergency transcutaneous airway access: a comparison at cricothyroid and tracheal sites.
abstract: BACKGROUND
  Oxygenation via the cricothyroid membrane (CTM) may be required in emergencies, but inadvertent tracheal cannulation may occur. In this study, we compared airway injury between the tracheal and CTM sites using different techniques for airway access.
  
  
  METHODS
  Anesthesiologists performed 4 airway access techniques on excised porcine tracheas. The techniques were 1) wire-guided (WGT), 2) trocar (TT), 3) needle cannula (NCT), and 4) surgical-scalpel with endotracheal tube (ST). Participants performed each technique at both the CTM and tracheal sites. Specimens were assessed for injury.
  
  
  RESULTS
  Injury was observed in 8 of 40 and 27 of 40 specimens at the CTM and tracheal sites, respectively (P < 0.001). Injury was more frequent at the tracheal site compared with the CTM in both the TT and ST groups (P = 0.02) but not for the NCT and WGT. The rank order for any injury at the tracheal site was ST (9 of 10) = TT (9 of 10) > WGT (6 of 10) > NCT (3 of 10) (P = 0.02, highest versus lowest), whereas there was no difference in injury at the CTM. The rank order for posterior injury at the tracheal site was TT (9 of 10) = ST (9 of 10) > WGT (5 of 10) > NCT (2 of 10) (P = 0.005, highest versus lowest). The rank order for penetrating injury at the tracheal site was ST (6 of 10) = TT (6 of 10) > WGT (2 of 10) > NCT (1 of 10) (P = 0.057, highest versus lowest). There was no difference in the incidence of lateral, superficial, or perforating injuries among sites and techniques. Fractures were more common at the tracheal site (15 of 40 vs 0 of 40, P < 0.001) and differed by technique. The rank order of fracture incidence at the tracheal site was ST (6 of 10) > WGT (5 of 10) > TT (4 of 10) > NCT (0 of 10) (P = 0.011, highest to lowest). Compression of >50% was seen in 10 of 40 vs 28 of 40 (P < 0.001) specimens at the CTM and tracheal sites, respectively. The rank order of compression of >50% of airway lumen for both sites was TT > ST > WGT > NCT (P = 0.03, P < 0.001, CTM and tracheal sites, respectively, highest versus lowest).
  
  
  CONCLUSIONS
  Airway injury and luminal compression were more common at the tracheal site than at the CTM. The ST and TT were associated with the highest incidence of injury. This has implications for emergency airway access in cases in which it may be difficult to accurately identify the CTM.
authors.affiliation: Department of Anaesthesia, Rotunda Hospital, Dublin, Ireland.
authors.forename: Nazar
authors.initials: N
authors.lastname: Salah
authors.forename: Ismat
authors.initials: I
authors.lastname: El Saigh
authors.forename: Niamh
authors.initials: N
authors.lastname: Hayes
authors.forename: Conan
authors.initials: C
authors.lastname: McCaul
mesh_terms: D000402:Airway Obstruction / Q000209:etiology; D000758:Anesthesia; D000818:Animals; D002404:Catheterization / Q000009:adverse effects* / Q000295:instrumentation; D004867:Equipment Design; D050724:Fractures, Cartilage / Q000209:etiology; D007442:Intubation, Intratracheal / Q000009:adverse effects* / Q000295:instrumentation; D007830:Larynx / Q000293:injuries* / Q000473:pathology; D023421:Models, Animal; D013552:Swine; D014132:Trachea / Q000293:injuries* / Q000473:pathology; D014135:Tracheal Stenosis / Q000209:etiology; D014140:Tracheotomy / Q000009:adverse effects* / Q000295:instrumentation; D014947:Wounds and Injuries / Q000209:etiology* / Q000473:pathology