title: Accuracy of a novel ultrasound technique for confirmation of endotracheal intubation by expert and novice emergency physicians.
abstract: BACKGROUND
  Recent research has investigated the use of ultrasound (US) for confirming endotracheal tube (ETT) placement with varying techniques, accuracies, and challenges. Our objective was to evaluate the accuracy of a novel, simplified, four-step (4S) technique.
  
  
  METHODS
  We conducted a blinded, randomized trial of the 4S technique utilizing an adult human cadaver model. ETT placement was randomized to tracheal or esophageal location. Three US experts and 45 emergency medicine residents (EMR) performed a total of 150 scans. The primary outcome was the overall sensitivity and specificity of both experts and EMRs to detect location of ETT placement. Secondary outcomes included a priori subgroup comparison of experts and EMRs for thin and obese cadavers, time to detection, and level of operator confidence.
  
  
  RESULTS
  Experts had a sensitivity of 100% (95% CI = 72% to 100%) and specificity of 100% (95% CI = 77% to 100%) on thin, and a sensitivity of 93% (95% CI = 66% to 100%) and specificity of 100% (95% CI = 75% to 100%) on obese cadavers. EMRs had a sensitivity of 91% (95% CI = 69% to 98%) and of specificity 96% (95% CI = 76% to 100%) on thin, and a sensitivity of 100% (95% CI = 82% to 100%) specificity of 48% (95% CI = 27% to 69%) on obese cadavers. The overall mean time to detection was 17 seconds (95% CI = 13 seconds to 20 seconds, range: 2 to 63 seconds) for US experts and 29 seconds (95% CI = 25 seconds to 33 seconds; range: 6 to 120 seconds) for EMRs. There was a statistically significant decrease in the specificity of this technique on obese cadavers when comparing the EMRs and experts, as well as an increased overall time to detection among the EMRs.
  
  
  CONCLUSIONS
  The simplified 4S technique was accurate and rapid for US experts. Among novices, the 4S technique was accurate in thin, but appears less accurate in obese cadavers. Further studies will determine optimal teaching time and accuracy in emergency department patients.
authors.affiliation: Cook County Hospital, Chicago, Illinois.
authors.forename: Michael
authors.initials: M
authors.lastname: Gottlieb
authors.affiliation: Cook County Hospital, Chicago, Illinois.
authors.forename: John M
authors.initials: JM
authors.lastname: Bailitz
authors.affiliation: Cook County Hospital, Chicago, Illinois.
authors.forename: Errick
authors.initials: E
authors.lastname: Christian
authors.affiliation: Cook County Hospital, Chicago, Illinois.
authors.forename: Frances M
authors.initials: FM
authors.lastname: Russell
authors.affiliation: Cook County Hospital, Chicago, Illinois.
authors.forename: Robert R
authors.initials: RR
authors.lastname: Ehrman
authors.affiliation: Cook County Hospital, Chicago, Illinois.
authors.forename: Basem
authors.initials: B
authors.lastname: Khishfe
authors.affiliation: Cook County Hospital, Chicago, Illinois.
authors.forename: Alexander
authors.initials: A
authors.lastname: Kogan
authors.affiliation: Cook County Hospital, Chicago, Illinois.
authors.forename: Christopher
authors.initials: C
authors.lastname: Ross
mesh_terms: D000328:Adult; D002983:Clinical Competence; D004630:Emergencies; D004632:Emergency Medical Services / Q000379:methods*; D004635:Emergency Medicine / Q000193:education; D004947:Esophagus / Q000000981:diagnostic imaging*; D006801:Humans; D007087:Illinois; D007396:Internship and Residency; D007442:Intubation, Intratracheal / Q000379:methods*; D010865:Pilot Projects; D012680:Sensitivity and Specificity; D016037:Single-Blind Method; D014132:Trachea / Q000000981:diagnostic imaging*; D014463:Ultrasonography