title: Real-time tracheal ultrasonography for confirmation of endotracheal tube placement during cardiopulmonary resuscitation.
abstract: OBJECTIVE
  This study aimed to evaluate the accuracy of tracheal ultrasonography for assessing endotracheal tube position during cardiopulmonary resuscitation (CPR).
  
  
  METHODS
  We performed a prospective observational study of patients undergoing emergency intubation during CPR. Real-time tracheal ultrasonography was performed during the intubation with the transducer placed transversely just above the suprasternal notch, to assess for endotracheal tube positioning and exclude esophageal intubation. The position of trachea was identified by a hyperechoic air-mucosa (A-M) interface with posterior reverberation artifact (comet-tail artifact). The endotracheal tube position was defined as endotracheal if single A-M interface with comet-tail artifact was observed. Endotracheal tube position was defined as intraesophageal if a second A-M interface appeared, suggesting a false second airway (double tract sign). The gold standard of correct endotracheal intubation was the combination of clinical auscultation and quantitative waveform capnography. The main outcome was the accuracy of tracheal ultrasonography in assessing endotracheal tube position during CPR.
  
  
  RESULTS
  Among the 89 patients enrolled, 7 (7.8%) had esophageal intubations. The sensitivity, specificity, positive predictive value, and negative predictive value of tracheal ultrasonography were 100% (95% confidence interval [CI]: 94.4-100%), 85.7% (95% CI: 42.0-99.2%), 98.8% (95% CI: 92.5-99.0%) and 100% (95% CI: 54.7-100%), respectively. Positive and negative likelihood ratios were 7.0 (95% CI: 1.1-43.0) and 0.0, respectively.
  
  
  CONCLUSIONS
  Real-time tracheal ultrasonography is an accurate method for identifying endotracheal tube position during CPR without the need for interruption of chest compression. Tracheal ultrasonography in resuscitation management may serve as a powerful adjunct in trained hands.
authors.affiliation: Department of Emergency Medicine, National Taiwan University Hospital, Taipei City, Taiwan. Electronic address: erichaochang@gmail.com.
authors.forename: Hao-Chang
authors.initials: HC
authors.lastname: Chou
authors.forename: Kah-Meng
authors.initials: KM
authors.lastname: Chong
authors.forename: Shyh-Shyong
authors.initials: SS
authors.lastname: Sim
authors.forename: Matthew Huei-Ming
authors.initials: MH
authors.lastname: Ma
authors.forename: Shih-Hung
authors.initials: SH
authors.lastname: Liu
authors.forename: Nai-Chuan
authors.initials: NC
authors.lastname: Chen
authors.forename: Meng-Che
authors.initials: MC
authors.lastname: Wu
authors.forename: Chia-Ming
authors.initials: CM
authors.lastname: Fu
authors.forename: Chih-Hung
authors.initials: CH
authors.lastname: Wang
authors.forename: Chien-Chang
authors.initials: CC
authors.lastname: Lee
authors.forename: Wan-Ching
authors.initials: WC
authors.lastname: Lien
authors.forename: Shyr-Chyr
authors.initials: SC
authors.lastname: Chen
mesh_terms: D000328:Adult; D022561:Advanced Cardiac Life Support; D000368:Aged; D000369:Aged, 80 and over; D016887:Cardiopulmonary Resuscitation / Q000379:methods*; D003199:Computer Systems; D004630:Emergencies; D005260:Female; D006801:Humans; D007442:Intubation, Intratracheal / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D014132:Trachea / Q000000981:diagnostic imaging*; D014463:Ultrasonography
keywords: Advanced cardiac life support; Cardiopulmonary resuscitation; Emergencies; Intratracheal; Intubation; Ultrasonography