title: Automatic detection of oesophageal intubation based on ventilation pressure waveforms shows high sensitivity and specificity in patients with pulmonary disease.
abstract: Unrecognised endotracheal tube misplacement in emergency intubations has a reported incidence of up to 17%. Current detection methods have many limitations restricting their reliability and availability in these circumstances. There is therefore a clinical need for a device that is small enough to be practical in emergency situations and that can detect oesophageal intubation within seconds. In a first reported evaluation, we demonstrated an algorithm based on pressure waveform analysis, able to determine tube location with high reliability in healthy patients. The aim of this study was to validate the specificity of the algorithm in patients with abnormal pulmonary compliance, and to demonstrate the reliability of a newly developed small device that incorporates the technology.
  
  
  
  Intubated patients with mild to moderate lung injury, admitted to intensive care were included in the study. The device was connected to the endotracheal tube, and three test ventilations were performed in each patient. All diagnostic data were recorded on PC for subsequent specificity/sensitivity analysis.
  
  
  
  A total of 105 ventilations in 35 patients with lung injury were analysed. With the threshold D-value of 0.1, the system showed a 100% sensitivity and specificity to diagnose tube location.
  
  
  
  The algorithm retained its specificity in patients with decreased pulmonary compliance. We also demonstrated the feasibility to integrate sensors and diagnostic hardware in a small, portable hand-held device for convenient use in emergency situations.
authors.affiliation: Department of Anesthesia and Intensive Care Medicine, Maria Middelares Hospital, Ghent, Belgium; Department of Anesthesiology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands. Electronic address: AlainKalmar@gmail.com.
authors.forename: Alain F
authors.initials: AF
authors.lastname: Kalmar
authors.affiliation: Department of Anesthesiology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
authors.forename: Anthony
authors.initials: A
authors.lastname: Absalom
authors.affiliation: Department of Electronics and Information Systems (ELIS), Ghent University, Gent, Belgium.
authors.forename: Pieter
authors.initials: P
authors.lastname: Rombouts
authors.affiliation: Department of Electronics and Information Systems (ELIS), Ghent University, Gent, Belgium.
authors.forename: Jelle
authors.initials: J
authors.lastname: Roets
authors.affiliation: Department of Neurosurgery, Ghent University Hospital, Ghent, Belgium.
authors.forename: Frank
authors.initials: F
authors.lastname: Dewaele
authors.affiliation: Department of Electronics and Information Systems (ELIS), Ghent University, Gent, Belgium.
authors.forename: Pascal
authors.initials: P
authors.lastname: Verdonck
authors.affiliation: Department of Anesthesiology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
authors.forename: Arjanne
authors.initials: A
authors.lastname: Stemerdink
authors.affiliation: Department of Critical Care, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
authors.forename: Jan G
authors.initials: JG
authors.lastname: Zijlstra
authors.affiliation: Department of Emergency Medicine, Antwerp University Hospital and University of Antwerp, Edegem, Belgium; Emergency Medicine, Ghent University, Gent, Belgium.
authors.forename: Koenraad G
authors.initials: KG
authors.lastname: Monsieurs
mesh_terms: D000368:Aged; D000465:Algorithms; D004947:Esophagus; D005260:Female; D006801:Humans; D007362:Intensive Care Units; D007442:Intubation, Intratracheal / Q000009:adverse effects / Q000295:instrumentation* / Q000401:mortality; D008171:Lung Diseases / Q000628:therapy*; D055370:Lung Injury / Q000628:therapy*; D008297:Male; D019300:Medical Errors / Q000401:mortality / Q000517:prevention & control; D008875:Middle Aged; D011859:Radiography; D015203:Reproducibility of Results; D012121:Respiration, Artificial / Q000379:methods; D012129:Respiratory Function Tests / Q000295:instrumentation*; D012680:Sensitivity and Specificity
keywords: Automatic detection algorithm; Emergency intubation; Oesophageal intubation; Pulmonary compliance