title: The incidence of gastroesophageal reflux and tracheal aspiration detected with pH electrodes is similar with the Laryngeal Mask Airway and Esophageal Tracheal Combitube--a pilot study.
abstract: OBJECTIVE
  Aspiration as a result of gastroesophageal reflux (GER) and regurgitation remains a serious potential problem in anesthetized patients. The incidence of GER with either the Esophageal Tracheal Combitube (ETC) or the laryngeal mask airway (LMA) was investigated using tracheal and esophageal pH electrodes.
  
  
  METHODS
  Following approval by the Institutional Review Board and written informed consent, 57 patients of ASA physical status I to III were randomly assigned to receive either an LMA (Group I, n = 28) or an ETC (Group II, n = 29) during general anesthesia. All patients were paralyzed and received positive pressure ventilation. Two monocrystalline antimony catheters were used for pH monitoring: one unipolar catheter with a single pH sensor for tracheal pH measurements and one bipolar catheter with proximal and distal sensors for pharyngeal and esophageal pH measurements, respectively.
  
  
  RESULTS
  One episode of GER occurred in a patient in Group II, yet there were no pH changes reflected in the oropharyngeal or tracheal regions. There were 3/25 (12%) patients in Group I vs 1/25 (4%) patients in Group II that met the pH criterion for aspiration (pH below 4.0 that lasted at least 15 sec), yet no patient developed any clinical signs of aspiration. In all patients, hemodynamic and respiratory variables remained stable throughout the period of measurement (data not included).
  
  
  CONCLUSIONS
  In this pilot study, the ETC appears comparable to the LMA regarding the incidence of GER and tracheal acid aspiration.
authors.affiliation: Department of Anesthesiology, University of Texas-Houston Medical School, Houston, Texas 77030, USA. carin.a.hagberg@uth.tmc.edu
authors.forename: Carin A
authors.initials: CA
authors.lastname: Hagberg
authors.forename: Tigran N
authors.initials: TN
authors.lastname: Vartazarian
authors.forename: Jacques E
authors.initials: JE
authors.lastname: Chelly
authors.forename: Andranik
authors.initials: A
authors.lastname: Ovassapian
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D005764:Gastroesophageal Reflux / Q000453:epidemiology* / Q000209:etiology; D006801:Humans; D006863:Hydrogen-Ion Concentration; D015994:Incidence; D007442:Intubation, Intratracheal / Q000009:adverse effects* / Q000295:instrumentation; D017214:Laryngeal Masks / Q000009:adverse effects*; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D011015:Pneumonia, Aspiration / Q000453:epidemiology* / Q000209:etiology; D014133:Tracheal Diseases / Q000453:epidemiology* / Q000209:etiology