title: Pepsin as a marker for pulmonary aspiration.
abstract: BACKGROUND
  Although assessment for aspiration of small volumes of gastric contents in tube-fed patients receiving mechanical ventilation is important, available methods for this purpose are not wholly satisfactory. A potential method is immunoassay of tracheal secretions for the gastric enzyme pepsin.
  
  
  OBJECTIVE
  To determine the frequency with which pepsin in suctioned tracheal secretions from acutely ill, tube-fed patients receiving mechanical ventilation could be detected via an immunoassay.
  
  
  METHODS
  A convenience sample of 136 specimens of suctioned tracheal secretions was collected from 30 acutely ill, tube-fed adults receiving mechanical ventilation. Multiple samples were obtained from 26 of the 30 patients (range, 2-11 per subject). An immunoassay with rooster polyclonal antibodies to purified human pepsin was used to detect pepsin in the secretions.
  
  
  RESULTS
  Fourteen specimens tested positive for pepsin. Secretions from 5 patients accounted for the 14 pepsin-positive results. A significant relationship was found between the position of the head of the bed and the presence of pepsin in tracheal secretions (P<.001). Of the 14 pepsin-positive specimens, 13 (92.9%) were obtained from subjects in a flat position.
  
  
  CONCLUSIONS
  A pepsin immunoassay can be used to detect pepsin in human tracheal secretions. If pepsin in tracheal secretions is considered an indicator of aspiration of gastric contents, aspiration occurred in 5 of the 30 subjects. A flat position is strongly associated with the presence of pepsin in tracheal secretions.
authors.affiliation: School of Nursing, St Louis University, Mo, USA.
authors.forename: Norma A
authors.initials: NA
authors.lastname: Metheny
authors.forename: Yie-Hwa
authors.initials: YH
authors.lastname: Chang
authors.forename: Jing Song
authors.initials: JS
authors.lastname: Ye
authors.forename: Sharon J
authors.initials: SJ
authors.lastname: Edwards
authors.forename: Julie
authors.initials: J
authors.lastname: Defer
authors.forename: Thomas E
authors.initials: TE
authors.lastname: Dahms
authors.forename: Barbara J
authors.initials: BJ
authors.lastname: Stewart
authors.forename: Kathleen S
authors.initials: KS
authors.lastname: Stone
authors.forename: Ray E
authors.initials: RE
authors.lastname: Clouse
mesh_terms: D004750:Enteral Nutrition; D005750:Gastric Juice / Q000201:enzymology; D006801:Humans; D007118:Immunoassay; D007442:Intubation, Intratracheal; D010434:Pepsin A / Q000032:analysis*; D011015:Pneumonia, Aspiration / Q000175:diagnosis* / Q000209:etiology; D012121:Respiration, Artificial; D013396:Suction; D014132:Trachea / Q000378:metabolism
chemical_list: D010434:Pepsin A