Pepsin as a marker for pulmonary aspiration.
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.
Metheny
Norma A
NA
School of Nursing, St Louis University, Mo, USA.
Chang
Yie-Hwa
YH
Ye
Jing Song
JS
Edwards
Sharon J
SJ
Defer
Julie
J
Dahms
Thomas E
TE
Stewart
Barbara J
BJ
Stone
Kathleen S
KS
Clouse
Ray E
RE
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
D010434:Pepsin A