[Prospective study on the gastro-pulmonary infection route of ventilator-associated pneumonia].
OBJECTIVE
To explore the role of gastro-pulmonary infection route in the development of ventilator-associated pneumonia (VAP), so as to improve the management of VAP.


METHODS
Forty-three patients who received mechanical ventilation (MV) were enrolled in the study. Intra-gastric contents were labeled with (99)mTc-DTPA. Randomized two-period crossover trial was employed to determine the radioactive level in the oropharyngeal and bronchial secretion when patients were in supine or semi-reclining position. Gastric juice, oropharyngeal secretion and tracheal lavage fluid were collected for bacterial culture every other day. Bronchoalveolar lavage fluid (BALF) was harvested from those suspected of VAP for quantitative bacterial culture. Infrequent-restriction site amplification (IRS-PCR) was employed in the identification of the identity of the bacteria from intra-gastric colonization with those causing VAP. The sIgA content in the BALF was determined.


RESULTS
The gastroesophageal regurgitation rate was higher (89.7%) with lower aspiration rate (28.5%) in patients receiving MV. Moreover, the aspiration rate and the radioactivity of deep tracheal aspirates in patients in supine position were significantly higher than those in semi-reclining position (P < 0.01). There was high homology of the bacteria isolated from intra-gastric colonization with that causing VAP (55.8%). The sIgA content in BALF in VAP patients was evidently lower than that in non-VAP patients (P < 0.01).


CONCLUSIONS
Regurgitation and aspiration of stomach contents are very common in patients receiving MV. Intra-gastric colonized bacteria might be one of the important origins causing VAP. The lowering of sIgA in BALF in patients with MV could be a risk factor for VAP.
Zhang
Qing-ling
QL
Nursing Department, Xinqiao Hospital, The Third Military Medical University, Chongqing 400037, P.R. China.
Liu
Ming-hua
MH
Liu
Yu-fu
YF
Wang
Xian-yuan
XY
Fu
Wei-ling
WL
D001419:Bacteria / Q000302:isolation & purification; D001992:Bronchoalveolar Lavage Fluid / Q000382:microbiology; D018592:Cross-Over Studies; D005764:Gastroesophageal Reflux / Q000150:complications / Q000000981:diagnostic imaging; D006801:Humans; D018410:Pneumonia, Bacterial / Q000209:etiology*; D011187:Posture; D011446:Prospective Studies; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals; D012121:Respiration, Artificial / Q000009:adverse effects*; D012141:Respiratory Tract Infections / Q000209:etiology*; D013272:Stomach Diseases / Q000209:etiology*; D016683:Supine Position; D016284:Technetium Tc 99m Pentetate
D019275:Radiopharmaceuticals; D016284:Technetium Tc 99m Pentetate