Risk factors for pneumonia, and colonization of respiratory tract and stomach in mechanically ventilated ICU patients.

Risk factors for the development of ventilator-associated pneumonia (VAP) and colonization of the respiratory tract and stomach with enteric gram-negative bacteria (EGB) and Pseudomonadaceae were determined in 141 ventilated patients using univariate analysis and the Cox proportional hazards model. VAP was caused by EGB in 14 patients (10%), and by Pseudomonadaceae in 19 patients (13%). The duration of ventilation was a significant risk factor for VAP caused by EGB and Pseudomonadaceae, and for acquired colonization in oropharynx, stomach, and trachea with these species. Of 20 other variables, oropharyngeal colonization with EGB on admission (hazard ratio [HR] = 4.5) and an infection on admission (HR = 2.7) were selected as risk factors for VAP caused by EGB. Acquired colonization with Pseudomonadaceae in oropharynx (HR = 5.0) was the most important risk factor for VAP caused by these species. Gastric colonization with EGB or Pseudomonadaceae were no risk factors for VAP. For acquired oropharyngeal colonization with EGB only the duration of ventilation was a risk factor, whereas preceding colonization of the trachea with Pseudomonodaceae and duration of ventilation were risk factors for acquired oropharyngeal colonization with these species. In the Cox model, only the duration of ventilation was significantly related to acquired gastric colonization with EGB. Preceding colonization of the orophayrnx and of the trachea with Pseudomonadaceae were risk factors for acquired colonization with these species in the stomach. Twelve patients with VAP (46%) and 38 without VAP (33%) died (p = 0.21). In conclusion, duration of ventilation and colonization of the upper respiratory tract are the most important risk factors for VAP caused by EGB or Pseudomonadaceae.

[1]  C. Mason,et al.  Bacterial colonization: pathogenesis and clinical significance , 1993 .

[2]  J. Sanford,et al.  Changing pharyngeal bacterial flora of hospitalized patients. Emergence of gram-negative bacilli. , 1969, The New England journal of medicine.

[3]  R. Rodríguez-Roisín,et al.  Gastric and pharyngeal flora in nosocomial pneumonia acquired during mechanical ventilation. , 1993, The American review of respiratory disease.

[4]  F. V. van Tiel,et al.  The role of intragastric acidity and stress ulcus prophylaxis on colonization and infection in mechanically ventilated ICU patients. A stratified, randomized, double-blind study of sucralfate versus antacids. , 1995, American journal of respiratory and critical care medicine.

[5]  P. Montravers,et al.  Nosocomial pneumonia in ventilated patients: a cohort study evaluating attributable mortality and hospital stay. , 1993, The American journal of medicine.

[6]  J. Ibáñez,et al.  Gastroesophageal reflux in intubated patients receiving enteral nutrition: effect of supine and semirecumbent positions. , 1992, JPEN. Journal of parenteral and enteral nutrition.

[7]  T. Calandra,et al.  High circulating levels of interleukin-6 in patients with septic shock: evolution during sepsis, prognostic value, and interplay with other cytokines. The Swiss-Dutch J5 Immunoglobulin Study Group. , 1991, The American journal of medicine.

[8]  R. Woolson,et al.  Hospital-acquired pneumonia. Attributable mortality and morbidity. , 1989, American journal of epidemiology.

[9]  M. Mandelli,et al.  Long-term Respiratory Support and Risk of Pneumonia in Critically III Patients , 1989 .

[10]  P. Francioli,et al.  Nosocomial Pneumonia in Mechanically Ventilated Patients Receiving Antacid, Ranitidine, or Sucralfate as Prophylaxis for Stress Ulcer , 1994, Annals of Internal Medicine.

[11]  W. Knaus,et al.  APACHE II: a severity of disease classification system. , 1985 .

[12]  R. Rodríguez-Roisín,et al.  Pulmonary Aspiration of Gastric Contents in Patients Receiving Mechanical Ventilation: The Effect of Body Position , 1992, Annals of Internal Medicine.

[13]  C. Andrews,et al.  Diagnosis of Nosocomial Bacterial Pneumonia in Acute, Diffuse Lung Injury , 1981 .

[14]  F. V. van Tiel,et al.  Continuous enteral feeding counteracts preventive measures for gastric colonization in intensive care unit patients , 1994, Critical care medicine.

[15]  B. Make,et al.  Risk factors for pneumonia and fatality in patients receiving continuous mechanical ventilation. , 1986, The American review of respiratory disease.

[16]  T. Inglis,et al.  Gastroduodenal dysfunction and bacterial colonisation of the ventilated lung , 1993, The Lancet.

[17]  W. Zimmerli,et al.  Role of gastric colonization in nosocomial infections and endotoxemia: a prospective study in neurosurgical patients on mechanical ventilation. , 1989, The Journal of infectious diseases.

[18]  M. Dauge,et al.  Prospective evaluation of the protected specimen brush for the diagnosis of pulmonary infections in ventilated patients. , 1984, The American review of respiratory disease.

[19]  L. B. Palmer,et al.  Gastric flora in chronically mechanically ventilated patients. Relationship to upper and lower airway colonization. , 1995, American journal of respiratory and critical care medicine.

[20]  J. Rello,et al.  Nosocomial respiratory tract infections in multiple trauma patients. Influence of level of consciousness with implications for therapy. , 1992, Chest.

[21]  G. D. Thomas,et al.  Nosocomial respiratory infections with gram-negative bacilli. The significance of colonization of the respiratory tract. , 1972, Annals of internal medicine.

[22]  F. V. van Tiel,et al.  The stomach is not a source for colonization of the upper respiratory tract and pneumonia in ICU patients. , 1994, Chest.

[23]  A. Hance,et al.  Evaluation of clinical judgment in the identification and treatment of nosocomial pneumonia in ventilated patients. , 1993, Chest.

[24]  M. Kollef.  Ventilator-Associated Pneumonia , 2005 .

[25]  B. Celli,et al.  Nosocomial pneumonia in intubated patients given sucralfate as compared with antacids or histamine type 2 blockers. The role of gastric colonization. , 1987, The New England journal of medicine.

[26]  M. Niederman.  Gram-negative colonization of the respiratory tract: pathogenesis and clinical consequences. , 1990, Seminars in respiratory infections.

[27]  C. Liu,et al.  Enteral nutrition in patients receiving mechanical ventilation. Multiple sources of tracheal colonization include the stomach. , 1986, The American journal of medicine.

[28]  L. Mandell,et al.  Clinical Investigations in Critical CareGastric Colonization by Gram-Negative Bacilli and Nosocomial Pneumonia in the Intensive Care Unit Patient: Evidence for Causation , 1992 .

[29]  R. Rodríguez-Roisín,et al.  Incidence, risk, and prognosis factors of nosocomial pneumonia in mechanically ventilated patients. , 1990, The American review of respiratory disease.