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Postoperative pneumonia: a prospective study of risk factors and morbidity
K S Ephgrave1, R Kleiman-Wexler, M Pfaller
1Surgical Service, Veterans Affairs Medical Center, Iowa City, Iowa.
Background:
Postoperative pneumonia (PP) is a major complication that has been linked to microaspiration of pathogens originating in the gastrointestinal tract. This prospective study was performed to define the role of gastric bacterial aspiration in the development of PP.
Methods:
Informed consent was obtained before operations from 140 veterans scheduled for major elective procedures requiring nasogastric tubes, and cultures were obtained of the gastric contents and sputum twice daily after operation.
Results:
PP developed in 26 (18.6%) of 140 patients. The patients who had PP did not differ from those with no pneumonia after operation except for a history of chronic obstructive pulmonary disease, which was found in 38.5% of those with PP compared with 20% of patients with no pneumonia (p < 0.05). Morbidity was increased in association with PP, because length of stay in the surgical intensive care unit (6.2 vs 2.6 days), days intubated (2.7 vs 0.6), total postoperative days (15.3 vs 8.4), and mortality rates (19.2% vs 1.7%) were greater than in patients with no pneumonia. Gastric pathogens were present on entry in 38% of patients, and 32% of these had PP compared with 13% whose initial gastric cultures were sterile (p = 0.01). Colonization of sputum for greater than 24 hours with gastric pathogens occurred in 28% of patients. These patients had a 40% incidence of PP compared with 12% in patients without such evidence of microaspiration (p < 0.01).
Conclusions:
PP is a morbid postoperative complication associated with not only chronic obstructive pulmonary disease but also the presence of gastric bacteria during operation and transmission of gastric bacteria to the pulmonary tree after operation.
Insights
Postoperative pneumonia (PP) is linked to gastrointestinal bacteria. This study found that the presence of gastric bacteria during surgery and their transmission to the lungs significantly increases PP risk and associated complications.
Area of Science:
- Medical Microbiology
- Surgical Infections
- Pulmonology
Background:
- Postoperative pneumonia (PP) is a significant complication following major surgery.
- It is often associated with the microaspiration of pathogens from the gastrointestinal tract.
- Understanding the role of gastric bacterial aspiration is crucial for prevention.
Purpose of the Study:
- To investigate the role of gastric bacterial aspiration in the development of postoperative pneumonia.
- To identify risk factors associated with PP in patients undergoing major elective procedures.
Main Methods:
- A prospective study involving 140 veterans undergoing major elective surgery requiring nasogastric tubes.
- Gastric content and sputum cultures were collected twice daily post-operation.
- Patient data including comorbidities, length of stay, intubation duration, and mortality were recorded.
Main Results:
- Postoperative pneumonia (PP) developed in 18.6% of patients.
- Patients with PP had a higher incidence of chronic obstructive pulmonary disease (38.5% vs. 20%).
- The presence of gastric pathogens pre-operatively (38% of patients) and sputum colonization with gastric pathogens (>24 hours) were significantly associated with increased PP incidence (p < 0.01).
- PP was associated with increased morbidity, including longer ICU stays, intubation times, and higher mortality rates.
Conclusions:
- Gastric bacterial presence during surgery and subsequent pulmonary transmission are key factors in PP development.
- Chronic obstructive pulmonary disease is also a risk factor for PP.
- These findings highlight the importance of managing gastric contents and preventing bacterial translocation in surgical patients to reduce PP incidence.