Selective decontamination of the digestive tract (SDD) using topical antimicrobial agents for
oral decontamination and the use of SDD to prevent gastric colonization in critically ill,
mechanically ventilated, or ICU patients appear to reduce the incidence of VAP (26,83,135,140–142),
although the widespread use of antimicrobial prophylaxis is not recommended, and this issue
remains unresolved.
When the pH of the stomach contents is raised, its infective organism load may increase.
Thus, H 2 blockers and proton pump inhibitors are risk factors for VAP (143) and unsuitable in
patients without a high risk of gastrointestinal bleeding (120). Moreover, the preferential use of
sucralfate or H 2 -blocking agents remains an unresolved issue (2). Impairing gastroesophageal
reflux reduces the risk of aspiration. Accordingly, a semirecumbent position (95,98–101,144–146)
and the use of an inflated esophageal balloon (in patients with a nasogastric tube and enteral
feeding tube) during mechanical ventilation (147) can reduce gastroesophageal reflux and, thus,
lower the risk of bronchial aspiration of gastric contents.
When used in an individual patient, the breathing circuit (i.e., ventilator tubing and
exhalation valve and the attached humidifier) should not be routinely changed. The circuit
should be replaced only when visibly soiled or not working properly (2).
Compared with open endotracheal suction systems, closed systems reduce cross-
contamination between the bronchial system and gastric juices (148), but increase colonization
rates of ventilator tubing with MDR microorganisms (149). There is no increase in VAP
frequency (149), however, and closed endotracheal suction systems may be in fact associated
with lower rates of VAP relative to open systems (148). The current SHEA/IDSA recommen-
dation is to keep the ventilatory circuit closed during condensate removal (150). Closed suction
systems do not have to be changed every day (151,152), and a policy of weekly changes of the
in-line suction catheter offers substantial cost savings, with no significant increase in the
incidence of VAP (153).
Adequate sputum clearance above the endotracheal cuff is essential if VAP is to be
minimized. Subglottic suctioning is effective at removing secretions above the endotracheal
cuff (2,39,95,154) and reduces the incidence of VAP nearly by half (risk ratio¼0.51; 95% CI,
0.37 to 0.71) (155), primarily by reducing early-onset pneumonia. Endotracheal tube cuff
pressure should be at least 20 cm H 2 O to prevent leakage of bacterial pathogens around the
cuff into the lower respiratory tract (156,157).
Good humidification is important for sputum clearance (158), although passive as
opposed to active humidification devices have been related to a lower VAP incidence (152,159).
The use of rotational therapy with kinetic or continuous lateral rotational therapy beds is
not considered a routine part of VAP prevention in SHEA/IDSA recommendations (2,150,160).
Table 3 Preventing Ventilator-Associated Pneumonia in Acute Care Hospitals—SHEA/IDSA Practice
Recommendation (Continued)
Recommendation Category
- Use an endotracheal tube with in-line and subglottic suctioning for all eligible
patients
B-II- Ensure that all ICU beds used for patients undergoing ventilation have a built-in
tool to provide continuous monitoring of the angle of incline
B-IIIIII. Approaches that should not be considered a routine part of VAP prevention
- Do not routinely administer intravenous immunoglobulin, white-cell-stimulating
factors (filgrastim or sargramostim), enteral glutamine or chest physiotherapy
A-III- Do not routinely use rotational therapy with kinetic or continuous lateral rotational
therapy beds
B-II- Do not routinely administer prophylactic aerosolized or systemic antimicrobials B-III
IV. Unresolved issues - Avoidance of H2 antagonist or proton pump inhibitors for patients without a high
risk of gastrointestinal bleeding - Selective digestive tract decontamination for all patients undergoing ventilation
- Use of antiseptic-impregnated endotracheal tubes
- Intensive glycemia control
Source: Ref. 150.
Nosocomial Pneumonia in Critical Care 185