Ventilator–Associated Pneumonia (VAP)

Ventilator–associated pneumonia (VAP) is defined as pneumonia that occurs 48 hours or more after endotracheal intubation or within 48 hours after endotracheal tube removal. Prevention of VAP is important as it would improve clinical outcome and reduce cost.

Early Onset: that occurs within 48 to 72 hours after tracheal intubation, most often due to antibiotic sensitive bacteria (e.g., methicillin-sensitive Staphylococcus aureus, Haemophilus influenza and Streptococcuspneumoniae)

Late Onset:
VAP that occurs after 72 hrs of ventilation, frequently caused by antibiotic-resistant pathogens (e.g., methicillin-resistant Staphylococcus aureus, Pseudomonas aeruginosa, Acinetobacter species, and Enterobacter species).

Pathogenesis:
The pathogenesis of ventilator-associated pneumonia usually requires

1. bacterial colonization of the aero digestive tract and
2. the aspiration of contaminated secretions into the lower airway

Therefore, strategies to prevent VAP should focus on reducing the bacterial colonization in the aero digestive tract.

Diagnosis of HAP and VAP
Criteria for clinical diagnosis                                
A new or progressive infiltration on CXR plus 2 of the following clinical criteria:

1. New onset or increase of body temperature
2. Purulent tracheal secretion

3. White blood cell count of > 12,000 cells/mm

4. worsening ventilator parameter

These clinical criteria, if present, should be followed by appropriate further microbiological investigations to confirm the diagnosis.

Prevention:
To prevent ventilator-associated pneumonia, clinicians involove in caring for patients should participate in programs.

Nonpharmacologic strategies:

1. Effective Hand Washing and the Use of Protective Gowns and Gloves
2. Semirecumbent Positioning of Patients
3. Avoidance of Large Gastric Volumes    to prevent aspiration.
4. Oral (Non-Nasal) Intubation
5. Routine Maintenance of Ventilator Circuits
6. Continuous Subglottic Suctioning
7. Use of close suction catheter and its replacement
8. Postural Changes

Pharmacological startgies:

• Use of acid lowering agent OR stress ulcer prophylaxis.

Bacterial colonization of the stomach, enhanced by the administration of pH-lowering drugs (e.g., histamine H2-receptor antagonists and antacids), is an important source of pathogens that can cause pneumonia. The administration of sucralfate into the stomach has been found to prevent bleeding from stress ulcers without lowering gastric pH.

• Administration of Antibiotics

Previous exposure to antibiotics is an important risk factor for colonization of the lower respiratory tract by antibiotic-resistant organisms such as P. aeruginosa and MRSA that results in subsequent development VAP. Therefore, eliminating or reducing the unnecessary use of antibiotics should be the primary goal in preventing antibiotic-resistant nosocomial infections.

• Chlorhexidine Oral Rinse

Bacteria that have accumulated in dental plaque have been implicated as a source of pathogens in ventilator-associated pneumonia. Chlorhexidine which is an antiseptic solution used in dental plaque, is effective in the control of ventilator-circuit colonization and pneumonia caused by antibiotic-resistant bacteria.Oropharyngeal decontamination with chlorhexidine solution reduces the occurrence of VAP.