aka Pulmonary Puzzle 017
Caring for the intubated and mechanically ventilated patient in the emergency department is no trivial task. The care we deliver to these patients in their early hours of critical illness can have a drastic effects in reducing their morbidity, and mortality, as well as their length of stay upstairs. The care that we provided to these sick, and sometimes crashing, patients saves lives but also comes with a bundle of potential of complications.
One of bugbears of mechanically ventilating an intubated patient is the invisible spectre of ventilator-associated pneumonia (VAP). A recent article highlights that we can make a huge difference downstairs in preventing a complication that most of us in the ED will never see!
Grap, M. et.al. (2012). Ventilator-Associated Pneumonia: The potential critical role of emergency medicine in prevention. The Journal of Emergency Medicine. Vol. 42, No 3. pp353-362. PMID: 20692786
Q1. What is ventilator-associated pneumonia?
VAP is defined as pneumonia occurring in a mechanically ventilated patient that is neither present nor developing at time of intubation.
- Ventilated patients can be boarded in ED for extended periods of time, so interventions to prevent VAP are must be initiated downstairs in the emergency department.
Q2.What is the epidemiology of ventilator-associated pneumonia?
VAP is estimated to be responsible for 27-47% of ICU acquired infections, and it is the second most common nosocomial infection in the United States.
- 10-20% of mechanically ventilated patients will develop VAP,.
- VAP leads to prolonged mechanical ventilation, increased ICU and hospital length of stays, with an associated increased morbidity and mortality, adding an average additional US$40,000 cost in hospital services provided.
Q3. What is the pathophysiology of ventilator-associated pneumonia?
VAP is thought to result from leakage of contaminated oraphrayngeal secretions around the endotracheal cuff into the lungs.
- VAP can be either:
— early onset (developing by 48-72 hours after intubation), or
— late onset (developing after 72 hours)
- Early onset VAP organisms (e.g. Haemophilus influenza and Streptococcus spp.) are generally community acquired.
- Bugs causing late onset VAP are different — they include enteric Gram-negative rods and methicillin-sensitive Staphylococcus aureus (MRSA).
- Trauma patients succumbing to severe head and neck injuries are at higher risk of developing VAP.
Q4.What are the 4 simple preventative measures you can do downstairs, to prevent ventilator-associated pneumonia?
1. Patient position
Elevate the head of the bed to 30-45°
- Elevation is a simple, easy and very effective way of preventing VAP, if there are no contraindications (spinal injury, prone ventilation).
- The supine position is an independent risk factor for mortality in mechanically ventilated patients.
- Enterally fed patients with the head of the bed elevated to at least 45° have lower ratesof gastric aspiration and pneumonia.
- Sitting the patient up also improves ventilation and oxygenation.
2. Oral Cavity care
Apply oral chlorhexidine solution to the oral cavity.
- Dental plaque, and the the build up of bacterial flora in the oral cavity (especially Streptococci) have been thought to contribute to the development of VAP.
- Recent literature supports the practice of applying oral chlorhexadine solution to the oral cavity soon after intubation then every 12 hours while intubated.
- There is very limited evidence to support brushing the teeth of intubated patients with a soft tooth brush, but this may help prevent VAP by removing dental plaque.
Suction the ET tube periodically
- Patients that are intubated and deeply sedated cannot swallow or cough so bacterial laden secretions build up in the subglottic space.
- The ETT cuff is a barrier to the aspiration of large volume secretions but with patient movement and repositioning of the ETT tube microaspiration of these secretions can still occur.
- Removal of these secretions either by frequent suctioning is recommended to reduce the incidence of VAP.
Ensure the ETT cuff pressure is between 20-30cm H2O
- Maintaining an optimal ETT cuff seal provides an excellent barrier to secretions entering the lung.
- The recommended range for ETT cuff pressure is 20-30cm H2O, with greater risk of pneumonia if cuff pressures are below 20cm.
- Studies have shown that cuff pressures do drop, some to as low as 9cm H2O after 4 hours.
- Current recommendations is are to check cuff pressure as soon as possible after intubation, then every 4 hours to maintain cuff pressures between 20-30cm H2O.
Q5. So, what are the 4 key take home points on preventing VAP?
- Sit them up!
- Clean the mouth!
- Suck them out!
- Keep the cuff up!
References and Links
- Grap, M. et.al. (2012). Ventilator-Associated Pneumonia: The potential critical role of emergency medicine in prevention. The Journal of Emergency Medicine. Vol. 42, No 3. pp353-362. PMID: 20692786