CHAPTER 96 NOSOCOMIAL PNEUMONIA
The two broad classes of pneumonia are nosocomial and community-acquired pneumonia. Nosocomial pneumonia is often referred to as hospital-acquired pneumonia (HAP), defined as pneumonia occurring 48 hours or more after admission that was not incubating at the time of admission. Postoperative pneumonia is essentially HAP, except in a patient who has undergone a surgical procedure. Finally, ventilator-associated pneumonia (VAP) refers to pneumonia occurring 48 hours or more after initiating mechanical ventilation via endotracheal intubation or tracheostomy.
RISK FACTORS AND PREVENTIVE MEASURES
Nonmodifiable versus Modifiable Risk Factors
While the greatest risk factor for VAP is the duration of mechanical ventilation, there are many other independent predictors, including modifiable and nonmodifiable risk factors (Table 1).
Nonmodifiable Factors | Modifiable Factors Affording Prevention Strategies |
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ICU, Intensive care unit.
Putting All Risk Factors Together
Croce et al. recently reported a post-trauma VAP probability calculation formula incorporating many of these risk factors. The probability of VAP (PVAP) equals ef(x)/(1 + ef(x)), where f(x) = −3.08 – 1.56 ( mechanism of injury, penetrating = 1, blunt = 0) − 0.12 (Glasgow Coma Scale score) + 1.37 (spinal cord injury where yes = 1, no = 0) + 0.30 (chest abbreviated injury score) + 1.87 (emergency laparotomy where yes = 1, no = 0) + 0.67 (units of blood transfused in the resuscitation room) + 0.05 (Injury Severity Score) + 0.66 (intubation in either the field or the resuscitation room, where yes = 1, no = 0). Over 2 months, this formula was 95% accurate in predicting subsequent development of VAP.