Appendix. VAP Teaching Cases

Case 1 (Adult)
A 24-year-old man attempts suicide by ingesting an unknown amount of lorazepam and diphenhydramine.  His girlfriend finds him unconscious in bed.  Empty pill bottles are sitting on the nightstand.  When medics intubate him at the scene for airway protection, they note vomitus in the posterior oropharynx.  In the emergency department, he is unresponsive on the ventilator with temperature 36.5ºC, blood pressure 125/70 mm Hg, pulse 104 beats/min, and respiratory rate 16 breaths/min.  Saturations are 98% on an inspired fraction of oxygen (FiO2) of 0.4.  A detailed physical exam is otherwise normal.  Complete blood count, electrolytes, and liver function tests are normal.  Urine toxicology screen reveals benzodiazepines.  An electrocardiogram reveals sinus tachycardia.  Chest radiograph shows a right lower lobe opacity.  Gastric lavage recovers several small pill fragments.  He is admitted to the ICU.  Six hours later, he is gradually awakening on the ventilator.  Temperature is 38ºC.  His oxygen requirement has increased to FiO2 0.5 to maintain a saturation of 93%.  Exam reveals crackles at the right base.  His white blood count (WBC) is 16,000/mm3 and his chest radiograph shows a slightly larger right lower lobe opacity. 

Does this patient have ventilator-associated pneumonia (VAP)? 
•	No—this patient does not have VAP.  
•	By definition, VAP is an infection occurring after intubation.  This patient presented with a history of a witnessed aspiration event due to impaired consciousness and a pneumonia on the initial film.  The elevated temperature, leukocytosis, and infiltrate in a dependent lobe are consistent with aspiration pneumonitis.  This is a type of acute lung injury after aspiration of acidic gastric contents.
•	The early timing argues against a bacterial infection, and empiric broad-spectrum antibiotics are not absolutely necessary in aspiration pneumonitis unless symptoms fail to resolve within the next 48 hours.122  Although many clinicians treat aspiration pneumonitis with prophylactic antibiotics, this approach has never been shown to improve outcomes.

Case 2 (Adult)
A 78 year old woman is mechanically ventilated in the intensive care unit for exacerbation of her chronic obstructive pulmonary disease (COPD).  She lives in a nursing home.  At admission, a sputum culture reveals normal flora and the chest radiograph shows hyperinflation with clear lung fields.  During the first three days, she remains afebrile and slowly improves with systemic corticosteroids, inhaled bronchodilators, and levofloxacin.  On day 4, her temperature is 37.6ºC and the respiratory therapist comments that sputum volume has increased over the past day.  Examination reveals an elderly woman resting comfortably on the ventilator.  Lungs reveal faint crackles at the right base.  WBC is 13,500/mm3 and the chest radiograph shows a possible new infiltrate in the right lower lobe.  A repeat chest radiograph later that day confirms this new finding. The remainder of her workup reveals no other cause for the leukocytosis.

Does this patient have ventilator-associated pneumonia (VAP)? 
•	Yes—this patient has VAP. 
•	This mechanically ventilated adult patient has leukocytosis and at least two clinical criteria (change in sputum and crackles). (Figure 1).  
•	Her chest radiographs show a new infiltrate.  Given her underlying COPD, two serial radiographs are required to definitively establish the diagnosis of VAP.  Nonetheless, it would be appropriate to start antibiotics for presumptive VAP after the initial radiograph showed a new infiltrate.
•	This patient is at risk for antibiotic-resistant pathogens because she is a nursing home resident (Figure 5).  Therefore, she should be empirically treated with triple antibiotic therapy until culture results are known.  It would be prudent to call her nursing home and ask whether they have local infection surveillance data—such information might help guide the initial antibiotic selection.

Case 3 (Immunocompromised)
A 35 year old man with newly-diagnosed Hodgkin’s disease is brought to the hospital with septic shock.  He received his first cycle of chemotherapy ten days ago.  Upon arrival, his temperature is 38.7ºC, blood pressure 78/40 mm Hg, pulse 134 beats/min, respiratory rate 24 breaths/min, and saturations 94% on 6 liters via nasal cannula.  His chest radiograph shows a left upper lobe pneumonia.  Despite prompt treatment with broad-spectrum antibiotics, intravenous fluids and pressors, his blood pressure drops further and he is electively intubated.  He is transferred to the ICU.  WBC is 1,100/mm3 (absolute neutrophil count 250/mm3), sputum reveals 3+ gram-positive cocci, and he is initially treated with levofloxacin, pipercillin, and vancomycin.  Granulocyte colony stimulating factor is given.  On day 3, blood and sputum cultures are growing a pan-resistant pneumocccus, and the vancomycin is stopped.  His temperature is 37.4ºC and blood pressure 110/65 mm Hg without vasopressors.  He easily passes a spontaneous breathing trial and plans are made to extubate him after rounds.  One hour later, he spikes a temperature to 38.5ºC.  The absolute neutrophil count is currently 400/mm3.  The morning chest radiograph shows a new left lower lobe infiltrate, in addition to the original left upper lobe pneumonia.  Bronchoscopy with quantitative bronchoalveolar lavage ultimately reveals 12,000 colonies/ml of Pseudomonas aeruginosa.  Repeat blood and urine cultures are negative.  

Does this patient have ventilator-associated pneumonia (VAP)? 
•	Yes—this patient has VAP. 
•	This patient is immunocompromised from recent chemotherapy (Figure 2).  He was originally admitted with pneumococcal pneumonia and sepsis, but now he also has P. aeruginosa VAP.  He meets the clinical criteria (fever), radiographic criteria (new infiltrate), and microbiologic criteria (quantitative BAL).  Even if his team chooses to extubate him later that day, he still has VAP.  Prompt initiation of antibiotic therapy is indicated (Figure 5).  Initial empiric double coverage for P. aeruginosa is necessary until sensitivities return.
•	The criteria for diagnosing VAP in immunocompromised patients are slightly more rigorous because this population is at risk for numerous other infections.  Although clinicians often diagnose VAP using clinical and radiographic findings, these criteria are technically insufficient to make the diagnosis in immunocompromised patients.  Ideally, immunocompromised patients should also have microbiological or histopathological criteria.  It is important to consider all potential infectious sources in a mechanically ventilated immunocompromised patient and avoid reflexively attributing every fever to VAP.

Case 4 (Infant)
A 6 month old infant arrives in the ED with 3 days history of poor feeding, increasing respiratory rate, and lethargy over the past four hours.  Temperature is 38.1ºC and room air saturations 97%.  Admission chest radiograph is normal.  Complete blood count and chemistries are normal.  Cultures are obtained.  The child is admitted to the PICU for observation, and then intubated after he exhibits periodic breathing and apnea.  He is mechanically ventilated for 2 days, then successfully extubated.  Temperature is 38.2ºC.  Lung exam is clear.  The following day, the child requires increasing oxygen to maintain saturations above 93%.  Breath sounds are coarse.  Tracheal secretions are increased in volume and yellow in color.  Chest radiograph reveals a new right upper lobe opacity.  The WBC has risen to 17,000/mm3.

Does this patient have ventilator-associated pneumonia (VAP)? 
•	Yes—this infant has VAP (figure 4).
•	This patient developed pneumonia within 48 hours after intubation and mechanical ventilation.  Although this patient had a systemic illness prior to hospitalization (presumably viral), he developed a lobar pneumonia within 48 hours after being mechanically ventilated. For this reason, he also has VAP.

Case 5 (Pediatric)
A 4 year old girl is admitted to the PICU after undergoing surgery for multiple lower extremity and abdominal burns.  The child remains intubated after surgery because she is slow to wake up.  Admission chest radiograph is clear.  On day 2, her chest radiograph shows a faint new right middle lobe opacity and sputum culture is sent.  On day 3, dressing changes are performed under general anesthesia.  Immediately after this procedure, the temperature rises to 39.1ºC.  Blood and skin cultures are also sent.  Later that day, the nurse reports increased suctioning requirements (every 1-2 hours) and she mentions the secretions are “greenish.”  Crackles are heard over the right chest.  The WBC was 11,000/mm3 on admission and today is 18,400/mm3.  Today’s chest radiograph reveals progressive consolidation in the right middle and right lower lobes.  The required FiO2 has increased from 0.3 at admission to 0.55 today.

Does this patient have ventilator-associated pneumonia (VAP)? 
•	Yes—this patient has VAP. 
•	This mechanically ventilated pediatric patient has developed pneumonia (Figure 3).  The child has at least three clinical criteria including fever, leukocytosis (acute WBC increase), change in sputum, crackles, and worsening gas exchange.  Two chest radiographs show a new and progressively increasing pneumonia.   The findings on hospital day 3 are highly suggestive of VAP, and prompt initiation of appropriate antibiotic therapy is indicated (Figure 5).