Tip:
Highlight text to annotate it
X
Patient AH is an elderly woman with chronic lung and cardiac disease
admitted to the ICU following a stroke.
On day 6, AH developed a productive cough, decreased air
entry bilaterally and lethargy. Her O2 Sat was
87 percent on 15 litres by face mask. She was febrile,
short of breath and her blood pressure had dropped.
Her white count was elevated and a chest x-ray
showed a new infiltrate.
Sputum and blood samples were sent and AH was diagnosed with hospital-acquired
pneumonia
or HAP.
HAP is the second most common hospital-acquired infection and occurs
anywhere in the hospital. In the ICU intubated patients develop
ventilator-associated pneumonia or VAP.
Hap is defined as a pneumonia that develops more than 48 hours after
admission,
while a diagnosis of VAP requires patients to have been mechanically
ventilated
for more than 48 hours at the time of infection onset.
Like all pneumonia syndromes, the diagnosis is based on the appropriate
constellation
of clinical signs and symptoms and can mimic
other syndromes, like heart failure, or pulmonary embolism.
A scoring tool such as the Clinical Pulmonary Infection Score
(CPIS) can aid in the diagnosis of HAP or VAP,
and a score greater than six correlates with the presence of high bacterial
counts in the lungs.
It can be used to risk stratify patients and to guide both starting and stopping
antibiotics.
Once appropriate respiratory samples have been sent for culture,
prompt initiation of appropriate empiric antibiotics
is essential for good patient outcomes.
The core bugs in HAP or VAP are the usual respiratory culprits --
Streph. pneumo, and H. flu - plus Staph. aureus
and some gram-negative bugs -- like E coli Enterobacter species, or
Klebsiella species or proteus.
To identify target bugs, guidelines place
emphasis on the duration of time in hospital prior to the onset of infection.
The longer the time in hospital the greater the likelihood of colonization.
There are risk factors
for infection with more difficult to treat organisms, such as Pseudomonas,
MRSA and ESBLs.
These risk factors include recent hospital admissions,
antibiotic use, immunosuppression,
and known colonization with any of these organisms.
Empiric therapy should target the core bugs
and account for these risk factors.
Combination therapy for Pseudomonas infections is common
but not supported by the literature.
Only if you are worried about pseudomonas or other multi-drug
resistant organisms
is it reasonable to start with empiric combination therapy.
For most patients a single antimicrobial is sufficient.
Once you're a bug identified or if cultures remain negative at 48 hours,
narrow or target therapy for the remaining treatment.
Our patient AH was admitted from home for six days,
and she hasn't been on antibiotics during her admission.
However, if she had been intubated since admission she would be considered a VAP
and at risk of infection with more difficult to treat bugs.
Seven days of antibiotics should be sufficient to treat most cases of
HAP and VAP.
14 days, minimum, is recommended to treat bacteremic S. aureus pneumonia.
Key messages; start antibiotics promptly,
target core bugs,
consider patient risk factors; combination therapy should be tailored
once culture results are available;
treat most patients for seven days.