Approach to Pneumonia in Patients with ARDS
Richard G. Wunderink MDNorthwestern University
Chicago IL USA
Pneumonia and ARDSCommunity-acquired pneumonia is the
most common infectious cause of ARDSViral pneumonia very significant mortalityAspiration pneumonitis is often confusedVAP as a cause of ARDS is uncommon
ARDS secondary to pneumonia has the highest associated mortality
BAL Neutrophilia
85.4 80.482.2
37.8
82.3 77.1
0
20
40
60
80
100
High
ly Pos
*
Ster O
ff AB
ICO >
2%
ICO >
7%
Pos G
S
Therap
y Chan
ge
PM
N %
(95
% C
I)
* BAL > 106, PSB > 105 cfu/ml
BAL Amylase
Visual inspection of data – clear separation >80 IU/L
14 patients with 20 BALs >80 IU/L 5/14 BALs diagnostic colony
counts as well (2 oral flora only)
3/14 known esophogeal disease
6/14 severe neurologic disease
9/14 suspected aspiration 10/14 subsequently diagnosed
swallowing dysfunction No significant pancreas-
specific amylase (N=78)
13862
42.7
2
13.8
434
24.5
1
10
100
1000
10000
100000
Raw value Log transf
Mea
n an
d 95
% C
I
N= 136 consecutive BALs
13
ARDS and VAPVAP occurs frequently in ARDS
ARDS and VAP: Incidence
60
28
43
55
3228
3731
23
0
10
20
30
40
50
60
%
Delclaux Meduri Chastre Markowicz
VAP Recurrent VAP Non-ARDS
ARDS and VAP: Mortality
78
92
6352
72
57 59
47
0
50
100
Mor
tali
ty (
%)
Delclaux Meduri Chastre Markowicz
VAP No VAP VAP, no ARDS
ARDS and VAP: Diagnosis
VAP occurs frequently in ARDSVAP hard to diagnose in ARDS
Frequent empirical antibiotic useMultiple other potential causes of signsPre-existing CXR abnormalities
ARDS and VAP: Diagnosis
VAP occurs frequently in ARDSVAP hard to diagnose in ARDS
Frequent empirical antibiotic use Multiple other potential causes of signs Pre-existing CXR abnormalities
Quantitative culture techniques (bronchoscopic or nonbronchoscopic) are more likely to define true VAP in
ARDS
Invasive versus Clinical Diagnosis of VAP
25.8
16.2
5.8 4.97.5
11.5
2
14
0
5
10
15
20
25
30
Mortality*(%)
Organ FailureDay 7
Antibiotic-Free days
No antibiotics(%)
ClinicalInvasive
* 14 Day: 28-Day severity-adjusted mortality significantly
higher also ( RR 1.25, 95% CI 1.05-1.47)
ARDS and VAP: Response to Treatment
VAP occurs frequently in ARDSVAP hard to diagnose in ARDS
Ineffective antibiotic therapy for VAP is difficult to detect in ARDSHigh frequency of MDR pathogens like
Pseudomonas and MRSACompromises ability to use “therapeutic response”
to assess presence of pneumonia
Treatment Failure in VAP
53
62
43.6
60
0
10
20
30
40
50
60
70
Fai
lure
(%
)
Luna Ionas Chastre Luyt
Resolution of VAP
5
3
6
3
8
6
10
7
6 6
0
1
2
3
4
5
6
7
8
9
10
Dur
atio
n to
Res
olut
ion
(Day
s)
Fever PaO2/FiO2 WBC ETA QC All
Mean
Median
Dennesen, AJRCCM, 2001
Clinical Pulmonary Infection Score (CPIS)
OriginalTemperatureLeukocytosisSecretionsPaO2/Fio2 ratioCXR pattern (0
points for ARDS)
ModificationsLeukocytosis definitionSecretion definitionCXR definitions
Resolution of VAP
Survivors
All patients
Nonsurvivors
Luna, Crit Care Med, 2003
Resolution of VAP
Procalcitonin Response to VAPProcalcitonin Response in VAP
-50
0
50
100
150
200
250
300
350
400
450
Responders
Nonresponders
104 cfu/ml
Qu
anti
tati
ve C
ult
ure
(cf
u/m
l)
MRSA VAP: Microbiologic Response to Vancomycin
16.7
84.6
67
46
0102030405060708090
%
<1000 cfu/ml 28 day Mortality
MRSA
Control VAP
p < 0.05
Baughman, J Intensive Care Med, 2003
Repeat PSB after 72 hours
Follow-up Bronchoscopy in Nonfermenter VAP
0
25
19.2
38.9
23.1
38.9
0
5
10
15
20
25
30
35
40
14 Day 28 Day MechanicalVentilation
Follow-upNo Follow-up
P = 0.008
Mortality
Pneumonia and ARDS
Pneumonia common cause of ARDSVAP common complication of ARDSVAP difficult to diagnosis
May need more aggressive approach to both initial diagnosis and subsequent evaluation
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