Epidemiology and the Risk Factors for Mortality in Ventilator-Associated Pneumonia

Full text

309
ABSTRACT
Objective: Ventilator-associated pneumonia (VAP) is the most common hospital-aquired infections in intensive care units (ICUs) and
associated with prolonged hospital stay, increased mortality and cost. This study aims to analyse the epidemiology and the risk factors
affecting 30 day-mortality in VAP.
Method: Adult patients with VAP were included in the study. Data were obtained from infection control commitee records. Patients were
followed up for mortality until 30 days after onset of VAP or until death for the patients died within 30 days. Survivor and non-survivor groups
were compared as for the predictors of mortality.
Results: A total of 183 VAP patients were evaluated. Early-onset VAP was observed in 16 (8.7%), and late-onset VAP in 167 (91.3%) patients.
Acinetobacter baumannii was the most common cause of VAP (49.2%), followed by Pseudomonas aeruginosa (19.7%) and Klebsiella
pneumoniae (13.7%). Carbapenem resistance was seen in 78 (42.6%) patients and among them, most frequently Acinetobacter baumannii
(62.8%, 49/78), followed by Klebsiella pneumoniae (20.5%, 16/78), Pseudomonas aeruginosa (14.1%, 11/78) and Escherichia coli (2.6%, 2/78)
were isolated. Thirty day-mortality rate was 46.4% (n=85). In univariate analysis; malignity, blood transfusion, renal replacement therapy,
Higher APACHE II, SOFA and SAPS 2 scores on the day of VAP onset and Acinetobacter baumannii were found to be more common in non-
survivor group. According to the Cox-regression analysis, only SOFA score on the day of VAP onset and Acinetobacter baumannii were
independent predictors of mortality. Although rate of trauma patients was significantly higher in survivor group, in multivariate analysis it
was not a protective factor for mortality.
Conclusion: The most common cause of VAP was Acinetobacter baumannii and carbapenem resistance was seen in more than half of
Acinetobacter baumannii and Klebsiella pneumoniae isolates. Higher SOFA score on the day of VAP onset and Acinetobacter baumannii
infections were found to be independently associated with 30-day mortality in VAP patients.
Keywords: ventilator-asociated pneumonia, mortality, SOFA score, Acinetobacter baumannii
ÖZ
Amaç: Ventilatörle ilişkili pnömoni (VİP), yoğun bakım üniteleri (YBÜ)’de en sık hastane kaynaklı infeksiyonlardan biridir ve uzun süreli hasta-
ne yatışı, artan ölüm oranı ve maliyet ile ilişkilidir. Bu çalışma, YBÜ’de VİP tanılı hastalarda epidemiyoloji ve 30 günlük mortaliteyi etkileyen
risk faktörlerini irdelemeyi amaçlamaktadır.
Yöntem: Erişkin VİP hastaları çalışmaya dahil edildi. Hasta verileri enfeksiyon kontrol komitesi kayıtlarından elde edildi. Hastalar VİP başlan-
gıcından 30 gün sonrasına kadar veya 30 gün içinde öldüyse ölene kadar mortalite açısından takip edildi. Yaşayan ve ölen hastalar risk faktö-
reri açısından karşılaştırıldı.
Bulgular: Çalışmaya toplam 183 VİP hastası dahil edildi. Erken başlangıçlı VİP 16 (%8,7) hastada, geç başlangıçlı VİP 167 (%91,3) hastada
görüldü. En sık VİP etkeni Acinetobacter baumannii idi (%49,2), bunu Pseudomonas aeruginosa (%19,7) ve Klebsiella pneumoniae (%13,7)
izledi. 78 (%42.6) hastada karbapeneme direnç görüldü. Bu hastalarda sıklık sırasına göre Acinetobacter baumannii (% 62.8, 49/78), Klebsiella
pneumoniae (%20.5, 16/78), Pseudomonas aeruginosa (%14.1, 11/78) ve Escherichia coli (%2.6, 2/78) izole edildi. Çalışmada otuz günlük
mortalite oranı %46,4 (n=85) olarak bulundu. Tek değişkenli analizde; ölen grupta malignite, kan transfüzyonu, renal replasman tedavisi,
APACHE II, SOFA ve SAPS II skorları ve Acinetobacter baumannii sıklığının daha fazla olduğu görüldü. Cox-regresyon analizine göre, sadece VİP
geliştiği andaki SOFA skoru ve Acinetobacter baumannii mortalitenin için bağımsız risk faktörü olarak bulundu. Yaşayan grupta travma has-
talarının oranı anlamlı olarak daha yüksek olmasına rağmen, travma çok değişkenli analizde mortalite için koruyucu bir faktör değildi.
Sonuç: VİP hastalarında en sık etken Acinetobacter baumannii idi ve karbapenem direnci Acinetobacter baumannii ve Klebsiella pneumoniae
izolatlarının yarısından fazlasında görüldü.VIP geliştiği andaki SOFA skoru yüksekliği ve Acinetobacter baumannii infeksiyonu VIP hastalarında
30 günlük mortalite ile bağımsız olarak ilişkili bulundu.
Anahtar kelimeler: ventilatörle ilişkili pnömoni, mortalite, SOFA skoru, Acinetobacter baumannii
Epidemiology and the Risk Factors for Mortality in Ventilator-Associated
Pneumonia
Ventilatör ile İlişkili Pnömonide Epidemiyoloji ve Mortalite ile İlişkili Risk
Faktörleri
Med J Bakirkoy 2020;16(3):309-16
doi: 10.5222/BMJ.2020.43760
© Telif hakkı Sağlık Bilimleri Üniversitesi Bakırköy Dr. Sadi Konuk Eğim ve Araşrma Hastanesi’ne air. Logos Tıp Yayıncılık tarandan yayınlanmaktadır.
Bu dergide yayınlanan bütün makaleler Creave Commons Af-GayriTicari 4.0 Uluslararası Lisansı ile lisanslanmışr.
© Copyright Health Sciences University Bakırköy Sadi Konuk Training and Research Hospital. This journal published by Logos Medical Publishing.
Licenced by Creave Commons Aribuon-NonCommercial 4.0 Internaonal (CC BY)
Cite as: Yesilbag Z, Tekdos Seker Y. Epidemiology and the risk factors for mortality in ventilator-associated pneumonia. Med J Bakirkoy 2020;16(3):309-16.
Zuhal Yesilbag1 , Yasemin Tekdos Seker2
Received: 01.09.2020 / Accepted: 16.09.2020 / Published Online: 30.09.2020
Corresponding Author:
✉ zuhalyes@gmail.com
1Department of Infectious Diseases and Clinical Microbiology, Health Science University, Bakirkoy Dr. Sadi Konuk Education and Research
Hospital, Istanbul, Turkey
2Department of Anesthesiology and Reanimation, Health Science University, Bakirkoy Dr. Sadi Konuk Education and Research Hospital,
Istanbul, Turkey
Z. Yesilbag 0000-0002-7210-1084
Y. Tekdos Seker 0000-0001-6924-9814
Original Arcle
Medical Journal of Bakirkoy
ID ID

310
Med J Bakirkoy 2020;16(3):309-16
INTRODUCTION
Ventilator-associated pneumonia (VAP) is defined as
the pneumonia developed more than 48 hours after
intubation in patients on mechanical ventilation. It is
one of the most common hospital-aquired infections
in intensive care units (ICUs) and associated with
prolonged duration of hospital stay, increased mor-
tality rate and cost (1-4).
VAP develops in approximately 10–40% of patients
on mechanical ventilation, with large variations
among ICUs. Mortality rates due to VAP has been
reported varying from 20% to 50% in the literature
(5-8). Prior studies have identified the risk factors that
affect the prognosis of VAP (9-11). Multidrug-resistant
(MDR) microorganisms, the severity of illness, and
inadequate initial antibiotic therapy have been identi-
fied as determinants of ICU mortality in patients with
VAP. Underlying diseases such as chronic obstructive
pulmonary disease (COPD) are also believed to effect
the mortality in VAP patients (12). This study aims to
analyse the epidemiology of VAP and identify the risk
factors affecting 30 day-mortality of the patients with
VAP in a tertiary care hospital ICU.
MATERIALS and METHODS
This retrospective study was conducted in a 612-bed
tertiary care hospital which has a 31-bed
Anesthesiology and Reanimation ICU, nine-bed neu-
rology ICU, 16-bed coronary ICU, seven-bed cardio-
vasculary ICU, 26-bed neonatal ICU and a 16-bed
pediatric ICU. We performed the study in
Anesthesiology and Reanimation ICU which accepts
patients from both medical and surgical wards. The
study was approved by the Ethics Committee.
Adult patients with VAP (≥18 years) who were hospi-
talized in ICU between January 2016 and January
2019 were included in the study. VAP is defined as a
new or progressive pulmonary infiltration occurring
more than 48 h after intubation in combination with
at least 2 of the following criteria: temperature
>38.5°C or <36.5°C; change in character of sputum
(purulent or increased amount of sputum); white
blood cell count >10000 cells/mm3 or <4000 cells/
mm3 (13). VAP is classified as early-onset VAP, occur-
ring within 4 days of intubation, and late-onset VAP,
occuring on the fifth day or later, after intubation.
Respiratory samples were obtained from either
endotracheal aspirate (ETA) or bronchoalveolar
lavage (BAL) to determine the causative microorgan-
ism and quantitative culture cut-off points of >106
CFU/ml and >104 CFU/ml were used respectively. In
cases with recurrent VAP, only the first episode was
included in the study. The patients who had pneu-
monia at admission, multiple microorganisms in the
ETA culture or the patients who did not meet the
VAP criteria despite the growth of microorganisms in
the ETA culture were excluded from the study. Data
about demographic characteristics, underlying dis-
eases, length of ICU stay, invasive procedures, dura-
tion of mechanical ventilation prior to VAP, and
causative microorganisms were retrieved from the
infection control commitee records. Acute Physiology
and Chronic Health Evaluation (APACHE) II score,
Sequential Organ Failure Assessment (SOFA) score
and Simplified Acute Physiology Score (SAPS II) were
recorded both on the admission day and the day of
VAP onset. Patients were followed up for mortality
until 30 days after onset of VAP or until death for the
patients died within 30 days. Statistical analyses
were performed by using the Statistical package for
Social Sciences version 25.0 for Windows (SPSS Inc.,
Chicago, IL, USA). Descriptive data were presented as
mean±standard deviation, frequency, median and
percentage values. Categorical variables were com-
pared using chi- square test and Fisher’s Exact test.
The normality of continuous variables was tested
with the Kolmogorov- Smirnov test. Student’s t-test
was used for comparing the normally distributed
continuous variables and, Mann-Whitney U test for
comparing the continuous variables which were not
normally distributed. Cox regression analysis was
used for multivariate analysis to evaluate the inde-
pendent variables associated with 30-day mortality.
The “p” values less than or equal to 0.05 (p≤0.05)
were considered as statistically significant.
RESULTS
A total of 183 VAP patients were enrolled in the
study. Out of them, 116 (63.4%) were male and 67
(36.6%) were female with an overall mean age of
53.15±20.88 years (min: 18, max: 94). Early-onset
VAP was observed in 16 (8.7%) patients and late-
onset VAP in 167 (91.3%) patients. Acinetobacter

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Z. Yesilbag and Y. Tekdos Seker, Epidemiology and Mortality in Ventilator-Asssociated Pneumonia
baumannii was the leading cause of VAP (49.2%),
followed by Pseudomonas aeruginosa (19.7%) and
Klebsiella pneumoniae (13.7%). The distribution of
microorganisms that caused VAP was shown in
Figure 1. Carbapenem resistance was seen in 78
(42.6%) patients and among them, Acinetobacter
baumannii (62.8%, 49/78), Klebsiella pneumoniae
(20.5%, 16/78), Pseudomonas aeruginosa (14.1%,
11/78) and Escherichia coli (2.6%, 2/78) were isolat-
ed. The carbapenem resistance rates for each micro-
organizm was shown in Figure 2. Colistin resistance
was seen only in Klebsiella pneumoniae species in 4
(2.2%) patients. Secondary bloodstream infections
were seen in seven patients, four of them were
infected with Acinetobacter baumannii, two of them
with Klebsiella pneumoniae and one of them with
S.aureus.
Thirty day-mortality rate was found to be 46.4%
(n=85) in the study. Survivor and non-survivor groups
Sex, n (%)
Male
Female
Age, year (mean±sd)
Hospitalizaon before ICU, n (%)
Length of ICU stay, day, median (IQR)
APACHE II on admission, median (IQR)
SOFA on admission, median (IQR)
SAPS II on admission, median (IQR)
APACHE II on the day of VAP onset, median (IQR)
SOFA on the day of VAP onset, median (IQR)
SAPS II on the day of VAP onset, median (IQR)
Duraon of mechanical venlaon before VAP, day, median (IQR)
Type of VAP, n (%)
Early
Late
Trauma, n (%)
Secondary BSI, n (%)
Carbapenem resistance, n (%)
Colisn resistance, n (%)
Underlying diseases, n (%)
Hypertenon
Heart failure
Diabetes mellitus
Chronic renal failure
Coronary artery disease
Malignity
COPD
Neurological diseases
Invasive procedures, n (%)
Tracheostomy
Blood transfusion
CVC
Nazogastric tube
Total parenteral nutrion
Hemodialysis/CRRT
Microorganism, n (%)
Klebsiella pneumoniae
Acinetobacter baumannii
Pseudomonas aeruginosa
Staphylococcus aureus
Table 1. Mortality associated risk factors in venlator-associated pneumonia.
Survivor
(n=98)
67 (68.4)
31 (31.6)
50.62±21.03
40 (40.8)
32 (21-47)
20 (15-25)
8 (5-10)
45 (36-23)
18 (12-23)
4 (3-7)
39 (31-49)
11 (7-19)
7 (7.1)
91 (92.9)
34 (34.7)
2 (2)
36 (36.7)
1 (1)
24 (24.5)
6 (6.1)
13 (13.3)
9 (9.2)
11 (11.2)
3 (3.1)
8 (8.2)
7 (7.1)
75 (76.5)
74 (75.5)
82 (83.7)
97 (99)
52 (53.1)
26 (26.5)
11 (11.2)
38 (38.8)
24 (24.5)
7 (7.1)
Non-survivor
(n=85)
49 (57.6)
36 (42.4)
56.14±20.42
40 (47.1)
31 (21-48)
20 (15-26)
9 (6-11)
48 (37-61)
24 (19-28)
10 (6-3)
48 (43-60)
11 (7-18)
9 (10.6)
76 (89.4)
15 (17.6)
5 (5.9)
42 (49.4)
3 (3.5)
25 (29.4)
9 (10.6)
14 (16.5)
14 (16.5)
7 (8.2)
13 (15.3)
5 (5.9)
4 (4.7)
60 (70.6)
78 (91.8)
75 (88.2)
85 (100)
55 (64.7)
51 (60)
13 (15.3)
52 (61.2)
12 (14.1)
3 (3.5)
p
0.13
0.08
0.39
0.85
0.18
0.06
0.16
<0.001*
<0.001*
<0.001*
0.94
0.41
0.009*
0.17
0.08
0.33
0.45
0.27
0.54
0.13
0.49
0.003*
0.54
0.48
0.36
0.003*
0.37
1
0.11
<0.001*
0.41
0.003*
0.07
0.28
OR
1.63
1.28
0.65
0.40
3
1.68
3.5
1.28
1.81
1.28
1.95
0.71
5.71
0.70
0.64
0.73
3.61
1.46
1.87
1.62
4.1
1.42
2.48
0.5
0.47
95% CI
0.34-1.15
0.71-2.31
0.23-1.82
0.20-0.80
0.56-15.88
0.93-3.03
0.36-34.77
0.66-2.47
0.61-5.33
0.56-2.92
0.79-4.76
0.26-1.92
1.57-20.81
0.22-2.23
0.18-2.27
0.38-1.42
1.46-8.88
0.89-2.94
1.63-2.15
0.89-2.94
2.22-7.75
0.60-3.38
1.37-4.51
0.23-1.08
0.11-1.9
OR: Odd’s rao, sd: standard deviaon, IQR: interquarle range VAP: venlator-associated pneumonia, BSI: Bloodstream infecon,
CVC: Central venous catheter CRRT: connuous renal replacement therapy

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Med J Bakirkoy 2020;16(3):309-16
were compared to determine the predictors of mor-
tality. Demographic characteristics including age and
sex, APACHE II, SOFA and SAPS II scores at ICU admis-
sion, length of ICU stay, the median duration of
mechanical ventilation prior to VAP onset were not
statistically different between two groups. The pro-
portion of patients with early and late-onset VAP
were similar in both survivor and non-survivor groups
(p=0.41). Among underlying diseases, the history of
malignity was found to be at significantly higher
rates in non-survivor group (p=0.003, OR:5.71, 95%
CI:1.57-20.81). In terms of invasive procedures in
ICU, the rates of blood transfusion and hemodialy-
sis/continuous renal replacement therapy (CRRT)
were more frequently applied in non-survivor group
(p=0.03, OR:3.61, 95% CI:1.46-8.88, p<0.001, OR:4.1,
95% CI:2.22-7.75) Although APACHE II, SOFA and
SAPS II scores at admission were not statistically dif-
ferent between each group, they were found to be
higher in non-survivors on the day of VAP onset.
When comparing survivor and non-survivors in terms
of microorganisms causing VAP, only Acinetobacter
baumannii isolates were found to be at a signifi-
cantly higher rates in non-survivor group (p=0.01,
OR:1.82, 95% CI:1.12-2.96). Pseudomonas aerugino-
sa and Klebsiella pneumoniae infections were seen
more commonly in non-survivor group, but the dif-
ference was not statistically significant. Variables
that were found to be significant in univariate analy-
sis were evaluated with Cox regression analysis to
predict independent factors associated with the
mortality of VAP. Only SOFA score on the day of VAP
onset and Acinetobacter baumannii were found to
be independently asociated with 30-day mortality.
Results of univariate and multivariate analysis are
shown in Tables 1 and 2.
In the univariate analysis, rate of patients hospital-
ized with trauma was seen significantly higher in
survivor group (p=0.009, OR:0.4, 95% CI:0.2-0.8).
However, according to the Cox regression analysis,
trauma was not found to be an independent factor
for the survival of VAP patients (p=0.36, OR:0.74,
95% CI:0.39-1.40).
DISCUSSION
Although there are several guidelines for preventing
ventilator-associated pneumonia, VAP continues to
be one of the most common hospital-acquired infec-
Acinetobacter baumannii
Klebsiella pneumoniae
Pseudomonas aeruginosa
Escherichia coli
Staphylococcus aureus
Other Gram-negave bacilli
Acinetobacter
baumannii
Klebsiella
pneumoniae
Pseudomonas
aeruginosa
Escherichia
coli
70%
60%
50%
40%
30%
20%
10%
0%
2,7%
40
30,5
66,6
54,4
Figure 1. Distribuon of bacteria that caused venlator-
associated VAP Figure 2. Carbapenem resistance rates for each bacteria.
APACHE II on the day of VAP onset, median (IQR)
SOFA on the day of VAP onset, median (IQR)
SAPS II on the day of VAP onset, median (IQR)
Trauma, n (%)
Malignity, n (%)
Blood transfusion, n (%)
Hemodialysis/CRRT, n (%)
Acinetobacter baumannii, n (%)
Table 2. Cox regression analysis of risk factors for mortality in venlator-associated pneumonia.
Survivor
(n=98)
18 (12-23)
4 (3-7)
39 (31-49)
34 (34.7)
3 (3.1)
74 (75.5)
26 (26.5)
38 (38.8)
Non-survivor
(n=85)
24 (19-28)
10 (6-3)
48 (43-60)
15 (17.6)
13 (15.3)
78 (91.8)
51 (60)
52 (61.2)
p
0.11
0.03*
0.80
0.36
0.11
0.11
0.2
0.01*
OR
1.03
1.07
0.99
0.74
1.73
2.10
0.7
1.82
%95 CI
0.99-1.07
1-1.14
0.97-1.02
0.39-1.40
0.88-3.39
0.83-5.33
0.4-1.21
1.12-2.96

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Z. Yesilbag and Y. Tekdos Seker, Epidemiology and Mortality in Ventilator-Asssociated Pneumonia
tions seen in ICUs. VAP rates vary between each
hospital and each ICU and it has been stated at dif-
ferent rates in the studies. While the incidence of
VAP was 10.8/1000 ventilator days in a study con-
ducted in Thailand, it was found as 50.87/1000 ven-
tilator days in another study in Argentina (14,15). In our
country, it was found to be 16.1/1000 ventilator days
in the study of Engin et al, 8.98/1000 ventilator days
in the study of Erbay et al, and 23.3 in the study of
Uslu et al. (16-18). In our study, the VIP incidence was
found to be 12.5/1000 ventilator days. Even in the
same unit, VAP incidence may change over time.
Therefore, it is important to follow the rates with
surveillance regularly, and taking measures when
there is an increase in VAP rates.
In the studies, Gram-negative bacteria have been
reported as the most common isolates in VAP
patients. Among these, the most common bacteria
are Acinetobacter baumannii, Pseudomonas aerugi-
nosa, and Klebsiella pneumoniae (19-28). In our study,
the microorganisms caused VAP were similar to
those studies regarding their order of frequency
(Figure 1). Acinetobacter baumannii strains were
isolated in half of our patients and Pseudomonas
aeruginosa strains were isolated in 20% of the
patients.
One of the most important issue in nosocomial infec-
tions is the increasing antibiotic resistance over the
years. Increasing rates of resistance against carbap-
enems, which were used in the treatment of MDR
microorganisms, cause serious difficulties in the
treatment of these patients and increase mortality
and morbidity (29,30). In our study, carbapenem resis-
tance was observed in 42.6% of the patients.
Acinetobacter spp. and Klebsiella pneumoniae iso-
lates have been reported to develop resistance to
most antibiotics at increasing rates over the years
(22,27,31). In the “European Antimicrobial Resistance
Surveillance Network” (EARS-Net) 2017 report, car-
bapenem resistance among Klebsiella pneumoniae
isolates were reported as 64.7% in Greece, 29.7% in
Italy and 22.5% in Romania (32). In Turkey, Candevir-
Ulu et al. found carbapenem resistance to be 48% in
the study conducted in ICUs in 2012 (33). Akgül et al.
reported that the carbapenem resistance against
K.pneumoniae strains increased to 66.9% in 2014 (34).
In our study, although carbapenem resistance was
54.4% against Acinetobacter strains which were
responsible for half of the VAP cases, it was higher
(66.6%) against Klebsiella pneumoniae strains. As
another finding, carbapenem resistance was found
to be 40% in E.coli strains which were isolated in only
5 patients. With the widespread use of colistin for
Gram-negative bacteria resistant to carbapenems,
colistin resistance has also become a problem for
these bacteria (35,36). Koçak et al. found that 39.5% of
81 carbapenem-resistant K.pneumoniae isolates
were also resistant to colistin (37). In our study, 4
(25%) of 16 carbapenem-resistant Klebsiella pneu-
moniae strains were also found to be resistant to
colistin.
VAP has the highest mortality rates among noso-
comial infections. In our study, the 30-day mortal-
ity rate was found to be higher (46.4%). VAP mor-
tality rates have been reported in studies varying
between 14-70% (38,39). In a study conducted in
China, the 30-day mortality rate was 42.8%, in a
Brazilian study 35%, in another study overall mor-
tality in VAP patients was found to be 32.4 percent
(40,6). There are several factors affecting mortality
in the patients with VAP. In our study, survivor and
non-survivors were compared to evaluate the risk
factors affecting 30-day mortality. Although there
are several studies showing that older age has
negative impact on survival, in our study no statis-
tical difference was observed between two groups
in terms of their mean ages. When the underlying
diseases were evaluated, the rate of malignancy
was found to be significantly higher in the non-
survivor group. In two studies conducted in Turkey,
the history of coronary artery disease was found
to be independently associated with mortality in
VAP patients (28,41). In a study conducted in Thailand,
history of malignancy was found to be associated
with mortality, similar to our study (19).
Immunosuppression predisposes patients to infec-
tions by impairing the host defense. But et al.
found that corticosteroid use and history of malig-
nancy were found to be higher in non-survivor
group, similar to our study (28). Considering the
effect of invasive procedures on mortality, blood
transfusion and hemodialysis/CRRT were found to
have a higher impact on mortality in the non-sur-
vivor group, but these variables lost their signifi-
cance in multivariate analysis (Table 2).

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Med J Bakirkoy 2020;16(3):309-16
When considering the univariate analysis, the pro-
portion of patients with a history of trauma was
found to be significantly higher in the survivor group
(Table 1). Similarly, In a study performed in 2010,
trauma and nontrauma groups were compared in
VAP patients, and mortality was found to be lower in
trauma patients (42). In our data, when comparing the
patients with and without trauma, it was seen that
patients hospitalized due to trauma were signifi-
cantly younger, with relatively fewer underlying dis-
eases and with lower scores both on admission and
the day of VAP onset. The low mortality in trauma
patients was attributed to these reasons.
APACHE II, SOFA and SAPS II scale scores at admis-
sion were not statistically different between each
group, but when looking at scores at the time of VAP
onset, it was seen that all scores of these scales were
significantly higher in the non-survivor group (Table
1). Studies have shown that severity of illness is
important for the prognosis after infections (8,43,44).
High scores in our study are compatible with the lit-
erature. According to the results of multivariate
analysis, the SOFA scores at the time of VAP onset
was independently associated with mortality. In a
study carried out by Inchai et al, SOFA and SAPS II
scores at the time of VAP onset were found to be
associated with mortality (19). In a study in China,
SOFA scores were independently associated with
mortality in VAP patients, and in another study,
APACHE II scores at the time of VAP onset were
found to be a poor indicator for prognosis (40,45). In
our study, only the SOFA scores at the time of VAP
onset and Acinetobacter baumannii were found to
be independent predictors of 30-day mortality in
VAP patients (Table 2). Acinetobacter baumannii
strains isolated in VAP patients have been shown in
many studies to increase the mortality, and our
results were compatible with the literature in this
respect (46,47).
The retrospective design and being a single-centre
study are the major limitations of our study. Also our
study did not investigate data about antimicrobial
treatment, therefore we could not evaluate the
effect of appropriateness of the antibiotherapy on
mortality.
In conclusion, according to our results the most com-
mon cause of VAP was Acinetobacter baumannii
isolated in half of the patients. Carbapenem resis-
tance, one of the most important treatment chal-
lenges, was seen in more than half of Acinetobacter
baumannii and Klebsiella pneumoniae isolates. Our
study also has shown that VAP is associated with
high mortality as well as high SOFA score on the day
of VAP onset and Acinetobacter baumannii infec-
tions with poor outcome.
Ethics Committee Approval: Approval was obtained
from Bakirkoy Dr. Sadi Konuk Training and Research
Hospital Clinical Research Ethics Committee (202-12
/ 08.06.2020).
Conflict of Interest: none.
Funding: none
Informed Consent: It is a retrospective study.
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