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SOME RELATED FACTORS TO NOSOCOMIAL INFECTION 
IN THE INTENSIVE CARE UNIT OF 
NATIONAL HOSPITAL FOR TROPICAL DISEASES 
 Doan Quang Ha1; Nguyen Van Kinh1 
 Nguyen Vu Trung1; Nguyen Van Chuyen2 
SUMMARY 
Objectives: To describe some of factors related to nosocomial infection in Intensive Care 
Unit of National Hospital for Tropical Diseases (2011 - 2012). Subjects and methods: A prospective 
study evaluating some of factors related to nosocomial infection in Intensive Care Unit from Jan 
2011 to Dec 2012 on 682 inpatients. Results: Invasive interventions were associated with nosocomial 
infection, including: gastrostomy, mechanical ventilation, central venous catheterization, 
angioplasty and catheterization. There is a relation between duration of therapy and the risk of 
nosocomial infection. Patients hospitalized for 10 - 15 days had the highest risk of hospital-
acquired infection. Risk factors for hospital pneumonia: Intubation for more than 5 days; risk 
factors for hospital sepsis: central venous catheterization more than 3 days; risk factors for 
urinary tract infection: urinary catheter more than 3 days. Conclusions: Medical invasive 
interventions and duration of therapy are the main factors influencing nosocomial infection in the 
Intensive Care Unit of National Hospital for Tropical Diseases. 
* Keywords: Nosocomial infection; Related factors. 
INTRODUCTION 
Nosocomial infections (NI) is a 
bacterial infection that patients suffer 
during hospitalization, which is one of the 
main causes of morbidity and mortality for 
patients in hospitals around the world [2]. 
NI is usually caused by antibiotic-resistant 
bacteria, which makes it difficult to treat, 
prolong hospital stay, increase the risk of 
death and the cost of treatment. 
In the European Union, the annual 
mortality rate from infections with resistant 
strains is 25,000 and in the United States 
over 63,000. According to a survey conducted 
by the WHO in 55 hospitals in 14 countries, 
the average NI rate was 8.7% wheres 
West Mediterranean: 11.8%; Southeast 
Asia: 10.0%; Europe: 7.7% and Western 
Pacific 9.0%, among of which pneumonia 
accounts for the highest rate, followed by 
septicemia, surgical site infections and 
urinary tract infections. 
These infections account for 80% of all 
cases of NI and causes huge economic 
losses including increased cost of 
treatment and reduced labor. Each year, 
it costs of the US 5.7 billion for patient care, 
much higher than the cost of influenza 
prevention [3]. 
1. National Hospital for Tropical Diseases 
2. Vietnam Military Medical University 
Corresponding author: Doan Quang Ha (
[email protected]) 
 Date received: 10/10/2018 
 Date accepted: 30/11/2018 
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Nosocomial infection at intensive care 
unit (ICU) is twice or 3 times higher than 
other departments in the hospital [4]. 
In Vietnam, there is no research on NI in 
ICU wards of NI, yet adequate analysis of 
risk factors related to NI has been made 
to provide appropriate intervention. 
This study aims: To describe some of 
the risk factors associated with NI in the 
ICU of the National Hospital for Tropical 
Diseases (2011 - 2012), as a scientific basis 
for interventions. 
SUBJECTS AND METHODS 
1. Subjects, location, time. 
* Subjects: 
Patients who were treated in ICU of 
National Hospital for Tropical Diseases 
from 01 - 1 - 2011 to 31 - 12 - 2012. 
* Location: ICU of National Hospital for 
Tropical Diseases. 
* Time: January 1st 2011 - December 
31st 2012. 
2. Methods. 
* Research design: 
A prospective, case-control analysis of 
relacted factors of NI in ICU, the National 
Hospital for Tropical Diseases. 
* Sample size and sampling method: 
- Sample size: 
Total sample size of patients with NI in 
ICU who had treatment in period from 
January 1, 2011 to December 31, 2012. 
- Sampling method: 
Select randomly, continuous pattern. 
All patients eligible for ICU admission will 
be selected. 
- Inclusion criteria: 
Patients were treated in the ICU at 
least than 48 hours. 
- Exclusion criteria: 
Patients who had NI before admission to 
the ICU or have manifestations of NI 
within the first 48 hours since admission 
to the ICU. 
* Research variables and methods of 
data collection: 
- Research variables: 
+ Major variables: 
Case definition: The NI standard is 
based on the WHO 2002 standard [1]. 
Time is calculated from 48 hours after 
entering Emergency-Intensive Care Department 
to 48 hours after leaving Emergency-
Intensive Care Department. 
. Secondary variables: 
. Duration of treatment at ICU: from 
hospitalization to the discharge of Emergency- 
Intensive Care Department. 
. The entire duration of treatment: the 
time patient were treated in hospital. 
- Independent variables: 
+ Invasive intervention: 
Intubation & mechanical ventilation, 
nasal continuous positive airway pressure, 
peripheral venous catheterization, central 
venous catheterization, urinary catheterization, 
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gastroenteric tube feeding. Other interventions: 
drainage of pleural cavity, peritoneal cavity, 
aerosol, hemodialysis 
. Drug treatment: 
Antibiotics: When antibiotics are used, 
there is evidence of bacterial infection in 
patients. 
Other drugs: Corticosteroids, H2 blockers, 
vasopressors and inotropes (dopamine 
and dobutamine), macromolecules, muscle 
relaxants (diazepam and phenobarbital) 
are included when administered to patients 
for a minimum of 24 hours. 
. Blood transfusion: When a patient 
receives blood transfusions and blood 
products. 
. Parenteral nutrition: When the patient 
is fed with a solution containing protein or 
fat for at least 24 hours. 
. Time to place the instruments, or use 
the drug before NI: From the time of 
intervention until the detection of NI. 
If the patient does not have NI, it will be 
calculated from the time of placing or 
using the drug until the end of the 
intervention or when leaving the ICU. 
* Data collection: 
- Initial evaluation of the patient: 
Patients eligible for the study were 
examined, performed diagnostic tests and 
assessed their status, recorded gender, 
age, comorbidity, if any, date of entry. The 
initial information will be filled in the form. 
- Patient monitoring and evaluation: 
All patients were taken care, monitored 
and treated according to the hospital regimen 
in accordance with the condition and under 
the same control conditions of the NI. 
Patient interventions and treatments 
were documented on the date and time of 
use. Monitor and evaluate the NI related 
signs of each position. 
- Urinary catheterization: Test urine 
every 72 hours until urinary catheters 
were removed, when there is urine nitrite (+) 
and/or white blood cell (+), it was 
suspected of urinary tract infection. 
- Endotracheal intubation: When there 
is clinical febrile or changes in sputum or 
crackles lung sound, chest X-ray is 
indicated. 
- Intravenous catheter insertion: When 
there is a change in the injection site right 
away, or manifestation of the infectious 
disease syndrome, carry out tests to 
identify infections. 
- Tests to identify cases: 
Blood culture is done when the patient 
shows signs of infection: 
+ There are 2 of the following 4 criteria: 
fever > 38.50C; rapid pulse; rapid breathing; 
neutropenia increases or decreases with 
age or rate neutrophil > 10%. 
+ Evidence of infection or suspected 
by examination, test. Blood is collected 
from peripheral blood at a volume of 
1 - 2 mL with sterile syringe, inserted into 
blood culture bottle BactecPeds plus/F and 
cultured with automatic BACTEC 9420. 
- Get a chest X-ray, obtain sputum by 
nasotracheal aspiration method (NTA) or 
use the endotracheal tube if the patient is 
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intubated, when the patient have such 
symptoms as: cough, increased sputum, 
purulent sputum, hear crackles lung sound. 
Sputum suction device is a specialized 
sterile one designed specifically for the nose 
and trachea or suctioned through the 
endotracheal tube. Evaluate the quality of the 
specimen based on the Bartlett standard. 
- Urine culture was performed on the 
3rd day after urinary catheterization and 
repeated when having symptoms: Dysuria, 
urinary retention, pain in pubic bone, or 
cloudy urine; if urinary catheters were not 
available, urine culture should be performed 
when there are symptoms: dysuria, urinary 
retention, pain in pubic bone, or leucocyte 
ornitrite in the urinalysis. Urine was 
obtained from a sterile syringe from the 
collecting tube of the urine vesicle if the 
urinary catheter was placed. A specimen 
was considered positive when there is at 
least 105 CFU/mm3. 
- Culture pus from wounds and secretions 
from drainage pipes to find pathogens. 
Pus, fluid, and wound secretions are 
removed by using sterile syringes or 
sterile sticks and then placed in sterile 
vials and sent to the laboratory. The 
specimens are then cultured to find the 
bacteria on aerobic and fungal environments 
if suspected of fungus. 
Interpretation of results: If an agent is 
isolated, it wil be considered as the 
cause of the disease. In the case of 
specimens cultured from two or more 
agents, the dominant agent will be 
considerd as the cause of the infection. 
In cases where the results are negative 
but there are still doubts, they might be 
cultured again. 
- Case definition and questionnaire 
completion: 
Patients were monitored for 48 hours 
after leaving the ICU, if there were NI 
symptoms during this period, it was also 
referred to as NI in the ICU. Case 
definition was in accordance with the 
WHO 2002 standard. The patient's final 
result was evaluated until discharge, 
total time in the ICU, the length of 
hospital stay and the cost of treatment 
were recorded. 
Complete the questionnaire when the 
patient left the ICU within 48 hours. Check 
the questionnaire, compared with the medical 
record when discharged. 
* Data analysis: 
Data were processed statistically by 
SPSS 22.0 software. 
Comparison and correlation: Comparing 
the exposure factors in two groups with NI 
and non-NI: Using t-test when comparing 
two means, test χ2 compares two ratios 
and Fisher's test compares two ratios 
have small samples; considered significance 
with p < 0.05 for two-sided. 
Determination of risk factors: Risk 
factors were analyzed by logistic regression. 
Significant risk factors in logistic regression 
analysis will have a corresponding regression 
coefficient β. 
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RESULTS 
1. Distribution of NI. 
Table 1: Relationship between invasive intervention and the NI. 
Non-NI (n = 383) NI (n = 299) 
Invasive intervention 
n % n % 
p-values 
Gastric sonde 159 41.5 146 48.8 0.057 
Endotracheal intubation or ventilation 45 11.8 158 52.8 < 0.001 
Central venous catheterization 12 3.1 121 40.47 < 0.001 
Intravenous exposures 0 0.0 75 25.1 < 0.001 
Angioplasty catheterization 6 1.6 60 20.1 < 0.001 
Urinary catheter 107 28.9 105 35.1 0.015 
Pleural effusion 53 13.8 32 10.7 0.219 
Peritoneal drainage 31 8.1 14 4.7 0.075 
Intravenous transfusion 
01 line intravenous transfusion 
02 lines intravenous transfusion 
03 lines intravenous transfusion 
174 
170 
39 
45.4 
44.4 
10.2 
134 
134 
31 
44.8 
44.8 
10.4 
0.987 
Intravenous invasive interventions were associated with the NI, including gastric 
ulcer, endotracheal intubation - ventilation, central venous catheterization, intravenous 
exposures, angioplasty and urinary catheter. 
Table 2: Comparison of instrumental use index between the two groups with NI and 
non-NI by type of invasive intervention. 
Non-NI (n = 383) NI (n = 299) 
Invasive intervention Time 
(n = 2,843) 
IUI Time (n = 3,384) 
IUI 
p 
Gastric sonde 651 0.229 1.412 0.364 < 0.001 
Endotracheal intubation 232 0.082 1.836 0.473 < 0.001 
Central venous catheterization 49 0.017 1.187 0.306 < 0.001 
Intravenous exposures 0 - 212 0.055 < 0.001 
Angioplasty catheterization 15 0.005 171 0.044 < 0.001 
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Urinary sonde 350 0.123 299 0.091 < 0.001 
Pleural effusion 115 0.04 103 0.027 0.004 
Peritoneal drainage 70 0.025 45 0.012 < 0.001 
Average 185,3 0.065 664.8 0.171 < 0.001 
(Indicators use interventions [IUI)] = Instrument insertion time [INT]/total time of therapy) 
Figure 1: Correlation between instrument insertion time and IUI in group of NI. 
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IUI in group of non-NI. 
The mean of IUI in NI patients was higher than in non-NI patients (p < 0.001). 
The results of figures 1 and 2 showed that there was a correlation between 
instrument insertion time and IUI. Long instrument placement increases the IUI, 
also increases the risk of NI. 
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Figure 3: Correlation between the number of NI cases and 
the number of days treated at the ICU. 
The number of NI cases increased gradually in the treatment group after 5 days. 
The number of NI was the highest in patients with 10 - 15 days. 
2. The results of analysis of some risk factors related to NI. 
Table 3: Relationship between some risk factors of hospital pneumonia. 
Hospital pneumonia Invasie intervention 
Total 
Yes n = 135 Non n = 547 
OR (95%CI) p 
Endotracheal intubation 203 (29.8) 68 (33.5) 135 (66.5) 3.0 (2.5 - 3.6) 0.001 
Endotracheal intubation 
> 5 days 181 (26.5) 46 (25.4) 135 (74.6) 3,9 (3.1 - 5.1) 0.001 
Block H2 216 (31.7) 49 (22.7) 167 (77.3) 1.3 (0.9 - 1.9) 0.215 
Gastric sonde 305 (44.7) 65 (21.3) 240 (78.7) 1.2 (0.8 - 1.7) 0.386 
Sedative 198 (29.0) 45 (22.7) 153 (77.3) 1.3 (0.9 - 1.9) 0.244 
Muscle relaxant 107 (15.7) 26 (24.3) 81 (75.7) 1,4 (0.8 - 2.2) 0.234 
Multivariate analysis revealed that the risk factors for hospital pneumonia were 
intubation with OR 3.0 (2.5 - 3.6), duration of intubation with OR 3.9 (3.1 - 5.1). The use 
of sedative, H2 blockers, peptic ulcer and muscle relaxant was not a risk factor for 
multivariate analysis (p > 0.05). 
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Table 4: Multivariate analysis of risk factors for sepsis. 
Sepsis 
Invasive intervention Total 
Yes, n = 75 (%) No, n = 607 (%) 
OR (95%CI) p 
Central venous 
catheterization 133 (19.5) 75 (56.4) 58 (43.6) 2.3 (1.9 - 2.8) 0.001 
Central venous 
catheterization > 3 days 132 (19.4) 75 (56.8) 57 (43.2) 2,3 (1.9 - 2.8) 0.001 
No of intravenous 
transfusion ≥ 3 days 70 (10.3) 12 (17.1) 58 (82.9) 1.8 (0.9 - 3.5) 0.104 
Intravenous exposures 75 (11.0) 75 (100) 0 (0) 0.001 
Intravenous nutrition 155 (22.7) 17 (11.0) 138 (89.0) 1.0 (0.6 - 1.8) 1.00 
Blood transfusion 217 (31.8) 26 (12.0) 191 (88.0) 1,2 (0.7 - 1.9) 0.600 
By multivariate analysis, the risk factors for sepsis were placement of central 
venous catheterization with OR 2.3 (1.9 - 2.8); keep venous catheterization more 
3 days with OR 2.3 (1.9 - 2.8); 100% of all cases of intravenous exposures were 
related to sepsis, transfusion 3 days, intravenous nutrition, blood transfusion was not a risk 
factor (p > 0.05). 
Table 5: Single-variable analysis of risk factors for urinary tract infections. 
Urinary tract infections 
Invasive intervention 
Yes, n = 16 (%) No, n = 666 (%) 
OR (95%CI) p 
Urinary catheter 16 (7.5) 196 (92.5) 1.08 (1.04 - 1.12) 0.001 
Keep urinary catheter > 3 days 16 (7.5) 196 (92.5) 1.08 (1.04 - 1.12) 0.001 
Single-variable analysis revealed that risk factors for urinary tract infections were 
urinary sonde OR = 1.08 (1.04 - 1.12) and time to urinary sonde > 3 days, OR 1.08 
(1.04 - 1.12). 
Table 6: Multivariate analysis of risk factors for infection of intravenous transfusion site. 
Infection of intravenous 
transfusion site Invasive interventions 
Yes, n = 63 (%) No, n = 619 (%) 
OR (95%CI) p 
Central venous catheterization (b) 36 (26.3) 97 (73.7) 7.2 (4.2 - 12.4) 0.001 
Number of intravenous transfusion 
sites (a) ≥ 2 33 (8.8) 341 (91.2) 0,9 (0.5 - 1.5) 0.692 
Blood circulation drugs 13 (7.8) 153 (92.2) 0,8 (0.4 - 1.5) 0.540 
 (a: Venous; b: Central venous) 
Risk factors of infection for venous catheterization sites were central venous 
catheterization with OR 7.2 (4.2 - 12.4). Intravenous and blood circulation drugs were 
not risk factors for infection of catheterization sites. 
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DISCUSSION 
Nosocominal infections in ICU are often 
the highest in most hospitals [3]. 
This situation is explained by the fact 
that in the ICU area more and more 
patients are at high risk of developing 
high levels of NI, such as severe disease, 
requiring multiple invasive procedures. 
Therefore, prevention of the NI is very 
important in ICU ward. For effective 
prevention, it is important to identify risk 
factors, on the basis of which measures to 
prevent and control NI well suited. 
Multivariate analysis results of each 
type of NI indicate that the risk factor for 
pneumonia is intubation with endotracheal 
time more than 5 days; the risk factor for 
hospital sepsis is intravenous central venous 
catheterization, maintenance of intravenous 
central venous catheterization more than 
3 days and intravenous exposure; the risk 
factors for urinary tract infection are urinary 
catheterization and urinary retention time 
more than 3 days. 
Some domestic and foreign authors’ 
findings: Nguyen Viet Hung et al (2012) 
reported a relationship between NI and 
urinary done (OR = 3.5, p < 0.01), respiratory 
ventilation (OR = 2.9, p < 0.05) [4]. 
This result was consistent with the 
results from the US hospital surveillance 
statistics of 83% of bacterial pneumonia 
associated with artificial ventilation, 97% 
of urinary tract infections occured in 
patients with urinary catheterization and 
87% sepsis occurred in patients receiving 
central venous catheters [4]. 
At the ICU of National Hospital for 
Tropical Diseases, most patients suffer 
from serious diseases and have undergone 
many invasive procedures such as respiratory 
ventilation, intravenous central venous 
catheter, urethral catheter... These results 
show that there needs to focus resources 
facilities on control of NI in the ICU area 
of the hospital, particularly the need for 
increased sterilization practice in the care 
of patients with invasive interventions 
involving the airway, blood vessels and 
urinary tract. 
CONCLUSSION 
Invasive interventions were associated 
with NI including intubation, respiratory 
ventilation, central venous catheterization, 
arterial catheterization and urinary sonde. 
There was a correlation between the duration 
of treatment and the risk of NI. Patients 
hospitalized for 10 - 15 days have a 
higher risk of NI. 
Risk factors for hospital pneumonia 
was endotracheal intubation more than 
5 days; the risk factors for hospital sepsis 
were central venous catheterization for 
3 days and intravenous exposures; the 
risk factor for urinary tract infection was 
the duration of the urinary catheter more 
than 3 days. 
REFERENCES 
1. Nguyen Viet Hung et al. Rate of related 
factors and hospital infectious agents in Bachmai 
Hospital. Journal of Practic Medicine. 2012, 869 (5). 
2. Ministry of Health. Guidelines for Hospital 
Infection Control. Medical Publishing House. 2013. 
3. World Health Organization. Report on 
burden of endemic health care - associated 
infection worldwide. 2011. 
4. World Health Organization. Prevention 
of hospital - acquired infections. Practical Guide. 
WHO Press. 2002.