Keywords
infections - neurosurgical intensive care unit - risk factors - lumbar and ventricular
drain - Glasgow coma score
Introduction
Health care–associated infections (HAIs) are most commonly associated with invasive
medical devices or surgical procedures. Millions of patients are affected by HAIs
worldwide every year, leading to significant morbidity and mortality as well as financial
loss for health systems.[1] The HAIs burden is also significantly higher in low- and middle-income nations as
compared with high-income countries, especially in patients admitted to intensive
care units. Urinary tract infection is the most frequent HAI in high-income countries,
whereas surgical site infection (SSI) is at the forefront in the low-income group,
affecting up to one-third of operated patients. In high-income countries, approximately
30% of patients in intensive care units (ICUs) are affected by at least one HAI.[2]
In the neurosurgical and neurocritical patient population, HAI rate depends on the
severity of neurological illness at presentation and the exposure to invasive devices
such as endotracheal tube (ET), central venous catheters (CVCs), and urinary catheters,
in addition to neuroscience specific devices, such as ventricular or lumbar catheters.
Although common causes of infection in a neurosurgical ICU (NSICU) patient are the
same as those for any critically ill patient, specific considerations should be made
for infections because of depressed level of consciousness and surgical opening of
the cranial vault.[3] Most of the time, clinical signs and symptoms of neurological patients with infectious
fever and noninfectious fever markedly overlap.[4]
A majority of neurosurgical patients requiring ICU admission comprise those who have
head injuries, subarachnoid hemorrhages, or complications of neurosurgical procedures.
Only a minority will be admitted with preexisting intracranial or spinal infections,
whereas majority will develop infections while they are in the ICU.[5] High rate of infections are associated with long ICU stay, polytrauma, indiscriminate
use of antibiotics, and lumbar puncture (LP)/Ommaya drain.
Good practices for infection prevention and control measures reduce the opportunities
for resistant pathogens to spread in health care facilities.[6] Additionally, timely microbiological surveillance and assessment of antimicrobial
resistance are important for dealing with HAIs. There is paucity of quality data in
literature about the HAI rates in NSICUs in India. We are sharing our experience from
a dedicated NSICU of a tertiary care center in north India.
Ethical Statement
This is a retrospective collection of data, which did not entail any direct contact
with the patient; hence, the consent was waived. This study was approved by scientific
and ethics committee of our hospital.
Study Design and Patient Population
This is retrospective and observational study in NSICU. It was conducted in a 506-bedded
tertiary care hospital with a 13-bedded dedicated NSICU. Data were analyzed over a
span of 3 years from January 2014 to December 2016.
Patients and Methods
Annual admission of patients in our NSICU is approximately 800 to 900. During this
study period, 2,608 patients were admitted into the NSICU directly from home, road
traffic accident (RTA) via triage, respiratory ward, medical ward, nephrology ward,
and also transferred from other hospital. Out of 2,608 patients, culture was received
in 229 patients after 48 hours of admission and was positive. Patients whose initial
cultures were positive within 48 hours of ICU admission were not included. Status
of the patient was assessed using the Glasgow coma score (GCS) and other medical conditions
on admission. Laboratory results and specific clinical indicators were used to categorize
infections as per CDC (Centers for Disease Control and Prevention) nosocomial infection
surveillance definitions.[7] Infection control bundles were followed and analyzed on monthly basis.
Sample Collection and Processing
Samples were collected aseptically whenever there was a suspicion of infections and
as a routine protocol if patients transferred from other hospitals. Samples included
urine, blood, and endotracheal secretion, in addition to cerebrospinal fluid, wound
aspirate, bronchoalveolar lavage fluid, pleural fluid when indicated, and stool for
Clostridium difficile polymerase chain reaction (PCR) in specific cases. Swab for methicillin-resistant
Staphylococcus aureus (MRSA) was taken only if the patient came from another hospital.
All samples were transported to the clinical microbiology laboratory for immediate
processing. Blood was cultured in the BacT Alert 3D system (Biomerieux, France). The
other samples were processed according to established standardized protocol and current
Clinical and Laboratory Standards Institute (CLSI) guideline.[8]
Isolates were identified to the species level and antimicrobial susceptibility testing
was done using Vitek Excel (Biomerieux, France). Quality control was done using American
Type Culture Collection (ATCC) strain.
Statistical Analysis
Data were analyzed using spread sheet. Statistics were analyzed based on percentage,
mean, and median values or interquartile ranges (IQRs), as appropriate. p Values < 0.05 were considered statistically significant. Univariate analysis was
employed to determine the contribution of clinical variables to the prediction of
acquisition of infections in the ICU. Also, we calculated the odds ratios of risk
factors for developing HAIs in ICU.
Results
Out of 2,608 patients, culture collected from 229 patients after 48 hours of admission
was positive. Out of 229 patients, male-to-female ratio was 2:1 with an age range
of 1 to 94 years, and length of stay (LOS) in the ICU ranged from 2 to 60 days ([Table 1]). The most common diagnosis on admission was intracranial hemorrhage 62 (27%), followed
by space-occupying lesion (SOL) 53 (23%), spine involvement 46 (20%), stroke 23 (10%),
RTA 20 (8%), and subarachnoid hemorrhage 17 (7%) ([Fig. 1]). Patients admitted with low GCS were 103 (44.9%), whereas 126 (55.1%) patients
had high GCS. For outcome analysis, patients were distributed into two subgroups according
to survival status (died or transferred out to HDU/room/ward). In the present study,
mortality rate was 17.4% (40/229) ([Table 2]).
Table 1
Baseline demographic and clinical characteristics of patients (number, %, mean, IQR)
|
Variables
|
n = 229
|
Percentage (%)
|
Mean
|
Median (IQR)
|
|
Abbreviations: GCS, Glasgow coma score; IQR, interquartile range; RTA, road traffic
accident.
|
|
Gender
|
|
|
|
|
|
Female
|
73
|
31.9
|
|
|
|
Male
|
156
|
68.1
|
|
|
|
Age (y)
|
|
|
52 y
|
|
|
1–14
|
6
|
2.6
|
|
|
|
15–60
|
131
|
57.2
|
|
|
|
61–90
|
92
|
40.2
|
|
|
|
GCS
|
|
|
|
|
|
Low GCS (3–8)
|
103
|
44.9
|
|
|
|
High GCS (9–15)
|
126
|
55.1
|
|
|
|
Length of ICU stay (day)
|
|
|
6 days
|
5 (8–3)
|
|
2–7
|
173
|
75.5
|
|
|
|
8–60
|
56
|
24.5
|
|
|
|
Locations before ICU admissions
|
|
|
|
|
|
From other hospitals
|
19
|
8.2
|
|
|
|
Home
|
94
|
41.2
|
|
|
|
RTA
|
25
|
10.9
|
|
|
|
Triage
|
63
|
27.5
|
|
|
|
Transferred from various wards within the hospital
|
28
|
12.2
|
|
|
|
Mortality rate
|
40
|
17.4
|
|
|
Fig. 1 Distribution of cases admitted in neurosurgical ICU (n = 229). AVM, arteriovenous malformation; ICH, intracerebral hemorrhage; IVH, intraventricular
hemorrhage; NPH, normal-pressure hydrocephalus; RTA, road traffic accident; SAH, subarachnoid
hemorrhage; SDH, subdural hemorrhage; SOL, space-occupying lesion.
Table 2
Percentage of mortality in relation to GCS score
|
GCS
|
Number of deaths (n = 40/229)
|
Percentage (17.4%)
|
|
Abbreviation: GCS, Glasgow coma score.
|
|
3–8
|
29
|
12.6
|
|
9–15
|
11
|
4.8
|
Out of 229 patients, 167 were intubated, 115 were urinary catheterized, and 164 were
on CVC in the internal jugular vein and subclavian vein. Patients transferred from
other hospitals, RTAs via triage were 107 (46.6%), patients admitted directly from
home were 94 (41.2%), and 28 (12.2%) were transferred from various wards and ICUs
within hospitals. Out of 229 culture-positive patients, 53 cases developed HAIs (53/2,608
[2.03%]) ([Table 3]). Among 53 HAIs, 29 developed early-onset (between 3 and 7 days on ICU admission),
whereas 24 had late-onset infections. A total of 57 laboratory-confirmed positive
cultures were identified in 53 patients. The most common infection was urinary tract
infections in 35 patients, followed by bloodstream infection (BSI) in 15 cases. One
patient had two episodes of catheter-associated urinary tract infection (CAUTI) and
another patient had two episodes of BSI. A total of 2 cases of skin-soft tissue infections
(SSI), and only one patient had pneumonia.
Table 3
Distribution of health care-associated infections (HAIs)[1]
[7]
|
Type of infection
|
No. of infections
|
Device days
|
HAI calculation
|
HAI rate
|
|
Abbreviations: CAUTI, catheter-associated urinary tract infection; CLABSI, central
line-associated bloodstream infection; HAI, health care-associated infection; SSI,
surgical site infection; VAP, ventilator-associated pneumonia.
|
|
VAP
|
1
|
4,350
|
No. of VAP/No. of ventilatory days × 1,000
|
0.22
|
|
CLABSI
|
15
|
4,361
|
No. of CLABSI/No. of central line days × 1,000
|
3.43
|
|
CAUTI
|
35
|
5,895
|
No. of CAUTI/No. of catheter days × 1,000
|
5.93
|
|
SSI
|
2
|
215 (No. of surgery)
|
No. of SSI/Total no. of surgery × 100
|
0.9%
|
Microbiological Distribution of Pathogens Identified
Thirteen different species of pathogenic microorganisms were identified out of 57
isolates ([Fig. 2]). Overall, the most common organism causing HAI was Klebsiella pneumoniae (24%), followed by Escherichia coli (22%). The percentage of multidrug-resistant (MDR) organism among gram-negative bacilli
was 26%. In infected patients, we followed culture-directed sensitivity. No case of
C. difficile infection and MRSA was noted.
Fig. 2 Distribution of microorganisms isolated in various infections (n = 53). BSI, bloodstream infection; SSI, surgical site infection; UTI, urinary tract
infection.
Univariate Analysis of Risk Factors of HAIs in the NSICU
Using univariate analysis, statistically significant association of risk factors in
development of HAIs are antibiotics use before ICU admission (p < 0.001, odds ratio [OR] = 6.775), presence of devices such as ET (p < 0.001, OR = 7.450), urinary catheter (p = 0.002, OR = 2.386), central line (p < 0.001, OR = 8.022), location before admission (p = 0.038, OR = 2.063), ICU stay > 7 days (p = 0.003, OR = 2.724), and malignancy (p = 0.001, OR = 8.775) ([Table 4]).
Table 4
Univariate analysis of risk factors for neurosurgical intensive care unit-acquired
infections (n = 229)
|
Risk factors
|
HAI (53 patients)
|
Non-HAI (176 patients)
|
p-Value
|
Odds ratio
|
|
Abbreviations: GCS, Glasgow coma score; HAI, health care-associated infection; ICU,
intensive care unit; NSICU, neurosurgical intensive care unit; RTA, road traffic accident.
|
|
Use of antibiotic before NSICU admission
|
|
|
|
|
|
Yes
|
41 (18%)
|
59 (25%)
|
< 0.001
|
6.775
|
|
No
|
12 (5.2%)
|
117 (51%)
|
|
Endotracheal intubation
|
|
|
|
|
|
Yes
|
53 (23%)
|
114 (50%)
|
< 0.001
|
7.450
|
|
No
|
0
|
62 (27%)
|
|
Urinary catheterization
|
|
|
|
|
|
Yes
|
53 (23%)
|
62 (27%)
|
0.002
|
2.386
|
|
No
|
0
|
114 (50%)
|
|
Presence of central line
|
|
|
|
|
|
Yes
|
53 (23%)
|
111 (48%)
|
< 0.001
|
8.022
|
|
No
|
0
|
65 (28%)
|
|
Location before admission
|
|
|
|
|
|
Within the hospital wards/other hospital/RTA/emergency
|
38 (16%)
|
97 (42%)
|
0.038
|
2.063
|
|
Home
|
15 (6%)
|
79 (34%)
|
|
Age (y)
|
|
|
|
|
|
< 60
|
32 (14%)
|
105 (45.8%)
|
1.000
|
1.030
|
|
> 61
|
21 (9%)
|
71 (31%)
|
|
Sex
|
|
|
|
|
|
Male
|
35 (15%)
|
121 (52.8%)
|
0.738
|
0.883
|
|
Female
|
18 (7.8%)
|
55 (24%)
|
|
Malignancy
|
|
|
|
|
|
Yes
|
7 (3%)
|
3 (1%)
|
0.001
|
8.775
|
|
No
|
46 (20%)
|
173 (75%)
|
|
Length of ICU stay
|
|
|
|
|
|
≥7
|
24 (10%)
|
41 (18%)
|
0.003
|
2.724
|
|
< 7
|
29 (12.6%)
|
135 (60%)
|
|
GCS
|
|
|
|
|
|
Low GCS (3–8)
|
17 (7%)
|
83 (36%)
|
0.080
|
0.595
|
|
High GCS (9–15)
|
33 (14%)
|
96 (42%)
|
Discussion
In the present study, the incidence of infection was 2.03%, which is similar to study
by Dettenkofer et al[9] but less as compared with Orsi et al.[10] The study by Kumar et al showed that prevalence rate of infection in neurosurgical
patients was high (18%) when it was not a dedicated NSICU.[11] In our study, CAUTI are most prevalent followed by BSIs, whereas in other studies,
the most common infection was respiratory tract, followed by infections of the urinary
tract.[9]
[10]
[12] We observed only a single case of ventilator-associated pneumonia (VAP) as compared
with other studies. The VAP patient was operated upon in other hospital for head injury
and admitted to our ICU with bilateral lower-zone consolidation. We have a low VAP
rate because of the practice of closed suction and placement of subglottic ETs for
all ventilated patients. Additionally, on initiation of ventilation, sterilized expiratory
cassette is attached on ventilator and again changing the sterilized expiratory cassette
every week for long-term ventilated patients.
Catheter-associated urinary tract infections were most common in the study by Chacon
et al,[13] which was similar to our study. We observed that CAUTI rate was 5.93, which was
similar to a study by Orsi et al and Abulhasan et al in NSICUs.[10]
[14] The reason for relatively higher CAUTI in our study was that neurosurgical patients
required prolonged and multiple urinary catheterization. Our central line-associated
bloodstream infection (CLABSI) rate was 3.43, which was much lower than that reported
by Orsi et al.[10] In our study, CVC lines were changed whenever there was a clinical indication, but
in the study by Orsi et al, CVC line days were not mentioned. Most common organisms
were gram-negative bacilli in our study, and this was similar to other studies.[9]
[11]
[13]
[15]
[16] Our study shows K. pneumoniae as the most common organism in overall HAIs, whereas E. coli was most common in CAUTI. A significant finding was that no C. difficile infection and MRSA were observed in our study. This could be because of HAI bundles
we followed for prevention of infection.
Our study showed significant association of risk factors in development of HAIs. Indiscriminate
use of antibiotics in ICU, prolonged use of devices, such as ET, urinary catheter,
and central venous line, and condition of patients at the time of admission, ICU stay
> 7days, and malignancy played a major role in the development of infection in general
ICU.[17]
[18] Thus patients, regardless of type of ICU, have similar rate of infection with the
use of invasive devices. In addition, in neuro patients, other factors, such as diabetes
mellitus, hypertension, malignancy, chronic renal failure, and use of steroid for
reducing peritumoral edema in space-occupying lesions pre- or postoperatively, influence
the incidence of HAIs. The ICU infection may be expected to escalate because of more
complex neurosurgical procedures that are prolonged, thereby exposing patients to
higher incidence of infection. Because infection is related to the length of ICU stay,
early shifting of neurosurgical patients to an appropriately staffed high-dependency
unit/ward is likely to result in reduction in the infection rate.[11]
In the present study, mortality rate was 17.4%, which was similar to the study by
Orsi et al[10] and Laborde et al.[15] Deaths in low GCS cases were 12.6%, whereas in high GCS these were 4.8%. We observed
that mortality may not directly relate to infection but may be an attributable cause
of death.
The primary role of an infection-control program is to reduce the risk of hospital-acquired
infection, thereby protecting patients, health care workers, and visitors.[19] Antibiotic stewardship programs aim to optimize rational antibiotic use while minimizing
antibiotic resistance, thus improving patient safety. This new era in HAI epidemiology
is characterized by increasing scrutiny and regulation, and consumer demands for more
transparency and accountability, along with calls for rapid reductions in HAI rates.[20]
NSICU Protocol and Infection Control Practices Followed in Our Hospital
We give prophylactic surgical antibiotic within 60 minutes before incision: (1) injectable
cefuroxime single dose in clean cases, (2) cefuroxime (24 hours) and single dose of
amikacin intraoperatively in spinal surgery with implant, (3) cefuroxime with amikacin
and metronidazole for 72 hours in clean cerebrospinal fluid (CSF) leak cases. Infection
control bundles followed in our hospital are CDC guided. There is a provision of a
separate hand rub, artificial manual breathing unit (AMBU) bag, thermometer, bed pan,
deep vein thrombosis (DVT) pump, and stethoscope for each bed. We follow regular communication
of intensivist and clinical microbiologist on daily basis. We have separate nurses
for wound care, bedsore, and SSIs, restricted visitors/visiting hours in ICU, etc.
Key concerns are proper hand hygiene, pre-surgery body wash with chlorhexidine below
the neck, rational antibiotic policy, optimal device site care, maximum barrier precaution,
daily review, and care.
