Original Article

Statewide Trends in Intracranial Pressure Monitor Use in 36,915 Patients with Severe
Traumatic Brain Injury in a Mature Trauma System over the Past 18 Years
Nikolaos Mouchtouris, Justin Turpin, Nohra Chalouhi, Fadi Al Saiegh, Thana Theofanis, Somnath Das,
Syed Omar Shah, Jack Jallo

- OBJECTIVE: Intracranial pressure (ICP)eguided ther- recommendations from the Brain Trauma Foundation
apy has been the mainstay of treatment of patients guidelines.
with severe traumatic brain injury (TBI), but recent
data have questioned its efficacy. The aim of this study
was to demonstrate trends in compliance to TBI
guidelines and use of ICP-guided care in a mature
trauma system. INTRODUCTION
METHODS: A retrospective analysis was conducted of

T
- raumatic brain injury (TBI) affects an estimated 10 million
36,915 patients with severe TBI collected by the Pennsyl- people annually worldwide.1 In the United States, TBI
vania Trauma Systems Foundation. The registry includes all contributed to 30% of all injury-related deaths in 2002e
patients >18 years old with a diagnosis of TBI with a 2006 and was associated with approximately 2.8 million emer-
Glasgow Coma Scale score £8 who were admitted from gency department visits, hospitalizations, or deaths in 2013.2,3 In
patients with TBI, the most frequent cause of death and disability
January 2000 to December 2017.
is high intracranial pressure (ICP) defined as an ICP >20 mm Hg.4
- RESULTS: Of 36,915 patients, 73.6% were men with a Uncontrolled ICP can lead to brain herniation, impaired cerebral
median age of 43.0
21.3 years. An ICP monitor was perfusion, and further brain damage.5 Because of its
placed in 16.3% of all patients. The rate of ICP monitoring fundamental place in the care of patients with severe TBI and its
ranged from 17.8% of patients in 2000e2004 to 16.7% in relationship to overall outcomes, ICP monitoring has been
included in every guideline for severe TBI published by the
2005e2009, 16.4% in 2010e2014, and 12.8% in 2015e2017
Brain Trauma Foundation (BTF).6 However, despite its routine
(P < 0.001). The most statistically significant decrease was
use in this population, the effectiveness of ICP monitoring has
noted from 2014 (16.4%) to 2015 (14.1%, P [ 0.042). The not been well established. This is in part due to the lack of
percent decrease in ICP monitoring from 2000e2014 to clinical equipoise in well-developed countries to perform a trial
2015e2017 was equivalent for patients with Glasgow Coma with a subgroup that does not receive an ICP monitor. Although
Scale scores of 3e5 (L4.0%) and 6e8 (L4.5%). recent data have questioned efficacy of ICP monitoring in
improving patient outcome and medical practice, a wealth of
- CONCLUSIONS: As studies emerged that demonstrated
evidence remains that aggressive management of intracranial
unclear benefit of ICP monitoring in improving care in hypertension leads to better outcomes.7-11
patients with severe TBI, there was a significant Up until the third edition of the BTF guidelines, ICP monitoring
statewide decline in the use of ICP monitoring after 2014 was recommended in patients with severe TBI with an abnormal
among all TBI subpopulations despite noteworthy limi- computed tomography scan or in patients with TBI with a normal
tations in the aforementioned studies and clear computed tomography scan but with 2 of the following risk

Key words Department of Neurosurgery, Thomas Jefferson University and Jefferson Hospital for
- Intracranial pressure monitoring Neuroscience, Philadelphia, Pennsylvania, USA
- Neurocritical care To whom correspondence should be addressed: Jack Jallo, M.D., Ph.D.
- Trauma [E-mail: Jack.Jallo@jefferson.edu]
- Traumatic brain injury Citation: World Neurosurg. (2019) 130:e166-e171.
https://doi.org/10.1016/j.wneu.2019.06.025
Abbreviations and Acronyms
Journal homepage: www.journals.elsevier.com/world-neurosurgery
BTF: Brain Trauma Foundation
GCS: Glasgow Coma Scale Available online: www.sciencedirect.com
ICP: Intracranial pressure 1878-8750/$ - see front matter ª 2019 Elsevier Inc. All rights reserved.
TBI: Traumatic brain injury

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 ORIGINAL ARTICLE
NIKOLAOS MOUCHTOURIS ET AL. STATEWIDE TRENDS IN ICP MONITORING OVER 18 YEARS

factors: age >40 years, unilateral or bilateral motor posturing, or Statistical analysis was carried out with IBM SPSS Version 24.0
systolic blood pressure <90 mm Hg.12 However, the fourth edition (IBM Corporation, Armonk, New York, USA).
of the BTF guidelines recommends the management of patients
with severe TBI using ICP monitoring regardless of the RESULTS
aforementioned criteria. These recommendations are based on
Analysis included 36,915 patients >18 years old with a diagnosis of
level IIB evidence consisting primarily of retrospective cohort
severe TBI as defined by GCS score 8. Median age was 43.0
studies and 1 prospective cohort study showing significantly

21.3 years, and 73.6% of patients were men. A GCS score of 3
lower mortality in patients treated with an ICP monitor.13-15
was recorded in 72.6% of patients, and GCS score of 6 was
Despite the latest BTF guidelines, however, several studies have
recorded in 21.3% of patients (Table 1). The mean Injury Severity
questioned the effectiveness of ICP monitoring.16-18 Among these
Score was 23.1
14.6. An ICP monitor was placed in 16.3% of all
is the BEST:TRIP (Benchmark Evidence from South American
patients. In 5-year periods, the rate of ICP monitor use ranged
Trials: Treatment of Intracranial Pressure) trial, a large multicenter
from 17.8% of patients (n ¼ 1703) in 2000e2004 to 16.7%
randomized controlled study published in December 2012 that
(n ¼ 1815) in 2005e2009, 16.4% (n ¼ 1787) in 2010e2014, and
suggested that care based on the use of ICP monitoring was not
12.8% (n ¼ 719) in 2015e2017 (P < 0.001).
superior to care based on imaging and clinical examination.19 In
The annual rate of ICP monitor placement is displayed in
addition, ICP monitoring has been associated with worse
Figure 1. A statistically significant decrease in ICP monitor use was
survival, increased mechanical ventilation, and increased levels
noted from 2014 (16.4%) to 2015 (14.1%) (P ¼ 0.042). A greater
of therapy intensity.20,21
percentage of patients <40 years old underwent ICP monitor
Given these new data, there has been increased skepticism
placement (19%) compared with patients 40 years old (14.0%)
among neurosurgeons regarding the benefits of ICP monitoring.
(P < 0.001). The percentage of patients <40 years old versus
In a 1991 survey of 219 trauma centers, 35% routinely used ICP
40 years old who underwent ICP monitoring is displayed in
monitoring,15 whereas a Canadian survey in 2000 showed only
Figure 2. Use of ICP monitoring was significantly greater in
20% of neurosurgeons stated that they were highly confident
patients <40 years old in every year except for 2000 and 2007.
that ICP monitoring improved outcomes.16 We suspect that the
Both groups showed a similar trend throughout this period with
recent published literature has negatively impacted the use of
a significant decrease after 2014. The percentage of patients who
ICP-guided critical care among all TBI subpopulations. The pur-
underwent ICP monitoring stratified by GCS score is displayed
pose of this study was to report the annual trends in use of ICP
in Figure 3A and B (GCS scores 3e5 and GCS scores 6e8,
monitoring in the mature trauma system of Pennsylvania over the
respectively). For GCS scores 3e5, a significant difference in use
past 18 years and determine if there was a decline in usage despite
was seen in the years 2001, 2002, 2005, 2007, 2010, 2011, and
the updated guidelines. It is hoped that this study will help guide
2012 (Figure 3A). For GCS scores 6e8, a significant difference in
future research toward improving guideline-based ICP
use was seen in the years 2006, 2010, and 2014 (Figure 3B). The
management.
percent decrease in ICP monitoring from 2000e2014 to 2015e
2017 was similar for patients with GCS scores of 3e5 (4.0%)
MATERIALS AND METHODS and 6e8 (4.5%).

Patient Selection and Variables DISCUSSION

The study protocol was approved by the University Institutional
The use of ICP monitoring in the treatment of TBI can be traced
Review Board. We conducted a retrospective analysis of 36,915
back to the 1960s, when elevated ICP was first identified as playing
patients with a diagnosis of severe TBI with a Glasgow Coma Scale
a key role in the death of patients with TBI.17 The frequency of ICP
(GCS) score 8 who were admitted to hospitals in Pennsylvania
monitor device placement has varied significantly over the years,
from January 2000 to December 2017. The patient registry was
ranging from 10.8% to 67%.7,10,12-14,18,19 The first guidelines for
collected and maintained by the Pennsylvania Trauma Systems
use of ICP monitoring were published by the BTF in 1996 and
Foundation. Date of admission, patient age and sex, GCS score on
delineated the indications for ICP monitoring. Subsequent edi-
admission, and use of an ICP monitoring device were collected for
tions of BTF guidelines published in 2000, 2007, and 2016 rein-
all the patients. Data on the trauma center level were not available
forced the indications for ICP monitoring.6,20,21 The most recent
for each patient. Data collection was conducted securely without
recommendations are based on level IIB evidence consisting of
sharing of identifiable personal health information. Individual
retrospective cohort studies and 1 prospective cohort study, all of
patient consent was not obtained given the retrospective, non-
which reported a decrease in mortality when ICP monitors were
interventional design of the study that was based on query of an
used.7,11,12
existing database.
However, recent publications have questioned the benefit of ICP
monitoring for the treatment of severe TBI. BEST:TRIP, a ran-
Statistical Analysis domized clinical trial by Chesnut et al.,9 demonstrated that ICP
Data are presented as mean and median for continuous variables monitoring was not superior to management based on imaging
according to their normal distribution curve and as frequency for and clinical examination in South America given that there was
categorical variables. Univariable analysis was carried out using no difference in 6-month mortality. The trial comprised 324 pa-
unpaired t test, c2 test, or Fisher exact test as appropriate. tients with severe TBI admitted to 6 hospitals in Ecuador and
P values of 0.05 were considered statistically significant. Bolivia. It is difficult to extrapolate the findings of this study to the

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NIKOLAOS MOUCHTOURIS ET AL. STATEWIDE TRENDS IN ICP MONITORING OVER 18 YEARS

Table 1. Patient Characteristics

All Patients ICP-Guided Treatment Clinical-Based Treatment
Patient Characteristics (N [ 36,929) (n [ 6024, 16.3%) (n [ 30,891, 83.7%) P Value

Age 43.0
21.3 41.2
18.7 46.9
21.6 <0.001

Male sex, % 73.6 76.3 73.1 <0.001
GCS score
Mean 3.93
1.65 3.90
1.58 3.93
1.66 0.163
Median (IQR) 3.0 (5) 3.0 (5) 3.0 (5)
3 26,797 (72.6%) 4315 (71.6%) 22,482 (72.8%)
4 1106 (3.0%) 238 (4.0%) 868 (2.8%)
5 1182 (3.2%) 246 (4.1%) 936 (3.0%)
6 2788 (7.6%) 461 (7.7%) 2327 (7.5%)
7 2790 (7.6%) 501 (8.3%) 2289 (7.4%)
8 2252 (6.1%) 263 (4.4%) 1989 (6.4%)
ISS 23.1
14.6 31.6
11.3 21.4
14.7 <0.001

ICP, intracranial pressure; GCS, Glasgow Coma Scale; IQR, interquartile range; ISS, Injury Severity Score.

general population because it had multiple limitations. There was intense use of resources. Other retrospective studies also suggest
a lack of external validity given that intensive care units in Ecuador that ICP monitoring may increase the risk of mortality, ventilation
and Bolivia may not use the same resources as in the United States days, intensive care unit length of stay, complications, and func-
or Europe where the guidelines were established. This is especially tional outcomes.10,14
true for prehospital and posthospital care, which can widely vary Despite some negative studies, several studies have reported
between countries, and this may have contributed to long-term promising findings supportive of ICP monitoring. Farahvar et al.7
outcomes. Additionally, the group with imaging management studied 1202 patients with an ICP monitor and 244 without an ICP
required a physician at the bedside for 24 hours/day, which may monitor who were admitted at a Level I or II hospital in the state of
not be able to be extrapolated to the rest of the world given this New York in 2000e2009. They demonstrated that 2-week mortality

Figure 1. Annual rate of intracranial pressure monitoring publication of the Brain Trauma Foundation guidelines
device placement in 2000e2017 in the state of and of landmark trial BEST:TRIP is displayed. ICP,
Pennsylvania. The annual rate was 15.1%e21.1% in intracranial pressure; TBI, traumatic brain injury; BTF,
2000e2014, but significantly declined to 14.1% in Brain Trauma Foundation.
2015, 12.8% in 2016, and 11.3% in 2017. The timing of

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NIKOLAOS MOUCHTOURIS ET AL. STATEWIDE TRENDS IN ICP MONITORING OVER 18 YEARS

Figure 2. Annual rate of intracranial pressure (ICP) study period. Asterisks denote the years when the
monitoring use in 2000e2017 for patients <40 years difference in ICP monitoring was statistically
old and 40 years old. The rate of ICP monitoring is significant (P < 0.05). ICP, intracranial pressure.
greater in patients <40 years old in every year of

was significantly higher in patients without ICP monitors placed (Figure 2). Regarding GCS score, there did not appear to be a clear
(33.2% vs. 19.6%, P < 0.0001). ICP monitoring was also a sig- relationship between GCS score and use of ICP monitoring, as
nificant predictor of 2-week mortality in the multivariable logistic statistical difference was noted in only a few years, dispersed
regression model after controlling for age, GCS score, hypoten- throughout the study period (Figure 3A and B).
sion, computed tomography scan findings, and pupillary abnor- A similar trend in compliance to the BTF guidelines has been
malities (odds ratio, 0.63; 95% confidence interval, 0.41e0.94; noted in Japan in recent years. The rate of ICP-guided therapy
P ¼ 0.02). Their findings were corroborated by Gerber et al.,22 initially increased from 34.1% in 1998 to 55% in 2011 and then
who showed a significant decrease in the case-fatality rate in significantly decreased to 28% in 2017.23,24 A meta-analysis by
New York State in 2001e2009 from 22% to 13% (P < 0.0001). Khormi et al.25 showed extensive variability in the adherence of
Interestingly, these authors noted an increase in the adherence to the various BTF recommendations. The guideline for ICP
the BTF guidelines during that time frame with an increase in the monitoring in severe TBI was adhered to in 46.4%. Factors such
use of ICP monitoring from 56% to 75% (P < 0.0001) as well as the as younger age, more severe neurologic injury, and need for
use of cerebral perfusion pressure as a treatment metric from 15% surgical treatment increased adherence, whereas coagulopathy
to 48% (P < 0.0001). Furthermore, Alali et al.11 investigated the or low systolic blood pressure steered physicians away from ICP
mortality rate based on ICP monitoring use between hospitals. monitoring. Similarly, in our study, patients in the ICP-guided
They compared hospitals with the highest use of ICP monitoring therapy group were on average younger and had a higher
with hospitals with the lowest and showed an odds ratio of 0.52 severity of neurologic injury than patients without an ICP monitor,
(95% confidence interval, 0.35e0.78) for mortality when but variables such as their coagulation profile and blood pressure
receiving care in the hospitals with highest ICP monitoring use. were not a part of our study.
The recent body of literature that pointed out the limitations of Although our study demonstrates a clear downtrend in the
ICP monitoring has influenced decision making in the manage- use of ICP-guided treatment of severe TBI, certain limitations
ment of severe TBI. Our study showed a significant statewide need to be taken into consideration when interpreting our
decline in the use of ICP monitors after 2014. The incidence of ICP findings. Our data were collected from a large patient registry,
monitoring was 15.1%e21.0% in 2000e2014 and decreased and there are a few important clinical variables that were not
significantly to 11.3%e14.1% in 2015e2017. Our findings included in the analysis. These include patient comorbidities,
demonstrated a clear downward trend in the use of ICP monitors GCS score before and after admission, hospital-acquired com-
for TBI treatment in Pennsylvania over the last 4 years (Figure 1). plications, trauma center level, need for decompressive hemi-
Although the compliance rate of ICP monitoring was significantly craniectomy, code status, and goals of care by the family, all of
higher in patients <40 years old in almost all the years studied, a which affect the treating physician’s decision making.
steady decline in use was noted as well after 2014 regardless of age Furthermore, despite the universal adoption of the GCS for

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 ORIGINAL ARTICLE
NIKOLAOS MOUCHTOURIS ET AL. STATEWIDE TRENDS IN ICP MONITORING OVER 18 YEARS

Figure 3. (A and B) Annual rate of intracranial pressure monitoring use in monitoring after 2014, no clear pattern is seen when stratified by GCS score.
2000e2017 stratified by Glasgow Coma Scale (GCS) scores 3e5 (A) and Asterisks denote the years when a significant difference between GCS
6e8 (B). Whereas there is a downward trend in intracranial pressure groups was seen. ICP, intracranial pressure; GCS, Glasgow Coma Scale.

evaluation of this patient population, there is a lack of reliability The pressing need to better understand the indications for ICP
in the GCS scoring by first responders. Evaluating the trends in monitor insertion is unveiled by the seemingly increasing skepti-
ICP monitoring in a large patient population over 18 years limits cism among neurocritical care and neurosurgery practitioners
this bias. Additionally, our data come from a single state over a regarding the benefit of ICP-guided therapy in patients with severe
long period, and caution is needed when generalizing our TBI. More studies and stronger evidence are needed to guide
findings, as they may not reflect every trauma system. The management of severe TBI. In the meantime, guideline-based
trauma center level was not available in this registry; however, treatment is clear regarding ICP monitoring and should remain
the American College of Surgeons requires all Level I, II, and III the mainstay of good clinical care.
centers with neurosurgical coverage to have adequate ICP-
monitoring capabilities. Given these limitations, the goal of
our work was to depict the current status of use of ICP moni- CONCLUSIONS
toring in a mature trauma system and demonstrate the impact As studies emerged that demonstrated unclear benefit of ICP
recent landmark papers had on its use, whereas identifying the monitoring in improving care in patients with severe TBI, there
reasons for decreased compliance and refining the indications was a significant statewide decline in use of ICP monitoring after
for ICP monitoring remains outside our scope. 2014 among all TBI subpopulations despite noteworthy

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 ORIGINAL ARTICLE
NIKOLAOS MOUCHTOURIS ET AL. STATEWIDE TRENDS IN ICP MONITORING OVER 18 YEARS

limitations in the aforementioned studies and clear recommen- ACKNOWLEDGMENTS

dations from the BTF guidelines. Most of these studies were These data were provided by the Pennsylvania Trauma Systems
based on small patient populations; more randomized controlled Foundation (Mechanicsburg, Pennsylvania, USA). The Foundation
trials are needed to further elucidate the benefits of ICP moni- specifically disclaims responsibility for any analyses, in-
toring and guide its use. terpretations, or conclusions.

10. Shafi S, Diaz-Arrastia R, Madden C, Gentilello L. monitoring on outcomes after severe traumatic
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