264 AANA Journal ? August 2020 ? Vol. 88, No. 4 www.aana.com/aanajournalonline
Postoperative nausea and vomiting (PONV) is an
unpleasant complication following anesthesia and
surgical procedures experienced by both adults and
children. Compared with adults, children are 2 times
more likely to experience PONV. Many studies have
identified and independently validated risk factors
associated with the development of PONV in the pediatric
population. Chief among these are patient age
greater than 3 years, surgical duration greater than
30 minutes, surgical type, and a history of PONV. The
purpose of this evidence-based practice change was to
investigate if preoperative documentation of a patient’s
PONV history will lower PONV rates postoperatively. A
PONV history assessment tab was created to aid in
the documentation of the patient’s PONV history, and
a retrospective chart review was conducted 2 months
before and 2 months after the practice change. A total
of 2,279 preintervention cases were compared with
2,006 postintervention cases. Rates of PONV dropped
22%, from 153 preintervention cases to 120 postintervention
cases, demonstrating a significant (P = .0043)
decrease in PONV rates following a patient’s reported
history of PONV. Documentation of a patient’s PONV
history preoperatively led to a decrease in postoperative
rates of PONV.
Keywords: Pediatric, postoperative nausea and vomiting,
risk assessment
Pediatric Postoperative Nausea and Vomiting:
Assessing the Impact of Evidence-Based
Practice Change
Robert W. Simon, DNP, MS, CRNA
The issue of postoperative nausea and vomiting
(PONV) is not new. What was once referred
to as a “big little problem” in the early 1990s
is now quite substantial.1,2 A serious complication,
PONV has been associated with a higher
mortality rate in both the adult and pediatric populations.
3 Although rarely fatal, PONV has been associated
with increased patient dissatisfaction and discomfort,
dehydration, electrolyte disturbances, prolonged discharge
from the recovery unit, unanticipated hospital
admissions, prolonged hospital stays, wound dehiscence,
aspiration pneumonia, esophageal rupture, and increased
healthcare costs.3
On average, children experience 2 times the rate of
PONV compared with adults.4-6 A systematic review
concluded that the rate of PONV in children ranged from
42% in low-risk patients to as high as 80% in high-risk
patients.4,7 Kovac8 ranked PONV as the fourth most
common cause of unexpected hospital admissions in pediatric
surgical patients. In a more recent survey, patients
reported that vomiting ranks higher than pain as the most
feared and unpleasant outcome following surgery.9,10
The etiology of PONV in children is complex and multifactorial.
1,6,8,11 Multiple studies have identified surgical
time greater than 30 minutes, a history of motion sickness
or PONV, age greater than 3 years, use of inhalational
anesthetics, opioid administration, and type of surgery as
the biggest influence on the development of PONV.3,7,12,13
Although some factors cannot be adjusted (age and
surgery type), other factors can be modified (intravenous
anesthesia over inhalational anesthesia, opioid-sparing
techniques) to mitigate the development of PONV.
Several independent predictors of PONV in both the
adult and pediatric populations have been identified by
the American Society of Anesthesiologists.14 In adults,
independent predictors of PONV include female gender,
a patient history of PONV, a patient history of motion
sickness, nonsmoking status, and the use of perioperative
opioids.15 For the pediatric population, independent
predictors of PONV include age greater than 3 years,
surgical type, surgical length, a patient or family history
of motion sickness, and a patient or family history of
PONV.15 The American Society of PeriAnesthesia Nurses
stresses that a patient’s baseline risk for PONV should be
objectively assessed via a validated risk score based on
independent predictors.15
Multiple preoperative screening tools such as the
Eberhart score, the Koivuranta score, and the Apfel score,
have been developed and validated to aid in identifying
these risk factors.1,14 However, these particular screening
tools are specific to the patient population and cannot
be reliably used in the pediatric population because of
poor prognostic abilities. In response, the Society of
Ambulatory Anesthesia guidelines advocate for the use
of a simplified screening tool to evaluate baseline risk
factors in the pediatric population.14,15
Use of a simplified predictive PONV score identifies
surgical patients at low, medium, and high risk. This alerts
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healthcare practitioners to the potential need for antiemetic
therapy and influences the likelihood that the appropriate
treatment regimen is selected. Preoperative identification
has been shown to significantly decrease the rate of occurrence
of PONV and to improve patient outcomes.12,16
However, provider practice surrounding the preoperative
identification of PONV risk factors has been described
as disorganized and inconsistent.9 This is attributed
to a lack of knowledge among healthcare providers
regarding risk factors and PONV screening tools.9,17 Many
practitioners and institutions do not regularly employ an
evidence-based PONV scoring system despite documented
benefits and current guideline recommendations.9
In 2000, a randomized double-blind placebo-controlled
trial was conducted to determine the weighted
cost that a single episode of nausea and/or vomiting can
have on the US healthcare system.18 The median cost per
episode of nausea was $194, and the median cost per
episode of emesis was $303.18 Direct and indirect costs
were included, and many of the expenses were attributed
to the need for more hospital-based services and staff as
opposed to medication prices.18
The use of a PONV risk scoring system has the potential
to decrease the frequency of PONV in midrisk to
high-risk populations and can avoid the potential side
effects associated with administration of prophylactic antiemetics
in low-risk patients.1,9,10,14-16 Identification of
potential PONV risk factors can also result in a decrease
in the direct and indirect financial costs of PONV.18
Currently there are 3 risk scoring systems available
for use in clinical practice (Table 1). The Apfel
and Koivuranta Scoring systems are indicated for adult
patients, whereas Eberhart’s postoperative vomiting in
children (POVOC) scoring system is meant for use in
pediatric patients.6,9,14,18
Literature Review
• Search Method. The purpose of a search for evidence
was to answer the following PIOT (patient, intervention,
outcome, time) clinical question: In children undergoing
nonemergent surgery (P), what are effective screening
tools (I) to predict postoperative nausea and/or vomiting
(O) within 24 hours of surgery (T)? To identify
all available evidence, the author conducted a review
using the MEDLINE, Cochrane, Cumulative Index to
Nursing & Allied Health Literature (CINAHL), Joanna
Briggs Institute (JBI) Evidence-based Practice, and the
National Guideline Clearinghouse databases. The search
string consisted of free-text phrases and medical subject
heading (MeSH) indexing terms: (ped* OR child* OR
you* OR preschoo* OR Adolescen* OR teen* AND post*
nausea and vomiting OR PONV OR post* nausea OR post*
vomiting AND predict* OR assess*). For identification
of additional and potentially relevant data sources, each
article that matched the PIOT criteria was examined
along with its respective reference lists. Studies referenced
in matching articles were reviewed for relevance
and were included if matching the PIOT criteria.
Limits included defining the population term pediatrics.
For purposes of this search, pediatrics is defined as
ages 2 to 18 years. The rationale for this is that children
younger than 2 years may present with an increased likelihood
of vomiting caused by medical conditions, such as
pyloric stenosis. Additionally, children aged up to 2 years
do not tend to have a fully developed chemoreceptor
trigger zone, one of the main pathways for development
of postoperative nausea and/or vomiting.8 The search was
also restricted to human subjects studies. For maximal
data return, the search was not limited to peer-reviewed
articles or English-only articles. Figure 1 presents the
flow of the search process.
• Search Results. A total of 383 articles were found
via the databases, and another 10 articles were discovered
from the reference lists from other studies. This
search uncovered a clinical practice guideline based on
a systematic review.15 After final elimination of articles
synthesized in the review, 5 cohort studies and a 2016
integrative review were retained for analysis.
Table 1. Risk Scoring Systems for Postoperative Nausea and Vomiting
Abbreviations: PONV, postoperative nausea and vomiting; POVOC, postoperative vomiting in children.
Risk factor Apfel score1 Koivuranta score POVOC score4,10
Female gender X X
History of PONV X X X
History of motion sickness X X X
Nonsmoker X X
Planned postoperative opioid X
Duration of surgery > 60 min X
Duration of surgery > 30 min X
Age > 3 y X
Strabismus surgery X
Family history of PONV/motion sickness X
266 AANA Journal ? August 2020 ? Vol. 88, No. 4 www.aana.com/aanajournalonline
• Clinical Practice Guideline. Antiemetic medications
have been associated with adverse effects ranging from
mild headaches to QT prolongation to cardiac arrest.15
Because of inherent differences between pediatric and
adult populations, clinical decisions about the need for
prophylactic antiemetics cannot be based on stand-alone
risk factors; rather, a patient’s baseline risk of experiencing
PONV must be assessed via a validated risk score
based on independent predictors.15
Age is a significant risk factor in the development of
postoperative vomiting, particularly in the younger age
group. People older than 3 years but younger than 50
years were found to be at the greatest risk, with an odds
ratio (OR) of 1.79 (95% confidence interval [CI] = 1.39-
2.3).15 Female gender has been identified as a predictor
of PONV in the adult population, but this is not necessarily
true in the pediatric population.15 Although there are
overlapping risk factors between 2 different adult scoring
systems (Table 1), the Society for Ambulatory Anesthesia
determined that these predictors were not applicable
in the pediatric population and that a pediatric scoring
system was needed.
At the time of the 2014 guideline update, only one
pediatric simplified scoring system had been reviewed
and validated: Eberhart’s postoperative vomiting in children
(POVOC) score.15 The POVOC score includes 4
independent predictors of postoperative vomiting in
children. These are an age greater than 3 years, patient
and/or family history of PONV, strabismus surgery,
and duration of surgery longer than 30 minutes.15 This
scoring system assigns 1 point to any “yes” answers and
0 points to any “no” answers. The total points that can
be achieved is 4, with 4 points being deemed high risk,
and 2 to 3 points being designated as moderate risk. In
children, the presence of 0, 1, 2, 3, and 4 of these risk
factors correlates with a risk of PONV of 9%, 10%, 30%,
55%, and 70%, respectively.15
• Cohort Studies. A wide variety of clinical settings,
from outpatient surgical centers19,20 to hospital-based
operating rooms,21-23 were represented. A total of 2,822
Figure 1. Search Flow Diagram
Abbreviation: PICO, patient (or population), intervention, comparison, outcome.
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children were included across the 5 studies. Individual
sample sizes ranged from 100 at a single hospital22 to
2,211 across 11 hospitals.20 Ages of the children included
in these studies ranged from 0 months21 to 19 years.20
Children undergoing routine, nonemergent pediatric
surgery comprised much of the population, although
one study20 did include pediatric patients undergoing
emergency surgery in their study. A variety of pediatric
surgical procedures were represented, including many
otolaryngologic procedures,20,23 dental procedures,22 and
oncologic procedures.21 All children in these studies
received general anesthesia, although neither anesthetic
agents nor airway devices were specified.
• Patient Factors. All 5 cohort studies identified patient
age as a risk factor. In studies with patients beginning
at birth, ages greater than 2 years21 or greater than 3
years20,23 were at greater risk. Bourdaud et al20 reported
an adjusted odds ratio (AOR) of 2.46 in children greater
than 3 years but less than 6 years. Children between 6 and
13 years were found to be at higher risk,22 with an AOR
of 3.09.20 In contrast, Kapoor et al19 found children 11 to
14 years to be at risk as well. Chau et al23 reported an OR
of 1.4 for any child greater than 3 years as well as a 40%
increase in this number for every 2-year increase in age.
Patient history of motion sickness (OR = 4.4)23 or
previous postoperative vomiting (AOR = 1.81)20 and a
family history of either motion sickness or PONV (OR
= 5.3)23 were identified as independent risk factors.
Female gender in children aged more than 13 years was
identified as a risk factor in 2 studies only.19,22
• Surgical Factors. Anesthesia duration greater than
45 minutes was identified as an independent risk factor
in one study with an AOR of 1.44.20 Surgical type was
identified as a risk factor in 3 of the 5 cohort studies.21-23
For patients with malignancy, orthopedic procedures and
neurosurgery seem to be risk factors.21 Otolaryngologic
procedures, herniorrhaphy, laparotomy,19,20 and strabismus
surgery (OR = 2.13)20 were associated with higher
levels of postoperative vomiting.
• Postoperative Factors. Postoperative administration
of opioids in the presence of postsurgical pain has been
identified as a risk factor in pediatric patients by 4 of the
5 cohort studies.19-22 One study estimated the AOR to be
2.76 in pediatric surgical patients receiving opioids postoperatively.
20 The frequency and doses of postoperative
opioids were not disclosed by all the studies.
• Integrative Review. Comparison of existing PONV
scoring systems identified many similarities between the
Apfel and Koivuranta adult scoring systems, with female
gender being the highest predictor for PONV in adults.18
In the pediatric population, it was determined that both
age and previous personal or family history of motion
sickness and/or PONV influence the likelihood of experiencing
PONV.18 Similarities among the 3 scoring systems
include a patient history of PONV and/or motion sickness.
In reviewing the literature, the author acknowledged
other independent risk factors not originally included
in Eberhart’s POVOC scale. Whereas Eberhart’s original
POVOC score design focused only on strabismus surgery
as a risk factor, recent evidence gained from newer pediatric
studies has incorporated other surgical procedures
such as hernia repair, orchiopexy, penile surgery, orthopedic
surgery, and other types of emetogenic surgeries.18
• Application to Practice. The clinical practice guidelines
recommend the use of the POVOC scoring system
for pediatric patients. This simplified scale includes 4
independent predictors of postoperative vomiting in
children: age greater than 3 years, patient and/or family
history of PONV or postoperative vomiting, strabismus
surgery, and surgical duration greater than or equal to
30 minutes. This system may be limited because it includes
only one surgical type: strabismus surgery. Newer
evidence gleaned from pediatric studies has independently
validated other surgical types, such as urology,
otolaryngology, orthopedic, and general surgical procedures.
Incorporating these procedures when screening
for PONV, in conjunction with strabismus surgery, may
result in the identification of higher-risk patients.
Methods
Findings obtained from the literature review were presented
at the hospital’s monthly quality improvement
(QI) meeting. It was discovered that the hospital, via
use of its electronic medical record (EMR) system, was
already screening for 3 of the 4 risk factors identified via
the POVOC scale. The institution was also screening for
PONV risk factors in patients undergoing urology, orthopedic,
otolaryngology, and general surgical procedures.
The single risk factor that was not consistently being
screened for or documented was the patient’s history of
postoperative nausea and/or vomiting. A brief inquiry
revealed the lack of a PONV history assessment tab in
the preanesthetic assessment data forms. The hospital’s
information technology department then created a PONV
history assessment tab.
• Intervention. To ensure full compliance with documentation
of PONV history, the history assessment tab
was made a “hard stop,” meaning the screening provider
had to select either “yes” or “no,” or the provider would
not be able to proceed to the next screen. When a provider
documented “yes” under the PONV history tab, a
reminder message would populate intraoperatively. This
reminder message would alert the anesthesia provider
that the patient has a history of PONV and might require
antiemetic prophylaxis. For the purposes of this project,
creation of the PONV history assessment tab and subsequent
documentation of the patient’s PONV history will
be considered the intervention or “practice change.”
• Design. A retrospective chart analysis of de-identified
patient data before and after the practice change was
268 AANA Journal ? August 2020 ? Vol. 88, No. 4 www.aana.com/aanajournalonline
obtained via convenience sampling. Comparison data
were collected for the 2 months before and 2 months
after practice change. In total, 2,279 preintervention
cases were collected and compared with 2,2006 postintervention
cases.
• Setting. The setting for this study was a 21-bed
pediatric operating room located in a 527-bed nonprofit
pediatric hospital. This department performs more than
30,000 surgical cases per year, not including nonoperating
room procedures or cardiac surgeries. Approval of
this project was granted for exempt review by the institutional
review board (IRB) of both the participating
institution and the university. All data were de-identified
by the hospital before review by the author. No consents
were deemed necessary for this project.
• Sample. De-identified data were collected using the
“modified” POVOC criteria (certain surgical procedure
types besides strabismus surgery). For data to be included,
the patient’s age had to have been greater than
or equal to 3 years but less than 18 years old; surgical
duration must have been 30 minutes or greater; and
surgical type must have been strabismus, urologic, orthopedic,
otolaryngologic, or general surgical procedure.
Additionally, the surgical cases must have been scheduled
as elective operations and not considered emergent.
Data not matching the criteria, as well as patients
undergoing more than 1 surgical procedure under the
same anesthetic, were excluded. The number of eligible
preintervention cases was 2,279 compared with 2,006
postintervention cases, for a total sample population of
4,285. Table 2 provides a breakdown of preintervention
and postintervention data by surgical type.
• Data Collection. Preintervention and postintervention
data were pooled from and collected via EMR review
for 2 months before and 2 months after practice change
implementation. The de-identified data were examined
and filtered based on the predetermined inclusion and
exclusion criteria. Data received consisted of the following
information: surgical date, surgical type, duration of
procedure, and the presence of emesis within 12 hours
postoperatively. Given the subjective nature of nausea
and the inability of younger children to accurately describe
it, nausea data were not collected. Although the
data were filtered by patient age, demographical data
such as gender or age were not collected or obtained by
the author. All data were stored in compliance with the
institution’s IRB via secured and encrypted electronic
servers in the research department on-site.
• Data Analysis. The expected outcome was a reduction
in postoperative vomiting rates following implementation
of the PONV history assessment tab. The aggregate
data were composed of 3 components: surgical service,
surgical length, and the presence of emesis within 12
hours following the postoperative period. Categorical data
were summarized using percentages and counts. Data
regarding the occurrence of postoperative emesis were
analyzed via the ?2 test to determine differences between
the preintervention and postintervention groups.
A null hypothesis and alternative hypothesis were
created. The null hypothesis stated that a practice change
will not cause a decrease in PONV rates. The alternative
hypothesis stated that a practice change will cause a
decrease in PONV. All raw data were checked for errors
and analyzed using a spreadsheet (Excel, Microsoft) with
significance determined as P < .05. To help decrease the
likelihood of a type 1 error, the author used a 5% level
of significance (an ? of .05 was selected) and 95% confidence
intervals.
• Costs. The creation of the PONV history assessment
tab required submission of various forms and applications
to the hospital’s IT department. Because the design
of the tab mimicked other current tabs, it was able to
be easily incorporated within the preanesthesia assessment
evaluation section. This also meant that there was
a limited added cost since the tab did not need to be
custom designed.
This retrospective chart view involved the collection
and generation of multiple computerized reports. At the
time this project was being conducted, the anesthesia QI
department was collecting similar information related to
another unrelated project reviewing the amount of time
that patients ingested nothing by mouth. Because of the
similarities in demographic data (age restrictions, surgical
case types and lengths), the QI department was able
to modify current data reports to generate the PONV
reports, incurring little to no additional expense.
Results
The preintervention group consisted of 2,279 patients
aged 3 to 18 years old undergoing nonemergent surgi-
Table 2. Preintervention and Postintervention Demographics
Surgical type No. of preintervention cases No. of postintervention cases
General surgery 594 528
Ophthalmology 176 127
Orthopedics 525 497
Otolaryngology 661 602
Urology 323 252
Total 2,279 2,006
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cal procedures. The cases were divided into 5 groups
based on surgical type: general surgery, ophthalmology,
orthopedics, otolaryngology, and urology. Most cases
were otolaryngologic (29%), followed by general surgery
(26%), orthopedics (23%), urology (14%), and ophthalmology
(8%). Figure 2 provides a graphical representation
of preintervention surgical types.
The postintervention group consisted of 2,006 patients
aged 3 to 18 years old undergoing nonemergent surgical
procedures. As with the preintervention data, the cases
were divided into the same 5 groups based on surgical
type. Once again, most of the cases were otolaryngologic
(30%), followed by general surgery (26%), orthopedics
(25%), urology (13%), and ophthalmology (6%). Figure
3 provides a graphical representation of postintervention
surgical types.
From the 2,279 preintervention cases, only 153 patients
experienced PONV (?2 = 1.4353). Of these, patients
undergoing orthopedic procedures experienced the
highest rate of PONV (54), followed by general surgical
patients (49). Table 3 provides an overview of the rate of
PONV for each service.
By comparison, only 120 cases of the 2,006-case postintervention
group reported PONV (P = .0043). This
accounted for a roughly 22% total decrease in PONV
rates between groups. As with the preintervention group,
the highest incidence of PONV was found in orthopedic
patients (n = 44), followed by general surgical patients (n
= 33). Between the groups, ophthalmologic patients experienced
the highest decrease in PONV rates (50%), followed
by general surgical patients (30%) otolaryngologic
patients experienced a 27% decrease, whereas orthopedic
patients experienced only a 19% decline. Of note, the
incidence of PONV almost doubled in the urology postintervention
group (7 reported preintervention cases vs 12
postintervention cases). More research is needed to better
understand these findings. Table 3 provides an overview
of postintervention PONV rates for each service. Figure 4
compares the PONV rates by service between both groups.
Discussion
The creation and subsequent use of the PONV history assessment
tab resulted in a clinical and statistical decrease
in reported PONV rates in pediatric patients undergoing
orthopedic, otolaryngologic, ophthalmic, and general
surgical procedures. This finding correlates with the
previously established independent risk factors discussed
in the current literature. Of note, orthopedic procedures
accounted for the highest occurrence of PONV in both
groups despite it being the third highest total number of
cases compared with general surgical and otolaryngology
services. Patients undergoing orthopedic procedures did
experience a 19% decrease in PONV rates between groups
following the creation of the PONV assessment tab.
In contrast, an increase in PONV rates was observed in
patients undergoing urologic procedures. This observa-
Table 3. Preintervention and Postintervention PONV
Rates by Service
Abbreviations: PONV, postoperative nausea and vomiting; +,
history of PONV present; −, no history of PONV.
Service type PONV+ PONV− Total
Preintervention
General surgery 49 545 594
Ophthalmology 2 174 176
Orthopedics 54 471 525
Otolaryngology 41 620 661
Urology 7 316 323
Total 153 2,126 2,279
Postintervention
General surgery 33 495 528
Ophthalmology 1 126 127
Orthopedics 44 453 497
Otolaryngology 30 572 602
Urology 12 240 252
Total 120 1,886 2,006
Figure 2. Preintervention Surgical Case Types Figure 3. Postintervention Surgical Case Types
270 AANA Journal ? August 2020 ? Vol. 88, No. 4 www.aana.com/aanajournalonline
tion reinforces the notion that urologic procedures carry
a higher risk of PONV rates compared with other surgical
types. It also suggests that prior assessment of a patient’s
PONV history may not have as much an impact on PONV
rates in this surgical milieu.
Except for the urologic population, a patient history of
PONV may be a more important indicator of PONV than
originally theorized. Subsequent decreases in PONV rates
in ophthalmology (50%), general surgery (30%), otolaryngology
(27%), and orthopedics (19%) procedures
following the intervention demonstrate this. Regarding
urology, and perhaps even orthopedics, surgical type or
service may be a more important risk factor.
• Limitations. This study has several limitations.
Children undergoing surgery for the first time, who
therefore would not have a history of PONV, were not
eliminated from this study. This study examined only
nonemergent cases in a select group of surgical types and
did not examine emergency cases or “combined” cases
wherein more than 1 surgical service is involved but the
patient remains under a single anesthetic.
• Implications for Practice and Future Research. This
project demonstrated the importance of screening for
independent predictors for PONV in the pediatric surgical
population. Using a modified POVOC score that
incorporated other independently validated surgical procedures
appeared beneficial. The presence of the PONV
assessment tab improved PONV rates postoperatively and
should remain in place at this institution.
Multiple research questions remain following this
project. The increase in postintervention urology PONV
rates is puzzling and would need to be further investigated.
Other investigations can center on practitioner response
and attitudes regarding the creation of the PONV
tab as well as the intraoperative reminder message in the
EMR. Studies can be conducted to see if the reminder
message itself had any impact on PONV rates.
Conclusion
The results of this project demonstrate a statistically significant
decrease in PONV rates following the preoperative
assessment of PONV predictors, specifically a history
of PONV. The use of the modified PONV risk assessment
tool led to a decrease in pediatric PONV.
Figure 4. Comparison of PONV Rates by Service
Before and After Intervention
Abbreviation: PONV, postoperative nausea and vomiting.
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AUTHOR
Robert W. Simon, DNP, MS, CRNA, is a staff nurse anesthetist for the Holy
Redeemer Health System in Pennsylvania and serves as Didactic Education
Coordinator and faculty member for the Frank J. Tornetta School of Anesthesia
at Einstein Medical Center Montgomery, Norristown, Pennsylvania.
Email: robsimon@comcast.net.
DISCLOSURES
The author has declared no financial relationships with any commercial
entity related to the content of this article. The author did not discuss offlabel
use within the article.
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