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State Behavioral Scale (SBS) A Sedation Assessment Instrument for Infants and Young Children Supported on Mechanical Ventilation

State Behavioral Scale (SBS) A Sedation Assessment Instrument for Infants and Young Children Supported on Mechanical Ventilation - Clinical Hub, UW Health Clinical Tool Search, UW Health Clinical Tool Search, Questionnaires, Related


State Behavioral Scale (SBS) A Sedation Assessment Instrument
for Infants and Young Children Supported on Mechanical
Ventilation
Martha A.Q. Curley, RN, PhD, FAAN, Sion Kim Harris, PhD, Karen A. Fraser, RN, Rita A.
Johnson, RN, BSN, and John H. Arnold, MD
Critical Care and Cardiovascular Program
Clinical Research Program
Clinical Research Center
Medical-Surgical Intensive Care Unit
Children's Hospital Boston, USA
Abstract
Objective—To develop and test the reliability and validity of the State Behavioral Scale (SBS) for
use in describing sedation/agitation levels in young intubated patients supported on mechanical
ventilation.
Design—Prospective, psychometric evaluation. Pairs of trained pediatric critical care nurse
evaluators simultaneously and independently assessed a convenience sample of pediatric ICU
patients along eight state/behavioral dimensions and a Numeric Rating Scale (NRS) of 0 (extremely
sedated) to 10 (extremely agitated). The eight dimensions were derived from the sedation/agitation
literature and expert opinion and included respiratory drive, response to ventilation, coughing, best
response to stimulation, attentiveness to care provider, tolerance to care, consolability, and movement
after consoled, each with 3–5 levels.
Setting—18-bed Pediatric Medical-Surgical ICU and 26-bed Pediatric Cardiovascular ICU in a
university-affiliated academic children’s hospital.
Patients—Ninety-one intubated mechanically ventilated patients 6 wks to 6 years of age provided
a median of 2 observations (IQR: 1–3) for a total of 198 sets of observations. Excluded were
postoperative patients or those receiving neuromuscular blockade.
Interventions—Patients were observed for 1 min then incremental levels of stimulation were
applied until patient response. After 2 minutes of consoling, the state behavioral assessment and NRS
were completed.
Measurements—Weighted kappa and intra-class coefficients (ICC) were generated to assess inter-
rater reliability of the eight dimension and NRS ratings. Distinct state behavior profiles were
empirically identified from the dimension ratings using hierarchical cluster analysis using a squared
Euclidean distance measure and between-groups linkage. Construct validity of these profiles was
assessed by comparing group mean NRS scores using one-way analysis of variance.
Corresponding Author: Martha A.Q. Curley, R.N., PhD; Children’s Hospital Boston; Critical Care and Cardiovascular Program; Farley
559; 300 Longwood Ave; Boston, MA 02115; Office: 617-355-6886; Fax: 617-730-0126; Martha.Curley@Childrens.Harvard.edu.
Funding: NIH/NICHD 5R21HD045020-02; GCRC MO1-RR02172
the authors have no financial interests to disclose.
NIH Public Access
Author Manuscript
Pediatr Crit Care Med. Author manuscript; available in PMC 2006 October 28.
Published in final edited form as:
Pediatr Crit Care Med. 2006 March ; 7(2): 107–114.
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Main Results—Weighted kappa scores for all 198 dimension ratings ranged from .44 to .76
indicating moderate to good inter-rater reliability. The ICC of .79 was high for NRS ratings. Cluster
analysis revealed 5 distinct state profiles with mean NRS ratings of 1.1, 2.5, 4.0, 5.3, and 7.6, all of
which differed significantly from each other (F=75.8, p<0.001), supporting the profiles’ construct
validity.
Conclusions—Based on empirically derived state behavior profiles, we have constructed the SBS
to allow systematic description of the sedation-agitation continuum in young pediatric patients
supported on mechanical ventilation. Further studies including prospective validation and describing
the effect of SBS implementation on clinical outcomes including the quality of sedation and length
of mechanical ventilation are warranted.
Keywords
sedation; agitation; pediatric intensive care; child; nursing assessment
Ensuring the comfort of critically ill infants and children is integral to the practice of pediatric
critical care. Humane pediatric intensive care often includes the administration of sedatives,
once pain, physiologic imbalance and environmental stressors have been addressed.[1] Over
90% of infants and children supported on mechanical ventilation receive some form of sedative
therapy. [2] Sedation in this patient population is required for anxiolysis, amnesia, facilitation
of care, patient safety in avoidance of adverse events and for decreasing oxygen consumption.
For most young patients supported on mechanical ventilation, the goal of sedation is to attain
a calm but responsive state [2,3] that protects the young patient from self-harm. Inadequate
sedation is associated with potentially dangerous complications such as unplanned
endotracheal extubation. [4] High-dose, long-term, and continuous intravenous sedation has
been associated with prolonged weaning from mechanical ventilation and/or withdrawal
syndrome. [5–7] Therefore, insufficient or excessive sedation is likely to add to the personal
and financial burden of intensive care.
Variability complicates the use of sedation in the pediatric intensive care unit (PICU) setting.
First, a patient’s sedative needs vary depending on the nature and course of their illness, drug
interaction with concomitant therapies, and their response to therapy. [8,9] Some patients
require deep sedation to tolerate synchronous modes of mechanical ventilation while others
appear comfortable with light sedation even when supported on unconventional modes of
ventilatory support. [10] Next, from a systems perspective, multidisciplinary staff with varying
levels of expertise change several times over the working day. This means that patients are
exposed to multiple subjective assessments of their sedation requirements, by several staff
members, which may result in patients receiving varying dosages of sedation depending upon
who performed the assessment. [11,12]
Valid and reliable tools that standardize the description of a pediatric patient’s behavioral state
while supported on mechanical ventilation would enhance systematic assessment and
documentation of a patient’s response to sedation, allow patient-specific alterations in the
therapeutic regimen, and help avoid insufficient or excessive sedative use. [13,14] Such an
assessment tool would enhance interdisciplinary agreement on the desired level of sedation,
provide a foundation for the development of guidelines that would decrease unnecessary
variation in the care [15–17] and permit objective study of the pharmacodynamics of sedative
agents in the pediatric population. [18] From a research perspective, Kollef and colleagues
[5] suggest that sedation practices should be standardized in any investigation employing the
duration of mechanical ventilation as an outcome variable.
While desirable, tools assessing the sedation-agitation continuum in the pediatric patient have
not been adequately tested or have conceptual flaws. Specifically, the psychometrics of the
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Ramsay scale, [19] an often cited sedation scale used in the adult population, has never been
evaluated in an ICU setting. In addition, Ramsay’s 6 levels of sedation are neither mutually
exclusive nor clearly defined. [20] The COMFORT scale, [14,21] the most commonly used
tool in the pediatric population, [12] was designed to assess distress in ventilated children but
distress was operationalized to include the constructs of both pain and agitation. Noting that
the eight dimensions of the COMFORT scale are often included in other pain instruments, van
Dijk and others [22] supported the use of the COMFORT scale to assess postoperative pain in
infants. From a clinical perspective, separate valid and reliable pain and agitation assessment
tools would allow more targeted therapeutic management. [23]
The purpose of this study was to empirically construct and demonstrate preliminary construct
validity and inter-rater reliability of a pediatric sedation assessment scale, the State Behavioral
Scale (SBS), for use in young critically ill pediatric patients supported on mechanical
ventilation.
MATERIALS AND METHODS
Data Collection Instrument
A state behavioral assessment tool was derived from our previous work describing pediatric
ICU nurses’ descriptions of agitation, [24] the literature on sedation tools used in the adult
population, [25–27] and expert opinion from a pediatric anesthesiologist and pediatric critical
care clinical nurse specialist. Two adult ICU sedation scales, the Sedation-Agitation Scale
(SAS) [25] and its derivative, the Motor Activity Assessment Scale (MAAS) [27,28] served
as templates. As presented in Figure 1, we retained descriptors that could be evaluated in a
cognitively immature patient population and added several descriptors important to the care
of young patents supported on mechanical ventilation. Our tool included ratings along the
following 8 dimensions: respiratory drive, response to ventilation, coughing, best response to
stimulation, attentiveness to care provider, tolerance to care, consolability, and movement after
consoled. Each dimension contained 3–6 levels that incrementally described the sedation-
agitation continuum.
Operational definitions included the following: Sedation, a calm tranquil state that allays
anxiety and excitement; Agitation, excitement accompanied by increased motor activity;
Attention, the ability to open eyes and notice surroundings; Response, the ability to open eyes,
or raise eyebrows, or turn head toward stimulus or move limbs; Distress, sudden increase in
heart rate or blood pressure, and or a decrease in SpO2, or increase in movement. The 0–10
Numeric Rating Scale (NRS) with 0 equal to “extremely sedated” and 10 equal to “extremely
agitated” served as a reference standard. We did not include changes in heart rate and blood
pressure as distinct dimensions in the state behavioral assessment because of consistently low
sensitivity and specificity in predicting agitation. [21,24,29] We also did not include the
patient’s ability to communicate, follow commands, or attempts to sit or climb out of bed
because these items are not consistently developmentally appropriate across the 6 week to 6
year age group.
Patient Sample
Between 2000 and 2004 we enrolled a convenience sample of patients, 6 weeks to 6 years of
age, who were intubated and mechanically ventilated in either the Medical-Surgical ICU or
Cardiovascular ICU in a university-affiliated academic children’s hospital in the Northeast.
Enrollment was stratified in 3 age groups (6 weeks to 1 year, 1 to 3 years and 3 to 6 years) to
ensure an almost equal distribution of age within our sample. We excluded patients receiving
neuromuscular blockade; post-operative patients; patients assessed to be in pain by their
bedside nurse, patients who were considered physiologically unstable (those experiencing any
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increase in ventilator or vasopressors support in the previous 2 hours), and patients at risk for
opioid withdrawal. Exclusion criteria were selected to eliminate patients incapable of providing
behavioral clues and patients more likely to provide pain-related clues. Data collection did not
alter in any way the current practice and/or the administration of sedatives. The study was
approved by the Institutional Review Board and need for informed consent was waived because
data were de-identified, considered to be low-risk and were collected during routine patient
care.
Data Collection
A pair of trained pediatric critical care nurse evaluators simultaneously and independently
conducted state behavioral assessments of each intubated, mechanically-ventilated pediatric
patient in the sample. As part of their training prior to study implementation, a total of five
critical care nurses were instructed on the use of the state behavioral assessment tool and NRS
over the study period. After instruction, each nurse conducted five concurrent assessments per
protocol with the principal investigator. The group then discussed their assessments and
reached consensus on the best score within each dimension of the state behavioral assessment
and NRS. Data collection commenced when the nurse raters agreed that they had reached a
common understanding of the 8 state behavioral dimensions and the NRS and there was 95%
agreement between the critical care nurse rater and principal investigator with disagreements
not crossing more than one level in any dimension. Training data were not included in the final
analyses.
Patients were enrolled as soon as possible after meeting criteria and were assessed daily for a
maximum of 6 days. Prior to data collection, patients were presumed to be supported on
appropriate ventilator settings. Data collection was conducted at a time when the bedside nurse
was completing planned cares when two evaluators were available. If endotracheal extubation
was planned, the patient was assessed just prior to the procedure.
First, patients were observed undisturbed for 1 minute. Second, the patient’s nurse provided
progressive stimuli, as necessary, to elicit a patient’s response. Specifically, the nurse first
spoke the patient’s name using a calm voice, then, if there was no response, spoke the patient’s
name and gently touched the patient’s body. If there was still no response, the patient’s response
to a planned noxious stimulus was assessed such as endotracheal suctioning or less than 5
seconds of nail bed pressure. Finally, the patient was repositioned, then consoled by the nurse
and/or parent. After 2 minutes of consoling, evaluators completed the state behavioral
assessment and gave a NRS rating. In evaluating the coughing dimension, the evaluator was
allowed to query the bedside nurse about this dimension if a suctioning procedure was not
observed. In addition to the behavioral ratings, demographic data, including age, gender,
admission functional health, [30] admission PRISM III [31] and the use of mechanical
ventilation and sedative use at the time of assessment were recorded.
Statistical Analysis
We generated descriptive statistics (means and standard deviations, medians and interquartile
ranges, response proportions) on sample patient demographic characteristics including age,
sex, race/ethnic group, primary and secondary diagnoses, cerebral and overall performance,
and risk of mortality. We assigned numeric codes to each level of each state behavioral
dimension for analyses, with 1 for the first level, and a high of 3 to 6 depending on the number
of levels within a dimension. After reviewing frequency distributions, the respiratory drive and
response to ventilation dimensions were collapsed into one dimension for subsequent analyses.
The dimensions were collapsed because few patients exhibited, under respiratory drive,
spontaneous but ineffective exhaled tidal volume or, under response to ventilation,
unsynchronized with mechanical ventilation compromising oxygenation and ventilation.
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Inter-rater agreement for the 7 dimension ratings, consisting of ordinal data, was assessed using
weighted kappa coefficients generated with PROC FREQ in SAS®. [32] We examined inter-
rater agreement on the NRS rating, a continuous variable, with intraclass correlation
coefficients generated in SPSS 12.0 using a one-way random effects model. We analyzed inter-
rater reliability using all available paired ratings, which included multiple rating occurrences
for some patients. Since there may have been intra-cluster correlation among multiple ratings
of the same patient, we also conducted these analyses using only the first rating of each patient,
as well as a randomly-selected single rating for each patient. In order to explore whether inter-
rater agreement varied by patient age group, all inter-rater reliability analyses were stratified
by the 3 patient age groups.
To identify distinct state behavior profiles based on dimension ratings, we conducted
hierarchical cluster analysis using a squared Euclidean distance measure to assess similarity/
dissimilarity across variables, and between-groups linkage method for combining clusters. We
ran the cluster analysis using data from Rater 1 only, Rater 2 only, and data averaged across
the two raters. In addition, we conducted these analyses using all rating occurrences, as well
as using only data from a randomly-selected single rating for each patient. Random selection
of a single rating per patient was deemed preferable to using the first rating for each patient in
these analyses since the first ratings tended to reflect more sedated states compared to
subsequent ratings. Patients were generally more sedated immediately following intubation.
Since the 7 dimensions had differing response scale ranges, we ran the cluster analyses using
standardized scores, where item scores were converted into z-scores. We chose the number of
clusters by examining the agglomeration schedule and identifying the “elbow” in the curve of
the distance measure across the cluster-joining steps (the point where the distance coefficient
made a sudden jump in size). While this method of identifying the number of clusters indicated
that there were likely to be 5 clusters or state-behavior profiles, we evaluated 3, 4, and 5 cluster
solutions in subsequent analyses, in order to further determine the appropriateness of the 5-
cluster solution. After examining the median scores for each of the 7 SBS dimensions across
the clusters, we determined that the 5-cluster solution was appropriate, with the 5 groups
showing distinct profiles of scores across the 7 state dimensions. To assess discriminant validity
of the profiles, we used a one-way analysis of variance (ANOVA), with a post-hoc Tukey HSD
test, to compare mean scores on the NRS variable across the 5 cluster groups. A two-sided p-
value of less than 0.05 indicated statistical significance. All cluster and mean score comparison
analyses were performed with SPSS 12.0 software (Chicago, IL ).
Specific information needed (frequency distributions and correlations between raters) to
perform power calculations for kappa coefficients was not known, leading to the need for
preliminary data to be collected through this study. However, cross-sectional analyses on 90
subjects provides 82% power to detect inter-rater correlations of 0.30 and 98% power to detect
correlations of 0.40. Thus, we anticipated that our sample size of 90 subjects should be
sufficient to detect moderate to high correlations and kappa coefficients and would provide
enough pilot data for us to develop appropriate follow-up studies.
RESULTS
Ninety-one patients were enrolled. Patient demographic data are presented in Table 1. Most
patients were cognitively and functionally normal for age. [30] The majority of the 91 patients
(N=57; 63%) were intubated and mechanically ventilated for pulmonary parenchymal disease,
with the rest having airways disease. Although conventional methods were used to ventilate
most patients, 9% (N=8) were supported on high frequency oscillatory ventilation (HFOV)
and 3% were supported on extracorporal membrane oxygenation (ECMO). Mortality rate was
13%. Almost all (95%) of the patients were receiving sedation. The most prevalent sedation
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plan (73%) included a combination of opioids and benzodiazepines. Pairs of nurse evaluators
assessed the 91 patients during 198 rating occurrences (396 total observations). Most patients
provided one (46%) or two (23%) sets of paired observations.
In analysis of inter-rater agreement across all 198 available paired ratings, weighted kappa
coefficients ranged from .44 (consolability) to.76 (respiratory drive/response to ventilation)
across the 7 dimension ratings, indicating moderate to good inter-rater agreement (see Table
2).[33] This conclusion was additionally supported by weighted kappas generated from
analysis of data which included only the first rating for each patient (range .55 to .77), and of
a randomly-selected single rating for each patient (range .54 to .74, data not shown). The actual
concordance rates for the 7 SBS dimensions (percent of ratings where the two raters gave the
exact same rating), using all 198 available ratings, ranged from 66% (tolerance to care) to 85%
(respiratory drive/response to ventilation) (data not shown).
Similarly, inter-rater agreement for the NRS rating was good, with an ICC of .79 across all 198
paired ratings, .83 using only data from the first ratings, and .79 using randomly-selected single
ratings.
The level of inter-rater agreement did not differ by patient age group, except for the coughing
dimension. In analyses of all 198 paired ratings, the weighted kappa for this dimension was
significantly lower in the youngest age group of 6 weeks to 1 year (.55, 95%CI .41–.69),
compared to the weighted kappa in the oldest age group of 3 to 6 years (.81, 95% CI .68–.93).
The middle age group, ages 1 to 3 years, had a weighted kappa of .73 (95% CI .68–.93).
In Table 2, we show the state behavioral profiles of the 5 groups identified from cluster analysis.
We present the results of analysis of all 198 ratings which did not differ from those of 91
randomly selected single patient ratings. Also, since inter-rater agreement was generally good
for the paired dimension ratings, we are presenting the results of cluster analysis using averaged
data for the rater pairs. As shown by the median scores on each of the 7 dimensions, and mean
NRS ratings, these 5 groups had distinct profiles of scores. Specifically, these cluster groups
had significantly different mean scores on the NRS (one-way ANOVA F=75.8, df=4, p<0.001),
with each group differing from all other groups in post-hoc pairwise comparisons (all p<.002),
supporting the discriminant validity of these 5 profiles.
Using the median scores on the 7 dimensions and mean NRS scores for each group (see Table
2), the 5 profiles were then aligned to a bipolar numeric scale ranging from −3 to +1. We
selected this metric because our group had experience using a modified MAAS [27] with a
bipolar scale that clinicians described as logical and readily recalled; specifically, negative
numbers equated to a less active states and more positive numbers equated to more active states.
This bipolar numeric rating scale was also used in the original Sedation-Agitation Scale for
critically ill adults. [26] The first cluster group with a mean (95% CI) NRS score of 1.1 (0.7–
1.6) was linked to a SBS dimension of −3 while the fourth cluster group with a mean NRS
score of 5.3 (4.9–5.6) was equated with a SBS dimension of 0. The remaining −2, −1 and +1
values were then aligned around these fixed points.
Table 3 presents the empirically generated pediatric State Behavioral Scale (SBS) with
standardized definitions given for each point on the scale, similar to those used in the adult
MAAS. [27] We also added a +2 agitated level because, though rarely observed thus not
empirically captured in this study, experienced clinicians have cared for patients exhibiting
these agitated behaviors in the pediatric ICU.
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DISCUSSION
We empirically constructed a standardized State Behavioral Scale (SBS) to describe the
sedation-agitation continuum in an extremely vulnerable patient sample of young pediatric
patients supported on mechanical ventilation. The SBS was derived from ratings of 7 content
dimensions (originally 8, but 2 dimensions were combined) derived from the literature and
expert opinion and we describe adequate content validity and interrater reliability of these
dimensions. An ideal sedation scale for pediatric intensive care should be valid and reliable,
developmentally appropriate, integrate the multidimensional goals of sedation, be easy to
complete and interpret, contain precise discriminating criteria at each level, and be useful in
directing sedative therapy. [34–36] We believe the SBS meets these criteria.
The SBS was specifically designed for and tested in young intubated mechanically ventilated
patients – a population who often experience extremes in level of sedation over their normal
trajectory of illness. The tool reflects the presence and severity of the clinical conditions for
which sedation is administered in this population. [20,36] We designed the SBS to require an
evaluation of patient response to a progressive stimulus. This approach is familiar to intensive
care clinicians as it is similar to the progressive stimulus performed during a neurological exam.
We believe that appropriate levels of sedation should help the young patient through necessary
care procedures that require a stimulated state while avoiding over-sedation when not
stimulated.
The dimensions include descriptors that have been previously described to be associated with
agitation. [24] More negative scores reflect a more sedated state. More positive scores reflect
a more agitated state. The single-digit bipolar numeric avoids the complexity of summing
multiple dimension scores and is logical in that the use of negative numbers for sedation and
positive number for agitation and zero score for neither sedation nor agitation may enhance
clinician recall of the measure. Each level contains multiple descriptors increasing the
likelihood that a patient’s behavior can be mapped to a single level. The SBS was developed
to augment a clinician’s clinical judgment. Differentiating behavioral distress from physiologic
distress requires the clinician to interpret patient behavior within the context of their evolving
clinical state.
Although the ease with which the nurse evaluators rated each dimension was not systemically
described, the overall experience of the raters was that the dimensions were clear and that
completion of the behavioral assessment tool and NRS was easily accomplished in less than
two minutes after the stimulation protocol was implemented. However, some dimensions may
be more challenging to rate than others, for example, a patient may console differently to a
nurse’s voice/touch and to a known caregiver’s voice/touch. The relatively low weighted kappa
reported for consolability may also be in part due to a sensitivity of the kappa to the response
distribution, which in the case of this item, was highly skewed. Over 95% of ratings by either
rater consisted of “self-regulates” or “able to calm; distractible,” with only 4% giving a rating
of “does not consistently calm” or “unable to console.” The actual concordance rate between
raters for this item was moderately high, at 69% among all 198 ratings (79% among first ratings,
74% among randomly-selected single ratings), indicating inter-rater agreement comparable to
the other dimensions.
Except for the coughing dimension, the level of inter-rater agreement did not differ by patient
age group. The weighted kappa for coughing was significantly lower in the youngest age group
(6 weeks to 1 year) compared to the weighted kappa in the oldest age group (3 to 6 years). It
should be noted that coughing was the only dimension that was not always directly observed.
We are unable to determine in this study whether coughing is a more salient dimension for
certain age groups compared to others, thus affecting inter-rater agreement across the age
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groups. However, inter-rater agreement of the coughing dimension may become more
consistent across age groups when bedside nurses directly observe the phenomenon. Future
studies evaluating the new SBS tool should assess the ease/difficulty in which the rating is
made.
It is not surprising that an extreme agitated state was not well observed in this patient sample.
While these behaviors do occur, we hypothesize that nurses immediately intervene to manage
evolving unsafe and inconsolable behaviors in young intubated mechanically ventilated
patients. Our findings are similar to those of Sessler et al [37] who validated the Richmond
Agitation-Sedation Scale (RASS) in a wide distribution of critically-ill adult patients. The
RASS ranges from −5 (unresponsive) to +4 (combative). Only 10% of their observations were
in the +1 restless to +3 very agitated range and none were noted to be +4 combative.
We recommended that sedation assessment be completed at the start of normal cares at a
frequency that aligns with the patient’s clinical state. The Joint Commission for the
Accreditation of Hospitals suggests that pain scoring be considered the 5th vital sign. [38] We
suggest that sedation scoring should be completed with the patient’s pain assessment every
four hours and also before and after an intervention that impacts the patient’s level of sedation.
The use of a convenience sample was a limitation of this study and may reduce the
generalizability of our findings. Data collection required the presence of two trained observers
which precluded consecutive sampling. Data collection also did not alter current practice and/
or the administration of sedatives; thus, few patients exhibited an agitated state. Specifically,
seven patients accounted for a total of eight +1/+2 SBS ratings (one patient accounted for two
ratings). Our data indicated that nurses were successful in keeping their patients in a more
sedated state while intubated. Towards the end of the data collection period, we attempted to
identify more awake patients by focusing on the enrollment of patients just before endotracheal
extubation. Next, although we excluded patients assessed to be in pain we cannot be completely
certain that these developmentally nonverbal or verbal intubated patients were pain-free. Pain
and sedation scoring require clinical judgment and an evaluation of the context of patient
trajectory and history. Future studies should test the construct validity of this instrument
compared with a valid and reliable pain tool. Future studies should also assess the sensitivity
of the SBS to assess a change in a patient’s state over time or after sedative administration to
determine its usefulness in informing patient-specific alterations in the therapeutic regimen
and to describe the effect of illness/injury on the patient’s state behavior. Finally, since the
SBS tool was developed using ratings of patients ages 6 weeks to 6 years who were
physiologically stable and not rated to be in pain, other studies are needed to assess the
appropriateness of this tool for use in populations not included in this study. Additional studies
are also needed, using much larger samples, to assess the validity of the SBS profiles within
each of the three pediatric age groups included in this study. While we had equal representation
of the three age groups in our sample, we had too few observations in the agitated range to be
able to conduct cluster analyses stratified by age group.
In summary, of primary concern to all clinicians caring for critically ill pediatric patients is to
limit the negative impact of the illness on the developing child. Many factors contribute to the
process of providing this humanistic element of care, one of which includes assuring an
adequate level of sedation. We believe that the PICU environment taxes the adaptive capacities
of even our most resilient patients and that our preverbal patients are at a particular disadvantage
as they are cognitively immature to process the importance of tolerance to invasive procedures,
instrumentation and support. The State Behavioral Scale describes the sedation-agitation
continuum in this vulnerable group.
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Acknowledgements
We are indebted to the pediatric critical care nurses and our patients and their families who supported this study, David
Wypij, PhD who provided comments early in the design of the study; and Michelle Labrecque, MSN, RN and Patricia
Jones MSN, RN who assisted with patient screening and data collection.
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Figure 1.
Behavioral Assessment Tool and Numeric Rating Scale
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Table 1
Patient Demographics
Characteristic (N=91)
Age (months) 18 (4.4–34.5)
Age group No. (%)
 6 weeks to 1 year 38 (42%)
 1 to 3 years 31 (34%)
 3 to 6 years 22 (24%)
Female sex No. (%) 34 (37%)
Race or ethnic group No. (%)
 White 63 (69%)
 Black 4 (4%)
 Hispanic 11 (12%)
 Asian/Pacific Islander `3 (3%)
 More than one group 10 (11%)
Pediatric Cerebral Performance Category‡ 1 (1, 2)
Pediatric Overall Performance Category§ 1 (1, 3)
Pediatric Risk of Mortality III scores|| 6 (0–12)
Mortality 12 (13%)
Primary Diagnosis No. (%)
 Pulmonary 46 (51%)
 Cardiovascular 12 (13%)
 Neurological 9 (10%)
 Infectious disease/Sepsis 6 (7%)
 Congenital anomaly 6 (7%)
 Gastrointestinal 5 (6%)
 Oncology/Bone Marrow Transplant 5 (6%)
 Metabolic/trauma 2 (2%)
Secondary Diagnoses No. (%) 45 (49%)
Values with parentheses are number (percentage) or medians (first quartile, third quartile). Because of rounding, percentages may not total 100.

Pediatric Cerebral Performance Category score ranges from 1 (normal cognitive development) to 6 (brain death). [30]
§
Pediatric Overall Performance Category score ranges from 1 (good overall performance) to 6 (brain death). [30]
||
Scores from the Pediatric Risk of Mortality III can range from 0-74, with higher scores indicating higher probability of death. [31]
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Table 2
Median score (interquartile range) on each State Behavior Scale (SBS) dimension and mean (95%CI) numeric
rating scale score (NRS), within each of 5 rating groups generated from cluster analysis using all ratings (N=198).
Inter-rater reliability coefficients (weighted kappa and intra-class correlation [ICC]) for each SBS dimension and
NRS using all ratings, and using only the first rating per patient (n=91).
SBS Dimension −3 (n=33)
Median (IQ
range)
−2 (n=72)
Median (IQ
range)
−1 (n=26)
Median (IQ
range)
0 (n=59)
Median (IQ
range)
+1/+2 (n=8)
Median (IQ
range)
Weighted
Kappa
ALL
(95% CI)
Weighted
Kappa
FIRST
(95% CI)
Respiratory Drive/
Response to ventilation
No
spontaneous
respiratory
effort
1.0 (1.0–
1.5)
Spontaneous
and
effectively
supported
breathing
3.0 (3.0–3.0)
Spontaneous
but
ineffective/
effectively
supported
breathing
2.8 (1.9–3.0)
Spontaneous
and effective
breathing
3.0 (3.0–3.0)
Spontaneous
and effective/
Having
difficulty
synchronizing
with ventilator
3.0 (3.0–3.9)
.76 (.67–.
84)
.77 (.65–.
88)
Coughing No cough/
coughs only
when
suctioned
2.0 (1.0–
2.0)
Coughs only
when
suctioned pr
when
repositioned
3.0 (2.0–3.9)
Coughs only
when
suctioned or
when
repositioned
2.0 (2.0–3.0)
Coughs when
repositioned/
Occasional
spontaneous
cough
3.5 (3.0–4.0)
Occasional
spontaneous
cough
4.0 (4.0–4.0)
.68 (.59–.
77)
.76 (.64–.
87)
Best Response to
Stimulation
No response
to noxious
stimuli
1.0 (1.0–
2.0)
Responds to
noxious
stimuli/
touch
2.0 (1.6–3.0)
Respond to
touch/voice
3.5 (3.0–4.0)
Responds to
voice/No
external
stimulus
required to
elicit response
4.5 (4.0–5.0)
Responds to
voice/No
external
stimulus
required to
elicit response
4.8 (3.6–5.0)
.71 (.64–.
78)
.65 (.54–.
76)
Attentiveness to Care
Provider
Unable to
pay
attention to
care
provider
1.0 (1.0–
1.0)
Unable to
pay attention
to care
provider
1.0 (1.0–1.0)
Able to pay
attention to
care
provider but
drifts off
after
stimulation
1.5 (1.0–2.0)
Spontaneously
pays attention
to care
provider
(infant fixes
and follows)
3.0 (2.5–3.0)
Drifts off/
Spontaneously
pays attention
2.5 (1.8–2.5)
.69 (.61–.
76)
.67 (.56–.
78)
Tolerance to Care Does not
distress with
any
procedure
(including
noxious)
1.0 (1.0–
1.0)
Will distress
with noxious
procedure
1.5 (1.0–2.0)
Distresses
with
procedures
2.5 (2.0–3.0)
Distresses
with
procedures
2.5 (2.0–3.0)
Intermittently
unsafe
4.5 (4.0–5.0)
.63 (.55–.
71)
.60 (.48–.
73)
Consolability Self-
regulates/
modulates
own
behavior
1.0 (1.0–
1.0)
Self-
regulates/
modulates
own
behavior
1.0 (1.0–1.0)
Able to calm
with
comforting
touch or
voice when
stimulus
removed
1.5 (1.5–2.0)
Able to calm
with
comforting
touch or voice
when stimulus
removed
2.0 (1.5–2.0)
Does not
consistently
calm despite 5
minute
attempt to
console
2.8 (2.5–3.4)
.44 (.32–.
55)
.62 (.46–.
77)
Movement after Consoled Does not
move
1.0 (1.0–
1.0)
Does not
move/
Occasional
movement
of
extremities
or shifting of
position
1.0 (1.0–1.5)
Occasional
movement
of
extremities
or shifting of
position
2.0 (2.0–2.0)
Occasional
movement/
Increased
movement
(restless,
squirming)
2.0 (2.0–2.5)
Increased
movement
(restless,
squirming)
3.0 (2.6–3.0)
.61 (.52–.
70)
.55 (.43–.
68)
Mean NRS (95%CI) 1.1 (0.7–
1.6)
2.5 (2.1–2.9) 4.0 (3.4–4.5) 5.3 (4.9–5.6) 7.6 (6.9–8.4) ICC=.
79 (.73–.
84)
ICC=.
83 (.76–.
89)
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Table 3
State Behavioral Scale (SBS)
Score as patient’s response to voice then gentle touch then noxious stimuli (planned endotracheal suctioning or
<5 seconds of nail bed pressure)
Score Description Definition
−3 Unresponsive No spontaneous respiratory effort
No cough or coughs only with suctioning
No response to noxious stimuli
Unable to pay attention to care provider
Does not distress with any procedure (including noxious)
Does not move
−2 Responsive to noxious
stimuli
Spontaneous yet supported breathing
Coughs with suctioning/repositioning
Responds to noxious stimuli
Unable to pay attention to care provider
Will distress with a noxious procedure
Does not move/occasional movement of extremities or shifting of position
−1 Responsive to gentle
touch or voice
Spontaneous but ineffective nonsupported breaths
Coughs with suctioning/repositioning
Responds to touch/voice
Able to pay attention but drifts off after stimulation
Distresses with procedures
Able to calm with comforting touch or voice when stimulus removed
Occasional movement of extremities or shifting of position
0 Awake and able to
calm
Spontaneous and effective breathing
Coughs when repositioned/Occasional spontaneous cough
Responds to voice/No external stimulus is required to elicit response
Spontaneously pays attention to care provider
Distresses with procedures
Able to calm with comforting touch or voice when stimulus removed
Occasional movement of extremities or shifting of position/increased movement (restless, squirming)
+1 Restless and difficult to
calm
Spontaneous effective breathing/Having difficulty breathing with ventilator
Occasional spontaneous cough
Responds to voice/No external stimulus is required to elicit response
Drifts off/Spontaneously pays attention to care provider
Intermittently unsafe
Does not consistently calm despite 5 minute attempt/unable to console
Increased movement (restless, squirming)
+2 Agitated May have difficulty breathing with ventilator
Coughing spontaneously
No external stimulus required to elicit response
Spontaneously pays attention to care provider
Unsafe (biting ETT, pulling at lines, cannot be left alone)
Unable to console
Increased movement (restless, squirming or thrashing side-to-side, kicking legs)
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