Journal of Pediatric Nursing (2013) 28, e2–e9 The Texas Children’s Hospital Pediatric Advanced Warning Score as a Predictor of Clinical Deterioration in Hospitalized Infants and Children: A Modification of the PEWS Tool Donnett Bell MS, RN, CNS, PNP-BC ⁎, Anh Mac MSN, RN, CPN, Yvette Ochoa BSN, RN, Mary Gordon PhD, RN, CNS-BC, Mary Ann Gregurich PhD, MPH, Tangula Taylor MBA, BSN, RN, NE-BC Texas Children’s Hospital, Houston, TX Key words: Pediatric warning score; Screening tool; Pediatric clinical deterioration; Early warning score; Risk assessment; Pediatric safety Purpose: The purpose of this study was to examine the psychometric properties of the Texas Children's Hospital Pediatric Advanced Warning Score (PAWS) instrument as an indicator of clinical deterioration in infants and children. Design and methods: A retrospective chart review of 150 infants and children was performed. Results: The overall Cronbach's alpha score was 0.75. The estimate of interrater reliability was 0.740. Implications: The Texas Children's Hospital Pediatric Advanced Warning Score instrument was found to be reliable and valid. © 2013 Elsevier Inc. All rights reserved. PEDIATRIC PATIENTS ARE admitted to acute care settings today with higher acuities and comorbidities than in years past. In order to safely manage more complex patients, acute care nurses have added many new clinical skills into their daily practices. Higher acuity children are sometimes atrisk for deterioration. Therefore, a robust system for early recognition and timely treatment of deterioration is recommended (Haines, Perrott, & Weir, 2006). Thus, nurses routinely assess for clinical deterioration in acute care and successfully manage deterioration by getting help to the bedside for emergency interventions and/or transfer the child to a higher level of care. The goal is to identify deterioration early to prevent a cardiac arrest from occurring in acute care. The tool studied in acute care is the Texas Children’s Hospital (TCH) Pediatric Advanced Warning Score (PAWS). It is a modification of the Pediatric Early Warning Score (PEWS) tool to assess deterioration in the pediatric ⁎ Corresponding author: Donnett Bell, MS, RN, CNS, PNP-BC. E-mail address: dxbell@texaschildrenshospital.org 0882-5963/$ – see front matter © 2013 Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.pedn.2013.04.005 patient population. This study examines the psychometric properties of the TCH PAWS tool as an indicator of clinical deterioration in infants and children during hospitalization. This paper does not compare the psychometrics of the TCH PAWS tool to the psychometrics of the PEWS tool. Approximately 3% of children admitted to hospitals require immediate medical assistance for the treatment of actual or impending cardiopulmonary arrest (McCabe, Ducan, & Heward, 2009 & Parshuram, Middaugh, & Hutchinson, 2009). Previous studies have highlighted clinical antecedents associated with in-hospital cardiopulmonary arrests such as clinical deterioration involving either respiratory or mental function, systolic blood pressure changes, hypoxia, or azotemia (Kause, Prytherch, Parr, Flabouris, & Hillman, 2004 & Lee, Bishop, Hillman, & Daffurn, 1995). Significant attention should be given to the fact, that children deteriorate quickly and depending on their age and cognitive ability some will not be able to communicate what they are feeling, which adds a layer of complexity to the clinical assessment (Haines et al., 2006). Pediatric Advanced Warning Score (PAWS) Studies by Tucker, Brewer, Baker, Demeritt, and Vossmeyer (2009) and Monaghan (2005) describe how early warning scoring systems allow for prompt identification of deterioration, thus facilitating earlier intervention. The systems have rapid scoring capability because of the objectivity and ease-of-use (approximately 15–20 seconds) and have helped to increase confidence in nurses to recognize children at-risk for deterioration. Additionally, use of early warning tools promotes timely and efficient communication between nurses and physicians (Andrews & Waterman, 2005). Operationally, early warning scoring systems include a trigger (algorithm) for graded responses so that lower scores support minimal frequency of monitoring. As scores increase, the frequency of monitoring increases, which may trigger activation of the Rapid Response Team (RRT) and/or movement of the patient to higher intensity care areas (Goldhill, McNarry, Mandersloot, & McGinley, 2005). Rapid Response Teams have helped to decrease codes in acute care (Akre et al., 2010). Child Health Corporation of America Collaborative In 2007, our hospital joined a one-year collaborative with the Child Health Corporation of America (CHCA), which included 19 other hospitals throughout the country. The challenge of the collaborative was to eliminate codes in acute care by identifying deterioration earlier and to intervene appropriately. Use of the Pediatric Early Warning Score (PEWS) was one of many changes that the collaborative suggested. The PEWS tool has 3 assessment parameters: behavior, cardiovascular, and respiratory. Each parameter has 4 categories of scoring (0–3 points). An additional 2 points may be added for patients receiving every 15 minutes of nebulizer treatment or persistent vomiting following surgery. The highest possible cumulative score is 13. Higher scores indicate poorer patient conditions. The PEWS tool was found to be a reliable and valid scoring system to identify risk for clinical deterioration. Tucker et al. (2009) found the PEWS tool identified children who needed a higher level of care (area under the curve = 0.89, 95% CI = 0.84–0.94, p b .001). Also, interrater reliability was assessed with two RNs independently scoring patients (intraclass coefficient = 0.92, p = .001). At the time of the collaborative, our hospital was not using an early warning-scoring tool. Thus the collaborative team decided to investigate the PEWS tool for possible implementation in our hospital. The Texas Children’s Hospital Pediatric Advanced Warning Score Tool A multidisciplinary team of physicians, nurses, and respiratory therapists reviewed the PEWS tool (Tucker et al., 2009), and decided to revise it before implementation e3 because the original study was done on a 24 bed general medical unit. Our patient population included patients with cardiac and surgical diagnoses, as well as patients with medical diagnoses. The primary modifications made to the PEWS tool were the words used to describe deterioration in some of the categories. The team wanted to evaluate the revised tool and its ability to capture deterioration in patients with cardiac, surgical and medical diagnoses. Permission to modify the PEWS tool was received from Tucker et al., 2009. The TCH PAWS tool has 3 assessment parameters: behavior, cardiovascular, and respiratory (Figure 1). Each assessment parameter can be scored between 0–3 points depending on the category of the findings. An additional 2 points may be added to the total score if respiratory treatments are needed every hour (versus every 15 minutes with PEWS) or if there is persistent vomiting following surgery. The rationale for this change was to comply with the routines for acute care policy, which specifies patients who require nebulizer treatments every hour for more than 4 hours require a higher level of care. The highest possible cumulative score is 13. Higher scores indicate poorer patient conditions. A modification was made to the respiratory parameter. Pulse oximetry was added as the monitor for breathing instead of the liters of oxygen per minute. No change was made to the respiratory rate criteria. Pulse oximetry is an accurate and reliable indicator of the level of oxygen circulating in the blood. It is widely available and used routinely in acute care, especially in the acute and chronic cardiac patient populations. Pulse oximetry is most helpful when used to trend oxygen saturation over time and also, it is a standard of practice for monitoring the respiratory system in our hospital. Therefore, the team changed the respiratory parameter to include changes in oxygen saturations within baseline limits, 5 points below baseline, or more than 5 points below baseline. Changes were made to the scoring criteria descriptors in the behavior parameter (Figure 1). The team removed category 1 term “sleeping” as a descriptor of behavior, because they felt the term did not sufficiently capture early symptoms of deterioration in mental status. Therefore, it was replaced with “irritable (consolable).” Category 2 was changed to “irritable (inconsolable).” The consensus among the team members was that irritable (consolable) behavior usually precedes irritable (inconsolable) behavior and are better descriptors of the observed behavior seen during deterioration. Category 3 descriptors remained “lethargic/ confused.” The “reduced response to pain” descriptor in category 3 was removed because it was considered a late sign of progression toward clinical deterioration. Changes in the Glasgow coma scale (GCS) were initially included as descriptors in the behavior category as an additional marker of neurological deterioration. The team felt GCS was a standard shift assessment parameter and would be easy to capture on the TCH PAWS tool. However, the GCS was not a significant predictor in the behavior category and therefore, it was removed from the final version of the PAWS tool. e4 D. Bell et al. Behavior 0 1 2 3 Playing/Appropriate Irritable (consolable) Irritable (inconsolable) Lethargic/confused Pink or baseline color and Cap. refill 1-2 seconds Pale or Cap. refill 3 seconds Pale & Cap. refill 4 seconds or Tachycardia of 20 above baseline or Diaphoresis Grey or Mottled or Cap. refill 5 seconds or Tachycardia 30 above baseline or Bradycardia 20 above baseline or O2 sats 5 pts below baseline or Moderate use of accessory muscles Slowing of RR below baseline & increased work of breathing or O2 sats > 5 points below baseline or Grunting or Severe Retractions Green = 0-2 Score Cardiovascular Respiratory RR and O2 sats within baseline limits and No signs of increased work of breathing 10 above baseline or Mild using accessory muscles RR RR Score 2 extra points for patients who are on every hour respiratory treatments or with persistent vomiting following surgery. Review VS at time of scoring & repeat if isolated score of 3 in any category OR total score of 4 obtained. Review O2 requirement & trend at time of scoring. Yello w = 3 Score Orange = 4 Score Red =5 or Score Figure 1 Texas Children’s Hospital (TCH) Pediatric Advanced Warning Score (PAWS). (Adapted with permission from: Tucker et al. (2009). Prospective Evaluation of a Pediatric Inpatient Early Warning Scoring System. Journal for Specialists in Pediatric Nursing). Diaphoresis was added to the cardiovascular parameter in category 2 as an early warning symptom for deterioration (heart failure). This addition to the cardiovascular parameter was made to accommodate deterioration in our large population of cardiac patients. The TCH PAWS tool considers the patients’ physiological parameters and baseline vital signs, and recommends trending at the time of scoring. The healthcare team utilizes the algorithm (Figure 2) to provide care by recommending more frequent assessments, medical interventions, or initiating a call to the RRT or code team. If a score of 3 (in any one category) or a total score of 4 or higher is reached, the algorithm suggests considering a RRT call. The algorithm was modified to capture escalation of concern from the intern to the senior resident at a score of 5 or higher. In addition, a code can be activated at a score of 6 or higher. The team felt waiting for a score of 7 or higher would only delay getting help to the bedside. The word, ‘consider’, was used throughout the algorithm as the team felt the healthcare provider should use the tool in combination with good clinical judgment. Prior to collecting data, PAWS education was provided to all acute care unit nurses and physicians. The education consisted of a one hour presentation of content and interactive discussion of various patient scenarios. Also stressed was the concept that a RRT or code could be initiated at any time based on the healthcare teams' assessment, regardless of TCH PAWS score. Individuals were trained to use the data collection instruments, at which point they assumed respon- sibility for training other data collectors. A statistician incorporated all data into the database. The hospital-wide roll out of RRT was March 2008. The pilot study of the TCH PAWS tool was started in July 2008. The house-wide rollout of the TCH PAWS tool was done in August 2009. Research Design and Methods The purpose of this study was to examine the psychometric properties of the TCH PAWS tool as an indicator of clinical deterioration in infants and children during hospitalization. The Baylor Institutional Review Board (IRB) approved this study. It was anticipated that the TCH PAWS tool could be useful as a reliable and valid indicator of early warning signs of clinical changes that warrant a rapid clinical response. The key psychometric properties to be examined are reliability and validity. Reliability establishes the consistency or repeatability of measurements made with the instrument and validity establishes if the instrument measures what it claims to measure. Additional aims for this study included quantifying: (a) the rate of calls made to the RRT, (b) the rate of communication among health care professionals, (c) the correlation between increased TCH PAWS with increased respiratory and heart rates, and (d) the correlation between increased TCH PAWS with decreased GCS scores. Interrater reliability was also established. Pediatric Advanced Warning Score (PAWS) e5 Figure 2 Texas Children’s Hospital (TCH) Pediatric Advanced Warning Score (PAWS) Algorithm. Impending cardiac or respiratory arrest is an automatic code red call *9999. If there are criteria for RRT call *9999. (Adapted with permission from: Tucker et al. (2009). Prospective Evaluation of a Pediatric Inpatient Early Warning Scoring System. Journal for Specialists in Pediatric Nursing.) e6 D. Bell et al. Design The study was a non-experimental retrospective research design. Sample Size and Setting The study was conducted with patients admitted to one of three acute care units: • General medicine/transplant unit • Pulmonary, adolescent, and endocrine unit • Cardiology unit These units manage a variety of patients with the following medical disorders such as; heart disease, cystic fibrosis, bronchiolitis, asthma, diabetes, seizure disorders, liver, kidney, adolescents with eating disorders, Crohns, pancreatitis, sickle cell, and cancer patients not receiving chemotherapy. These units also manage a variety of surgical disorders such as; heart, liver, kidney and lung pre and post transplant, and general surgical procedures (appendectomy, incision and drainage, and tonsillectomies). It was determined that 286 infants and children were admitted to the acute care settings at the hospital during the month of July 2008 and with the inclusion of cardiology patients this would be a total of approximately 500 patients. The TCH PAWS scores are obtained as part of routine quality care. For a population size of 500 infants and children with similar characteristics, a sample size of 150 patients was needed to make estimates with a sampling error of no more than ± 5 percent, at the 95 percent confidence level. Sample size was determined using determinations for simple random and systematic sampling methods for health studies (Lemeshow, Hosmer, Klar, & Lwanga, 1993). Sampling Procedure A retrospective chart review was performed for infants and children admitted to one of the three acute care units during the period of January 1, 2009 to June 1, 2009. The institution admitted approximately 21,168 patients during the study year. The sample size reflects 0.7 % of the patient population. Fifty infants' and children's charts were randomly selected from each unit for a total of 150 charts. Patients were included in the study if their length of stay was greater than 48 hours. A PAWS data collection tool was designed to record data for this particular chart review. Results Researchers reviewed the charts of 150 infants and children admitted in three acute care setting units from January 1, 2009 to June 1, 2009. The mean age of the infants and children in the review was 6.3 years (range: 0.2– 17.0 years), with almost 25% of subjects under one year of age and 50.7% of subjects female. Table 1 presents more detailed patient demographic information. Reliability analysis was used to examine the psychometric properties of the TCH PAWS tool. The analysis calculated the reliability of the measurement scales and the relationships between individual items in the scale. The inter-item correlation matrix showed positive correlations among individual items at the final measurement of the 48-hour time period (Table 2). The weakest correlations were with the behavioral measure category (0.414 with cardiovascular, 0.320 with respiratory). This weak correlation was also observed clinically. For example, when there is rapid deterioration in the respiratory and cardiovascular systems, the behavioral changes seem slower to become evident. Internal consistency of the TCH PAWS scores was measured using the Cronbach’s alpha coefficient, which is a single summary statistic measuring ‘reliability’ of all items to predict the acute changes in clinical status of infants and children during hospitalization. The overall Cronbach’s alpha reliability coefficient for the TCH PAWS score at the final measurement was 0.75, indicating adequate reliability of the instrument. In hospitalized infants and children in the acute care setting, an increasing TCH PAWS score of ≥ 5 resulted in calls to the rapid team response 80% of the time. There were a total of five (5) infants and children in the acute care setting whose first occurrence of a TCH PAWS score was ≥ 5 with four (4) calls made to the rapid response team. The majority of these patients were male (75.0%) with a mean age of 8.4 years. The patient with a TCH PAWS score of ≥ 5 that did not result in a call to the rapid response team was a female less than one year of age. When the first occurrence of a TCH PAWS score was 3 or 4 for hospitalized infants and children in the acute care setting, communication was established with the patient’s physician or the health care professionals. The chart review recorded on the TCH PAWS assessment data collection tool resulted in 8 team communications established Table 1 Patient Demographics. Gender Male Female Age ≤ 1 Year 1–3 Years 4–6 Years 7–12 Years N 12 Years Diagnosis Respiratory Surgery Medical Cardiology N Percentage 74 76 49.3% 50.7% 37 29 24 30 30 24.7% 19.3% 16.0% 20.0% 20.0% 42 24 63 21 28.0% 16.0% 42.0% 14.0% Pediatric Advanced Warning Score (PAWS) e7 Table 2 Inter-Item Correlational Matrix: Final Measure of the 48-Hour Time Period. Behavior score Behavior score Cardiovascular score Respiratory score Cardiovascular score Respiratory Score 1.000 .414 .414 1.000 .320 .820 .320 .820 1.000 out of a total of 10 patients having a TCH PAWS score of 3 or 4. Therefore the communication rate among health care professionals was 80%. Of these patients there was an equal number of males and females (50.0%) and a mean age of 1.96 years. The mean age of patients with a TCH PAWS score of 3 or 4 when health care professionals were not called (20%) was 2.13 years there also were an equal number of males and females. Of those patients when the rapid response and communication teams were not called, the diagnoses were evenly distributed between respiratory disorders, medical, and cardiology and no other remarkable differences with regard to their characteristics. Spearman's rank correlation coefficients were computed to evaluate the correlation between (a) increasing TCH PAWS respiratory scores with increasing respiratory rates, and (b) increasing TCH PAWS cardiovascular scores with increasing heart rates in hospitalized infants and children at each recorded measure during the 48-hour time period. All correlations were positively correlated, ranging from 0.261 to 0.406, and were considered statistically significant. Results of the correlation analysis are presented in Table 3. Spearman's rank correlation coefficients were computed between TCH PAWS cardiovascular scores and heart rates of hospitalized infants and children at every recorded measure during the 48-hour time period. All correlations were positively correlated, with three statistically significant correlations: the first measure (Time 1), Time 6, and the last measure of the 48-hour time period (Time 8). Results of the correlation analysis are presented in Table 4. To determine if increasing TCH PAWS scores correlated with decreasing GCS, Spearman’s rank correlation coeffiTable 3 PAWS 48-Hour Assessments, Spearmen’s Rank Correlation Coefficients, and PAWS Respiratory. Scores and respiratory rates Assessment Spearman’s rho p value Time Time Time Time Time Time Time Time 0.378 0.406 0.261 0.286 0.307 0.280 0.274 0.287 b 0.001 b 0.001 0.002 0.001 b 0.001 0.001 0.001 0.001 1 2 3 4 5 6 7 8 Table 4 PAWS 48-Hour Assessments, Spearmen’s Rank Correlation Coefficients, and PAWS Cardiovascular Scores and Heart Rates. Assessment Spearman’s rho p value Time Time Time Time Time Time Time Time 0.116 0.009 0.076 0.047 0.106 0.173 0.075 0.231 0.045 NS NS NS NS 0.041 NS 0.006 1 2 3 4 5 6 7 8 cients were computed between total TCH PAWS scores and GCS of hospitalized infants and children at every recorded measure during the 48-hour time period. At Time 1, TCH PAWS and GCS were negatively correlated (rho = − 0.240) and statistically significant (p = 0.004). The result of the correlation analysis at Time 2 was negatively correlated (rho = − 0.066) but not statistically significant. Results of the remaining correlation analyses (Time 3–Time 8) between the TCH PAWS and GCS were positive and not significant. Therefore, GCS was removed from the final TCH PAWS tool. Interrater reliability of observers' common interpretation of the TCH PAWS was done prospectively by computing the intraclass correlation coefficient (ICC). To capture the consistency of scores among nurses who evaluated the same patient's level of deterioration, two nurse raters assessed each patient’s level of deterioration with TCH PAWS at the same time point. There were 58 nurses, including float pool nurses that staff acute care units, who participated in evaluation of the ICC. The TCH PAWS total score strength of the relationship between both raters simultaneously was 0.851, with a 95% confidence interval 0.75–0.91. Individual items also yielded an acceptable ICC at 0.740, with a 95% confidence interval 0.60–0.84 (Table 5). Typically, TCH PAWS is used with a single observer, therefore the single measure score was used as a baseline for future interrater reliability studies. The relationship between the nurses’ scores ascertained that nurse raters dependably gave acceptable ratings. In 2008 (year before the study began) the rate of the RRT calls from acute care units was 4.88 per 1000 patient days. During the calendar year 2009, the rate of RRT calls from acute care units was 5.85 per 1000 patient days. One outcome goal of the collaborative was to minimize the number of codes in acute care. The code events decreased from 0.293 per 1000 patient days in 2008–0.256 per 1000 patient days in 2009. However, this decreased number of codes is not statistically significant. Prior to the study, the average length of time between codes on the pilot units was 18.1 days. The target goal of the acute care units was to double the number of days between codes, making the target number 36 days. The acute units exceeded their goal by achieving 258 days between codes during the period of 7/12/08 to 3/31/09. e8 Table 5 D. Bell et al. Interrater Reliability Assessment with ICC. Intraclass correlationa Single measures Average measures .740b .851c 95% Confidence interval F test with true value 0 Lower bound Upper bound Value df1 df2 Sig .603 .752 .835 .910 6.697 6.697 61 61 61 61 .000 .000 Two-way random effects model where both people effects and measures effects are random. The “Average” ICC refers to the interrater reliability of two raters combined. ‘Single’ ICC refers to the reliability of one nurse. According to McCabe, Ducan, & Heward (2009) implementation and reinforcement of an early warning system can take several years to achieve a reduction in code events and improve clinical outcomes. Therefore, the priority hospital-wide goal to decrease/eliminate code events in acute care units continues today. Implications for Practice The TCH PAWS tool was found to be a valid and reliable tool that was incorporated into clinical practice throughout the acute care units. During the early stages of the project, TCH PAWS was completed twice per 12-hour shift. After benchmarking with other pediatric hospitals that utilize early warning tools the assessment frequency was changed to every 4 hours. Initially, there was some resistance to the change in practice; however, it has since become a standard of care. Hospital policy has been updated to reflect the 4hour intervals of patient scoring. Tools that helped during the assimilation process included: leadership huddles with staff, and frequent educational opportunities, that assisted in demonstrating the value of TCH PAWS as it related to ensuring safety of hospitalized infants and children. During the pilot study, TCH PAWS was recorded on a separate form that led to poor compliance with score documentation. Since then, TCH PAWS documentation section has been incorporated into the electronic medical record. Texas Children’s Hospital Pediatric Advanced Warning Score as a Communication Tool Prior to transport to acute care, patients are given a TCH PAWS score by their transferring departments (emergency services, pediatric intensive care, progressive care, etc.). The score is used to communicate patients’ stability. If a patient’s score suggests that the patient may be of higher acuity and require an increase in intensity of services, relevant information is given to the charge nurse and the patient’s status is investigated by the Nursing Administrative Coordinator (House Supervisor) to ensure correct patient placement. The TCH PAWS tool is used at initial notification of deterioration and used subsequently after each intervention to determine if a patient’s condition has improved. The TCH PAWS tool is also used when a RRT is initiated and is part of the Situation Background Assessment Recommendation (SBAR) communication from bedside nurse to RRT nurse. The TCH PAWS tool is used extensively throughout the organization and is a vital part of the communication process. Future Implications The assessment of patients using TCH PAWS every 4 hours combined with consistently low scores may carry a risk of fatigue among the nurses. Future studies are needed to further describe this concept. The TCH PAWS tool has been incorporated in a new community-based facility within our healthcare system, which opened its inpatient beds in 2011. The TCH PAWS tool is included in criteria for transfer from the community hospital to the main hospital in the medical center. How Do I Apply This Information to Nursing Practice? The TCH PAWS tool was found to be reliable and valid to detect early clinical deterioration in children admitted to acute care services, thus allowing for early intervention. The TCH PAWS score can be used to trigger RRT activation. Rapid response team intervention has been associated with decreased code events in acute care areas. The TCH PAWS score is included in the handoff report when a patient is transferred to either a higher or lower level of care which facilitates discussion of the appropriateness of the transfer. This was noted by receiving nurses to be useful, particularly when a patient should not be transferred to a unit due to a higher TCH PAWS score. Implementation of TCH PAWS must be housewide and involve all disciplines to be successful as a communication tool among health professionals. Acknowledgments We would like to thank the staff on 12WT, 14WT, 15WT, Larry Jefferson, Moushumi Sur, Jennifer Hudnall, Jennifer Sanders, Shelly Nalbone, Christine Bartlett, Rhonda Wolfe, Cherida Bluford, Susan Iniguez, Rebecca Wolfe, Angela Morgan, Sharon Jacobson, Marilyn Hockenberry, and Julia Kuzin. References Akre, M., Finkelstein, M., Erickson, M., Liu, M., Vanderbilt, L., & Billman, G. (2010). Sensitivity of the pediatric early warning score to identify patient deterioration. Pediatrics, 125, 763–769. 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