Debra H. Fiser

Assessing the outcome of pediatric intensive care

To describe the short-term outcome of pediatric intensive care by quantifying overall functional morbidity and cognitive impairment, I developed the Pediatric Overall Performance Category (POPC) and the Pediatric Cerebral Performance Category (PCPC) scales, respectively. A total of 1469 subjects (1539 admissions) were admitted to the pediatric intensive care unit of Arkansas Childrens Hospital from July 1989 through December 1990. Patients were assigned baseline POPC and PCPC scores derived from historical information and discharge scores at the time of discharge from the hospital (or from the pediatric intensive care unit for patients with multiple hospitalizations). Delta scores were calculated as the difference between the discharge scores and the baseline scores. The changes in POPC and PCPC scores were associated with several measures of morbidity (length of stay in the pediatric intensive care unit, total hospital charges, and discharge care needs) and with severity of illness (pediatric risk of mortality score) or severity of injury (pediatric trauma score) (p less than 0.0001). Interrater reliability was excellent (r = 0.88 to 0.96; p less than 0.001). The POPC and PCPC scales are apparently reliable and valid tools for assessing the outcome of pediatric intensive care.

Sleep-associated breathing disorders in morbidly obese children and adolescents

Forty-one children and adolescents with a history of breathing difficulty during sleep and morbid obesity, defined as greater than 150% ideal body weight, underwent polysomnography to determine the incidence of sleep-associated breathing disorders. Seventeen patients also performed pulmonary function testing. The mean patient age was 10.3 +/- 4.4 (SD) years, and mean percent of ideal body weight was 208 +/- 42.2. A sleep history questionnaire showed that all patients snored, but frank apnea was reported in only 32%. The pulmonary function tests showed 18% (3/17) with a restrictive defect and 47% (8/17) with obstructive changes. The polysomnograms in 37% (15/41) of the patients were abnormal because of apnea, hypopnea, excessive arousals, or abnormalities in gas exchange. Multiple regression analysis demonstrated no significant association between weight, age, or gender and any physiologic measure on the polysomnogram. Most of the abnormal polysomnograms (13/15) were mildly abnormal, but two showed sufficiently severe abnormalities to require clinical intervention. We conclude that children and adolescents with morbid obesity are at risk for sleep-associated breathing disorders; their polysomnographic abnormalities are usually mild but rarely may be severe enough to require clinical intervention.

Relationship of pediatric overall performance category and pediatric cerebral performance category scores at pediatric intensive care unit discharge with outcome measures collected at hospital discharge and 1- and 6-month follow-up assessments.

Objective Given the current focus on outcomes, there is a crucial need for easily utilized measures that can effectively quantify morbidity or disability after a child’s critical illness or injury. The purpose of this study is to significantly extend the research on two such promising measures: the Pediatric Overall Performance Category (POPC) and the Pediatric Cerebral Performance Category (PCPC). Design Cross-sectional analysis of a sample of pediatric intensive care unit (PICU) discharges and a prospective follow-up of this cohort of children. Setting Arkansas Children’s Hospital. Patients Two hundred children (ranging in age from birth to 21 yrs) discharged from a PICU. Interventions None. Measurements and Main Results Data were collected at PICU discharge, hospital discharge, and 1- and 6-month follow-up assessments after hospital discharge. Measures utilized included the POPC (at PICU discharge), PCPC (at PICU discharge), Stanford-Binet Intelligence Scale, fourth edition (at hospital discharge), Bayley Scales of Infant Development, second edition (at hospital discharge), and the Vineland Adaptive Behavior Scales (at 1 and 6 months after discharge). Stanford-Binet Intelligence Quotients and Bayley Mental Developmental Index scores were significantly different across PCPC categories (p < .0001). Bayley Psychomotor Developmental Index scores and Vineland Adaptive Behavior Scales scores varied significantly across POPC categories (p < .0001). The test for linear trend was also significant for each of the comparisons. Conclusions The results of this study offer additional support for the use of the PCPC and POPC. These brief and easily completed measures can provide useful information regarding probable outcomes for pediatric intensive care patients when more extensive psychometric testing is not feasible or desirable.

Recommended Guidelines for Uniform Reporting of Pediatric Advanced Life Support: The Pediatric Utstein Style

This consensus document is an attempt to provide an organized method of reporting pediatric ALS data in out-of-hospital, emergency department, and in-hospital settings. For this methodology to gain wide acceptance, the task force encourages development of a common data set for both adult and pediatric ALS interventions. In addition, every effort should be made to ensure that consistent definitions are used in all age groups. As health care changes, we will all be challenged to document the effectiveness of what we currently do and show how new interventions or methods of treatment improve outcome and/or reduce cost. Only through collaborative research will we obtain the necessary data. For these reasons, and to improve the quality of care and patient outcomes, it is the hope of the task force that clinical researchers will follow the recommendations in this document. It is recognized that further refinements of this statement will be needed; these recommendations will improve only when researchers, clinicians, and EMS personnel use them, work with them, and modify them. Suggestions, recommendations, and other comments aimed at improving the reporting of pediatric resuscitation should be sent to Arno Zaritsky, MD, Eastern Virginia Medical School, Childrens Hospital of The Kings Daughter, Division of Critical Care Medicine, 601 Childrens Lane, Norfolk, VA 23507.

Volume-outcome relationships in pediatric intensive care units.

Context. Pediatric intensive care units (PICUs) have expanded nationally, yet few studies have examined the potential impact of regionalization and no study has demonstrated whether a relationship between patient volume and outcome exists in these units. Documentation of an inverse relationship between volume and outcome has important implications for regionalization of care. Objectives. This study examines relationships between the volume of patients and other unit characteristics on patient outcomes in PICUs. Specifically, we investigate whether an increase in patient volume improves mortality risk and reduces length of stay. Design and Setting. A prospective multicenter cohort design was used with 16 PICUs. All of the units participated in the Pediatric Critical Care Study Group. Participants. Data were collected on 11 106 consecutive admissions to the 16 units over a 12-month period beginning in January 1993. Main Outcome Measures. Risk-adjusted mortality and length of stay were examined in multivariate analyses. The multivariate models used the Pediatric Risk of Mortality score and other clinical measures as independent variables to risk-adjust for illness severity and case-mix differences. Results. The average patient volume across the 16 PICUs was 863 with a standard deviation of 341. We found significant effects of patient volume on both risk-adjusted mortality and patient length of stay. A 100-patient increase in PICU volume decreased risk-adjusted mortality (adjusted odds ratio: .95; 95% confidence interval: .91–.99), and reduced length of stay (incident rate ratio: .98; 95% confidence interval: .975–.985). Other PICU characteristics, such as fellowship training program, university hospital affiliation, number of PICU beds, and childrens hospital affiliation, had no effect on risk-adjusted mortality or patient length of stay. Conclusions. The volume of patients in PICUs is inversely related to risk-adjusted mortality and patient length of stay. A further understanding of this relationship is needed to develop effective regionalization and referral policies for critically ill children.

decomplexification in critical illness and injury: Relationship between heart rate variability, severity of illness, and outcome

Abstract Objectives: To determine if decomplexification of heart rate dynamics occurs in critically ill and injured pediatric patients. We hypothesized that heart rate power spectra, a measure of heart rate dynamics, would inversely correlate with measures of severity of illness and outcome. Design: A prospective clinical study. Setting: A 12‐bed pediatric intensive care unit (ICU) in a tertiary care childrens hospital. Patients: One hundred thirty‐five consecutive pediatric ICU admissions. Interventions: None. Measurements and Main Results: We compared heart rate power spectra with the Pediatric Risk of Mortality (PRISM) score, the Pediatric Cerebral Performance Category (PCPC), and the Pediatric Overall Performance Category (POPC). We found significant negative correlations between minimum low‐frequency and high‐frequency heart rate power spectral values recorded during ICU stay and the maximum PRISM score (log low‐frequency heart rate power vs. PRISM, r2 = .293, p < .001; and log high‐frequency heart rate power vs. PRISM, r2 = .243, p < .001) and outcome at ICU discharge (log low‐frequency heart rate power vs. POPC or PCPC, r2 = .429, p < .001; and log high‐frequency heart rate power vs. POPC or PCPC, r2 = .271, p < .001). Conclusions: Our data support the hypothesis that measures of heart rate power spectra are inversely related and negatively correlated to severity of illness and outcome in critically ill and injured children. The phenomenon of decomplexification of physiologic dynamics may have important clinical implications in critical illness and injury. (Crit Care Med 1998; 26:352‐357) For years, physicians have believed that physiologic systems existed in a so‐called “steady” or “homeostatic” state and that these systems exhibited a linear response when stimulated. It is now clear that physiologic systems exist in a nonlinear, dynamic state [1‐4]. In other words, physiologic systems constantly change over time and respond to stimuli in a nonlinear manner. Furthermore, healthy physiologic systems exhibit marked signal variability, while aging or diseased systems show a loss of variability [2,5]. This decreased variability, or increased regularity, in physiologic dynamics has been termed “decomplexification” [1]. Commonly monitored physiologic signals, including mean heart rate, blood pressure, and cardiac output, correlate poorly with survival in both experimental models of circulatory shock and in critically ill patients [6]. These first‐order linear measures do not adequately describe dynamic changes. Power spectral analysis of heart rate variability, a second‐order linear measure, allows for quantification in the frequency domain of dynamic changes in beat‐to‐beat heart rate oscillations [1,5‐10]. Power spectral analysis of heart rate variability has been used to quantify physiologic changes in many diseases, including hypovolemia, congestive heart failure, hypertension, diabetes mellitus, renal failure, cardiac transplantation, traumatic quadriplegia, and sepsis [10‐19]. We hypothesized that decomplexification of heart rate dynamics would occur over a broad range of critical illness and injury, and would inversely correlate with disease severity and outcome in a pediatric population. To test this hypothesis, we prospectively studied 135 consecutive admissions to the Strong Childrens Critical Care Center. We compared heart rate power spectra with a previously validated measure of severity of illness, the Pediatric Risk of Mortality (PRISM) score [20], and with validated measures of outcome from pediatric intensive care, the Pediatric Overall Performance Category (POPC) [21] and Pediatric Cerebral Performance Category (PCPC) [21] scores.

Relationship of illness severity and length of stay to functional outcomes in the pediatric intensive care unit : A multi-institutional study

Objective: The purpose of this study was to establish relationships between illness severity, length of stay, and functional outcomes in the pediatric intensive care unit (PICU) by using multi‐institutional data. We hypothesized that a positive relationship exists between functional outcome scores, severity of illness, and length of stay. Design: The study used a prospective multicentered inception cohort design. Setting: The study was conducted in 16 PICUs across the United States that were member institutions of the Pediatric Critical Care Study Group of the Society of Critical Care Medicine. Patients: In total, 11,106 patients were assessed, representing all admissions to these intensive care units for 12 consecutive months. Measurements: Functional outcomes were measured by the Pediatric Overall Performance Category (POPC) and Pediatric Cerebral Performance Category (PCPC) scales. Both scales were assessed at baseline and discharge from the PICU. Delta scores were formed by subtracting baseline scores from discharge scores. Other measurements included admission Pediatric Risk of Mortality scores, age, operative status, length of stay in the PICU, and diagnoses. Interrater reliability was assessed by using a set of ten standardized cases on two occasions 6 months apart. Main Results: Baseline, discharge, and delta POPC and PCPC outcome scores were associated with length of stay in the PICU and with predicted risk of mortality (p < .01). Incorporation of baseline functional status in multivariate length of stay analyses improved measured fit. Mild baseline cerebral deficits in children were associated with 18% longer PICU stays after controlling for other patient and institutional characteristics. Moderate and severe baseline deficits for both the POPC and PCPC score predict increased length of stay of between 30% and 40%. On the standardized cases, interrater consensus was achieved on 82% of scores with agreement to within one neighboring class for 99.7% of scores. Conclusions: These data establish current relationships for the POPC and PCPC outcome scales based on multi‐institutional data. The reported relationships can be used as reference values for evaluating clinical programs or for clinical outcomes research.

Variation in therapy and outcome for pediatric head trauma patients.

ObjectiveThis study was undertaken to examine variation in therapies and outcome for pediatric head trauma patients by patient characteristics and by pediatric intensive care unit. Specifically, the study was designed to examine severity of illness on admission to the pediatric intensive care unit, the therapies used during the pediatric intensive care unit stay, and patient outcomes. Data Sources and Setting Consecutive admissions from three pediatric intensive care units were recorded prospectively (n = 5,749). For this study, all patients with an admitting diagnosis of head trauma were included (n = 477). Data collection occurred during an 18-month period beginning in June 1996. All of the pediatric intensive care units were located in children’s hospitals, had residency and fellowship training programs, and were headed by a pediatric intensivist. MethodsAdmission severity was measured as the worst recorded physiological derangement during the period ≤6 hrs before pediatric intensive care unit admission. Therapies and resource use were based on the Therapeutic Intervention Scoring System with adaptations for pediatrics. The use of intracranial pressure monitoring was recorded on admission to the unit (within 1 hr) and at any time during the pediatric intensive care unit stay. Outcomes were measured at the time of pediatric intensive care unit discharge by the Pediatric Overall Performance Category scale. Risk factors for mortality were examined by using bivariate analyses with significant predictors as candidate variables in a logistic regression to predict expected mortality. Intracranial pressure monitoring and other therapies were added to the mortality prediction model to test for protective effects. Finally, race and insurance status were added to the model to test for differences in the quality of care. ResultsThe overall mortality rate for the entire sample was 7.8%. Mortality rates for children ≤1 yr old were significantly higher than for children >1 yr old (16.1% vs. 6.1%;p = .002). Comparisons by insurance status indicated that observed mortality rates were highest for self-paying patients. However, patient characteristics were not associated with use of therapies or standardized mortality rates after adjustment for patient severity. There was significant variation in the use of paralytic agents, seizure medications, induced hypothermia, and intracranial pressure monitoring on admission across the three pediatric intensive care units. In multivariate models, only the use of seizure medications was associated significantly with reduced mortality risk (odds ratio = 0.17; 95% confidence interval = 0.04–0.70;p = .014). ConclusionsTherapies and outcomes vary across pediatric intensive care units that care for children with head injuries. Increased use of seizure medications may be warranted based on data from this observational study. Large randomized controlled trials of seizure prophylaxis in children with head injury have not been conducted and are needed to confirm the findings presented here.

Hospitalizations for critically ill children with traumatic brain injuries: A longitudinal analysis*

Objective:This study examines the incidence, utilization of procedures, and outcomes for critically ill children hospitalized with traumatic brain injury over the period 1988–1999 to describe the benefits of improved treatment. Design:Retrospective analysis of hospital discharges was conducted using data from the Health Care Cost and Utilization Project Nationwide Inpatient Sample that approximates a 20% sample of U.S. acute care hospitals. Setting:Hospital inpatient stays from all types of U.S. community hospitals. Participants:The study sample included all children aged 0–21 with a primary or secondary ICD-9-CM diagnosis code for traumatic brain injury and a procedure code for either endotracheal intubation or mechanical ventilation. Interventions:None. Measurements and Main Results:Deaths occurring during hospitalization were used to calculate mortality rates. Use of intracranial pressure monitoring and surgical openings of the skull were investigated as markers for the aggressiveness of treatment. Patients were further classified by insurance status, household income, and hospital characteristics. Over the 12-yr study period, mortality rates decreased 8 percentage points whereas utilization of intracranial pressure monitoring increased by 11 percentage points. The trend toward more aggressive management of traumatic brain injury corresponded with improved hospital outcomes over time. Lack of insurance was associated with vastly worse outcomes. An estimated 6,437 children survived their traumatic brain injury hospitalization because of improved treatment, and 1,418 children died because of increased mortality risk associated with being uninsured. Improved treatment was valued at approximately

Differences in pediatric ICU mortality risk over time

17 billion, whereas acute care hospitalization costs increased by