Acute Asthma Intensity Research Score: updated performance characteristics for prediction of hospitalization and lung function

Prospective Observational Study of Clinical Outcomes After Intravenous Magnesium for Moderate and Severe Acute Asthma Exacerbations in Children

BACKGROUND

There is limited knowledge regarding whether intravenous magnesium (IV-Mg) improves outcomes in children with acute asthma exacerbations.

OBJECTIVE

To examine whether IV-Mg improves outcomes in children with moderate and severe exacerbations.

METHODS

We performed a secondary analysis using data from a prospective observational cohort of children aged 5 to 17 years with moderate and severe exacerbations. Standardized treatment included systemic corticosteroid and inhaled albuterol, with consideration of IV-Mg (75 mg/kg) for patients with insufficient response after 20 minutes. Propensity score (PS) models were used to examine associations of IV-Mg treatment with change in the validated Acute Asthma Intensity Research Score, hospitalization rate, and time to spacing of inhaled albuterol of 4 hours or more among hospitalized participants.

RESULTS

Among 301 children, median (interquartile range) age was 8.1 (6.4-10.2) years, 170 were Black (57%), 201 were male (67%), and 84 received IV-Mg (28%). In a PS covariate-adjusted multivariable linear regression model, IV-Mg treatment was associated with a 2-hour increase in the Acute Asthma Intensity Research Score (β-coefficient = 0.98; 95% confidence interval [CI], 0.20-1.77), indicating increased exacerbation severity. Three additional PS-based models yielded similar results. Participants receiving IV-Mg had 5.8-fold (95% CI, 2.8-11.9) and 6.8-fold (95% CI, 3.6-12.9) greater odds of hospitalization in PS-based multivariable regression models. Among hospitalized participants, there was no difference in time to albuterol of every 4 hours or more in a PS covariate-adjusted Cox proportional hazards model (hazard ratio = 1.2; 95% CI, 0.8-1.8).

CONCLUSIONS

Among children with moderate and severe exacerbations, IV-Mg is associated with increased exacerbation severity, increased risk for hospitalization, and no acceleration in exacerbation resolution among hospitalized participants.

Nebulized albuterol delivery is associated with decreased skeletal muscle strength in comparison with metered-dose inhaler delivery among children with acute asthma exacerbations

OBJECTIVE

Albuterol is a β2-agonist and causes an intracellular shift of potassium from the interstitium. Whole-body hypokalemia is known to cause skeletal muscle weakness, but whether this occurs as a result of hypokalemia from the intracellular shift during albuterol treatment is unknown. We sought to determine if albuterol total dose or route of administration (nebulization and/or metered-dose inhaler) is associated with skeletal muscle weakness.

METHODS

This was a prospective observational study using convenience sampling. Skeletal muscle strength was measured before and after 1 hour of albuterol treatment using a hand-grip dynamometer in participants aged 5-17 years with acute asthma exacerbation in the emergency department. We examined associations of albuterol dose and route of administration with changes in grip strength.

RESULTS

Among 50 participants, 10 received continuous albuterol by nebulizer and 40 received albuterol by metered-dose inhaler. The median (interquartile range) in change of grip was -7.8% (interquartile range, -23.3, +5.1) for those treated with a nebulizer and +2.4% (interquartile range, -5%, +12.7%) for those treated with a metered-dose inhaler (P = 0.036 for the difference). In a multiple linear regression model adjusted for the pretreatment Acute Asthma Intensity Research Score and age, participants treated with a nebulizer had a 12.9% decrease in skeletal muscle strength compared with those treated with a metered-dose inhaler.

CONCLUSION

Higher doses of albuterol administered via nebulization result in decreased skeletal muscle strength in patients with acute asthma; whereas, albuterol administration via metered-dose inhalers showed no effect on skeletal muscle strength.

Implementation and Improvement of Pediatric Asthma Guideline Improves Hospital-Based Care

BACKGROUND

Standardized pediatric asthma care has been shown to improve measures in specific hospital areas, but to our knowledge, the implementation of an asthma clinical practice guideline (CPG) has not been demonstrated to be associated with improved hospital-wide outcomes. We sought to implement and refine a pediatric asthma CPG to improve outcomes and throughput for the emergency department (ED), inpatient care, and the ICU.

METHODS

An urban, quaternary-care children's hospital developed and implemented an evidence-based, pediatric asthma CPG to standardize care from ED arrival through discharge for all primary diagnosis asthma encounters for patients ≥2 years old without a complex chronic condition. Primary outcomes included ED and inpatient length of stay (LOS), percent ED encounters requiring admission, percent admissions requiring ICU care, and total charges. Balancing measures included the number of asthma discharges between all-cause 30-day readmissions after asthma discharges and asthma relapse within 72 hours. Statistical process control charts were used to monitor and analyze outcomes.

RESULTS

Analyses included 3650 and 3467 encounters 2 years pre- and postimplementation, respectively. Postimplementation, reductions were seen in ED LOS for treat-and-release patients (3.9 hours vs 3.3 hours), hospital LOS (1.5 days vs 1.3 days), ED encounters requiring admission (23.5% vs 18.8%), admissions requiring ICU (23.0% vs 13.2%), and total charges ($4457 vs $3651). Guideline implementation was not associated with changes in balancing measures.

CONCLUSIONS

The hospital-wide standardization of a pediatric asthma CPG across hospital units can safely reduce overall hospital resource intensity by reducing LOS, admissions, ICU services, and charges.

Adapting an Evidence-Based Pediatric Acute Asthma Exacerbation Severity Assessment Tool for Pediatric Primary Care

INTRODUCTION

The purposes of this project were (a) to examine criteria derived from evidence-based pediatric acute asthma exacerbation assessment tools, asthma scores, and the acute asthma prediction rule validated and used in the emergency department and (b) to adapt these criteria for pediatric primary care.

METHOD

The three stages of the project included (a) identification of criteria in a literature review, (b) validation of the criteria by an expert panel, and (c) adaptation of the criteria in the design of an assessment tool.

RESULTS

The criteria were validated and adapted in the design of The Pediatric Acute Asthma Exacerbation Severity Assessment and Disposition Decision-Making Tool for Pediatric Primary Care.

DISCUSSION

The adaptation of criteria derived from the evidence and validated by an expert panel will inform and guide clinicians in assessing severity and support decision making in determining disposition of pediatric patients presenting with an acute asthma exacerbation in primary care.

Modification of an Established Pediatric Asthma Pathway Improves Evidence-Based, Efficient Care

OBJECTIVE

In September 2011, an established pediatric asthma pathway at a tertiary care children's hospital underwent significant revision. Modifications included simplification of the visual layout, addition of evidence-based recommendations regarding medication use, and implementation of standardized admission criteria. The objective of this study was to determine the impact of the modified asthma pathway on pathway adherence, percentage of patients receiving evidence-based care, length of stay, and cost.

METHODS

Cases were identified by using International Classification of Diseases, Ninth Revision, Clinical Modification diagnosis codes. Data were analyzed for 24 months before and after pathway modification. Statistical process control was used to examine changes in processes of care, and interrupted time series was used to examine outcome measures, including length of stay and cost in the premodification and postmodification periods.

RESULTS

A total of 5584 patients were included (2928 premodification; 2656 postmodification). Pathway adherence was high (79%-88%) throughout the study period. The percentage of patients receiving evidence-based care improved after pathway modification, and the results were sustained for 2 years. There was also improved efficiency, with a 30-minute (10%) decrease in emergency department length of stay for patients admitted with asthma (P = .006). There was a nominal (<10%) increase in costs of asthma care for patients in the emergency department (P = .04) and no change for those admitted to the hospital.

CONCLUSIONS

Modification of an existing pediatric asthma pathway led to sustained improvement in provision of evidence-based care and patient flow without adversely affecting costs. Our results suggest that continuous re-evaluation of established clinical pathways can lead to changes in provider practices and improvements in patient care.

The asthma prediction rule to decrease hospitalizations for children with asthma

PURPOSE OF REVIEW

The aim of the present review was to discuss the challenges around clinical decision-making for hospitalization of children with acute asthma exacerbations and the development, internal validation, and future potential of the asthma prediction rule (APR) to provide meaningful clinical decision-support that might decrease unnecessary hospitalizations.

RECENT FINDINGS

The APR was developed and internally validated using predictor variables available before treatment in the emergency department, and performed well to predict 'need-for-hospitalization.' Oxygen saturation on room air and expiratory phase prolongation were most strongly associated with need-for-hospitalization.

SUMMARY

Research on prediction rules in pediatric asthma is rare. We developed and internally validated the APR using clinically intuitive predictor variables that are available at the bedside. Before incorporation into electronic decision-support the APR must undergo external validation and an impact analysis to determine if use of this tool will change clinician behavior and improve patient outcomes.

Pulse Oximeter Plethysmograph Estimate of Pulsus Paradoxus as a Measure of Acute Asthma Exacerbation Severity and Response to Treatment

OBJECTIVES

Pulsus paradoxus is one of the few objective bedside measures of acute asthma exacerbation severity but is difficult to measure in tachypneic and tachycardic patients and in noisy clinical environments. Our primary objective was to examine whether pulse oximeter plethysmograph estimate of pulsus paradoxus (PEP) is associated with physiologic and symptom measures of acute exacerbation severity (airway resistance by impulse oscillometry [%IOS] and the Acute Asthma Intensity Research Score [AAIRS]). Secondary objectives were to validate the previous association of PEP with percent predicted forced expiratory volume in 1 second (%FEV1 ) and to examine associations of change of PEP with change of these outcomes after 2 hours of treatment.

METHODS

This was a secondary analysis of data from a prospective observational study of patients aged 5-17 years with acute asthma exacerbations. The predictor variable, PEP, was measured using a dedicated pulse oximeter and waveform analysis program. Outcome measures included the AAIRS, %IOS, and %FEV1 at baseline and after 2 hours of treatment. We examined associations of PEP with %IOS and the AAIRS at baseline using multiple linear regression models adjusted for age, sex, and race. As secondary analyses we similarly examined the association of PEP with %FEV1 at baseline and change of PEP with change of %IOS, the AAIRS, and %FEV1 after 2 hours of treatment using multiple linear regression models adjusted for the baseline value of the outcome measure and the AAIRS.

RESULTS

Among 684 participants (61% males; 61% African American) there were associations of baseline PEP with %IOS, the AAIRS, and %FEV1 (p < 0.001). Change of PEP after 2 hours of treatment was associated with change of %FEV1 (p < 0.001) and change of the AAIRS (p = 0.01) but not with change of %IOS (p = 0.60).

CONCLUSIONS

PEP demonstrates criterion validity in predicting baseline %IOS, the AAIRS, and %FEV1 , and responsiveness to change of the AAIRS and %FEV1 . Data contained in the oximeter plethysmograph waveform might be utilized as a continuous, objective measure of acute asthma exacerbation severity and real-time response to treatment.

Standardized Asthma Admission Criteria Reduce Length of Stay in a Pediatric Emergency Department

OBJECTIVES

Asthma is the most common chronic illness in children and accounts for > 600,000 emergency department (ED) visits each year. Reducing ED length of stay (LOS) for moderate to severe asthmatics improves ED throughput and patient care for this high-risk population. The objective of this study was to determine the impact of adding standardized, respiratory score-based admission criteria to an asthma pathway on ED LOS for admitted patients, time to bed request, overall percentage of admitted asthmatics, inpatient LOS, and percentage of pediatric intensive care unit (PICU) admissions.

METHODS

This was a retrospective study of a quality improvement intervention. Statistical process control methodologies were used to analyze measures 15 months before and after implementation of a modified asthma pathway (June 2010 to December 2012; pathway modification September 2011).

RESULTS

A total of 3,688 patients aged 1 through 18 years who presented to the ED with an asthma exacerbation during the study period were included. Patients were excluded if they were not eligible for the asthma pathway. Patient characteristics were similar before and after the intervention. Mean ED LOS and time to bed request for admitted asthmatics both decreased by 30 minutes. There was no change in percentage of asthma admissions (34%), mean inpatient LOS (1.4 days), or percentage of PICU admissions (2%).

CONCLUSIONS

Standardizing care for asthma patients to include objective admission criteria early in the ED course may optimize patient care and improve ED flow.