Predicting response to therapy in acute asthma

Admission predictability of children with acute asthma

OBJECTIVES

We aimed to evaluate the seasonal variations of acute asthma presentation in children and the utility of the pediatric asthma score (PAS) and its components in early admission prediction.

METHODS

As part of a randomized controlled trial addressing the clinical efficacy of budesonide nebulization in the treatment of acute asthma in children, the PAS was measured at baseline, 1^st, 2^nd, 3^rd, and 4^th h from the start of medications. Decision of admission was taken at or beyond the 2^nd h.

RESULTS

Out of a total 906 emergency department (ED) visits with moderate-to-severe acute asthma, 157 children were admitted. June to September had the lowest number of visits. The admission-to-discharge ratio varied throughout the year. During the ED stay, between baseline and 3^rd h, admission predictability of the total score improved progressively with a small difference between the 2^nd and 3^rd h. The total score remained the strongest predictor of admission at every time point compared to its individual components. The drop of PAS from baseline to the 2^nd h was not a good predictor of admission. Oxygen saturation (OS) and respiratory rate (RR) had relatively higher predictability than other components.

CONCLUSIONS

Decision of admission could be made to many children with moderate-to-severe acute asthma at the 2^nd h of ED stay based on their total PAS. OS and RR should be part of any scoring system to evaluate acute asthma in children.

Identifying barriers and facilitators to ambulance service assessment and treatment of acute asthma: a focus group study

Background

Acute asthma is a common reason for patients to seek care from ambulance services. Although better care of acute asthma can prevent avoidable morbidity and deaths, there has been little research into ambulance clinicians’ adherence to national guidelines for asthma assessment and management and how this might be improved. Our research aim was to explore paramedics’ attitudes, perceptions and beliefs about prehospital management of asthma, to identify barriers and facilitators to guideline adherence.

Methods

We conducted three focus group interviews of paramedics in a regional UK ambulance trust. We used framework analysis supported by NVivo 8 to code and analyse the data.

Results

Seventeen participants, including paramedics, advanced paramedics or paramedic operational managers at three geographical sites, contributed to the interviews. Analysis led to five themes: (1) guidelines should be made more relevant to ambulance service care; (2) there were barriers to assessment; (3) the approach needed to address conflicts between clinicians’ and patients’ expectations; (4) the complexity of ambulance service processes and equipment needed to be taken into account; (5) and finally there were opportunities for improved prehospital education, information, communication, support and care pathways for asthma.

Conclusions

This qualitative study provides insight into paramedics’ perceptions of the assessment and management of asthma, including why paramedics may not always follow guidelines for assessment or management of asthma. These findings provide opportunities to strengthen clinical support, patient communication, information transfer between professionals and pathways for prehospital care of patients with asthma.

PRAM score as predictor of pediatric asthma hospitalization

OBJECTIVES

The objective was to determine the association between asthma severity as measured by the Pediatric Respiratory Assessment Measure (PRAM) score and the likelihood of admission for pediatric patients who present to the emergency department (ED) with moderate-to-severe asthma exacerbations and who receive intensive asthma therapy.

METHODS

This was a secondary analysis of a prospective study of triage nurse-initiated steroid therapy in pediatric asthma. Children aged 2 to 17 years inclusive, presenting with moderate-to-severe acute asthma exacerbations (defined as PRAM ≥ 4), were included. To be eligible for inclusion in the study, children must have received "intensive asthma therapy," defined as nurse-initiated initial bronchodilator and oral steroid therapy at arrival to triage. PRAM scores were measured hourly as per ED protocol. The primary outcome was inpatient hospitalization; secondary outcome was ED stay greater than 8 hours. Logistic regression models were used to predict admission based on PRAM score at triage and then hourly thereafter. The area under the receiver operating characteristic curve (AUC) was calculated for each hour.

RESULTS

A total of 297 patients were included in the analysis, with an admission rate of 11.4% for patients receiving intensive therapy. The 3-hour PRAM (AUC = 0.85) significantly improved prediction of admission compared to PRAM at triage (p = 0.04).

CONCLUSIONS

The 3-hour PRAM scores best predicts the need for hospitalization. These results may be applied in clinical settings to facilitate the decision to admit or initiate more aggressive adjunctive therapy to decrease the need for hospitalization.

Utility of initial prehospital end-tidal carbon dioxide measurements to predict poor outcomes in adult asthmatic patients

STUDY OBJECTIVE

To determine if an initial (before treatment) prehospital end-tidal carbon dioxide (EtCO2) measurement in adult, non-chronic obstructive pulmonary disease (COPD), asthmatic patients predicts patient outcomes.

METHODS

This is a retrospective chart review of EtCO2 assessment data in a convenience sample of adult, asthmatic patients transported via advanced life support (ALS) units to a large, urban, academic hospital. Initial EtCO2 measurements were obtained routinely on all respiratory distress patients in the field, and emergency department physicians were unaware of the results. Data were analyzed using descriptive statistics, including percentages, means, and 95% confidence intervals (CI).

RESULTS

We reviewed data for prehospital initial EtCO2 measurements on 299 unique asthma patients (repeat visits by same patient were not included). Mean (SD) age was 43.1 years (12.5) and 142 (47.5%) were male. The mean EtCO2 measurement was 38.8 mmHg (SD ± 9.5; CI: 37.7-39.9; range: 14-82). Examination of initial EtCO2 measurements by deciles revealed that extreme values, in the lowest (14-28 mmHg) and highest (50-82 mmHg) deciles, experienced more markers of poor outcome than less extreme measurements. Patients were thus dichotomized by extreme (n = 59) or nonextreme (n = 240) EtCO2 measurements. More extreme patients were ultimately intubated (30.5 vs. 5.8%; p < 0.001; positive predictive value (ppv) = 30.5% ), and/or admitted to the intensive care unit (ICU) (28.8 vs. 6.7%; p <0.001; ppv = 28.8%), and/or died (5.1 vs. 0%; p = 0.007 [Fisher's exact test]; ppv = 5.1%), than nonextreme patients, respectively.

CONCLUSION

Extreme (both low and high) prehospital initial EtCO2 measurements may be associated with markers of poor patient outcomes. Future work will prospectively determine whether the addition of this information improves early recognition of severe asthma episodes beyond clinical assessment.

Prediction of unsuccessful treatment in patients with severe acute asthma

BACKGROUND

Clinical assessment can be used to identify which patients with acute asthma are at risk of unsuccessful initial treatment.

OBJECTIVE

To determine which elements of clinical assessment predict unsuccessful treatment, defined as needing critical care or any unplanned additional treatment.

METHODS

We analysed data from a large multicentre trial (the 3Mg trial). Adults with severe acute asthma underwent standardised clinical assessment, including peak expiratory flow rate (PEFR), up to 2 h after initiation of treatment. Standard care was provided other than blinded random allocation to trial treatment or placebo. Patients were followed up by record review up to 30 days. Unsuccessful treatment was defined as needing (1) critical care or (2) critical care or any unplanned additional treatment within 7 days of presentation. Logistic regression was used to identify predictors and derive a prediction model for each outcome.

RESULTS

Out of 1084 patients analysed, 81 (7%) received critical care and 157 (14%) received critical care or unplanned additional treatment. Baseline PEFR (p=0.017), baseline heart rate (p<0.001), other serious illness (p=0.019), PEFR change (p=0.015) and heart rate change (p<0.001) predicted need for critical care. Baseline PEFR (p=0.010), baseline heart rate (p<0.001), baseline respiratory rate (p=0.017), other serious illness (p=0.023), PEFR change (p=0.003) and heart rate change (p=0.001) predicted critical care or additional treatment. Models based on these characteristics had c-statistics of 0.77 and 0.69, respectively.

CONCLUSIONS

PEFR, heart rate and other serious illnesses are the best predictors of unsuccessful treatment, but models based on these variables provide modest predictive value.

Asthma vital signs at triage: home or admission (ASTHmA)

OBJECTIVES

Commonly used acute asthma scoring systems assess severity of symptoms, whereas other clinical models aim to predict hospitalization; all rely on a measure of response to treatment and use the same criteria across age ranges. This may not reflect a child's changing physiology and response to illness as he or she grows older.This study aimed to find age-specific objective predictors of hospitalization readily known at triage. The goal is to identify rapidly those who will likely need admission regardless of treatment administered or response to aggressive treatment in the emergency department (ED).

METHODS

Children between 1 and 18 years of age with a final primary ED International Classification of Diseases, Ninth Revision, diagnosis of asthma or asthma-related spectrum of disease were studied using data from the National Hospital Ambulatory Medical Care Survey. The primary outcome was hospital admission (observation unit, ward, monitored, or pediatric intensive care unit).Triage vital signs, mode of arrival, recent visits, emergency severity index score, as well as demographic and socioeconomic factors were incorporated into age-specific forward-selection multiple logistic regression models.

RESULTS

In 2,454,983 ED visits for asthma or reactive airway disease among children 1 to 18 years of age, patterns of vital sign predictors for admission varied by age group. Across all ages, diastolic hypotension at triage was an early, consistent, independent predictor of admission, especially in 1- to 3-year-olds (odds ratio, 6.27; 95% confidence interval, 6.01-6.54) and 3- to 6-year-olds (odds ratio, 17.95; 95% confidence interval, 16.80-19.17).

CONCLUSIONS

Age-specific assessment is important in the evaluation of acute asthma or reactive airway exacerbation. Diastolic hypotension may serve as an early warning indicator of severity of disease and need for hospitalization. Variability by age group in vital sign predictor for admission calls for further development or refinement of age-specific asthma assessment tools.

Focused assessment of patients with asthma in the emergency department

Asthma remains a common cause for presentation to the emergency department. Multiple clinical asthma scores (CAS) have been developed to assess the severity of an asthma exacerbation. The objective of this retrospective study was to determine if adoption of a CAS and asthma guidelines identifies patients with more severe asthma and to identify factors that predict the need for hospital admission. The results identified the admission rates in the pre- and post-CAS groups to be similar. Within the post-CAS group, patients requiring admission received more aggressive therapy and were frequently hypoxic on initial presentation. In conclusion, CAS aids in identifying severe asthma exacerbations. Lack of response to aggressive therapy or hypoxia on initial presentation should prompt the emergency department physician to arrange for admission.

Pitfalls in the evaluation of shortness of breath

This article illustrates the challenges practitioners face evaluating shortness of breath, a common emergency department complaint. Through a series of patient encounters, pitfalls in the evaluation of shortness of breath are reviewed and discussed.