Determinants of near fatality in acute severe asthma

Diagnosis and management of asthma in children

Asthma is the the most common chronic respiratory condition of childhood worldwide, with around 14% of children and young people affected. Despite the high prevalence, paediatric asthma outcomes are inadequate, and there are several avoidable deaths each year. Characteristic asthma features include wheeze, shortness of breath and cough, which are typically triggered by a number of possible stimuli. There are several diagnostic challenges, and as a result, both overdiagnosis and underdiagnosis of paediatric asthma remain problematic.Effective asthma management involves a holistic approach addressing both pharmacological and non-pharmacological management, as well as education and self-management aspects. Working in partnership with children and families is key in promoting good outcomes. Education on how to take treatment effectively, trigger avoidance, modifiable risk factors and actions to take during acute attacks via personalised asthma action plans is essential.This review aimed to provide an overview of good clinical practice in the diagnosis and management of paediatric asthma. We discuss the current diagnostic challenges and predictors of life-threatening attacks. Additionally, we outline the similarities and differences in global paediatric asthma guidelines and highlight potential future developments in care. It is hoped that this review will be useful for healthcare providers working in a range of child health settings.

Near-fatal asthma: a heterogeneous clinical entity

PURPOSE OF REVIEW

The aims of the present review were to describe the heterogeneous nature of near-fatal asthma (NFA) and to summarize the distinctive phenotypes identified in this subtype of asthma.

RECENT FINDINGS

Clinical, physiological, and histological studies have shown a large number of triggers, pathological mechanisms, and risk factors associated with NFA. Based on the demographic and clinical characteristics of the patients, the circumstances surrounding the asthma exacerbation and some distinctive features of the disease, several clinical profiles of asthma patients with NFA have been described. Recent data show new associations between some gene expression patterns and fatal asthma, as well as with some biological markers related to inflammatory or immunologic mechanisms in the airways. Also, the use of statistical methods, such as cluster analysis, allowed identifying and confirming different phenotypes of life-threatening asthma patients.

SUMMARY

NFA is a heterogeneous clinical entity, in which different patients' clinical profiles may coexist [e.g. rapid-onset NFA, NFA in patients with dyspnea hypoperception or sensitized to certain pneumoallergens (Alternaria alternata, soybean), NFA related to the menstrual cycle, brittle asthma]. Knowledge of these phenotypes as well as adequate and specific management strategies can reduce morbidity and mortality in patients suffering from NFA.

Assessing the risks and benefits of step-down asthma care: a case-based approach

Guidelines have called for pharmacologic stepped care to improve asthma treatment. Therapeutic options which have been approved provide physicians and their patients alternatives for stepping up asthma treatment to achieve control. However, few studies have been performed to identify and characterize procedures for optimal stepping-down treatment in patients with asthma. The resulting uncertainty as well as a lack of prioritization for asthma reassessment once control has been maintained has led to a lack of well-defined procedures for stepping down asthma treatment. However, recent studies provide guidance regarding the risks of stepping down asthma medications. This review uses case-based examples to demonstrate how health care providers may engage patients in discussions regarding guideline recommendations to promote individualized asthma care.

Use of mobile devices and the internet for multimedia informed consent delivery and data entry in a pediatric asthma trial: Study design and rationale

INTRODUCTION

Phase III/IV clinical trials are expensive and time consuming and often suffer from poor enrollment and retention rates. Pediatric trials are particularly difficult because scheduling around the parent, participant and potentially other sibling schedules can be burdensome. We are evaluating using the internet and mobile devices to conduct the consent process and study visits in a streamlined pediatric asthma trial. Our hypothesis is that these study processes will be non-inferior and will be less expensive compared to a traditional pediatric asthma trial.

MATERIALS/METHODS

Parents and participants, aged 12 through 17 years, complete the informed consent process by viewing a multi-media website containing a consent video and study material in the streamlined trial. Participants are provided an iPad with WiFi and EasyOne spirometer for use during FaceTime visits and online twice daily symptom reporting during an 8-week run-in followed by a 12-week study period. Outcomes are compared with participants completing a similarly designed traditional trial comparing the same treatments within the same pediatric health-system. After 8 weeks of open-label Advair 250/50 twice daily, participants in both trial types are randomized to Advair 250/50, Flovent 250, or Advair 100/50 given 1 inhalation twice daily. Study staff track time spent to determine study costs.

RESULTS

Participants have been enrolled in the streamlined and traditional trials and recruitment is ongoing.

CONCLUSIONS

This project will provide important information on both clinical and economic outcomes for a novel method of conducting clinical trials. The results will be broadly applicable to trials of other diseases.

The critically ill asthmatic--from ICU to discharge

Status asthmaticus (SA) is defined as an acute, severe asthma exacerbation that does not respond readily to initial intensive therapy, while near-fatal asthma (NFA) refers loosely to a status asthmaticus attack that progresses to respiratory failure. The in-hospital mortality rate for all asthmatics is between 1% to 5%, but for critically ill asthmatics that require intubation the mortality rate is between 10% to 25% primarily from anoxia and cardiopulmonary arrest. Timely evaluation and treatment in the clinic, emergency room, or ultimately the intensive care unit (ICU) can prevent the morbidity and mortality associated with respiratory failure. Fatal asthma occurs from cardiopulmonary arrest, cerebral anoxia, or a complication of treatments, e.g., barotraumas, and ventilator-associated pneumonia. Mortality is highest in African-Americans, Puerto Rican-Americans, Cuban-Americans, women, and persons aged ≥ 65 years. Critical care physicians or intensivists must be skilled in managing the critically ill asthmatics with respiratory failure and knowledgeable about the few but potentially serious complications associated with mechanical ventilation. Bronchodilator and anti-inflammatory medications remain the standard therapies for managing SA and NFA patients in the ICU. NFA patients on mechanical ventilation require modes that allow for prolonged expiratory time and reverse the dynamic hyperinflation associated with the attack. Several adjuncts to mechanical ventilation, including heliox, general anesthesia, and extra-corporeal carbon dioxide removal, can be used as life-saving measures in extreme cases. Coordination of discharge and follow-up care can safely reduce the length of hospital stay and prevent future attacks of status asthmaticus.

Pharmacologic approaches to life-threatening asthma

Following a peak in asthma mortality in the late 1980s and early 1990s, we have been fortunate to see a substantial decrease in asthma deaths in recent years. Although most asthma deaths occur outside the hospital, near-fatal events are commonplace, with anywhere from 2-20% of patients with acute asthma admitted to intensive care, and 2-4% intubated for respiratory failure. Standard therapies for acute severe and near-fatal asthma include administration of systemic corticosteroids, and frequent or continuous inhaled beta agonists. Controversy remains regarding the optimal therapy of those who fail to respond to these initial treatments, those who remain at risk of acute respiratory failure, and patients requiring mechanical ventilation. There remain significant gaps in our knowledge regarding relative benefits of intravenous versus oral corticosteroids, intermittent versus continuous beta agonists, and the role of various adjunctive treatments including intravenous magnesium, systemic beta agonists, aminophylline, and helium-oxygen mixtures. Using models and radiolabeled aerosols, there is a greater understanding regarding effective administration of inhaled beta-agonists in ventilated patients. There is limited available evidence for treatment of near-fatal asthma, a fact reflected by the significant variability in asthma critical care practice. Much of the data guiding treatment in this setting has been generalized from studies of acute asthma in the ED and from general populations of hospitalized patients with acute asthma. This review will focus on pharmacologic approaches to life-threatening asthma by reviewing current guideline recommendations, reviewing the scientific basis of the guidelines, and highlighting gaps in our knowledge in treatment of refractory acute or near-fatal asthma.

Acute severe asthma

Acute severe asthma remains a major economic and health burden. The natural history of acute decompensations is one of resolution and only about 0.4% of patients succumb overall. Mortality in medical intensive care units is higher but is less than 3% of hospital admissions. "Near-fatal" episodes may be more frequent, but precise figures are lacking. However, about 30% of medical intensive care unit admissions require intubation and mechanical ventilation with mortality of 8%. Morbidity and mortality increase with socioeconomic deprivation and ethnicity. Seventy to 80% of patients in emergency departments clear within 2 hours with standardized care. The relapse rate varies between 7 and 15%, depending on how aggressively the patient is treated. The airway obstruction in the 20-30% of people resistant to adrenergic agonists in the emergency department slowly reverses over 36-48 hours but requires intense treatment to do so. Current therapeutic options for this group consist of ipratropium and corticosteroids in combination with beta2 selective drugs. Even so, such regimens are not optimal and better approaches are needed. The long-term prognosis after a near-fatal episode is poor and mortality may approach 10%.

Prospective study of sudden-onset asthma exacerbations in children

OBJECTIVES

Sudden-onset asthma exacerbations among adults have more rapid treatment responses than do slower-onset exacerbations. We hypothesized that a similar pattern would be evident in children presenting to the emergency department (ED) with an asthma exacerbation.

METHODS

Prospective cohort study at 44 North American EDs. Parents of children, aged 2 to 17 years, underwent a structured interview in the ED and follow-up interview by telephone 2 weeks later.

RESULTS

Of 1184 enrolled children, 11% had sudden-onset asthma (ED presentation < or = 3 hours after symptom onset). Sudden-onset patients were older than slower-onset patients (8.9 vs. 7.7 years, respectively; P = 0.004) and more likely to be white (26% vs. 17%, P = 0.01). They were less likely to report a history of steroid use or asthma hospitalization and reported fewer ED asthma visits during the past year (all P < 0.05). Although initial pulmonary index scores were similar (4.0 vs. 4.3, P = 0.24), patients with sudden-onset asthma were less likely to receive steroid treatment (73% vs. 84%, P = 0.002), had shorter ED length of stay (128 minutes vs. 150 minutes, P = 0.01), and in unadjusted analyses, were less likely to be admitted (16% vs. 24%, P = 0.04).

CONCLUSIONS

Patients with sudden-onset exacerbations had similar acute asthma severity as those with slower-onset exacerbations but had shorter ED length of stay and were less likely to be admitted to the hospital, suggesting a more rapid response to treatment.

Review of guidelines and the literature in the treatment of acute bronchospasm in asthma

Asthma is a common chronic condition that disproportionately affects persons younger than 45 years. Asthma exacerbations can be sudden and severe, requiring treatment in the emergency department or hospitalization. Children younger than 15 years are 2-4 times more likely to have asthma as the first-listed hospital discharge diagnosis compared with those in other age groups. An estimated 12.8 million missed school days and 24.5 million lost work days due to asthma occurred in 2003. Drugs used in the treatment of acute asthma include inhaled beta(2)-agonists, oral corticosteroids, and inhaled anticholinergics. Levalbuterol was evaluated in several recent trials for treatment of asthma in the emergency department, for its effect in improving pulmonary function and on hospitalization rate. Theophylline, intravenous beta(2)-agonists, intravenous magnesium sulfate, and inhaled anesthetics have not been proven useful in the emergency management of asthma. The effectiveness of inhalation devices is dependent on age, cooperation of the patient, and technique.

Case-control study of severe life threatening asthma (SLTA) in a developing community

BACKGROUND

Distinct risk factors for asthma death have not been identified in developing communities. This study was conducted to distinguish risk factors for severe life threatening asthma (SLTA), a proxy for asthma death, in a developing country.

METHODS

A case-control study was performed at a University Hospital serving developing communities in the Western Cape Province, South Africa, over the period October 1997 to April 2000. Thirty consecutive patients with SLTA admitted to the intensive care unit (ICU) were compared with 60 chronic asthmatic patients, without a history of SLTA, who had attended the hospital outpatient respiratory clinic over the same period.

RESULTS

The risk of SLTA in comparison with controls increased with female sex (odds ratio (OR) 3.3, 95% CI 1.2 to 9.6, p = 0.02), rural residence (OR 8.1, 95% CI 2.6 to 25.3, p = 0.0005), and absence of a formal income (OR 5.7, 95% CI 2 to 16.6, p = 0.002). Cases were more likely to have had more than one hospital admission in the previous year (OR 8, 95% CI 2.5 to 25.2, p = 0.0009) and more than one emergency room visit in the previous year (OR 4.4, 95% CI 1.19 to 16.4, p = 0.04). Patients with SLTA were less likely to use inhaled corticosteroids (OR 5.6, 95% CI 1.9 to 16.5, p = 0.003) and more likely to use inhaled fenoterol (OR 6, 95% CI 2.2 to 16.2, p = 0.0004). Patients with SLTA also had lower mean (SE) forced expiratory volume in 1 second (FEV(1)) measurements (66.9 (9.5)% predicted v 82.5 (4.0)% predicted; p = 0.03) and lower FEV1/FVC ratios (60.7 (4.1)% predicted v 69.6 (1.9)% predicted; p = 0.05) documented before the episode of SLTA.

CONCLUSIONS

Risk factors for SLTA that are mainly analogous to those distinguished in other environments have been identified in a geographical area characterised by a third world socioeconomic context. Rural residence and poverty may increase the risk of SLTA.

Acute asthma in adults: a review

All patients with asthma are at risk of having exacerbations. Hospitalizations and emergency department (ED) visits account for a large proportion of the health-care cost burden of asthma, and avoidance or proper management of acute asthma (AA) episodes represent an area with the potential for large reductions in health-care costs. The severity of exacerbations may range from mild to life threatening, and mortality is most often associated with failure to appreciate the severity of the exacerbation, resulting in inadequate emergency treatment and delay in referring to hospital. This review describes the epidemiology, costs, pathophysiology, mortality, and management of adult AA in the ED and in the ICU.

The pulmonary physician in critical care . 12: Acute severe asthma in the intensive care unit

Most deaths from acute asthma occur outside hospital, but the at-risk patient may be recognised on the basis of prior ICU admission and asthma medication history. Patients who fail to improve significantly in the emergency department should be admitted to an HDU or ICU for observation, monitoring, and treatment. Hypoxia, dehydration, acidosis, and hypokalaemia render the severe acute asthmatic patient vulnerable to cardiac dysrrhythmia and cardiorespiratory arrest. Mechanical ventilation may be required for a small proportion of patients for whom it may be life saving. Aggressive bronchodilator (continuous nebulised beta agonist) and anti-inflammatory therapy must continue throughout the period of mechanical ventilation. Recognised complications of mechanical ventilation include hypotension, barotrauma, and nosocomial pneumonia. Low ventilator respiratory rates, long expiratory times, and small tidal volumes help to prevent hyperinflation. Volatile anaesthetic agents may produce bronchodilation in patients resistant to beta agonists. Fatalities in acute asthmatics admitted to HDU/ICU are rare.

Combined budesonide/formoterol turbuhaler treatment of asthma

OBJECTIVE

To provide product information; review and analyze the clinical literature studying combination therapy, budesonide, and formoterol in asthmatics; and to define the role for this therapy in asthma treatment.

DATA SOURCES

A MEDLINE search (1990-September 2001) was conducted to identify the primary literature. Bibliographies were reviewed for further relevant citations.

STUDY SELECTION/DATA EXTRACTION

All randomized, blinded, controlled studies at least 3 months in duration exploring the efficacy of the combination of budesonide and formoterol (in 1 or separate formulations) compared with other treatments were selected to be included in the review of clinical studies.

DATA SYNTHESIS

The combination of budesonide and formoterol was more effective than increasing the dose of budesonide in patients with moderate or severe persistent asthma and in patients with mild asthma not previously controlled with inhaled corticosteroids. Milder corticosteroid-naïve asthmatics did not derive benefit compared with inhaled corticosteroids alone.

CONCLUSIONS

Combination therapy in 1 device is a preferred treatment option in patients with moderate to severe persistent asthma and in those with milder asthma not controlled with inhaled corticosteroids. Advantages of this product include rapid onset of action, long duration of action, and a wide dosing range to assist with titration. Further research is required to evaluate this therapy in asthmatic children <5 years old and in patients with oral corticosteroid-dependent asthma. Investigations into the effect of this combination product on other disease outcomes, such as quality of life and productivity, will further define the role for this drug therapy.

The evaluation and management of acute, severe asthma

This article provides a systematic approach to the patient with acute, severe asthma. After a brief, focused evaluation prompt treatment with inhaled beta 2-agonists and systemic corticosteroids remains the cornerstone of treatment. Ipratropium bromide is now recognized as a useful addition for both adult and pediatric populations, whereas consideration of intravenous MgSO4 and theophylline is warranted for refractory patients. Ongoing evaluation of antileukotriene agents offers a possibility of these agents as alternative bronchodilators. Further research with a number of potential acute asthma agents will further expand treatment options for rapid symptomatic airway improvement and prevention of progressing airway obstruction, hospitalization, and potential respiratory failure.

Near-fatal asthma: a population-based study of risk factors

BACKGROUND

The study of near-fatal asthma (NFA) may provide a means to further our understanding of fatal asthma. Studies of NFA often are derived from a single ICU rather than from a defined population. We therefore aimed to identify factors distinguishing NFA patients (cases) from those persons treated in an emergency department (ED) [ED control subjects] and in the community (community control subjects [CCs]).

METHODS

This was a population-based case-control study conducted over 20 months of 45 NFA patients (age range, 5 to 50 years), 197 ED control subjects treated in an ED, and 303 CCs, all of whom were residents of Alberta.

RESULTS

The age distribution was similar between NFA patients and control subjects, with the majority being < 22 years of age (NFA patients, 68.9%; ED control subjects, 71.3%; CCs, 60.7%). Those patients with NFA were significantly more likely to have received a diagnosis before 5 years of age (66.6%), compared to ED control subjects (39.6%) and CCs (28.7%). The NFA group was significantly more likely to report moderate-to-severe disease and more frequent symptoms than the other groups. Therapy with bronchodilators was used most frequently by the NFA group compared to the ED control subjects and CCs (p < 0.001), as was therapy with inhaled steroids (p < 0.001) and oral steroids (p < 0.001). NFA patients had higher scores for vulnerability and were most likely to admit to stress as an asthma trigger. All groups had high exposure to cigarette smoke and pets.

CONCLUSION

NFA patients have many modifiable risk factors and many similarities to ED control subjects and CCs with asthma. General measures to improve asthma control and awareness of risks are required in all groups.

Inadequate asthma treatment practices and noncompliance in Israel

Childhood asthma morbidity and mortality are increasing despite improvements in asthma therapy. The changes over the past decade in the guidelines for treatment of children with severe asthma have led to a reduction in admissions and readmissions to the pediatric intensive care unit (PICU). The Israeli medical infrastructure is exemplary in its capability of extending appropriate medical services to its entire population. Our objective was to look at the background of preventive maintenance treatment and treatment during an acute episode in children admitted to PICUs with severe asthma, and to identify areas that could be targeted for change. A 5-year retrospective chart audit on acute asthma admissions was conducted in two PICUs of general community hospitals representative of the provision of medical care in Israel. The prehospitalization preventive management and acute treatment prior to PICU admission were evaluated, and the number of admissions and readmissions was recorded. The index admission was the first episode of acute asthma for only 3% of the children: 25% of patients required readmission, and 15% of these to the PICU. In spite of a proven history of acute exacerbations of the disease, only 60% were on continuous treatment between attacks, and 29% of them had abruptly discontinued treatment, most of them shortly before the onset of the index attack. Inhaled steroids were used as maintenance and preventive treatment by less than one-third of the children, with the other two-thirds receiving mainly beta-2 agonists drugs. In conclusion, an unacceptably large proportion of asthmatic children do not receive the recommended maintenance and preventive treatment because of poor compliance, lack of education, or insufficient healthcare provision. This has probably led to avoidable recurrences of acute asthma exacerbations and unnecessary use of PICU facilities. These findings suggest that steps for implementing recommended guidelines and an educational program are needed.

The Management of Acute Severe Asthma

Acute severe asthma exacerbations resulting in emergency department visits and hospitalization usually constitute a failure of long-term control therapy. However, even patients with relatively mild asthma can have severe life-threatening episodes. In both children and adults, viral respiratory infections are the major triggering event, although outbreaks of severe asthma have been associated with high concentrations of aeroallergens. Patients should be provided with written action plans on what to do for acute deterioration, and more severe patients may keep prednisone at home to begin after consultation with their physician. The primary therapy of acute asthma exacerbations remains frequent administration of aerosol β2-agonists and systemic corticosteroids for those patients not fully responding to the β2-agonists. Mild exacerbations may be treated with an increased dosage of inhaled corticosteroids. Patients at risk for acute exacerbations may benefit from peak flow measurement, particularly those who have difficulty perceiving airway obstruction. It is recommended that patients remain on full dose of prednisone until they achieve 70-80 percent of predicted normal or personal best peak flow. In the emergency department, the use of β2-agonists by metered-dose inhaler and holding chamber is as effective as nebulizer if given in a sufficient dose 6-10 puffs equivalent to 5 mg via nebulizer. In those patients not responding completely, the addition of ipratropium bromide has shown to produce additive bronchodilation and reduce hospitalizations. Other therapies such as magnesium sulfate, intravenous β2-agonists, heliox and ketamine have been used, but data demonstrating efficacy are insufficient to warrant recommending their general use.

Rapid-onset asthma attack: a prospective cohort study about characteristics and response to emergency department treatment

STUDY OBJECTIVES

(1) To determine the frequency of rapid-onset asthma attacks (ROAAs) and slow-onset asthma attacks (SOAAs) in adult patients with acute, severe disease (18 to 50 years old), who presented to an emergency department (ED); and (2) to establish whether ROAA patients differ from SOAA patients in terms of clinical and spirometric characteristics; and (3) in terms of the response of treatment.

SUBJECTS AND METHODS

Four hundred three patients (with peak expiratory flow [PEF] or FEV(1) of < 50% of predicted value) with acute exacerbations of asthma were enrolled in the trial using a prospective cohort study. Asthma attacks were classified as an ROAA (< 6 h of symptoms) or an SOAA (> or = 6 h). All patients were treated with albuterol, four puffs at 10-min intervals (100 microg per actuation), delivered by metered-dose inhaler with a spacer device during 3 h.

RESULTS

On the basis of previously determined criteria, 11.3% of patients were classified as having a ROAA. Male patients comprised 53.6% of the ROAA group (p = 0.03). In ROAA patients, the exacerbation was less likely to be attributed to respiratory tract infection (p = 0.001) and more likely to have no identifiable cause (p = 0.0001). Also, ROAA patients had lower pulmonary function (FEV(1)) at presentation (mean difference, - 0. 13; 95% confidence interval [CI], - 0.22 to - 0.04 L; p = 0.04) than SOAA patients. At the end of treatment, ROAA patients had an overall 48.0 L/min (95% CI, 14.1 to 81.8 L/min) greater improvement in PEF and a 0.31 L (95% CI, 0.08 to 0.54 L) greater improvement in FEV(1) than SOAA patients. Also, ROAA patients presented with less accessory muscle use (p < 0.05) and higher oxygen saturation (p = 0. 005). Finally, SOAA patients showed an increased incidence of hospital admission (relative risk, 3.89; 95% CI, 1.01 to 15.0).

CONCLUSIONS

Data from this study support the notion that ROAAs constitute a distinct but uncommon acute asthma ED presentation, with a predominance of male patients. Upper respiratory tract infection was not believed to be a significant trigger factor in these patients, and ROAA patients had rapid deterioration of their conditions followed by a more rapid response to treatment and a lower hospital admission rate than SOAA patients. Thus, we have identified a subgroup of patients who appear to have common characteristics with patients with sudden-onset near-fatal/fatal asthma.

Management of asthma exacerbations: home treatment

Asthma is a major cause of morbidity in children. Delays in care and inappropriate home management practices can contribute to morbidity and mortality. Guidelines for the diagnosis and management of asthma were developed in 1991 and revised in 1997 by The National Heart, Lung and Blood Institute. In this article we review the recommended pharmacological protocol for home treatment of asthma exacerbations, and then discuss in more detail behavioral components of asthma management, including monitoring of symptoms, seeking medical care, developing clinician-patient partnerships, and practical issues in equipment and medication usage. Discrepancies between guideline recommendations and current management practices are also discussed.

The pathobiology of acute asthma

Acute bronchial asthma is a common problem with immense medical and economic impacts. It is estimated that this disease affects 12 to 14 million people in the United States with costs in excess of $6 billion per year. Most of the morbidity and all of the mortality of asthma tends to be associated with acute exacerbations, and treatment of these events accounts for the majority of expenditures in money and health care resources. Unfortunately, the factors that contribute to the destabilization of asthma are rarely studied and much of the pathogenesis and pathobiology of acute asthma remains unknown. This article examines these issues and suggests treatment for acute asthma.

Risk factors for death from asthma. Prairie Provinces Asthma Study Group

BACKGROUND

Asthma mortality rates have increased in Canada and worldwide. Within Canada, the highest rates were seen in the prairie provinces.

OBJECTIVE

The objective was to determine risk factors for fatal asthma by comparing those who died of an acute exacerbation with those who attended an emergency department for treatment of asthma.

METHODS

The case-control study included all deaths from asthma among those aged 5 to 50 years in Alberta, Saskatchewan and Manitoba from November, 1992 through October, 1995 (cases). The 35 fatalities were matched to 209 controls by age, gender, time of the index event and residence.

RESULTS

Cases were more likely than controls to have had severe asthma, an unscheduled physician visit in the past year, a past hospitalization for asthma, and to have been intubated. Both groups reported frequent, regular asthma symptoms. Beta-agonist bronchodilator use was more common among cases, as was use in excess of prescribed amounts. Use of inhaled steroids did not differ between groups. Prior to the index event controls were more likely to report a cold or flu (OR = 0.27; 95% CI: 0.10 to 0.72) and that medications were "not working" (OR = 0.30; 95% CI: 0.12 to 0.71). Cases were more often sad and depressed (OR = 2.88; 95% CI: 1.03 to 8.05). Time between onset/recognition of symptoms and the event was significantly shorter for cases than controls.

CONCLUSIONS

Both groups tolerated high levels of regular symptoms, suggesting poor management. Opportunities for intervention existed for both groups near the time of the event. The short time between recognition of symptoms and death suggests patients at increased risk should monitor their condition closely and take action in response to predetermined criteria.

Management of the severe asthmatic

Asthma morbidity and mortality continue to increase. The clinical characteristics of the high risk asthmatic patient continue to be elucidated. These include historical features, current disease characteristics and psychosocial factors. Beta-Adrenergic agonists continue to be the mainstay of acute therapy. The following review details these topics.

Sudden-onset severe acute asthma: clinical features and response to therapy

OBJECTIVES

To characterize patients with sudden onset of severe acute asthma (SAA) and to examine whether this presentation is associated with rapid recovery.

METHODS

Retrospective cohort study of ED visits to a teaching hospital. Subjects were aged 18-64 years, with SAA (n = 225), defined as initial peak expiratory flow rate (PEFR) < or =40% of predicted. Visits for sudden-onset SAA (< or =3 hours of symptoms) were characterized and multivariate logistic regression was used to examine the association between sudden onset and rapid recovery.

RESULTS

Patient visits for sudden-onset SAA had different triggers as compared with those for the slower-onset group (p = 0.006). The sudden-onset patients were less likely to report an upper-respiratory-tract infection (17% vs 40%) and more likely to have an unidentifiable trigger (40% vs 19%). In the multivariate logistic regression model, sudden onset was a strong independent predictor of rapid response [odds ratio (OR) 4.3, 95% confidence interval (CI) 1.6-11.6]. Sudden-onset visits were less likely to lead to admission (23% vs 43%, p = 0.03).

CONCLUSIONS

These data suggest that different triggers may be involved in sudden-onset SAA and that sudden onset of symptoms is independently associated with rapid recovery. In their rapid deterioration and rapid response, these subjects share certain characteristics with "sudden asphyxic asthmatics" and may constitute a population suitable for further study of factors contributing to that condition. While these visits led to admission less frequently, prospective studies are necessary to provide information on duration of response and risk for relapse.

Rapid onset asthma: a severe but uncommon manifestation

BACKGROUND

Studies of asthma death and severe life threatening asthma (SLTA) include reports of patients who had rapid onset asthma. A study was undertaken to determine the relative frequency of rapid (< 6 hours duration) and slow (> or = 6 hours) onset attacks in patients admitted to hospital with acute severe asthma, and to establish whether those with rapid onset asthma differ in terms of risk factors for asthma morbidity and mortality such as indices of asthma severity/control, socioeconomic factors, health care, and psychological factors.

METHODS

A cross sectional study was performed on 316 patients aged 15-49 years admitted with acute severe asthma and interviewed within 24-48 hours of admission.

RESULTS

Patients underestimated the duration of the index attack. Only 27 (8.5%) were classified as rapid onset. There were more men in the rapid onset group than in the slow onset group (52% versus 26%), and there was evidence of socioeconomic advantage in the patients with rapid onset attacks. The rapid onset group had more previous episodes of SLTA and were more likely to present with SLTA, but there was no difference in length of stay in hospital. The rapid onset group were less likely to have presented to a GP during the index attack and were more likely to have used ambulance services. There was no difference between the groups in any psychological or health care measure.

CONCLUSIONS

Rapid onset attacks are an important but uncommon manifestation of asthma that are more likely to present with SLTA in patients who are more likely to have had previous SLTA. Male subjects are at increased risk of rapid onset attacks, and socioeconomic disadvantage, deficiencies in health care (ongoing and acute), and psychological factors are no more common in these patients than in those with attacks of slow onset. These data are consistent with the hypothesis that there is a small proportion of patients with rapid onset severe asthma who do not have the usual risk factors associated with asthma morbidity or mortality, and thus require different management strategies.

Medical and ventilatory management of status asthmaticus

Despite improved understanding of the basic mechanisms underlying asthma, morbidity and mortality remain high, especially in the "inner cities." The treatment of choice in status asthmaticus includes high doses of inhaled beta 2-agonists, systemic corticosteroids, and supplemental oxygen. The roles of theophylline and anticholinergics remain controversial, although in general these agents appear to add little to the bronchodilator effect of inhaled beta-agonists in most patients. Anti-leukotriene medications have not yet been evaluated in acute asthma. Other therapies, such as magnesium sulfate and heliox, have their advocates but are not recommended as part of routine care. If pharmacological therapy does not reverse severe airflow obstruction in the asthmatic attack, mechanical ventilation may be temporarily required. Based on our current understanding of ventilator-induced lung injury, optimal ventilation of asthmatic patients avoids excessive lung inflation by limiting minute ventilation and prolonging expiratory time, despite consequent hypercapnia. Unless respiratory function is extremely unstable, the use of paralytic agents is discouraged because of the increased risk of intensive care myopathy. Patients who have suffered respiratory failure due to asthma are at increased risk for subsequent death due to asthma (14% mortality at 3 years) and should receive very close medical follow-up. In general, severe asthmatic attacks can best be prevented by early intervention in the outpatient setting. In the words of Dr. Thomas Petty, "... the best treatment of status asthmaticus is to treat it three days before it occurs".

Determinants of management errors in acute severe asthma

BACKGROUND

It is hypothesised that, despite recent initiatives to improve asthma self-management including asthma education, detailed investigation of the sequence of events culminating in hospital admission will lead to the identification of important management errors and thus the likelihood that the majority of severe asthma attacks are preventable by currently available strategies, and that psychological, health care and socioeconomic factors are risk factors for such management errors.

METHODS

A cross sectional study was undertaken of 138 patients aged 15-50 years admitted to hospital (general ward or intensive care unit) with acute severe asthma who were assessed within 24-72 hours of admission using a number of previously validated instruments. A detailed history of events of the attack was assessed against predetermined criteria for non or delayed use of oral corticosteroids and non or delayed use of emergency ambulance services.

RESULTS

Subjects had evidence of severe chronic asthma and had acute severe asthma at presentation (n = 90, pH = 7.3 (0.2), PaCO2 = 7.2 (5.0) kPa) but duration of hospital stay was short (3.7 (2.6) days). Serious management errors occurred very frequently and most were deemed to have been made by the patient. Forward stepwise regression revealed that delayed or non-use of oral corticosteroids was predicted independently by lack of paying job (p = 0.02), high total use of inhaled beta agonists in the 24 hours before index admission (p = 0.04), loss of a job in the last year (p = 0.04), low frequency of use of oral corticosteroids in the last year (p = 0.06), concerns during the index attack about medical expenses (p = 0.07), and delay in the use of ambulance services (p = 0.05)--the model being responsible for 23% of the variance. Delayed or non-summoning of emergency ambulance services was predicted independently by total life events (p = 0.03), having something stolen in the last year (p = 0.003), panic during the index attack (p = 0.01), and concerns during the index attack about taking time off work (p = 0.07)--the model being responsible for 21% of the variance.

CONCLUSIONS

The results of this study show that, despite recent educational advances, serious management errors are common in those admitted to hospital with acute severe asthma and that most management errors relate to patient self-management behaviour. Serious management errors are predicted by a variety of socio-economic and psychological factors. While the results of this study are consistent with the widely held view that most acute severe attacks are theoretically preventable, the challenge for the future is to change patients' behaviour in the face of considerable adverse socioeconomic and psychological factors.

The acute asthmatic patient in the ED: to admit or discharge

Treating asthma in the emergency department (ED) always involves the potentially difficult decision as to whether to discharge the patient, to continue treatment, or to admit to the hospital. The following are useful guidelines. (1) The duration of the bronchospasm, frequency of visits, history of previous endotracheal intubation, pulse rate, and accessory muscle use are findings affecting successful discharge from the ED. (2) Patients with peak expiratory flow rate (PEFR) of < 20% and who do not respond to inhalant therapy, with PEFR values persisting at < 40% of predicted, will require 4 or more days to resolve and should be admitted to the hospital. (3) Patients with a PEFR between 40% and 70% of predicted after initial inhalant therapy may well be responsive to steroids in the ED, but an ED will adequately need to care for the patient for 5 to 12 hours while waiting for the onset of action of glucocorticoids. Discharged with glucocorticoids, this group has a 6% relapse rate within 10 days of the ED visit. (4) Patients with a PEFR of > or = 70% have a 14% relapse rate after discharge without glucocorticoids. Other reasons to consider admission are pneumonia, barotrauma, lability, prominent psychiatric difficulties, poor access to medications, poor educability, fear of steroids, patients on glucocorticoids or those who have recently stopped glucocorticoids, and evening discharges of patients from the ED, which all predispose to relapses of acute asthma. To decrease the relapse rate, provocative factors should be reviewed with the patient, as well as access to medication and use of spacers, inhaler techniques, PEFR meters, self-management plans, and referral to a defined appointment at 24 to 48 hours of the ED visit.

Nonprescription bronchodilator medication use in asthma

STUDY OBJECTIVE

Many persons with asthma self-medicate with widely available and potentially hazardous nonprescription medicines. This study assessed the demographic and clinical covariates of self-treatment with over-the-counter asthma medications (OTCs).

DESIGN AND SETTING

We conducted an analytical investigation using questionnaires and measures of lung function, comparing OTC and prescription medication users. We recruited adults with asthma by public advertisement.

SUBJECTS

We studied 22 exclusive prescription asthma medication users, 15 exclusive OTC users, and 13 other subjects who combined prescription medication use with self-treatment with asthma OTCs. All but one OTC user self-medicated with a nonselective, sympathomimetic metered-dose inhaler.

RESULTS

Taking income, access to care, and self-assessed disease severity into account, male gender was strongly associated with exclusive OTC use alone (odds ratio [OR]=8.9, 95% confidence interval [CI]= 1.3 to 61) and mixed OTC-prescription medication use (OR=9.7, 95% CI=1.1 to 83). The covariates of income, access to care, and self-assessed disease severity provided significant additional explanatory power to the model of exclusive OTC use (model chi2 difference 11.3, 5 df, p<0.05). Pulmonary function was similar among OTC and prescription medication users. However, prescription medication users' self-assessed asthma severity (mild compared to more severe) was associated with postbronchodilator reversibility of FEV1 obstruction (6% vs 18% reversibility, p<0.05) while exclusive OTC users' self-assessed severity showed the reverse pattern (19% vs 8%, p=0.2).

CONCLUSION

Asthma education programs attempting to discourage unregulated bronchodilator use should give consideration to this profile of the "asthmatic-at-risk."

Effect of age on bronchodilator response in acute severe asthma treatment

STUDY OBJECTIVES

This study was designed to evaluate the effects of age on bronchodilator response to salbutamol in patients with acute severe asthma in the emergency department.

SUBJECTS AND METHODS

Sixty-four sequential patients (mean age, 34.2+/-10.7 years) with acute asthma were enrolled in the trial. Using age as a major criterion, we divided the sample in two groups: the young one (age < or = 35 years, n=30) and the older (> 35 years, n=34). All patients were treated with salbutamol delivered with metered-dose inhaler into a spacer device, in a dose of four puffs every 10 min (100 microg per actuation) during 3 h.

RESULTS

Mean FEV1 improved significantly over baseline values for both groups (p=0.001). At final disposition, the mean percent of predicted FEV1 was 55.1+/-16.3% in the young group and 58.0+/-20.9% in the older group. There were no significant differences between both groups for FEV1 percent response at any point studied. A significant increase in heart rate over baseline was seen in the older group (p=0.001). Older patients also presented a higher incidence in nausea and tremor. Young and older patients with acute asthma achieved equivalent bronchodilation response to salbutamol.

CONCLUSIONS

We concluded that age is not a predictor of response to beta-agonists.

Asthma: better outcome at lower cost? The role of the expert in the care system

Asthma is a common disease for which morbidity and mortality have been increasing. This despite advances in the scientific understanding of asthma and in the pharmacologic armamentarium available to treat it. The dichotomy between knowledge and outcomes led us to review asthma from a systems perspective. We have presented data first to document failure in the current system of care and then to examine factors associated with improved outcomes. We found a disparity in outcome and costs when care given by experts was contrasted with care given by generalists. We conclude that "expert-based" care systems are superior from the perspective both of the patient and of the insurer; medical outcomes are better at lower overall cost. Managed care companies are in a unique position to identify asthmatics and to shift them from generalist to expert-based care when appropriate.

Near-fatal asthma in South Australia: descriptive features and medication use

BACKGROUND

Self-reported prior morbidity levels and medication use among survivors of a near-fatal asthma attack (NFA) were studied.

AIMS

To identify deficiencies in asthma management and opportunities for intervention.

METHODS

A hundred and twenty-seven consecutive patients aged 15 years or more presenting with a NFA to accident and emergency departments of teaching hospitals were interviewed.

RESULTS

High levels of morbidity due to asthma were reported. Most cases (79%) reported symptoms occurring at least weekly in the three months before their NFA. A mean of 20.8 days was reportedly lost from work, school or other usual daily activity in the 12 months before these events. Regular use of beta agonist as nebuliser solution was reported by 27% of cases, increasing to 34.5% in response to increased symptoms, while 41% reported use of nebulised beta agonist in response to the NFA event. Less than half of all cases (46%) reported using an inhaled corticosteroid on a regular basis. Oral corticosteroids were used by 33% of cases at times of increased symptoms in the preceding 12 months. However, only 7% of cases reported initiating or increasing oral corticosteroids at the time of the NFA.

CONCLUSIONS

Despite high levels of prior asthma morbidity, regular preventive inhaled corticosteroid use was not widespread in this series of NFA asthmatics. By comparison, over-reliance on regular beta agonist medication was common. Oral corticosteroids were rarely commenced in response to the NFA.

Death from asthma: rare but real

Asthma mortality has been increasing over the past 15 years. Since the incidence of fatal asthma is rare, death is perceived as an unexpected outcome. This paper reviews the nature of asthma, and the circumstances and characteristics of patients with fatal asthma attacks. In light of these features, the emergency care of acute asthma is discussed. Recommendations for improvement of prehospital and hospital care are made. Despite optimum therapy and management, death is sometimes unavoidable.

Acute asthma

The number of patients presenting to the emergency department with severe acute asthma exacerbations is increasing. Prompt and aggressive therapy often ameliorates the symptoms and decreases the morbidity and mortality associated with this disease. A directed history and physical examination should be performed, often simultaneously with treatment. The use of inhaled beta-adrenergic agents and the early use of corticosteroids will reverse most attacks. In addition, the use of anticholinergic agents may benefit selected patients. Despite aggressive treatment, some patients will require endotracheal intubation. Controlled intubation with proper sedation and paralysis will decrease the associated morbidity. Complications associated with mechanical ventilation may be prevented by decreasing the amount of auto-PEEP by controlled hypoventilation. Asthma, when incompletely or inadequately treated, can be a rapidly fatal disease process. Conservative approaches to patient admission based on strict objective pulmonary function testing should decrease morbidity and mortality.

Status asthmaticus complicated by atelectasis in a child

A case of an 11-year-old boy who was admitted for severe status asthmaticus complicated by extensive atelectasis is reported. Atelectasis involved all left lobes and the right upper lobe of the lung. Although the patient was refractory to maximal medical therapy and continued to deteriorate after intubation, he responded dramatically to the administration of isoflurane. Atelectasis was reduced immediately after fiberoptic bronchial lavage and the use of high frequency ventilation, with a marked improvement in blood gases. Isoflurane provided sedation during prolonged mechanical ventilation without significant adverse effects, aiding the care of this pediatric patient who ultimately recovered.

Risk factors for intubation of adult asthmatic patients

Our object was to describe demographic data from a population of adult asthmatics admitted to a regional tertiary medical center to identify risk factors for intubation. We performed a retrospective cohort study of all asthma admissions (International Classification of Diseases, Ninth Revision, Code 493.9) excluding cases with chronic obstructive pulmonary disease. This included all patients with asthma 20 years and above admitted to the University of California Davis Medical Center, Sacramento, from January 1, 1990 to June 30, 1993. A total of 375 asthma admissions were reviewed. There were 244 women (29 intubated) and 131 men (13 intubated) with a mean age of 40.7 (range 20-72) years. Of this group, 131 people were white, 140 black, 56 Hispanic, 42 Asian, and 6 American Indian. By National Heart, Lung, and Blood Institute Guidelines, there were 101 mild, 181 moderate, and 93 severe cases. Significant risk parameters identified for intubation were psychosocial problems [odds ratio (O.R.) 9.3; 95% confidence interval (C.I.) 6.8, 12.7], low socioeconomic group (O.R. 2.9; 95% C.I. 1.5, 5.8), little formal education (O.R. 5.4; 95% C.I. 2.8, 10.2), atopic allergy (O.R. 11.7; 95% C.I. 5.7, 23.7), duration of asthma > or = 15 years (O.R. 2.6; 95% C.I. 1.3, 5.3), previous intubation (O.R. 14.0; 95% C.I. 7.6, 25.6), upper respiratory infection (O.R. 4.0; 95% C.I. 2.2, 7.5), hospital admission for asthma within the last year (O.R. 5.3; 95% C.I. 2.7, 10.4), emergency room visit within the last year (O.R. 8.8; 95% C.I. 3.9, 20.1), and steroid dependency (O.R. 5.5; 95% C.I. 3.0, 10.2).(ABSTRACT TRUNCATED AT 250 WORDS)

[Severe acute asthma in adults]

Despite a better understanding of the physiopathology of asthma and the availability of potent drugs, severe acute asthma is still a frequent cause of death (1500 to 2000 patients die each year of asthma in France). Among the different clinical presentations, hyperacute attack with an attack duration (period from onset of attack to mechanical ventilation or to fatality) of less than 3 hours has to be individualized. The agents of choice in the treatment of acute life-threatening asthma are oxygen, beta-adrenergic sympathomimetic amines given intravenously or by nebulization, and corticosteroids. Theophylline is not any more the first choice of treatment but should not be rejected. Anticholinergics given by nebulization in combination with sympathomimetic agents are effective. Beside these treatment, hydratation and antibiotics are important adjunctive treatment. Mechanical ventilation is rarely necessary but has to be instituted either in emergency in case of near fatal asthma or electively because of deterioration of clinical status and blood gases, despite full medical treatment.