Death from bronchial asthma

Heliox for croup in children

BACKGROUND

Croup is an acute viral respiratory infection with upper airway mucosal inflammation that may cause respiratory distress. Most cases are mild. Moderate to severe croup may require treatment with corticosteroids (the benefits of which are often delayed) and nebulised epinephrine (adrenaline) (the benefits of which may be short-lived and which can cause dose-related adverse effects including tachycardia, arrhythmias, and hypertension). Rarely, croup results in respiratory failure necessitating emergency intubation and ventilation. A mixture of helium and oxygen (heliox) may prevent morbidity and mortality in ventilated neonates by reducing the viscosity of the inhaled air. It is currently used during emergency transport of children with severe croup. Anecdotal evidence suggests that it relieves respiratory distress. This review updates versions published in 2010, 2013, and 2018.

OBJECTIVES

To examine the effect of heliox compared to oxygen or other active interventions, placebo, or no treatment on relieving signs and symptoms in children with croup as determined by a croup score and rates of admission and intubation.

SEARCH METHODS

We searched CENTRAL, which includes the Cochrane Acute Respiratory Infections Group Specialised Register, MEDLINE, Embase, CINAHL, Web of Science, and LILACS, on 15 April 2021. We also searched the World Health Organization International Clinical Trials Registry Platform (apps.who.int/trialsearch/) and ClinicalTrials.gov (clinicaltrials.gov) on 15 April 2021. We contacted the British Oxygen Company, a leading supplier of heliox.

SELECTION CRITERIA

Randomised controlled trials (RCTs) and quasi-RCTs comparing the effect of heliox in comparison with placebo, no treatment, or any active intervention(s) in children with croup.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane. Data that could not be pooled for statistical analysis were reported descriptively.

MAIN RESULTS

We included 3 RCTs involving a total of 91 children aged between 6 months and 4 years. Study duration was from 7 to 16 months, and all studies were conducted in emergency departments. Two studies were conducted in the USA and one in Spain. Heliox was administered as a mixture of 70% heliox and 30% oxygen. Risk of bias was low in two studies and high in one study because of its open-label design. We did not identify any new trials for this 2021 update. One study of 15 children with mild croup compared heliox with 30% humidified oxygen administered for 20 minutes. There may be no difference in croup score changes between groups at 20 minutes (mean difference (MD) -0.83, 95% confidence interval (CI) -2.36 to 0.70) (Westley croup score, scale range 0 to 16). The mean croup score at 20 minutes postintervention may not differ between groups (MD -0.57, 95% CI -1.46 to 0.32). There may be no difference between groups in mean respiratory rate (MD 6.40, 95% CI -1.38 to 14.18) and mean heart rate (MD 14.50, 95% CI -8.49 to 37.49) at 20 minutes. The evidence for all outcomes in this comparison was of low certainty, downgraded for serious imprecision. All children were discharged, but information on hospitalisation, intubation, or re-presenting to emergency departments was not reported. In another study, 47 children with moderate croup received one dose of oral dexamethasone (0.3 mg/kg) with either heliox for 60 minutes or no treatment. Heliox may slightly improve Taussig croup scores (scale range 0 to 15) at 60 minutes postintervention (MD -1.10, 95% CI -1.96 to -0.24), but there may be no difference between groups at 120 minutes (MD -0.70, 95% CI -1.56 to 0.16). Children treated with heliox may have lower mean Taussig croup scores at 60 minutes (MD -1.11, 95% CI -2.05 to -0.17) but not at 120 minutes (MD -0.71, 95% CI -1.72 to 0.30). Children treated with heliox may have lower mean respiratory rates at 60 minutes (MD -4.94, 95% CI -9.66 to -0.22), but there may be no difference at 120 minutes (MD -3.17, 95% CI -7.83 to 1.49). There may be a difference in hospitalisation rates between groups (odds ratio 0.46, 95% CI 0.04 to 5.41). We assessed the evidence for all outcomes in this comparison as of low certainty, downgraded due to imprecision and high risk of bias related to an open-label design. Information on heart rate and intubation was not reported. In the third study, 29 children with moderate to severe croup all received continuous cool mist and intramuscular dexamethasone (0.6 mg/kg). They were then randomised to receive either heliox (given as a mixture of 70% helium and 30% oxygen) plus one to two doses of nebulised saline or 100% oxygen plus nebulised epinephrine (adrenaline), with gas therapy administered continuously for three hours. Heliox may slightly improve croup scores at 90 minutes postintervention, but may result in little or no difference overall using repeated-measures analysis. We assessed the evidence for all outcomes in this comparison as of low certainty, downgraded due to high risk of bias related to inadequate reporting. Information on hospitalisation or re-presenting to the emergency department was not reported. The included studies did not report on adverse events, intensive care admissions, or parental anxiety. We could not pool the available data because each comparison included data from only one study.

AUTHORS' CONCLUSIONS

Given the very limited available evidence, uncertainty remains regarding the effectiveness and safety of heliox. Heliox may not be more effective than 30% humidified oxygen for children with mild croup, but may be beneficial in the short term for children with moderate croup treated with dexamethasone. The effect of heliox may be similar to 100% oxygen given with one or two doses of adrenaline. Adverse events were not reported, and it is unclear if these were monitored in the included studies. Adequately powered RCTs comparing heliox with standard treatments are needed to further assess the role of heliox in the treatment of children with moderate to severe croup.

Acute severe asthma complicated with tension pneumothorax and hemopneumothorax

A 47-year-old patient presented to the emergency room with an attack of acute severe asthma. In spite of all primary measures, the patient was deteriorating. Arterial blood gases showed hypercarbia and acidemia. The patient was shifted to the intensive care unit connected to noninvasive ventilation for 3 h, without any obvious improvement. Decision was taken to intubate, ventilate, and keep her deeply sedated. On the 4^th day of ventilation, the patient developed sudden tension pneumothorax and she was near to arrest. Management for tension pneumothorax was immediate and successful. After that, chest X-ray and computerized tomography scan showed hemopneumothorax, for which a chest tube was inserted in both chest sides and blood transfusion was initiated immediately. After this incidence, the patient's parameters improved dramatically. Four days later, the patient was extubated and kept in intensive care unit till the chest tubes were removed and then shifted to the ward and discharged on day 15 from admission.

Heliox for croup in children

BACKGROUND

Croup is an acute viral respiratory infection with upper airway mucosal inflammation that may cause respiratory distress. Most cases are mild. Moderate to severe croup may require treatment with corticosteroids (from which benefits are often delayed) and nebulised epinephrine (adrenaline) (which may be short-lived and can cause dose-related adverse effects including tachycardia, arrhythmias, and hypertension). Rarely, croup results in respiratory failure necessitating emergency intubation and ventilation.A mixture of helium and oxygen (heliox) may prevent morbidity and mortality in ventilated neonates by reducing the viscosity of the inhaled air. It is currently used during emergency transport of children with severe croup. Anecdotal evidence suggests that it relieves respiratory distress.This review updates versions published in 2010 and 2013.

OBJECTIVES

To examine the effect of heliox compared to oxygen or other active interventions, placebo, or no treatment, on relieving signs and symptoms in children with croup as determined by a croup score and rates of admission and intubation.

SEARCH METHODS

We searched CENTRAL, which includes the Cochrane Acute Respiratory Infections Group's Specialised Register; MEDLINE; Embase; CINAHL; Web of Science; and LILACS in January and February 2018. We also searched the World Health Organization International Clinical Trials Registry Platform (apps.who.int/trialsearch/) and ClinicalTrials.gov (clinicaltrials.gov) on 8 February 2018. We contacted British Oxygen Company, a leading supplier of heliox (BOC Australia 2017).

SELECTION CRITERIA

Randomised controlled trials (RCTs) and quasi-RCTs comparing the effect of heliox in comparison with placebo or any active intervention(s) in children with croup.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane. We reported data that could not be pooled for statistical analysis descriptively.

MAIN RESULTS

We included 3 RCTs with 91 children aged between 6 months and 4 years. Study duration was from 7 to 16 months; all studies were conducted in emergency departments in the USA (two studies) and Spain. Heliox was administered as a mixture of 70% heliox and 30% oxygen. Risk of bias was low in two studies and high in one study due to an open-label design. We added no new trials for this update.One study of 15 children with mild croup compared heliox with 30% humidified oxygen administered for 20 minutes. There may be no difference in croup score changes between groups at 20 minutes (mean difference (MD) -0.83, 95% confidence interval (CI) -2.36 to 0.70). The mean croup score at 20 minutes postintervention may not differ between groups (MD -0.57, 95% CI -1.46 to 0.32). There may be no difference between groups in mean respiratory rate (MD 6.40, 95% CI -1.38 to 14.18) and mean heart rate (MD 14.50, 95% CI -8.49 to 37.49) at 20 minutes. The evidence for all outcomes in this comparison was of low quality, downgraded for serious imprecision. All children were discharged, but information on hospitalisation, intubation, or re-presenting to emergency departments was not reported.In another study, 47 children with moderate croup received one dose of oral dexamethasone (0.3 mg/kg) with either heliox for 60 minutes or no treatment. Heliox may slightly improve croup scores at 60 minutes postintervention (MD -1.10, 95% CI -1.96 to -0.24), but there may be no difference between groups at 120 minutes (MD -0.70, 95% CI -4.86 to 3.46). Children treated with heliox may have lower mean Taussig croup scores at 60 minutes (MD -1.11, 95% CI -2.05 to -0.17) but not at 120 minutes (MD -0.71, 95% CI -1.72 to 0.30). Children treated with heliox may have lower mean respiratory rates at 60 minutes (MD -4.94, 95% CI -9.66 to -0.22), but there may be no difference at 120 minutes (MD -3.17, 95% CI -7.83 to 1.49). There may be no difference in hospitalisation rates between groups (OR 0.46, 95% CI 0.04 to 5.41). We assessed the evidence for all outcomes in this comparison as of low quality, downgraded due to imprecision and high risk of bias related to open-label design. Information on heart rate and intubation was not reported.In the third study, 29 children with moderate to severe croup received intramuscular dexamethasone (0.6 mg/kg) and either heliox with one to two doses of nebulised saline, or 100% oxygen with one to two doses of adrenaline for three hours. Heliox may slightly improve croup scores at 90 minutes postintervention, but may have little or no difference overall using repeated measures analysis. We assessed the evidence for all outcomes in this comparison as of low quality, downgraded due to high risk of bias related to inadequate reporting. Information on hospitalisation or re-presenting to the emergency department was not reported.The included studies did not report on adverse events, intensive care admissions, or parental anxiety.We could not pool the available data because each comparison included data from only one study.

AUTHORS' CONCLUSIONS

Due to very limited evidence, uncertainty remains about the effectiveness and safety of heliox. Heliox may not be more effective than 30% humidified oxygen for children with mild croup, but may be beneficial in the short term for children with moderate to severe croup treated with dexamethasone. The effect may be similar to 100% oxygen given with one or two doses of adrenaline. Adverse events were not reported, and it is unclear if these were monitored in the included studies. Adequately powered RCTs comparing heliox with standard treatments are needed to further assess the role of heliox in the treatment of children with moderate to severe croup.

Heliox for croup in children

BACKGROUND

Croup is thought to be triggered by a viral infection and is characterised by respiratory distress due to upper airway inflammation and swelling of the subglottic mucosa in children. Mostly it is mild and transient and resolves with supportive care. In moderate to severe cases, treatment with corticosteroids and nebulised epinephrine (adrenaline) is required. Corticosteroids improve symptoms but it takes time for a full effect to be achieved. In the interim, the child is at risk of further deterioration. This may rarely result in respiratory failure necessitating emergency intubation and ventilation. Nebulised epinephrine may result in dose-related adverse effects including tachycardia, arrhythmias and hypertension and its benefit may be short-lived. Helium-oxygen (heliox) inhalation has shown therapeutic benefit in initial treatment of acute respiratory syncytial virus (RSV) bronchiolitis and may prevent morbidity and mortality in ventilated neonates. Heliox has been used during emergency transport of children with severe croup and anecdotal evidence suggests that heliox relieves respiratory distress.

OBJECTIVES

To examine the effect of heliox on relieving symptoms and signs of croup, as determined by a croup score (a tool for measuring the severity of croup).To examine the effect of croup on rates of admission or intubation (or both), through comparisons of heliox with placebo or any active intervention(s) in children with croup.

SEARCH METHODS

We searched CENTRAL 2013, Issue 10, MEDLINE (1950 to October week 5, 2013), EMBASE (1974 to November 2013), CINAHL (1982 to November 2013), Web of Science (1955 to November 2013) and LILACS (1982 to November 2013). In addition, we searched two clinical trials registries: the World Health Organization International Clinical Trials Registry Platform (WHO ICTRP) and clinicaltrials.gov (searched 12 November 2013).

SELECTION CRITERIA

Randomised controlled trials (RCTs) and quasi-RCTs comparing the effect of helium-oxygen mixtures with placebo or any active intervention(s) in children with croup.

DATA COLLECTION AND ANALYSIS

Two review authors independently identified and assessed citations for inclusion. A third review author resolved disagreements. We assessed included trials for allocation concealment, blinding of intervention, completeness of outcome data, selective outcome reporting and other potential sources of bias. We reported mean differences for continuous data and odds ratios for dichotomous data. We descriptively reported data not suitable for statistical analysis.

MAIN RESULTS

We included three RCTs with a total of 91 participants. One study compared heliox 70%/30% with 30% humidified oxygen administered for 20 minutes in children with mild croup and found no statistically significant differences in the overall change in croup scores between heliox and the comparator. In another study, children with moderate to severe croup were administered intramuscular dexamethasone 0.6 mg/kg and either heliox 70%/30% with one to two doses of nebulised saline, or 100% oxygen with one to two doses of nebulised racaemic epinephrine for three hours. In this study, the heliox group's croup scores improved significantly more at all time points from 90 minutes onwards. However, overall there were no significant differences in croup scores between the groups after four hours using repeated measures analysis. In a third study, children with moderate croup all received one dose of oral dexamethasone 0.3 mg/kg with heliox 70%/30% for 60 minutes in the intervention group and no treatment in the comparator. There was a statistically significant difference in croup scores at 60 minutes in favour of heliox but no significant difference after 120 minutes. It was not possible to pool outcomes because the included studies compared different interventions and reported different outcomes. No adverse events were reported.

AUTHORS' CONCLUSIONS

There is some evidence to suggest a short-term benefit of heliox inhalation in children with moderate to severe croup who have been administered oral or intramuscular dexamethasone. In one study, the benefit appeared to be similar to a combination of 100% oxygen with nebulised epinephrine. In another study there was a slight change in croup scores between heliox and controls, with unclear clinical significance. In another study in mild croup, the benefit of humidified heliox was equivalent to that of 30% humidified oxygen, suggesting that heliox is not indicated in this group of patients provided that 30% oxygen is available. Adequately powered RCTs comparing heliox with standard treatments are needed to further assess the role of heliox in children with moderate to severe croup.

Characteristics of allergic sensitization among asthmatic adults older than 55 years: results from the National Health and Nutrition Examination Survey, 2005-2006

BACKGROUND

Approximately 60% to 80% of children and young adults with asthma are sensitized to at least one allergen. In contrast, previous studies from specific subpopulations of older patients with asthma suggest that allergic sensitization is significantly lower in this age group. The prevalence and patterns of IgE-mediated sensitization have not been compared among a broad population of younger and older patients with asthma.

OBJECTIVE

To determine the prevalence and patterns of IgE-mediated sensitization among a broad population of younger and older patients with asthma.

METHODS

Data were obtained from the National Health and Nutrition Examination Survey (NHANES) 2005-2006 to compare IgE-mediated sensitization rates between younger (20-40 years) and older (≥55 years) patients with current asthma. Atopy was defined as a detectable serum IgE to at least 1 allergen in a panel of 19 allergens. The associations among sensitization, current asthma, and asthma control measures (health care use and symptoms) were examined by logistic regression.

RESULTS

In a group of 2,573 patients, either 20 to 40 years of age or 55 years or older, 108 (6.7%) and 43 (4.5%) patients with current asthma were identified, respectively. Allergic sensitization rates among the adults with asthma differed only moderately and not statistically significantly between the age groups; 75.4% of the younger and 65.2% of the older asthmatic patients were sensitized to at least 1 allergen. The association between sensitization and markers of asthma control did not appear to differ among the age groups.

CONCLUSION

Allergic sensitization in older patients with asthma may be more common than previously reported.

Depressive symptoms, low adherence, and poor asthma outcomes in the elderly

OBJECTIVE

To examine the impact of depressive symptoms on asthma outcomes and medication adherence in inner-city elderly patients with asthma.

METHODS

Cohort study of elderly asthmatics receiving primary care at three clinics in New York City and Chicago from 1 January 2010 to 1 January 2012. Depressive symptoms were ascertained with the Patient Health Questionnaire (PHQ-9). Outcomes included asthma control (Asthma Control Questionnaire, ACQ), asthma-related quality of life (Asthma Quality of Life Questionnaire, AQLQ), and acute resource utilization (inpatient and outpatient visits). Asthma medication adherence was evaluated using the Medication Adherence Reporting Scale (MARS).

RESULTS

Three hundred and seventeen participants ≥60 years were included in the study (83% women, 30% Hispanic, and 31% Black). In unadjusted analyses, participants with depressive symptoms were more likely to report poor asthma control (p < .001), worse AQLQ scores (p < .001), and higher rates of inpatient asthma-related visits (odds ratio [OR]: 2.03, 95% confidence interval [CI]: 1.04-3.99). Those with depressive symptoms also reported lower medication adherence (OR: 0.23, 95%CI: 0.10-0.54). Similar results were obtained in analyses adjusting for age, sex, race/ethnicity, income, asthma medication prescription, years with asthma, intubation history, comorbidities, and health literacy.

CONCLUSION

In this cohort of elderly inner-city participants, depressive symptoms were associated with poorer asthma control and quality of life, as well as with lower rates of adherence to controller medications. Future work exploring possible mediators, including adherence, might elucidate the relationship between depression and poorer asthma outcomes in this population.

The association between language proficiency and outcomes of elderly patients with asthma

BACKGROUND

Asthma is a growing cause of morbidity for elderly Americans and is highly prevalent among Hispanic people in the United States. The inability to speak English poses a barrier to patient-provider communication.

OBJECTIVE

To evaluate associations between limited English proficiency, asthma self-management, and outcomes in elderly Hispanic patients.

METHOD

Elderly patients with asthma receiving primary care at clinics in New York City and Chicago were studied.

RESULTS

Of 268 patients in the study, 68% were non-Hispanic, 18% English-proficient Hispanic, and 14% Hispanic with limited English proficiency. Unadjusted analyses showed that Hispanic persons with limited English proficiency had worse asthma control (P = .0007), increased likelihood of inpatient visits (P = .002), and poorer quality of life (P < .0001). We also found significant associations between limited English proficiency and poorer medication adherence (P = .006). Similar results were obtained in multiple regression analyses adjusting for demographics, asthma history, comorbidities, depression, and health literacy.

CONCLUSION

Limited English proficiency was associated with poorer self-management and worse outcomes among elderly patients with asthma. Further understanding of mechanisms underlying this relationship is necessary to develop interventions that improve asthma outcomes in this vulnerable population.

Heliox for croup in children

BACKGROUND

Croup, a common acute clinical syndrome in children up to the age of six, is thought to be triggered by a viral infection, and is characterised by a varying degree of respiratory distress due to upper airway inflammation and oedema of the subglottic mucosa. Corticosteroids, now part of the standard treatment for croup, improve symptoms but it takes time for their full effect to be achieved. Meanwhile, the child remains at risk of deterioration and developing respiratory failure necessitating emergency intubation and ventilation. Helium-oxygen (heliox) inhalation has been successful in the treatment of upper airway obstruction. Anecdotal evidence suggests that heliox relieves respiratory distress in children, but it remains unclear whether there is robust evidence to support the implementation of heliox for croup into clinical practice.

OBJECTIVES

To examine the effect of heliox on relieving symptoms and distress, determined by a croup score (a tool for measuring the severity of croup) or clinical assessment variables, through comparisons with placebo or active treatment(s) in children with croup.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2009, issue 2) which contains the Acute Respiratory Infections (ARI) Group's Specialised Register; MEDLINE (1950 to June week 3 2009); EMBASE (1974 to 2009 week 25) and CINAHL (1982 to June 2009).

SELECTION CRITERIA

Randomised controlled trials (RCTs) and quasi-RCTs comparing the effect of helium-oxygen mixtures with placebo or any active treatment in children with croup.

DATA COLLECTION AND ANALYSIS

Both authors independently identified and assessed citations for relevance. We assessed included trials for risk of bias using allocation concealment, blinding of intervention, completeness of outcome data, selective outcome reporting and other potential source of bias. We calculated mean differences for continuous data. We presented data not suitable for statistical analysis as descriptive data.

MAIN RESULTS

Two eligible RCTs were included (22 intervention, 22 controls). Neither trial compared heliox inhalation with placebo. One study compared heliox with 30% humidified oxygen whilst the other compared it to 100% oxygen with additional racaemic epinephrine nebulisation. There was no significant difference in change of croup score between intervention and control groups.

AUTHORS' CONCLUSIONS

At present there is a lack of evidence to establish the effect of heliox inhalation in the treatment of croup in children. A methodologically well-designed and adequately powered RCT is needed to assess whether there is a role for heliox therapy in the management of children with croup.

Complexities of diagnosis and treatment of allergic respiratory disease in the elderly

Atopic diseases such as rhinitis and asthma are relatively common in children and young adults. However, many patients aged >65 years are also affected by these disorders. Indeed, the literature suggests that between 3-12% and 4-13% of individuals in this age range have allergic rhinitis and asthma, respectively. However, these numbers are most likely underestimates because atopic diseases are frequently not considered in older patients. The diagnosis of both allergic rhinitis and asthma in older patients is more difficult than in younger patients because of a wide differential diagnosis of other diseases that can produce similar symptoms and must be excluded. Furthermore, treatment of these disorders is complicated by the potential for drug interactions, concern about the adverse effects of medications, in particular corticosteroids, and the lack of drug trials specifically targeting treatment of older patients with allergic rhinitis and asthma.

Outcome of patients with severe asthma in the intensive care unit

BACKGROUND

Because little has been reported about the outcome of severe asthma outside the US and western Europe, we performed a retrospective case analysis of patients treated in the medical intensive care unit (MICU) of a university hospital in Riyadh, Saudi Arabia, to determine the management, complications and outcome of severe asthma requiring ICU admission.

METHODS

The records of patients with severe asthma admitted to the MICU between the periods of January 1996 to December 2003 were reviewed. Sixty-one episodes from 54 patients were studied, of which 27 (44%) were male.

RESULTS

All patients were hypercapnic; 23 (38%) were ventilated. The Acute Physiological and Health Evaluation (APACHE) score II was significantly higher in the ventilated group (P<0.0001). The pH was significantly lower and PaCO2 was significantly higher in the ventilated group (P<0.0001). All patients survived. Only 42% of patients our series received inhaled corticosteroids before admission.

CONCLUSION

Our results suggest that severe asthma requiring ICU admission is now safely managed in ICUs. Our results are comparable to recently published data on the treatment of severe asthma in the ICU.

Halothane, an effective infrequently used drug, in the treatment of pediatric status asthmaticus: a case report

Asthma is the most common chronic disease of childhood. Despite a better understanding of the disease process and its management, status asthmaticus continues to be a life-threatening event. The use of volatile inhaled anesthetics is infrequently reported as adjunctive therapy to conventional treatment of this condition. We report the use of halothane in a mechanically ventilated pediatric patient with life-threatening status asthmaticus who was admitted to the pediatric intensive care unit (PICU) after failing to respond to standard medical therapy and noninvasive positive pressure ventilation. A 12-year-old African American male was seen in the emergency department and treated with intravenous corticosteroids, beta-agonist therapy. He deteriorated rapidly and required endotracheal intubation and mechanical ventilation. Two hours later, the patient developed an acute, severe respiratory acidosis (pH=6.97, PaCO2=171, PaO2=162, BE=1.7). Halothane was started at 2% by using the Siemens Servo 900C anesthesia ventilator. Improvement in both arterial blood gases and exhaled tidal volume were noted 30 minutes after initiation of the anesthetic gas. The patient remained on halothane for a total of 36 hours. No adverse effects associated with the use of halothane were noted. The patient was extubated to BiPAP 16/6, FiO2=0.30 at 68 hours and was discharged home 5 days later.

The impact of guidelines on long-term asthma care: a study of hospitalised patients in Malta

OBJECTIVE

To compare actual practice to that recommended in asthma guidelines, published in Malta in February 1998, with respect to the management of asthma. These were the first national clinical guidelines to be published locally.

METHOD

A piloted, structured interview was conducted with patients between 14-59 years who were hospitalised with an admission diagnosis of acute asthma. In the case of repeated admissions, only the first interview was considered. All interviews were carried out by either of two clinical pharmacists and lasted about 30 min. The four-year prospective study started in February 1997 (one year before publication of guidelines and aimed at collecting baseline data) and finished in January 2001 (three years after publication of the local guidelines).

MAIN OUTCOME MEASURES

Inhaled steroids on admission. Patient partnership: use of a written self-management plan and home peak flow monitoring. Patient compliance with inhaled steroids.

RESULTS

304 patients (68% females; mean population age 33.9 years SD +/- 13.41) were interviewed over the four-year period. The difference in proportions test (Z-test) was used to analyse the data comparing years 2, 3 and 4 with year 1. No statistical differences were found when comparing the groups for inhaled steroid treatment on admission or availability of a home peak flow meter. Similarly, no differences were found between groups when comparing compliance with inhaled steroids. A statistically significant increase in availability of a self-management plan was found over the study period (3% in year 1; 1% in year 2; 11% in year 3; 9% in year 4), but the overall use of such plans remains disappointingly low.

CONCLUSION

With the exception of an increased use of self-management plans, there appears to be lack of adherence to guidelines with consequent undertreatment of asthma, despite the fact that guidelines were published three years ago. This indicates a need to ensure better dissemination and implementation strategies to promote adherence. It is suggested that the clinical pharmacist is well-placed to promote adherence to guidelines.

Use of anti-asthmatic medications in elderly Taiwanese patients

The aim of this study was to assess the use of anti-asthmatic medications in Taiwanese geriatric asthmatic patients. We used computerized prescription databases from the National Health Insurance Program, Taiwan, and classified drugs according to the Anatomical Therapeutic Chemical Classification System to analyze the patterns and extent of medication use in people aged over 65 years, and the influence of physician specialty on the prescription of anti-asthmatics. A total of 708,624 prescriptions for 226,018 patients were analyzed. Oral medications were most often prescribed. Only 3.94% and 7.79% of patients were treated with inhaled corticosteroids and inhaled short-acting beta-agonists, respectively. Pulmonologists prescribed significantly more inhaled anti-asthmatics, except for cromolyn, than other types of physicians. More males than females were prescribed each category of anti-asthmatic medications, except for ketotifen. In conclusion, physicians in Taiwan do not prescribe as many inhaled anti-inflammatory agents for the treatment of asthma in the elderly as suggested in international treatment guidelines.

Trends in asthma mortality in Japan

Asthma mortality has been increasing in many developed countries in recent years, so we have described the epidemiological features of asthma in Japan. Data on all certified asthma deaths from 1950 to 1997 were obtained from The National Vital Statistics, published annually by the Ministry of Health and Welfare. Trends in crude and age-adjusted asthma mortality rates, as well as age-specific mortality rates, were analyzed. Age and birth cohort effects on mortality rates were also examined using multiplicative models. Between 1950 and 1980, crude asthma mortality rates steadily decreased in both sexes and began to level off thereafter. Age-adjusted mortality rates have also decreased since 1950, and showed a persistent downward trend in both sexes even in recent years. Asthma mortality rates were higher in males than in females during the entire study period. When analysis was restricted to those aged 5 to 34 years, an upward trend since 1980 was observed. The multiplicative model showed a rapidly decreasing cohort effect on mortality among those born after 1860. However, the slope increased in the cohorts born after 1950 in both sexes. The age effect increased linearly with advancing age after 50 years in both sexes. Overall asthma mortality rates have been decreasing during the past five decades in Japan, but the mortality rate has increased among the 5-34-year-old age group since 1980. The high fatality rate stemming from the overuse of beta 2-agonists may account for the mortality increase.

Gaps in asthma care of the oldest adults

OBJECTIVES

To assess the adequacy of asthma care reported by a group of older adults who were subsequently hospitalized for their asthma.

DESIGN

Prospective cohort study.

SETTING

Fifteen managed care organizations in the United States.

PARTICIPANTS

Adults with asthma, enrolled in managed care.

MEASUREMENTS

Patient survey of demographics, asthma symptoms, health status, comorbid conditions, asthma treatment, asthma knowledge, and asthma self-management at baseline and 1 year later.

RESULTS

Of 254 older adults, 38 (15.0%) reported being hospitalized for asthma at 1-year follow-up. Of these, 22.9% owned a peak flow meter (PFM). Of those with allergies, only about half (56.0%) had been told how to avoid allergens and had been referred for formal allergy testing. Adrenergic drug use was high in some patients. Nearly all (94.6%) used beta-agonist metered-dose inhalers (MDIs); 60.0% reported theophylline; 17.1% reported beta-agonist MDI overuse (>8 puffs per day); 10.5% reported beta-agonist MDI over-use and theophylline; and 13.2% reported both beta-agonist MDI over-use and oral beta-agonist use. Only 18.4% of respondents rated their overall asthma attack knowledge as excellent. Compared with nonhospitalized older adults, the hospitalized group reported care that was more consistent with guidelines, but also higher rates of potentially toxic combinations of adrenergic drugs. Compared with younger hospitalized adults, older hospitalized adults had clear deficiencies, including lower use of PFMs (55.3% vs 22.9%) and worse asthma self-management knowledge.

CONCLUSIONS

There are many opportunities to improve both the pharmacologic and non-pharmacologic care of older adults with asthma. Overuse of and potentially toxic combinations of inhaled and oral sympathomimetics should probably be avoided. Older asthmatics may also benefit from increased specialty referral, PFM use, allergy testing, and asthma teaching.

Perception of bronchoconstriction in elderly asthmatics

The impaired perception of bronchoconstriction in asthmatic patients may increase the risk of severe exacerbation. To characterize the perception of bronchoconstriction in elderly asthma patients, we compared the perception in older patients with that of younger patients. To determine the influence of perception of long-standing diseases, we further evaluated the perception in early-onset elderly asthma patients and in late-onset elderly asthma patients. The study group consisted of 80 stable asthmatic patients. The patients were grouped according to their age (group 1, < 60 years, n = 37, group 2, > or = 60 years, n = 43). Each group was separated into two subgroups according to the duration of symptoms (late-onset asthma 1A and 2A, < 5 years, early-onset asthma 1B and 2B, > or = 5 years). A histamine inhalation test was performed for each patient. Dyspnea was assessed by modified Borg scale. The Borg score in forced expiratory volume in 1 sec (FEV1) reduction by 20% was determined as perception score 20 (PS20). The mean perception scores of the elderly asthmatic patients were significantly lower than those of the younger asthmatic patients (group 1, PS20 = 2.35 +/- 0.17; group 2, PS20 = 1.37 +/- 0.12, p < 0.0001). The differences of mean perception score (PS20) between early- and late-onset subgroups were insignificant (IA, 2.63 +/- 0.30 and IB, 2.07 +/- 0.16, p = 0.101; 2A, 1.36 +/- 0.19 and 2B, 1.59 +/- 0.120, p = 0.91). The mean perception scores of male asthmatic patients were significantly lower than those of female patients (p = 0.03). There was a correlation between PS20 and % FEV1 in the younger group (r = 0.392, p = 0.02), but not in the elderly group (r = 139, p = 0.375). The correlation between PS20 and PD20 in both younger and elderly group was insignificant (p > 0.05). Elderly asthmatics perceive less intense respiratory distress for a decrease of 20% in FEV1 than do younger asthmatics. This underperception of bronchoconstriction may result in a delay in medical care during an acute asthmatic episode. Thus, we strongly recommend that elderly asthmatic patients should be followed up more frequently and closely.

Increased prevalence of asthma in Saudi Arabia

BACKGROUND

Bronchial asthma is among the most common chronic illnesses of childhood. A number of reports in the recent past suggest that the prevalence of asthma is increasing globally.

OBJECTIVE

To investigate the changing prevalence of asthma in the Kingdom of Saudi Arabia.

SUBJECTS AND METHODS

Two populations of schoolchildren between the ages of 8 and 16 years were studied using an internationally designed protocol in 1986 and 1995. The questionnaire used in these studies was very similar to the one used in the International Study of Allergy and Asthma in Childhood. A total of 2,123 school-children in 1986 (Jeddah and Riyadh) and 1,008 schoolchildren in 1995 (Hail and Gizan) were enrolled in the surveys. These cross-sectional studies of randomly selected schoolchildren were statistically analyzed using ANOVA and a Z test.

RESULTS

The comparison of data between Riyadh versus Hail (inland desert dry environment) and Jeddah versus Gizan (coastal humid environment) revealed that the prevalence of asthma in the similar populations increased significantly from 8% in 1986 to 23% in 1995 (P < .0001). Likewise, the prevalence of allergic rhinitis also increased from 20% to 25% (P < .003) since 1986. However, no significant change in the prevalence of eczema (from 12% to 13%) was noted between 1986 and 1995.

CONCLUSIONS

The study indicates that there was a significant increase in the prevalence of bronchial asthma and, to a lesser extent, in the prevalence of allergic rhinitis in the Kingdom of Saudi Arabia during this 9-year period. The study also revealed increased exposure to environmental factors such as tobacco smoke and indoor animals in Saudi houses. It seems that the continuing changes in contemporary life may well have contributed to the increased prevalence of asthma in the country.

Respiratory Disorders of the Elderly

Elderly are at increased risk for developing pulmonary disease over time. There has been an increase in the prevalence of and mortality from COPD and asthma in the industrialized world. In addition to the increase in these pulmonary diseases there are changes in the pulmonary function of the elderly due to structural changes with age, changes in gas exchange and changes in ventilatory response. This article reviews the epidemiology, diagnosis, prognosis, and therapy of asthma and briefly discusses the epidemiology and therapy of COPD with the emphasis on our elderly population.

Demographic characteristics of patients experiencing near-fatal and fatal asthma: results of a regional survey of 400 asthma specialists [see comment]

BACKGROUND

Case-control studies now describe a growing number of younger patients with varying levels of asthma severity who experience near-fatal or fatal asthma unexpectedly at home, en route to the hospital, or in public places.

OBJECTIVE

To collect case reports and analyze the demographic characteristics and patient profiles that may help identify predisposing factors which trigger near-fatal and fatal asthma episodes.

METHODS

In order to gather case reports and analyze the demographics and clinical characteristics of patients experiencing near-fatal and fatal asthma, a questionnaire on near-fatal and fatal asthma was distributed to 400 regional asthma specialists.

RESULTS

Forty physicians reported 25 cases of near-fatal asthma and 20 cases of fatal asthma. Twenty-five patients (13 males and 12 females) with a mean age of 29.4 years experienced near-fatal asthma. The time of onset of the near-fatal event was sudden (less than 3 hours) in 60% of cases and 76% of the episodes occurred at home or en route to the hospital. All 25 patients were using short acting inhaled beta agonists and 88% were reportedly using inhaled corticosteroids on a daily basis. Good to excellent compliance was noted in 60% of patients. Six patients were using a peak flow meter prior to their near-fatal attack. Predisposing psychosocial factors for life threatening asthma were noted in 44% of patients. Twenty patients, (4 males and 16 females) with a mean age of 21.7 years experienced fatal asthma. The time of onset of the fatal event was sudden (less than 3 hours) in 80% of cases and all but one patient died at home, en route to the hospital, or in a public place. All 20 patients were using short acting inhaled beta agonists, 80% were reportedly on daily inhaled corticosteroids and six patients were on oral corticosteroids. Good to excellent compliance was noted in 60% of patients. Only two patients were using a peak flow meter immediately prior to their fatal attack. Predisposing psychosocial factors for life threatening asthma were noted in 45% of decedent patients. Risk factors for fatal asthma included running in cold weather, over relying on home nebulizers, and a delay in seeking care on long holiday weekends.

CONCLUSIONS

While approximately 50% of the patients in this survey had moderate to severe asthma tainted by adverse psychosocial factors, nearly half of near-fatal and fatal attacks occurred suddenly and unexpectedly, outside the hospital in stable, younger, atopic, reportedly compliant patients utilizing inhaled corticosteroids on a daily basis. This regional survey supports the need for additional studies and the establishment of a national case registry to collect case reports and analyze the demographics and clinical characteristics of patients experiencing near-fatal and fatal asthma in order to further define the risk factors and develop preventative protocols for patients at risk for near-fatal or fatal asthma.

Hypnosis and asthma: a critical review

Asthma is among the most common chronic diseases of the western world and has significant effects on patients' health and quality of life. Asthma is typically treated with pharmaceutical products, but there is interest in finding nonpharmaceutical therapies for this condition. Hypnosis has been used clinically to treat a variety of disorders that are refractive to pharmaceutical-based therapies, including asthma, but relatively little attention has been given recently to the use of clinical hypnosis as a standard treatment for asthma. Significant data suggest that hypnosis may be an effective treatment for asthma, but it is premature to conclude that hypnosis is unequivocally effective. Studies conducted to date have consistently demonstrated an effect of hypnosis with asthma. More and larger randomized, controlled studies are needed. Existing data suggest that hypnosis efficacy is enhanced in subjects who are susceptible to the treatment modality, with experienced investigators, when administered over several sessions, and when reinforced by patient autohypnosis. Children in particular appear to respond well to hypnosis as a tool for improving asthma symptoms.

Evaluation of bone metabolism after the use of an inhaled glucocorticoid (flunisolide) in patients with moderate asthma

OBJECTIVE

We have investigated the effects of the inhaled corticosteroid flunisolide on bone metabolism and adrenal function in patients with moderate asthma.

SUBJECTS AND DESIGN

Twenty ambulatory patients (13 females, 7 males, mean age +/- SD of 36.4 +/- 12.4 years) with moderate asthma were recruited. None had taken corticosteroids for at least 1 month. Flunisolide 500 microg was given twice a day for 10 weeks, without any other medication. Blood and urine were collected before and at the end of treatment course. Cortisol (basal and 1 h after ACTH 250 microg i.v.) was measured to evaluate adrenal function. A peak cortisol response of 496 nmol/l was considered an adequate response. Serum ionized calcium, intact PTH, plasma osteocalcin (OC) and urinary pyridinoline (Pyr) and deoxy-pyridinoline (D-Pyr) were measured to evaluate bone metabolism. Wilcoxon paired test was performed for statistical analysis. Results are expressed as mean +/- SD.

RESULTS

In most patients (85%), there was no difference after treatment with flunisolide on basal and stimulated cortisol levels. We found a significant decrease of OC (3.55 +/- 1.42 to 2.97 +/- 1.05 nmol/l) and Pyr (66.4 +/- 20.0 to 59.5 +/- 24.9 pmol/micromol creatinine) levels after treatment (P < 0.05). We also observed a positive correlation between the variations seen in pre and post treatment values of OC and Pyr/D-Pyr.

CONCLUSIONS

The use of inhaled flunisolide 1000 microg/day for 10 weeks had no suppressive effect on adrenal function in the majority of asthmatic patients studied. However, the effects seen on bone and mineral metabolism, evidenced by the significant fall in osteocalcin and pyridinoline levels, may indicate a possible systemic effect of this drug. Clinical consequences of long-term treatment with flunisolide need to be further evaluated.

Heliox improves pulmonary mechanics in a pediatric porcine model of induced severe bronchospasm and independent lung mechanical ventilation

BACKGROUND: A helium-oxygen gas mixture (heliox) has low gas density and low turbulence and resistance through narrowed airways. The effects of heliox on pulmonary mechanics following severe methacholine-induced bronchospasm were investigated and compared to those of a nitrogen-oxygen gas mixture (nitrox) in an innovative pediatric porcine, independent lung, mechanical ventilation model. RESULTS: All of the lungs showed evidence of severe bronchospasm after methacholine challenge. Prospective definition of 'heliox response' was a 15% or greater improvement in lung function in the lung receiving heliox compared with the matched lung receiving nitrox. Seven out of 10 pigs responded to heliox therapy with respect to resistance and eight out of 10 pigs responded to heliox therapy with respect to compliance and tidal volume (P < 0.03). After crossover from nitrox to heliox, eight out of eight lungs significantly improved with respect to tidal volume, resistance and compliance (P < 0.001). After crossover from heliox to nitrox all eight lungs showed a significant increase in resistance and a significant decrease in tidal volume (P < 0.001). CONCLUSIONS: In a pediatric porcine model of acute, severe methacholine-induced bronchospasm and independent lung mechanical ventilation, administration of heliox improves pulmonary mechanics, gas flow, and ventilation. Administration of heliox should be considered for support of pediatric patients with acute, severe bronchospasm requiring mechanical ventilation through small artificial airways.

Severe acute asthma in a community hospital pediatric intensive care unit: a ten years' experience

BACKGROUND

The clinical literature on the incidence and subsequent mortality of asthma has come primarily from the experiences of large tertiary referral centers, particularly in Western Europe and North America. Consequently, very little has been published on the incidence, management, and outcome of asthma in smaller, community-based intensive care units.

OBJECTIVES

The purpose of this study was to explore the course and outcome of children with acute severe asthma treated within a community hospital PICU compared with those described in the literature from larger tertiary referral centers.

DESIGN

A retrospective analysis of 49 asthmatic children admitted to the Pediatric Intensive Care Unit (PICU) over a 10-year period was performed.

MEASUREMENTS AND RESULTS

The mean age was 5.2 years (range 2 months to 16 years), and the male:female ratio was 3:1. Duration of symptoms prior to admission to hospital was less than 24 hours in 60.4% of the patients. The majority of patients was not treated with either inhaled or oral steroids before admission. Drugs used in the PICU included nebulized beta2-agonists, theophylline, steroids, intravenous salbutamol, and intravenous isoproterenol. Although a pharmacologic approach was successful in the majority of patients, intubation and mechanical ventilation were necessary for progressive hypercapnea, exhaustion, and cardiorespiratory arrest in 11/49 of these patients. The average stay in the ICU for our patient group was 2.4 days. Intubated patients had a mean average stay of 3.5 days. Two patients had pneumothorax related to positive pressure ventilation, requiring chest tube insertion for drainage. There were no deaths among the 49 patients admitted to our PICU.

CONCLUSIONS

These data show that for acute severe asthma, outcome is comparable in a community PICU to a tertiary referral institution. We conclude that early ICU admission along with close monitoring is important in reducing morbidity and mortality in children with severe asthma.

Reductions in hospital use from self management training for chronic asthmatics

The purpose of this study was to assess the impact of asthma Self Management Training on the health status and resource use of patients with chronic asthma. The study consisted of a randomized control design of chronic asthmatic patients in a tertiary care center in India. The intervention group (153 patients) received four training sessions in addition to the regular care provided to the control group (150 patients). Health status and resource use were measured at baseline and over a one year follow-up period. The intervention group had significantly better health status (measured by breathing ability), fewer productive days lost, and lower resource use (hospitalizations and emergency room visits) than the control group. Total annual costs (direct and indirect) were also lower, though physician costs were not included in the assessment. Therefore, incorporation of asthma Self Management Training as part of clinical management of asthma can result in improvements in health status and reductions in hospital use.

The prevalence of allergic diseases in primary school children in Edirne, Turkey

BACKGROUND

Allergic diseases present a major health burden for children as shown by the rising morbidity and increased mortality from asthma. Information on the prevalences of allergic disorders and contributing factors as well will help to establish feasible measures to change this trend, and more efficient assignment of the limited health resources.

OBJECTIVE

To assess the prevalences of asthma and other allergic diseases and the contribution of various risk factors in primary school children in Edirne, Turkey.

METHODS

Children aged 7 to 12 in primary schools in the municipality and 24 villages of Edirne were surveyed via a questionnaire completed by the parents. The cumulative (lifetime) and current (last 12 months) prevalences of allergic diseases and the presence of passive smoking, atopic family history, animal contact and breast-feeding in infancy were determined.

RESULTS

A total of 5412 children (70.1% from the metropolitan and 29.9% from the rural area) were enrolled. The cumulative and current prevalences of all allergic diseases were 24.6% and 9.9% respectively. The cumulative (lifetime) prevalences of bronchial asthma, wheezing, allergic rhinitis and atopic dermatitis were 16.4%, 18.9%, 12.3% and 2.2%, and the current (last 12 months) prevalences were 5.6%, 5.8%, 4.5% and 0.9% respectively. Three-fourths of the children were exposed to tobacco smoke at home. Atopic heredity appeared the most prominent risk factor for any allergic disorder. Neither age, breast-feeding nor place of habitation affected the occurrence of allergic disorders. Animal contact was a significant risk factor for asthma and wheezing (adjusted odd ratios (OR) and 95% confidence intervals (CI) for current prevalences are 1.38 (CI = 1.04-1.83) and 1.35 (CI = 1.02-1.78) respectively), exposure to indoor tobacco smoke for wheezing (OR = 1.52, CI = 1.10-2.09), and male gender for asthma (OR = 1.50, CI = 1.16-1.93). Current prevalences for all allergic diseases were significantly lower than those previously reported in Ankara, Turkey.

CONCLUSIONS

Allergic diseases are a major health burden for primary school children in Edirne, Turkey. Although atopic heredity appears to be the foremost important risk factor, reduction of exposure to indoor tobacco smoke and animal contact, especially for those with atopic family history, are important preventive measures. The impact of environmental exposures on distinguishing prevalences of allergic diseases in Ankara and Edirne should be further investigated.

Deaths from asthma in Italy (1974-1988): is there a relationship with changing pharmacological approaches?

In this article we consider the relationship between asthma mortality rates, obtained from the Italian National Institute of Statistics (ISTAT), and the doses of all antiasthmatic drugs except systemic steroids sold in Italy in the years 1974-1988. The total asthma mortality rate showed three different trends: it decreased slowly until 1978 (period A); increased 10-fold from 1979 to 1985, rising from 0.30 to 4.17/100,000 (period B); and remained stable until 1988 (period C). More than half of the deaths in 1988 occurred in people 75 years of age or more. Men died more in the older age groups, while the mortality of women prevailed in the 35- to 54-year age group. In the 5- to 34-year age group the rate rose from 0.01 in 1978 to 0.21 /100,000 in 1986. Coding changes due to the 9th revision of the International Classification of Disease, adopted in Italy in 1979, probably increased the number of deaths being attributed to asthma in case of contemporary mention of bronchitis, a common diagnosis in older men, which showed the greatest increase in mortality. Increased prevalence and awareness of asthma may also have played a role. Although international comparisons strongly suggest undertreatment of asthma in Italy, the doses of anti-asthma drugs sold in Italy grew from 276 to 1,080 million from 1974 to 1985. During period B xanthine sales rose sevenfold and grew from 6.5 to 23.3% of the total doses, along with a twofold increase in beta 2-agonist and cromolyn sales. Period C was characterized by stable total doses (1155 million in 1988), with increases only in antiinflammatory and preventive drug sales. The increase in asthma deaths in Italy has been striking despite the contemporary rise in sales of all antiasthma drugs, particularly of beta 2-agonist metered aerosols and xanthine tablets. The increase in antiinflammatory and preventive drug sales may have contributed to the stabilization of asthma deaths during period C.

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.

Effect of a preprinted form on the management of acute asthma in an accident and emergency department

OBJECTIVE

To assess the effect of a preprinted form on the documentation of clinical data and compliance with the national guidelines for the management of asthma.

METHODS

Prospective audit six months before and after introduction of the form.

RESULTS

Use of the form improved the documentation of past asthma history (69% v 93%, P < 0.001), current treatment (81% v 95%, P < 0.01), predicted peak flow (23% v 75%, P < 0.001), per cent predicted peak flow (1% v 62%, P < 0.001), and respiratory rate (81% v 95%, P = 0.007). Compliance with the British recommendations for treatment improved with use of the form (50% v 89%, P < 0.001) The prescription of steroids on discharge did not improve significantly (26% v 44%, P > 0.05).

CONCLUSIONS

The preprinted form resulted in enhanced documentation of data and conformity with current guidelines for the management of asthma.

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.

Management of severe exacerbations of asthma

Asthma is a common disease that afflicts as many as 5% of Americans. Severe exacerbations of asthma can be life-threatening if not treated aggressively. Despite publication of therapeutic guidelines developed by experts in this field, the clinical management of severe exacerbations of asthma varies widely among institutions and practitioners. This article briefly reviews the pathophysiology of asthma and outlines a systematic, mechanistic approach to treating patients with severe asthma that integrates many clinical advancements made during the past 5 to 10 years.

Efficacy and safety of a rapid-sequence metaproterenol protocol in the treatment of acute adult asthma

A 6-month prospective study was performed to examine the efficacy and safety of a rapid-sequence nebulized metaproterenol regimen for the treatment of acute asthma in adults. Patients 18 years of age or older who were not pregnant and who had not received beta 2-agonist therapy were identified and started on a rapid-sequence metaproterenol regimen (15 mg) by the triage nurse. Pretreatment and posttreatment peak flow, respiratory rate, pulse rate, and blood pressure were documented. Patients also gave a pretreatment and posttreatment rating of the clinical severity of their attack using a 1-to-10 visual analogue scale. Fifty patients were entered into the study, with an average age of 38 years (range, 19 to 87 years). Data were analyzed using the Wilcoxon matched-pairs signed rank test. Patients showed statistically significant increases in peak flow (193 to 328 L/min, P < .00001) and systolic blood pressure (136 to 143 mm Hg, P < .0054). Statistically significant decreases were shown for respiratory rate (25 to 22 beats/min, P < .0001) and clinical severity (6.2 to 3.2, P < .00001). Thirty-three patients (71%) who completed the protocol experienced an increase in pulse rate. Ten (21%) had a pulse rate increase of more than 30 beats/min. Two (4.2%) had pulse rate increases of more than 40 beats/min. Four patients were removed after one or two nebulizers because of severe side effects. One patient's pulse rate increased to more than 200 beats/min. Although effective in reversing bronchospasm, the side effects of metaproterenol when used in rapid sequence are of major concern.

Is bronchial asthma a pancreatic disease?

Bronchial asthma and diabetes mellitus seldom occur in the same patient. The exact mechanism of this mutual exclusion is still unknown and its elucidation can make clear the physiopathology of both diseases. Clinical and experimental evidences suggest that insulin is a proinflammatory hormone and glucagon an antiinflammatory and a bronchodilator one. We hypothesize that the relationship between plasma insulin and glucagon may play an important role in bronchial asthma.

Acute, reversible left ventricular dysfunction in status asthmaticus

Three cases of rapidly reversible severe myocardial depression are described in patients with status asthmaticus. Initial echocardiograms obtained within 1 day of hospital admission revealed global left ventricular hypokinesis with ejection fractions of 11 to 34%. Follow-up echocardiograms obtained only 3 to 8 days later revealed marked improvement of left ventricular function. Possible mechanisms responsible for the observed rapidly reversible myocardial depression and the clinical implications of this finding are discussed.

Heliox therapy in acute severe asthma

STUDY OBJECTIVE

To assess how patients with respiratory acidosis from acute severe asthma respond to helium-oxygen (heliox) mixtures.

DESIGN

Consecutive case series.

SETTING

Urban community teaching hospital.

PATIENTS

Over a 2-year period, 12 asthmatics (mean age, 33.8 +/- 11.3 years) presented to the emergency department with acute respiratory acidosis (pH < 7.35 and PaCO2 > or = 45 mm Hg). All 12 patients were treated with heliox (60 to 70% helium/30 to 40% oxygen). Five patients received heliox through a ventilator and seven received heliox via face mask.

RESULTS

Arterial blood gases (ABGs) were drawn immediately before and at a mean of 49.2 +/- 25.2 min after beginning heliox therapy. No therapeutic interventions were made between ABGs. For the entire group, the mean PaCO2 decreased from 57.9 to 47.5 mm Hg (p < 0.005) and the arterial pH increased from 7.23 to 7.32 (p < 0.001). In an attempt to find characteristics that might predict the response to heliox, a clinically significant response to heliox was defined as a drop in PaCO2 (to normal or by > or = 15%) coupled with a rise in pH by > or = 0.05. Using this definition, there were eight responders (67%) and four nonresponders (33%). The responders had a shorter duration of symptoms (17.8 vs 78.0 h, p < 0.05) and a lower preheliox pH (7.20 vs 7.30, p < 0.05). All of the responders presented within 24 h of symptom onset. Three of the four nonresponders reported prolonged (> or = 96 h) duration of symptoms, and two eventually required intubation.

CONCLUSION

Heliox can rapidly improve ventilation in patients presenting to an emergency department with acute severe asthma with respiratory acidosis and a short duration of symptoms.

Respiratory mechanics in status asthmaticus. Effects of inhalational anesthesia

The incidence and severity of bronchial asthma has increased considerably in recent years. As a result, the number of patients requiring mechanical ventilation and more intensive medical therapy for treatment of refractory asthma has also increased. Despite this, available information concerning the quantitative changes in respiratory mechanics and the response to treatment that occur in such patients is limited. The present study describes the abnormalities in respiratory mechanics and the response to isoflurane anesthesia observed in three adults mechanically ventilated for treatment of status asthmaticus. Airway pressure, flow, and volume were measured during controlled mechanical ventilation in which the airway was periodically occluded in order to determine respiratory system mechanics. In two patients, the volume of hyperinflation and expiratory volume-flow relationship were also obtained. Inspiratory and expiratory indices of respiratory resistance were markedly abnormal. These abnormalities were associated with significant dynamic hyperinflation and high levels of intrinsic PEEP. Expiratory flow limitation was also identified in two patients by failure of low levels of applied positive end-expiratory pressure (PEEP) to alter the expiratory volume-flow relationship. Indices of respiratory resistance as well as the magnitude of dynamic hyperinflation and intrinsic PEEP improved considerably with isoflurane administration, after having been refractory to intensive conventional bronchodilator therapy. In summary, these results demonstrate the severity of abnormalities in respiratory mechanics present in ventilated patients with status asthmaticus and the potential therapeutic efficacy of inhalational anesthesia in this setting.

Mortality from airways disorders in Alberta, 1927-1987: an expanding epidemic of COPD, but asthma shows little change

Mortality from asthma has been reported to be increasing in recent years in many countries, including Canada. Alberta, and the prairie provinces generally, appear to have an excess of deaths from asthma compared to other provinces. We studied mortality from asthma and from chronic obstructive pulmonary disease (COPD) generally in Alberta between 1927 and 1987 using a data set compiled and recorded from Alberta Vital Statistics to describe birth cohorts' age-specific mortality rates. We also present the distribution of deaths in the years since 1987. There was a clear and sustained increase in mortality from COPD since 1950 after age 40 but no evidence to support the proposition that deaths from asthma were increasing in recent years; more recent data from Alberta Vital Statistics show no sustained increase since 1987, either. There was great variability from year to year and sporadically increased rates in a given year that were not sustained. These transient increases were observed particularly among females aged 10-14, 15-19, and 25-29 and among males aged 15-19, 25-29, and 80-84; however, there were also comparable decreases in asthma mortality of similar magnitude during the same time period in different age groups or in the other sex in the age group 10-14. We conclude that there is no excess of deaths from asthma over those expected by historical trends in Alberta at the present time but that the smoking-related epidemic of deaths from COPD continues unabated. The "smoothness" and consistency of the mortality trends suggest that physicians certifying deaths from these causes are using implicit diagnostic criteria that have not changed abruptly.

Assessment of an ambulatory care asthma program

In response to rising asthma morbidity and mortality, numerous comprehensive asthma programs have been developed. However, few studies have examined critically the effectiveness of such programs or the means by which treatment or outcome is altered. To assess the role of a specialized ambulatory asthma care program, we reviewed the interventions recommended to 344 patients referred for the assessment of asthma. A subset of 127 made return visits 6-12 months following their initial assessment, thereby allowing assessment of behavioral and physiological outcomes. At the initial consultation, the recommended medication changes were: inhaled beta-agonists +6% (p < 0.01), inhaled steroids +58% (p < 0.001), intranasal steroids +8% (p < 0.001), dry powdered formulations +13% (p < 0.01), theophylline -7% (p < 0.001). The percentage of patients using spacer devices increased 8% (p < 0.001). Comparing preassessment values to those at a visit at 6-12 months following assessment, a further 25% of patients taking inhaled steroids at the initial assessment had a change to either the dose, device, or frequency of administration. Mean FEV1 improved from 2.41 +/- 0.08 liters at the initial assessment to 2.64 +/- 0.09 liters at the 6-12-month visit (p < 0.001). There was an increase in the number of patients considered mild and not obstructed, with a corresponding decrease in the number considered moderately and severely obstructed (p < 0.05). The number of emergency room visits was reduced by more than 60% (p < 0.001) in patients followed for at least 6 months. We conclude that an ambulatory asthma program marked by increased use of inhaled anti-inflammatory medications and decreased use of theophylline can produce significant decreases in asthma exacerbations requiring hospital care, emergency room care, or systemic steroids while reducing the prevalence and severity of airflow limitation.

Ageing, late-onset asthma and the beta-adrenoceptor

Late-onset asthma in old age is a common clinical problem. There are similarities between receptor and post-receptor beta 2-adrenoceptor abnormalities reported in young asthmatics and in elderly normal subjects. Recent evidence lends some support to the idea of the 'aging' beta 2-adrenoceptor as a contributory factor in the development of late-onset asthma, although questions of the validity of the peripheral mononuclear cell model and of receptor tachyphylaxis to intrinsic and extrinsic beta-adrenoceptor agonists remain unresolved. Further work should focus on in vivo studies of airway receptor function and on beta 2-adrenoceptor-mediated pathways other than smooth muscle-related bronchoconstriction.