Acute severe asthma: oxygen and high dose beta agonist during transfer for all?

[Management of acute asthma]

INTRODUCTION

All patients with asthma are at risk of exacerbations. Mortality is often associated with failure to identify patients at risk and/or to appreciate the severity of acute episode, resulting in inadequate initial treatment, delay in referring to emergency care and inappropriate hospitalization rates, including delayed transfer to intensive care units. This review focuses on the management of acute severe and near fatal asthma.

STATE OF ART

Lung mechanics and cardiopulmonary interactions associated with airflow obstruction explain the physical presentation and severity criteria for exacerbations. The past and recent medical history, the initial evaluation of severity and the assessment of response to treatment direct the in-hospital management: emergency department visit, transfer to ward or intensive care unit. In any cases, the goals of therapy are summarized as oxygenation, repetitive inhalations of bronchodilators and early administration of systemic corticosteroids. Mechanical ventilation is required in a few patients with near fatal attacks resulting in asphyxia or progressive exhaustion despite maximal therapy. Controlled hypoventilation with permissive hypercapnia is the best strategy to avoid barotrauma. The role of adjunctive therapies, mainly halogenated agents and heliox, is discussed.

PERSPECTIVES AND CONCLUSION

During the last decade, asthma related mortality has decreased in France (<1000/year). The majority of deaths occur at home or during transport to the hospital but some deaths occur suddenly. Most deaths could be preventable if one adopts the approach that every exacerbation is potentially fatal. This practice should be more vigorously included in patient and general practitioner educational programs.

Prehospital EMS treatment of pediatric asthma and what happens before help arrives?

Many asthmatic children require assistance by emergency medical services (EMS) secondary to an acute asthma episode. What medication interventions are being utilized by EMS when responding to an asthma call for a child, and how does EMS management compare to home management given before ambulance arrival (pre EMS)? Sixty-one ambulance reports pertaining to acute asthma episodes in children aged 1 month to 15 years were collected and analyzed. There was no significant difference between likelihood to receive a beta 2-agonist nebulizer treatment pre-EMS arrival or by EMS. Oxygen was the most common EMS intervention.

Treatment of acute severe asthma with inhaled albuterol delivered via jet nebulizer, metered dose inhaler with spacer, or dry powder

Despite the increasing use of dry powder formulations in the ambulatory setting, there is a paucity of information on the efficacy of this therapeutic modality to treat acute severe asthma. In addition, studies that compared wet nebulization vs metered dose inhalers formulated with chlorofluorocarbon (CFCMDI) attached to holding chambers have yielded discrepant results. Thus, it is unclear which of the three delivery systems would elicit a superior bronchodilator response, particularly in patients with life-threatening asthma. In a prospective, randomized open design, we studied the response to inhaled albuterol (salbutamol) in 27 adult asthmatics presenting to the emergency department (ED) with an FEV1 <30% predicted. Subjects were treated with one of the following regimens (nine subjects in each group): group A, mean (SD) baseline FEV1 of 0.7 (0.2) L, received albuterol solution, 5 mg, via a nebulizer (Puritan-Bennett Raindrop; Lawrenceville, Ga) impelled with oxygen (O2) at 8 L/min; group B, baseline FEV1 of 0.6 (0.15) L, received albuterol, 400 microg, via a CFCMDI attached to a 145-mL valved aerosol holding chamber (Aerochamber; Trudell Medical; London, ON); and group C, baseline FEV1 of 0.6 (0.17) L, received albuterol powder, 400 microg, by another means (Rotahaler; Glaxo; Research Triangle Park, NC). All groups received the respective treatments on arrival in the ED, every 30 min during the first 2 h, and then hourly until the sixth hour. Clinical parameters and FEV1 were recorded on ED admission and 15 min after each dose of albuterol. At the time of ED admission, all patients also received continuous O2 and one dose of I.V. steroids (dexamethasone, 8 mg). The total dose of inhaled albuterol administered during the 6-h treatment was 45 mg of nebulized solution in group A and 3,600 microg of albuterol aerosol and dry powder in groups B and C, respectively. No significant differences were found in the population demographics, baseline FEV1, and arterial blood gas values on air. FEV1 improved significantly in all patients after the 6 h of treatment. The 6-h area under the curve FEV1 improved similarly with the three delivery methods despite differences in the total dose administered. No patient was discontinued during the trial or admitted to hospital and no evidence of cardiovascular adverse events was apparent in any of the study groups. These data support the view that the three delivery methods appear adequate to treat subjects with acute severe asthma.