Controversies in the Management of Acute Severe Asthma

Hadiarto Mangunnegoro

Dept of Respiratory Medicine

Faculty of Medicine University of Indonesia

Acute asthma or acute asthma exacerbation is a very common condition that can be found in emergency department (ED) in most hospitals world wide ranging from mild attacks to nearly fatal, even death can be occurred. In many countries, asthma mortality increased from the 1960s to the second half of the 1980s, due to better management of acute asthma in primary health care and hospitals, a recent downward trend was observed, overall asthma has a low mortality rate compared to other lung diseases. In Persahabatan Hospital only 2.0 % death occurred in hospital admitted patients.

However death still occur typically in patients with poorly controlled disease whose condition gradually deteriorates over a period of days or even weeks before the fatal attack. Infrequently, death occurs suddenly. Accordingly, most deaths are preventable, and a useful practice is to assume that every exacerbation is potentially fatal

The majority of deaths occur at home, work, or during transport to the hospital as also shown by data from Persahabatan Hospital in which 2.7% ( 6/2209) death on arrival occurred in ED.

There are two different pathogenic scenarios involved in the asthma attack progression, type 1 or slow-onset acute asthma and type 2 or asphyxic or hyperacute asthma. Type 1 characterized predominantly by airway inflammation ^.patients show a progressive (over many hours, days, or even weeks) clinical and functional deterioration prevalence of this type of asthma progression is between 80% and 90% of adults with acute asthma in ED. In the less common asthma progression scenario, bronchospasm is predominant and patients presenting with a sudden-onset asthma attack characterized by rapid development of airway obstruction (< 3 to 6 h after the onset of the attack).

Acute asthma is a medical emergency that must be diagnosed and treated urgently. The assessment of an asthma exacerbation constitutes a process with two different dimensions: (1) a static assessment to determine the severity of attack, and (2) a dynamic assessment to evaluate the response to treatment. Overall, it requires an analysis of several factors.

The severity of asthma exacerbations determines the treatment. The goals of treatment may be summarized as maintenance of adequate arterial oxygen saturation with supplemental oxygen, relieve airflow obstruction with repetitive administration of rapid-acting inhaled bronchodilators (β-agonists and anticholinergics), and reduce airway inflammation and to prevent future relapses with early administration of systemic corticosteroids. Controversies exist among different delivery on drug administration, combination therapy, inhaled versus oral or systemic drugs administration, including the benefit of i.v Mg.³

The patient should be hospitalized if, despite 2 to 3 hours of intensive treatment in the ED he or she still has significant wheezing, accessory muscle use, permanent requirement for oxygen to maintain SpO₂ ≥ 92%, and a persistent reduction in lung function (FEV₁ or PEF ≤ 40% of predicted), in much the same way that the presence of factors indicating high risk of asthma-related would lead to a decision to hospitalize the patient.

Patients with findings of severe airflow obstruction who improve minimally or deteriorate despite therapy should be admitted to an ICU. Clinical markers for this include respiratory distress, high pulse pressure or a falling pulsus in a patient with fatigue, or the patient’s subjective sense of impending respiratory failure. Other indications for ICU admission include respiratory arrest, altered mental status, SpO₂ < 90% despite supplemental oxygen, and a rising PaCO₂ coupled to clinical evidence of non resolution

Many patients admitted to the ICU with acute asthma simply require additional time for the therapies instituted in the ED to be continued and for respiratory function to improve. These patients often require a relatively brief period of time in the ICU; when improvement is clear, they can be discharged to the regular ward.

A few patients will require positive pressure ventilatory support because of progression to respiratory failure in advance of response to treatment or prior to treatment, and these challenging patients require specific ventilator strategies to be employed to optimize outcome.

Among patients sent home from the ED following acute asthma therapy, 17% will have a relapse and PEFR does not predict who will develop this outcome.The rate was slightly higher (21.7% ) in  Persahabatan Hospital .^2,4

Another study from Persahabatan Hospital demonstrated a significant advantage in overall maximal bronchodilator response when repeated high doses nebulized steroid or intravenous steroid combined with b₂ agonist in treatment of acute severe asthma⁵

References

1.        Rodrigo and Rodrigo. Acute Asthma in Adults. A review. Chest 2004;3:s

2.        Emerman CL et al. Prospective Multicenter Study of Relapse Following Treatment for Acute Asthma Among Adult Presenting to the Emergency Department. Chest. 1999; 115:919-927

3.        Fitzgerald M. Clinical Review Extracts from “Clinical Evidence” Acute Asthma”. BMJ 2001;323:841-845

4.        Husain B, Yunus Fet al. Relapse rate post asthma exacerbation treated with oral methyl prednisolon and other related factors. J Respir Indo 2004; 24:52-64

5.        Febrina S, Yunus F. The efficacy of nebulized versus systemic steroid in acute severe asthma. Paper presented at the Asia Pacific Society of Respirology. Kyoto Japan 2007