Pulmonary Disease and Critical Care· Topic 16.1 Obstructive and inherited airway disease· 16.1.3

Status asthmaticus

Status asthmaticus is a severe asthma exacerbation refractory to standard acute-care bronchodilator and glucocorticoid therapy, with impending or actual respiratory failure. ICU-level escalation adds IV magnesium sulfate, continuous nebulized SABA, and parenteral terbutaline, reserving intubation and a permissive-hypercapnia ventilator strategy for patients who fail this bundle.

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What this article covers

  • Overview

    A severe asthma exacerbation refractory to standard acute-care therapy, with impending or actual respiratory failure: status asthmaticus is the escalated, ICU-level continuation of an exacerbation…

  • Epidemiology

    A minority but the most dangerous subset of acute exacerbations: most exacerbations resolve with standard acute-care treatment; status asthmaticus is the fraction that progresses despite it and…

  • Risk factors

    History of a near-fatal asthma attack or prior intubation, the single strongest predictor of a future life-threatening exacerbation.

  • Pathophysiology

    Severe bronchospasm, mucosal edema, and mucous plugging produce very high airway resistance, far beyond a routine exacerbation, so air cannot exit the lung before the next breath begins.

  • Clinical features

    Severe-exacerbation vital signs define the syndrome: inability to speak in full sentences, accessory-muscle use, respiratory rate above 30/min, heart rate above 120/min, and SpO2 below 90% on ambient…

  • Differential diagnosis

    Anaphylaxis: acute bronchospasm after an exposure, but with urticaria, angioedema, or hypotension, multisystem findings that uncomplicated status asthmaticus lacks; see anaphylaxis.

  • Diagnosis

    Status asthmaticus is a clinical diagnosis established by known or presumed asthma with severe-exacerbation vital signs (respiratory rate 30/min, heart rate 120/min, SpO2 <90% on room air, inability…

  • Management

    First, give oxygen to maintain SpO2 above 93% by nasal cannula or face mask, titrated up as needed; never withhold oxygen while other therapies are arranged.

  • Complications

    Respiratory arrest, the most immediately life-threatening outcome of untreated or inadequately escalated status asthmaticus.

  • Prognosis

    Prior near-fatal attack or intubation is the strongest predictor of a future fatal or near-fatal episode, and should trigger the most aggressive follow-up and lowest threshold for acute-care presentation.

  • Prevention

    Identify high-risk patients using the mortality risk-factor profile (near-fatal attack or intubation history, ED/hospital visit in the past 12 months, poor adherence or oral glucocorticoid use…

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