A 28-year-old man is brought to the emergency department for shortness of breath that has been progressively worsening for the last 12 hours. The patient started a new job working in a warehouse, and he thinks that the dust and heat triggered his symptoms. He has had two prior hospitalizations for asthma; during one, he required intubation. The patient uses a fluticasone inhaler daily and an albuterol rescue inhaler as needed and has not had an exacerbation in 2 years. Temperature is 37 C (98.6 F), blood pressure is 158/90 mm Hg, pulse is 105/min, and respirations are 24/min. Pulse oximetry is 91% on room air. On examination, the patient is in respiratory distress. He has prominent bilateral inspiratory and expiratory wheezing. Venous blood pCO₂ is 30 mm Hg. Which of the following is the greatest risk factor for severe and life-threatening asthma in this patient?

Question

A 28-year-old man is brought to the emergency department for shortness of breath that has been progressively worsening for the last 12 hours. The patient started a new job working in a warehouse, and he thinks that the dust and heat triggered his symptoms. He has had two prior hospitalizations for asthma; during one, he required intubation. The patient uses a fluticasone inhaler daily and an albuterol rescue inhaler as needed and has not had an exacerbation in >2 years. Temperature is 37 C (98.6 F), blood pressure is 158/90 mm Hg, pulse is 105/min, and respirations are 24/min. Pulse oximetry is 91% on room air. On examination, the patient is in respiratory distress. He has prominent bilateral inspiratory and expiratory wheezing. Venous blood pCO₂ is 30 mm Hg. Which of the following is the greatest risk factor for severe and life-threatening asthma in this patient?

Quizplus · Accepted Answer

11ec25c8_d1f0_aa21_bc81_9f140df18e4a_MD0003_00 This patient has an asthma exacerbation. Although most exacerbations can be managed with bronchodilators (eg, albuterol) with or without glucocorticoids, they can be fatal in some cases. A major risk factor for severe, life-threatening asthma is a previous asthma exacerbation requiring intubation and/or admission to the intensive care unit. Although intubation and mechanical ventilation for asthma are uncommon, most patients with a life-threatening attack have a history of a near-fatal exacerbation. Another major risk factor is poorly controlled asthma, including recently increased symptoms (eg, nighttime awakenings) or increased albuterol use. A recent hospitalization, frequent visits to the emergency department, and multiple courses of systemic glucocorticoids are also indicative of inadequate control. Signs of impending respiratory failure during an acute asthma exacerbation include trouble speaking due to shortness of breath and marked use of accessory muscles (eg, chest wall retractions), which can cause fatigue over time. Significant vital sign instability (pulse >120/min, respirations >30/min) and hypoxia (oxygen saturation <90%) are also worrisome findings (Choices C and F). In addition, peak expiratory flow is an objective measure of lung function, and measurements ≤50% of predicted are consistent with a severe exacerbation. (Choice A) Age >65 is a minor risk factor for life-threatening asthma. (Choice B) Both inspiratory and expiratory wheezing, as seen in this patient, are common during asthma exacerbations. In contrast, the absence of wheezing due to diminished air flow during an exacerbation is concerning for impending respiratory failure. (Choice D) Respiratory acidosis due to muscle fatigue that causes CO₂ retention and hypercapnia (typically PaCO₂ >45 mm Hg) is indicative of severe airway obstruction and can manifest as lethargy, confusion, and altered mental status. Although arterial blood gas (ABG) measurement is the gold standard, venous blood gases are sometimes performed in the emergency setting (eg, due to convenience); a low pCO₂ on venous blood gas (as in this patient) helps exclude hypercapnia. Decreased levels are likely due to increased respiratory drive and tachypnea. Educational objective: Major risk factors for severe, life-threatening asthma include a history of prior intubation and recent poor asthma control. Impending respiratory failure should be considered in patients with accessory muscle use, hypoxia, tachypnea, and hypercarbia. References: Identification of patterns of factors preceding severe or life-threatening asthma exacerbations in a nationwide study. (http://www.ncbi.nlm.nih.gov/pubmed/29197099)

A 28-Year-Old Man Is Brought to the Emergency Department for Shortness