Near Fatal Asthma or Status Asthmaticus

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Near-Fatal Asthma:
Asthma causes over 2 million emergency department visits and 5,000 to 6,000 deaths annually in the United States.
Severe asthma accounts for 2% to 20% of ICU admissions, with up to one-third requiring intubation.
Many fatalities occur in the prehospital setting, emphasizing the need for early intervention.

Near Fatal Asthma Attack
No universally agreed diagnostic criteria
Typically associated with the presence of hypercapnia, acidemia, altered state of consciousness and the development of cardiorespiratory arrest requiring endotracheal intubation and mechanical ventilation

Pathophysiology
Key abnormalities include bronchoconstriction, airway inflammation, and mucous impaction.
Complications such as tension pneumothorax, lobar atelectasis, and pulmonary edema can contribute to fatalities.
Cardiac causes of death are less common in these cases.

Clinical Aspects
Wheezing severity does not correlate with the degree of airway obstruction; absence of wheezing may indicate critical obstruction.
Oxygen saturation levels may not reflect progressive hypoventilation, especially if oxygen is administered.
Other conditions causing wheezing include pulmonary edema, COPD, and pneumonia.

Initial Stabilization
Simultaneous administration of oxygen, bronchodilators, and steroids is essential.
Monitor patients closely for deterioration despite initial treatment.
Consultation or transfer to a pulmonologist or intensivist is appropriate if no improvement occurs.

Primary Therapy - Oxygen and Beta-Agonists
Provide oxygen to maintain saturation above 92%, even in patients with normal oxygenation.
Albuterol (salbutamol) is effective for rapid bronchodilation; typical dose is 2.5 to 5 mg every 15-20 minutes.
Continuous nebulization of albuterol at 10 to 15 mg per hour may be more effective for severe cases.

Primary Therapy - Corticosteroids
Systemic corticosteroids address airway inflammation but take 6 to 12 hours to show effects.
Administer steroids early; IV route is preferred in near-fatal cases due to vomiting risk.
Typical adult dose of methylprednisolone is 125 mg (range: 40 to 250 mg).

Adjunctive Therapies - Anticholinergics
Ipratropium bromide improves lung function modestly when combined with albuterol.
Nebulizer dose is 0.5 mg, with peak effectiveness at 60 to 90 minutes.
Tiotropium is a newer, longer-acting anticholinergic under study for acute asthma.

Adjunctive Therapies - Magnesium Sulfate
Intravenous magnesium sulfate improves pulmonary function and reduces hospital admissions.
Typical adult dose is 1.2 to 2 grams given over 20 minutes.
Nebulized magnesium sulfate improves function but does not reduce hospitalization rates.

Adjunctive Therapies - Epinephrine and Terbutaline
Subcutaneous epinephrine dose is 0.01 mg/kg, divided into three doses of approximately 0.3 mg.
Terbutaline dose is 0.25 mg subcutaneously, repeatable in 30 to 60 minutes.
These agents are more commonly used in pediatric patients.

Assisted Ventilation - Noninvasive Positive-Pressure Ventilation
Noninvasive positive-pressure ventilation (NIPPV) supports patients with respiratory failure.
Requires an alert patient with adequate spontaneous respiratory effort.
Bi-level positive airway pressure (BiPAP) allows control of inspiratory and expiratory pressures.

Assisted Ventilation - Endotracheal Intubation
Intubation does not resolve small airway constriction and risks complications like breath stacking and barotrauma.
Use the largest endotracheal tube available (8 or 9 mm) to reduce resistance.
Confirm tube placement immediately and obtain a chest radiograph.

Troubleshooting After Intubation
Breath stacking (auto-PEEP) can cause hyperinflation, pneumothorax, and hypotension.
Use slower respiratory rate (6 to 10 breaths per minute) and smaller tidal volumes (6 to 8 mL/kg).
Sedation may be required to optimize ventilation and minimize barotrauma.

Cardiac Arrest in Asthmatic Patients
Inadequate evidence exists to recommend heliox during cardiac arrest.
Insufficient evidence supports chest wall compression to relieve gas trapping.
Follow ACLS guidelines while considering underlying asthma complications.

Summary
Closely monitor patients for deterioration or complications during treatment.
Patients requiring intubation need care from experienced providers in an ICU setting.
Transfer to tertiary centers should be considered for refractory cases.