Pathophysiology
Asthma causes airflow obstruction through these four key mechanisms affecting the airways.
What are inflammation, airway edema, bronchospasm, and mucus plugging?
The single most important clinical indicator of impending respiratory failure in pediatric status asthmaticus.
What is a rising Co2?
Albuterol improves airflow during an asthma exacerbation by working through this mechanism.
What is β₂-agonism causing bronchodilation via smooth muscle relaxation?
These are your primary treatments for asthma
What is oxygen, fluids, beta agonist, steroids?
In the late, decompensating asthmatic, the blood gas will show this
What is hypocarbia that is now replaced by normocarbia or hypercarbia?
This physical exam finding — a drop in systolic blood pressure during inspiration — can indicate severe asthma.
What is pulsus paradoxus?
A pediatric asthma patient with a normal PaCO₂ on arrival is concerning because it often indicates this.
What is impending respiratory failure (they should be hypocarbic)?
Magnesium sulfate helps relieve severe asthma symptoms by blocking this ion’s entry into airway smooth muscle cells, preventing contraction.
What is inhibition of calcium influx?
These are side effects of a commonly used drug in - hyperglycemia, hypertension, agitation
What is steroids?
This therapy — sometimes used in the OR or PICU for severe, refractory status asthmaticus — provides bronchodilation through smooth muscle relaxation when other therapies fail.
What is inhaled anesthetic gas (e.g., isoflurane or sevoflurane)?
Hyperinflation in severe asthma leads to impaired venous return by increasing this parameter.
What is Intrathoracic pressure?
A patient on continuous albuterol may develop this electrolyte imbalance that increases risk of arrhythmia.
What is hypokalemia?
These two steroid options are most frequently used for severe asthma
What are methylprednisolone and dexamethasone?
Name 4 secondary agents used in the management of status asthmaticus
What is terbutaline, magnesium, ketamine, aminophylline?
This is the reason a fluid bolus is often given before intubating a child in severe asthma — positive-pressure ventilation can suddenly reduce this, leading to hypotension.
What is preload? (or to prevent post-intubation hypotension from loss of venous return)
This mechanism explains why a wheezing child who suddenly becomes “quiet” is an ominous sign.
What is critical airway narrowing causing minimal airflow (“silent chest”)?
These are four red flags that indicate severe, life-threatening asthma.
What are altered level of consciousness, inability to speak, absent breath sounds, and central cyanosis?
This medication used for its bronchodilatory and sedative properties in severe asthma can cause increased oral and airway secretions.
What is ketamine?
This medication used for severe asthma can increase heart rate, raise troponins, and has been associated with myocardial ischemia, especially at high infusion rates.
What is terbutaline?
A child with severe asthma who suddenly deteriorates and becomes hypotensive after intubation likely has this complication.
What is a tension pneumothorax or severe auto-PEEP causing obstructive shock?
In asthma, airway narrowing, mucus plugging, and uneven ventilation across lung regions lead to hypoxemia primarily because of this disturbance in the balance between airflow and blood flow.
What is V/Q mismatch?
This blood gas — pH 7.50, PaCO₂ 25, normal PaO₂ — is typical of an asthma patient who is still compensating well.
What is respiratory alkalosis from increased ventilation?
This second-line adjunct therapy can be used for its bronchodilatory and sedative effects during ventilated asthma.
What is ketamine infusion?
After a trial of high-flow nasal cannula, the patient remains hypoxic with increased work of breathing, and their CO₂ is beginning to normalize. This is the next step in escalation.
What is initiate BiPAP?
Refractory asthma with severe acidosis may require this advanced therapy
What is ECMO?