Bronchospasm: Causes, Signs, Treatment, and Key Concepts

Bronchospasm is a sudden or excessive narrowing of the bronchial airways caused by contraction of the smooth muscle that surrounds the bronchi and bronchioles. When this occurs, airflow becomes restricted, especially during exhalation.

The patient may develop wheezing, shortness of breath, chest tightness, coughing, air trapping, and increased work of breathing.

Bronchospasm is commonly associated with asthma and COPD, but it can also occur during aerosol therapy, sputum induction, suctioning, airway irritation, mechanical ventilation, allergic reactions, and certain procedures or medications.

What is Bronchospasm?

Bronchospasm refers to the contraction of the smooth muscle in the bronchial airways. These muscles normally help regulate airway diameter, but when they tighten excessively, the airway lumen becomes smaller. This narrowing increases airway resistance and makes it harder for air to move in and out of the lungs.

The terms bronchospasm and bronchoconstriction are closely related. Bronchoconstriction refers to the narrowing of the bronchial lumen, while bronchospasm specifically emphasizes the smooth muscle contraction that causes the narrowing. In clinical practice, the two terms are often used together because smooth muscle constriction is one of the main causes of reversible airway narrowing.

Bronchospasm may be mild and temporary, or it may become severe enough to interfere with ventilation and oxygenation. In some patients, it occurs as part of a chronic disease process. In others, it may be triggered suddenly by an irritant, medication, airway procedure, or allergic reaction.

Why Bronchospasm Matters

Bronchospasm is important because it can quickly increase the work of breathing. As the airway narrows, the patient must generate more pressure to move air through the lungs. This is especially problematic during exhalation because obstructed airways can trap gas in the lungs.

Even a small decrease in airway diameter can produce a major increase in resistance. This is explained by the relationship between airway radius and airflow resistance. When the airway radius becomes smaller, the pressure required to maintain airflow rises dramatically. This is why patients with bronchospasm may appear to struggle even when the airway narrowing seems modest.

Clinically, bronchospasm can lead to:

• Wheezing
• Coughing
• Chest tightness
• Shortness of breath
• Prolonged exhalation
• Air trapping
• Hyperinflation
• Increased peak airway pressure on the ventilator
• Auto-PEEP
• Increased work of breathing
• Poor ventilation in severe cases

Note: For respiratory therapists, bronchospasm is a high-priority finding because it often requires prompt assessment, treatment, and reassessment.

Common Causes of Bronchospasm

Bronchospasm can occur in several clinical situations. The most common causes are related to obstructive lung disease, airway irritation, allergic reactions, and exposure to triggering substances.

Asthma is one of the classic diseases associated with bronchospasm. During an asthma episode, the bronchial smooth muscle constricts, the airway lining becomes inflamed and swollen, and mucus production increases. These combined changes narrow the airways and make breathing more difficult.

COPD can also involve bronchospasm, especially during exacerbations. Although COPD is usually associated with persistent airflow limitation, many patients have some degree of reversible airway narrowing. This is why bronchodilator therapy is commonly used in COPD management.

Other causes and triggers include:

• Hypertonic saline
• Bland water aerosols
• Acetylcysteine
• Sputum induction
• Suctioning
• Smoke inhalation
• Allergic reactions
• Airway instrumentation
• Bronchoscopy
• Respiratory infections
• Exercise
• Cold air
• Strong odors or chemical irritants
• Certain medications
• Mechanical airway obstruction

Note:  may also occur as part of a broader airway reaction. For example, a patient exposed to an allergen may develop bronchospasm along with airway edema, increased secretions, mucus plugging, and wheezing.

Bronchospasm in Asthma

Asthma is one of the most important conditions associated with bronchospasm. In asthma, the airways are hyperresponsive, meaning they react strongly to certain triggers. These triggers may include allergens, exercise, cold air, respiratory infections, smoke, or irritants.

During an asthma attack, bronchial smooth muscle constricts. This narrows the airway and makes it harder for the patient to exhale. At the same time, airway inflammation and mucosal edema further reduce airway diameter. Thick secretions may also collect in the airway, creating mucus plugs and worsening obstruction.

The patient may experience coughing, wheezing, chest tightness, and shortness of breath. As obstruction worsens, exhalation becomes prolonged and incomplete. This can cause air trapping and hyperinflation, which further increases the work of breathing.

Severe asthma may progress to poor alveolar ventilation. Although the lungs may appear hyperinflated, this does not mean the patient is ventilating well. Instead, trapped gas prevents fresh air from entering effectively. As a result, oxygen levels may fall and carbon dioxide levels may rise.

Note: This is why bronchospasm in asthma must be treated quickly. Short-acting beta agonists such as albuterol and levalbuterol are commonly used for acute relief because they relax bronchial smooth muscle and improve airflow.

Bronchospasm in COPD

COPD includes chronic bronchitis and emphysema, both of which can increase airway resistance and impair airflow. Bronchospasm is not the only problem in COPD, but it can contribute to symptoms and worsening airflow limitation.

Patients with COPD may have persistent airway narrowing due to inflammation, mucus, airway collapse, and loss of elastic recoil. However, many patients also have a reversible component that improves after bronchodilator therapy. This is why bronchodilators are commonly recommended in COPD.

In an acute COPD exacerbation, bronchospasm may contribute to wheezing, dyspnea, prolonged exhalation, and air trapping. The patient may also retain secretions or develop worsening ventilation-perfusion mismatch. Respiratory therapists often help manage these patients with aerosolized bronchodilators, oxygen therapy, blood gas monitoring, noninvasive ventilation, or invasive mechanical ventilation when needed.

Note: For chronic stable COPD, long-acting bronchodilators may be used for maintenance therapy. These may include long-acting beta agonists or long-acting anticholinergic medications. However, during sudden bronchospasm, a fast-acting bronchodilator is usually preferred.

Signs and Symptoms of Bronchospasm

Bronchospasm often presents with a recognizable pattern, although symptoms can vary depending on severity and the underlying cause.

Common signs and symptoms include:

• Wheezing
• Shortness of breath
• Chest tightness
• Coughing
• Increased respiratory rate
• Prolonged expiratory phase
• Use of accessory muscles
• Diminished breath sounds in severe obstruction
• Anxiety or restlessness
• Increased work of breathing
• Difficulty speaking in full sentences

Wheezing is one of the most common findings, but it should not be interpreted in isolation. Wheezing may indicate bronchospasm, but it can also occur with airway edema, secretions, congestive heart failure, foreign-body aspiration, or partial airway obstruction.

A silent chest can be especially concerning. If a patient is in severe distress but wheezing becomes faint or absent, airflow may be extremely limited. This can indicate a life-threatening obstruction and requires immediate attention.

Assessment of Bronchospasm

Assessment begins with the patient’s history, clinical appearance, breath sounds, and response to therapy. The clinician should ask about known asthma, COPD, allergies, recent respiratory infections, medication use, exposure to irritants, and recent aerosol or airway procedures.

Auscultation may reveal wheezing, prolonged exhalation, or diminished breath sounds. The patient may report chest tightness, dyspnea, or difficulty getting air out. The therapist should also observe the breathing pattern, accessory muscle use, respiratory rate, oxygen saturation, and level of distress.

In pulmonary function testing, bronchospasm can be assessed by measuring airflow before and after bronchodilator therapy or after a bronchoprovocation stimulus. A decrease in FEV₁ after a challenge test suggests airway narrowing, while improvement after a bronchodilator suggests reversible obstruction.

Note: In the clinical setting, reassessment is just as important as initial assessment. After treatment, the therapist should evaluate whether breath sounds, symptoms, respiratory rate, work of breathing, oxygenation, and airflow have improved.

Bronchospasm and Bronchodilator Therapy

Bronchodilators are the primary medications used to reverse bronchospasm. They work by relaxing airway smooth muscle, improving airflow, and reducing airway resistance.

• Short-acting beta agonists are the preferred medications for acute bronchospasm. Common examples include albuterol and levalbuterol. These medications stimulate beta₂ receptors in bronchial smooth muscle, causing the airway muscles to relax. Because they have a rapid onset, they are commonly used as rescue medications.
• Long-acting beta agonists, such as salmeterol, formoterol, arformoterol, indacaterol, and olodaterol, are used more for maintenance therapy. They help maintain bronchodilation over time, especially in COPD or chronic airway disease. However, they are not the best choice for sudden acute bronchospasm.
• Anticholinergic bronchodilators also help reduce airway narrowing by blocking parasympathetic stimulation. Ipratropium is a short-acting anticholinergic, while tiotropium is a long-acting anticholinergic often used in COPD management.

Note: Acute bronchospasm usually requires a fast-acting rescue bronchodilator, while chronic stable airway narrowing may require maintenance bronchodilator therapy.

Medications That Are Not for Acute Relief

Not all respiratory medications are appropriate for acute bronchospasm. Some medications help prevent symptoms or control inflammation, but they do not provide rapid bronchodilation.

Examples include:

• Inhaled corticosteroids
• Leukotriene modifiers
• Cromolyn-like agents
• Monoclonal antibody therapy
• Other preventive asthma medications

These drugs may be useful in long-term asthma management, but they should not be selected as the primary treatment for sudden wheezing and severe shortness of breath. In an acute episode, the priority is to relieve bronchial smooth muscle constriction quickly.

Note: This distinction is important for clinical practice and board exams. A patient with acute bronchospasm needs a fast-onset bronchodilator, not a preventive medication that takes longer to work.

Bronchospasm as an Adverse Effect of Aerosol Therapy

Bronchospasm can occur during aerosol therapy, especially when the aerosol irritates the airway. Bland aerosol therapy is sometimes viewed as simple and low risk, but even sterile water aerosols may trigger bronchospasm in susceptible patients.

Hypotonic water solutions can irritate reactive airways. Distilled water delivered by ultrasonic nebulization may even be used in pulmonary function laboratories to provoke bronchospasm during bronchial hyperreactivity testing. This demonstrates that water aerosol can be a strong airway stimulus.

Hypertonic saline can also provoke bronchospasm. It is commonly used during sputum induction because it helps mobilize secretions for diagnostic sampling. However, because it is irritating to the airway, patients with asthma, COPD, or reactive airway disease should be monitored closely. Pretreatment with a short-acting bronchodilator may be needed.

Acetylcysteine is another aerosolized medication that can irritate the airway and cause bronchospasm. In patients at risk, a bronchodilator may be given before or with therapy to reduce this risk.

Note: If bronchospasm occurs during aerosol therapy, the treatment should be stopped, oxygen should be provided as needed, and bronchodilator therapy should be started when appropriate.

Bronchospasm During Sputum Induction

Sputum induction is a procedure used to help obtain lower respiratory secretions for diagnostic testing. It often involves inhalation of hypertonic saline, commonly in concentrations such as 3% to 10%.

Because hypertonic saline can irritate the airway, sputum induction may provoke bronchospasm. Patients with asthma, COPD, or other reactive airway conditions are at higher risk.

Before the procedure, the clinician should review the patient’s history and baseline status. A fast-acting bronchodilator may be given before the test. FEV₁ may be measured after bronchodilator therapy and used as a baseline during the procedure.

The procedure should be stopped if the patient develops significant respiratory distress, wheezing, dyspnea, chest tightness, or a major drop in FEV₁. A fall in FEV₁ of 20% or more from baseline is commonly used as a stopping point during certain bronchial challenge or induction procedures.

Note: This highlights an important principle: procedures that intentionally irritate the airway must include careful monitoring and a plan to reverse bronchospasm if it occurs.

Bronchospasm and Pulmonary Function Testing

Pulmonary function testing can help identify bronchospasm and airway hyperresponsiveness. This is especially useful when a patient has symptoms such as wheezing, cough, chest tightness, or shortness of breath, but baseline spirometry is normal or unclear.

Bronchodilator response testing evaluates whether airflow improves after a bronchodilator. If FEV₁ or peak flow improves significantly, this suggests reversible airway obstruction. This finding is often associated with asthma, but it may also occur in some patients with COPD.

Bronchoprovocation testing attempts to trigger airway narrowing under controlled conditions. Common methods include methacholine challenge, histamine challenge, mannitol challenge, exercise challenge, and eucapnic voluntary hyperventilation.

Methacholine and histamine are direct stimuli because they act directly on airway smooth muscle. Exercise, eucapnic voluntary hyperventilation, mannitol, and hypertonic saline are indirect stimuli because they provoke mediator release or airway changes that lead to narrowing.

FEV₁ is the most common measurement used to detect bronchospasm during these tests. A meaningful fall in FEV₁ after a challenge suggests airway hyperresponsiveness. After the test, bronchospasm should be reversed with an inhaled bronchodilator, and recovery should be documented.

Exercise-Induced Bronchospasm

Exercise-induced bronchospasm (EIB) refers to airway narrowing that occurs during or shortly after exercise. The term is preferred over exercise-induced asthma because asthma is a disease, while bronchospasm is a physiologic response.

EIB is related to heat and water loss from the airway during increased ventilation. As the patient breathes rapidly during exercise, the airway surface can cool and dry. In susceptible individuals, this can trigger mediator release and airway narrowing.

Patients may report coughing, wheezing, chest tightness, or shortness of breath during or after exercise. Symptoms often occur shortly after exercise rather than at the very beginning. Pulmonary function testing may show a decrease in FEV₁ after exercise.

Exercise challenge testing may be used when symptoms occur with exertion but resting spirometry is normal. Testing usually involves treadmill or cycle exercise followed by repeated spirometry measurements. A fall in FEV₁ after exercise supports the diagnosis.

Note: Treatment may involve pre-exercise bronchodilator therapy, trigger control, and long-term management when underlying asthma or airway hyperresponsiveness is present.

Bronchospasm in Mechanically Ventilated Patients

Bronchospasm is an important cause of increased airway resistance during mechanical ventilation. When the bronchial airways narrow, the ventilator must generate more pressure to deliver the same tidal volume.

A classic ventilator pattern is increased peak inspiratory pressure with unchanged plateau pressure. Peak inspiratory pressure reflects the pressure needed to overcome both airway resistance and lung or chest wall elastic forces. Plateau pressure is measured during an inspiratory pause when airflow has stopped, so it reflects static alveolar pressure and lung compliance.

When bronchospasm increases airway resistance, peak pressure rises because gas is harder to move through the narrowed airways. However, plateau pressure may remain unchanged because lung compliance has not necessarily worsened.

This pattern helps separate resistance problems from compliance problems. If both peak and plateau pressures increase, the problem is more likely reduced compliance, such as ARDS, atelectasis, pulmonary edema, or pneumothorax. If peak pressure rises while plateau pressure remains stable, the problem is more likely increased airway resistance, such as bronchospasm, secretions, mucus plugging, a kinked tube, biting the tube, or water in the circuit.

Bronchospasm, Air Trapping, and Auto-PEEP

Bronchospasm can cause air trapping because narrowed airways make exhalation slow and incomplete. If the next breath begins before the patient fully exhales, pressure remains in the lungs at the end of expiration. This trapped pressure is called auto-PEEP.

Auto-PEEP is common in severe asthma and COPD because these patients often have prolonged expiratory time constants. Bronchospasm, small airway collapse, secretions, mucus plugs, and reduced elastic recoil can all contribute.

On the ventilator, incomplete exhalation may be seen when the expiratory flow waveform does not return to baseline before the next breath begins. Clinically, the patient may show signs of increased work of breathing, difficulty triggering the ventilator, hypotension, or worsening hyperinflation.

Management depends on the cause. If bronchospasm is contributing, bronchodilator therapy is needed. Ventilator adjustments may also be required to allow more time for exhalation. This may include reducing respiratory rate, adjusting inspiratory time, reducing tidal volume when appropriate, or increasing expiratory time.

Capnography and Bronchospasm

Capnography can provide helpful information during bronchospasm. A classic finding is the “shark-fin” capnogram pattern. This waveform occurs because airflow obstruction causes slow, uneven emptying of alveolar gas during exhalation.

Instead of a normal rectangular waveform with a clear alveolar plateau, the capnogram develops a slanted upstroke and prolonged expiratory phase. This shape reflects delayed carbon dioxide emptying from obstructed airways.

As bronchodilator therapy improves airflow, the capnogram may begin to return toward a more normal shape. This makes capnography useful for monitoring the response to therapy, especially in severe asthma or ventilated patients with obstructive airway disease.

Note: Capnography should not be used alone. It should be interpreted along with breath sounds, work of breathing, oxygenation, ventilation, airway pressures, and the patient’s overall clinical status.

Bronchospasm During Airway Clearance and Suctioning

Airway clearance therapy and suctioning can sometimes trigger bronchospasm. Suctioning may irritate the airway, stimulate coughing, and provoke vagal or bronchial responses. Other possible complications include hypoxemia, bleeding, dysrhythmias, blood pressure changes, and increased intracranial pressure.

If bronchospasm occurs during suctioning or airway clearance therapy, the clinician should stop the procedure and assess the patient. Supplemental oxygen may be needed, and bronchodilator therapy may be appropriate. The patient should be monitored closely until the reaction improves.

Note: This is especially important in patients with asthma, COPD, reactive airways, or a history of bronchospasm during previous procedures. In some cases, bronchodilator pretreatment may be considered before airway-irritating therapies.

Bronchospasm in Pediatric Patients

In children, wheezing must be interpreted carefully. Although wheezing may suggest bronchospasm, it can also occur for other reasons. One important example is bronchiolitis.

In bronchiolitis, wheezing is often caused more by airway edema, inflammation, and mucus than by true bronchial smooth muscle constriction. Because of this, routine bronchodilator therapy is not always recommended. A trial of bronchodilator therapy may be considered in some cases, but it should continue only if there is objective improvement.

Foreign-body aspiration is another important cause of wheezing in children. If a child has sudden wheezing, asymmetric breath sounds, choking history, or persistent localized obstruction, the problem may not be bronchospasm. In that case, bronchoscopy may be needed to remove the foreign body.

Note: Wheezing in children should not automatically be treated as asthma or bronchospasm. The clinician must consider the patient’s age, history, onset of symptoms, breath sound pattern, and response to therapy.

Bronchospasm in Smoke Inhalation and Burn Injury

Smoke inhalation can irritate and injure the airway, leading to bronchospasm, airway edema, mucus production, and impaired gas exchange. Patients with smoke inhalation may also have elevated carboxyhemoglobin, hypoxemia, metabolic acidosis, and airway swelling.

Bronchospasm in this setting should be taken seriously because airway injury can worsen over time. Treatment may include oxygen therapy, aerosolized bronchodilators, airway clearance, and other therapies depending on the severity of inhalation injury.

Some treatment protocols may include bronchodilators, N-acetylcysteine, and heparin to help manage airway obstruction caused by secretions, fibrin casts, and inflammatory debris. The exact approach depends on the patient’s condition and institutional protocol.

Treatment Priorities for Bronchospasm

The treatment of bronchospasm depends on severity, cause, and clinical setting. However, several priorities are consistent.

• Identify and remove the trigger when possible. If bronchospasm begins during aerosol therapy, sputum induction, suctioning, or an airway procedure, the triggering therapy may need to be stopped.
• Assess oxygenation and ventilation. Supplemental oxygen should be provided when needed, especially if the patient is hypoxemic or in distress.
• Administer appropriate bronchodilator therapy. For acute bronchospasm, a short-acting beta agonist such as albuterol or levalbuterol is commonly used. Anticholinergic therapy may also be added, especially in COPD or severe obstructive episodes.
• Reassess the patient. Improvement should be seen in breath sounds, work of breathing, respiratory rate, symptoms, oxygenation, airflow, ventilator pressures, or capnography, depending on the situation.
• Escalate therapy when needed. Severe bronchospasm may require repeated or continuous aerosolized bronchodilator therapy, systemic corticosteroids, noninvasive ventilation, invasive mechanical ventilation, or emergency airway management.

Board Exam Takeaways

Bronchospasm is a common board exam topic because it connects assessment, pharmacology, pulmonary function testing, and mechanical ventilation.

High-yield points include:

• Acute bronchospasm is treated with a fast-acting bronchodilator
• Albuterol and levalbuterol are used for acute relief
• LABAs are not rescue drugs for acute bronchospasm
• Wheezing may suggest bronchospasm, but it is not always caused by bronchospasm
• Hypertonic saline and acetylcysteine can trigger bronchospasm
• Bronchodilator pretreatment may be needed before irritating aerosol therapy
• A drop in FEV₁ during bronchoprovocation testing suggests airway hyperresponsiveness
• Increased peak pressure with unchanged plateau pressure suggests increased airway resistance
• Bronchospasm can cause air trapping and auto-PEEP
• Capnography may show a shark-fin waveform during obstructive bronchospasm

Note: A useful exam mindset is to identify the cause of airway narrowing before choosing therapy. If bronchospasm is confirmed or strongly suspected, recommend a bronchodilator. If wheezing is due to edema, CHF, secretions, foreign-body aspiration, or bronchiolitis, the treatment may be different.

Bronchospasm Practice Questions

1. What is bronchospasm?
Bronchospasm is narrowing of the bronchial airways caused by contraction of bronchial smooth muscle.

2. What happens to airway resistance during bronchospasm?
Airway resistance increases because the bronchial airways become narrower.

3. Why does bronchospasm make breathing more difficult?
Bronchospasm makes breathing more difficult because narrowed airways restrict airflow, especially during exhalation.

4. What breath sound is commonly associated with bronchospasm?
Wheezing is commonly associated with bronchospasm.

5. What are common symptoms of bronchospasm?
Common symptoms include wheezing, shortness of breath, chest tightness, coughing, and increased work of breathing.

6. Why is bronchospasm important in respiratory care?
Bronchospasm is important because it can quickly worsen airflow obstruction and increase a patient’s work of breathing.

7. What type of medication is commonly used to treat acute bronchospasm?
A fast-acting bronchodilator, such as a short-acting beta agonist, is commonly used to treat acute bronchospasm.

8. Which medications are commonly used for acute bronchospasm?
Albuterol and levalbuterol are commonly used for acute bronchospasm.

9. Why are long-acting beta agonists not used as rescue drugs for acute bronchospasm?
Long-acting beta agonists are not used as rescue drugs because they are intended for maintenance therapy, not rapid relief.

10. What is the role of beta-agonist medications in bronchospasm?
Beta-agonist medications stimulate beta₂ receptors in airway smooth muscle, causing relaxation and bronchodilation.

11. What is the role of anticholinergic medications in bronchospasm?
Anticholinergic medications block parasympathetic effects that cause bronchial smooth muscle constriction.

12. Which anticholinergic medication is commonly associated with bronchodilation?
Ipratropium bromide is a common anticholinergic bronchodilator.

13. What disease is bronchospasm most classically associated with?
Bronchospasm is most classically associated with asthma.

14. How does asthma cause airflow obstruction?
Asthma causes airflow obstruction through bronchospasm, airway inflammation, mucosal edema, mucus production, and mucus plugging.

15. Why can bronchospasm cause air trapping?
Bronchospasm can cause air trapping because narrowed airways make exhalation slow and incomplete.

16. What is auto-PEEP?
Auto-PEEP is trapped pressure that remains in the lungs when the patient does not fully exhale before the next breath begins.

17. How can bronchospasm contribute to auto-PEEP?
Bronchospasm prolongs exhalation and can prevent complete emptying of the lungs, leading to trapped gas and auto-PEEP.

18. What ventilator pressure change is commonly seen with bronchospasm?
Bronchospasm commonly causes an increase in peak inspiratory pressure.

19. What happens to plateau pressure when bronchospasm is the main problem?
Plateau pressure often remains unchanged because bronchospasm primarily increases airway resistance rather than reducing lung compliance.

20. What does increased peak pressure with unchanged plateau pressure suggest?
It suggests increased airway resistance, which may be caused by bronchospasm, secretions, airway obstruction, or a kinked tube.

21. How does bronchospasm affect dynamic compliance?
Bronchospasm decreases dynamic compliance because it increases airflow resistance during breathing.

22. Why does bronchospasm not always decrease static compliance?
Static compliance reflects lung and chest wall elasticity, while bronchospasm mainly affects airway resistance.

23. What should be done if bronchospasm occurs during bland aerosol therapy?
The therapy should be stopped, oxygen should be provided if needed, and bronchodilator therapy should be started as appropriate.

24. Why can bland water aerosols trigger bronchospasm?
Bland water aerosols can irritate reactive airways and cause airway smooth muscle constriction.

25. Which type of saline is more likely to cause bronchospasm in reactive airway patients?
Hypertonic saline is more likely to cause bronchospasm because it is more irritating to the airway.

26. Why may isotonic saline be better tolerated than sterile water aerosol?
Isotonic saline may be better tolerated because it is less irritating to reactive airways than hypotonic water solutions.

27. What should be assessed before giving bland aerosol therapy to a patient at risk for bronchospasm?
The patient’s history, diagnosis, breath sounds, symptoms, and risk for reactive airway response should be assessed.

28. Which patients are more likely to develop bronchospasm from irritating aerosols?
Patients with asthma, COPD, or other reactive airway conditions are more likely to develop bronchospasm.

29. How often should patients receiving continuous bland aerosol therapy be reevaluated?
They should be reevaluated every 8 hours or whenever their clinical condition changes.

30. What is the primary hazard of aerosol drug therapy?
The primary hazard is an adverse reaction to the medication being administered.

31. What broader problem includes bronchospasm during aerosol drug therapy?
Bronchospasm is part of the broader problem of airway reactivity.

32. What should the therapist monitor during aerosol therapy to detect bronchospasm?
The therapist should monitor breath sounds, breathing pattern, appearance, work of breathing, and the patient’s subjective response.

33. When may continuous aerosolized bronchodilator therapy be needed?
Continuous aerosolized bronchodilator therapy may be needed when severe bronchospasm is not controlled by traditional dosing.

34. Why is bronchospasm considered reversible in many asthma patients?
It is considered reversible because bronchodilator therapy can relax airway smooth muscle and improve airflow.

35. What does bronchodilator response testing help determine?
Bronchodilator response testing helps determine whether airway obstruction is reversible.

36. What pulmonary function measurement is commonly used to detect bronchospasm?
FEV₁ is commonly used to detect bronchospasm.

37. What does a significant increase in FEV₁ after bronchodilator therapy suggest?
It suggests reversible airway obstruction and a positive response to bronchodilator therapy.

38. What is bronchoprovocation testing used to identify?
Bronchoprovocation testing is used to identify airway hyperresponsiveness.

39. When is a methacholine challenge test commonly indicated?
It is commonly indicated when a patient has symptoms suggestive of asthma or hyperactive airways but normal baseline spirometry.

40. What does a 20% drop in FEV₁ after methacholine suggest?
A 20% drop in FEV₁ suggests bronchospasm or airway hyperresponsiveness.

41. What is exercise-induced bronchospasm?
Exercise-induced bronchospasm is airway narrowing that occurs during or shortly after vigorous exercise.

42. Why is the term exercise-induced bronchospasm preferred over exercise-induced asthma?
It is preferred because asthma is a disease, while bronchospasm is a physiologic response.

43. What commonly triggers exercise-induced bronchospasm?
Heat and water loss from the airway during increased ventilation commonly triggers exercise-induced bronchospasm.

44. When does bronchospasm usually occur during exercise challenge testing?
It usually occurs immediately after exercise rather than during the early part of exercise.

45. What fall in FEV₁ after exercise may be consistent with increased airway sensitivity?
A 10% to 15% fall in FEV₁ after exercise may be consistent with increased airway sensitivity.

46. Why should pulse oximetry continue after exercise challenge testing?
Pulse oximetry should continue because oxygen desaturation may occur when bronchospasm develops after exercise.

47. What is eucapnic voluntary hyperventilation used for?
Eucapnic voluntary hyperventilation is used to provoke bronchospasm in patients with exercise-related symptoms.

48. Why can eucapnic voluntary hyperventilation trigger bronchospasm?
It can trigger bronchospasm by causing heat and water loss from the airway during high levels of ventilation.

49. What gas mixture is commonly used during eucapnic voluntary hyperventilation?
A mixture containing 5% CO₂, 21% O₂, and balance nitrogen is commonly used.

50. What should be done after bronchospasm occurs during pulmonary function challenge testing?
The bronchospasm should be reversed with an inhaled bronchodilator, and recovery should be documented with spirometry.

51. What is the main autonomic effect that relaxes bronchial smooth muscle?
Sympathetic stimulation relaxes bronchial smooth muscle.

52. What autonomic effect causes bronchial smooth muscle constriction?
Parasympathetic stimulation causes bronchial smooth muscle constriction.

53. Which neurotransmitter is associated with parasympathetic bronchoconstriction?
Acetylcholine is associated with parasympathetic bronchial smooth muscle constriction.

54. Which receptors are stimulated by beta-agonists to relieve bronchospasm?
Beta-agonists stimulate beta₂ receptors in bronchial smooth muscle.

55. What happens when beta₂ receptors are stimulated in the airways?
Stimulation of beta₂ receptors causes bronchial smooth muscle relaxation and bronchodilation.

56. What are sympathomimetic bronchodilators designed to do?
Sympathomimetic bronchodilators mimic sympathetic effects and relax bronchial smooth muscle.

57. What is the main purpose of quick-relief medications during an asthma attack?
Their main purpose is to rapidly relax constricted bronchial smooth muscle and improve airflow.

58. Why can bronchospasm cause prolonged exhalation?
Bronchospasm narrows the airways, making it harder for air to leave the lungs during exhalation.

59. What is the relationship between airway radius and resistance?
As airway radius decreases, airway resistance increases dramatically.

60. What happens to the work of breathing when airway resistance increases?
The work of breathing increases because the patient must generate more pressure to move air.

61. Why can a small decrease in airway diameter have a large effect on breathing?
A small decrease in airway diameter can greatly increase resistance and the pressure needed for airflow.

62. What happens if the airway radius is reduced to one-half of its original size?
The work required to move air can increase significantly, making breathing much more difficult.

63. Why can severe bronchospasm impair alveolar ventilation?
Severe bronchospasm can trap gas, limit fresh air entry, and reduce effective alveolar ventilation.

64. Why does hyperinflation not always mean the lungs are being overventilated?
Hyperinflation may occur because gas is trapped, even though fresh ventilation is inadequate.

65. What blood gas changes may occur with severe bronchospasm?
Severe bronchospasm may cause decreased oxygenation and increased carbon dioxide if ventilation becomes impaired.

66. What capnography pattern is associated with bronchospasm?
Bronchospasm is associated with a shark-fin capnography waveform.

67. Why does bronchospasm produce a shark-fin capnogram?
It produces a shark-fin waveform because obstructed airways empty carbon dioxide slowly and unevenly.

68. What should happen to the capnogram after effective bronchodilator therapy?
The waveform should begin returning toward a more normal shape as airflow improves.

69. Why should wheezing not always be treated as bronchospasm?
Wheezing can also be caused by airway edema, secretions, CHF, foreign-body aspiration, or partial airway obstruction.

70. What treatment is more appropriate if wheezing is caused by congestive heart failure?
Treatment should focus on the heart failure, such as diuresis and possibly positive inotropic support, rather than only bronchodilation.

71. What should be suspected if a child has wheezing related to foreign-body aspiration?
A partial airway obstruction from the foreign body should be suspected.

72. What may be required if wheezing is caused by foreign-body aspiration?
Bronchoscopy may be required to remove the foreign body.

73. Why are bronchodilators not routinely recommended for bronchiolitis?
In bronchiolitis, wheezing is often caused by airway edema and mucus rather than true bronchospasm.

74. When may a bronchodilator trial be considered in bronchiolitis?
A bronchodilator trial may be considered if wheezing and respiratory distress persist, but it should continue only with objective improvement.

75. What is the best approach to treating a patient with wheezing?
The best approach is to identify the underlying cause of wheezing before choosing the treatment.

76. What should be given first when multiple inhaled medications are ordered?
The bronchodilator should be given first to open the airways and improve delivery of the medications that follow.

77. Why should acetylcysteine sometimes be preceded by a bronchodilator?
Acetylcysteine can irritate the airway and trigger bronchospasm, so a bronchodilator may help prevent airway narrowing.

78. What should the therapist do if airway clearance therapy causes bronchospasm?
The therapist should stop the therapy, return the patient to the original position, provide oxygen as needed, monitor closely, and notify the physician.

79. What is one possible complication of suctioning related to airway narrowing?
Bronchospasm is a possible complication of suctioning.

80. Why can suctioning trigger bronchospasm?
Suctioning can irritate the airway and stimulate a reactive bronchial response.

81. What patient group should be monitored closely during sputum induction?
Patients with asthma, COPD, or other reactive airway disease should be monitored closely.

82. Why is albuterol often given before sputum induction?
Albuterol may be given before sputum induction to reduce the risk of bronchospasm from hypertonic saline.

83. What finding during sputum induction suggests the procedure should be stopped?
The procedure should be stopped if the patient develops wheezing, dyspnea, chest tightness, respiratory distress, or a significant fall in FEV₁.

84. What FEV₁ change may require termination of sputum induction?
A fall in FEV₁ of 20% or more from baseline may require termination of the procedure.

85. What is the purpose of measuring FEV₁ after bronchodilator pretreatment before sputum induction?
The postbronchodilator FEV₁ can be used as the baseline for comparison during the procedure.

86. What type of stimulus is methacholine during bronchoprovocation testing?
Methacholine is a direct stimulus because it acts directly on airway smooth muscle.

87. What type of stimulus is exercise during bronchoprovocation testing?
Exercise is an indirect stimulus because it triggers airway narrowing through heat and water loss and mediator release.

88. What are examples of indirect bronchoprovocation stimuli?
Indirect stimuli include exercise, eucapnic voluntary hyperventilation, mannitol, adenosine, propranolol, and hypertonic saline.

89. What are examples of direct bronchoprovocation stimuli?
Methacholine and histamine are examples of direct bronchoprovocation stimuli.

90. Why is FEV₁ commonly used during bronchial challenge testing?
FEV₁ is commonly used because it is simple to perform, reproducible, and reflects airflow obstruction.

91. What does a negative challenge test generally mean?
A negative challenge test means the provoking stimulus did not produce a significant fall in FEV₁ during the testing period.

92. What should the technologist be prepared to do during exercise challenge testing?
The technologist should be prepared to monitor the patient and reverse severe bronchospasm with an inhaled bronchodilator.

93. Why should patients avoid vigorous exercise before exercise challenge testing?
They should avoid vigorous exercise because a refractory period after exercise may affect the test results.

94. How long should patients generally be free from respiratory infection before EIB testing?
Patients should generally be free from respiratory infection for 3 to 6 weeks before exercise-induced bronchospasm testing.

95. What is the usual recovery time after exercise-induced bronchospasm?
Spontaneous recovery usually occurs within 20 to 40 minutes.

96. What does persistent expiratory flow before the next ventilator breath suggest?
It suggests incomplete exhalation, which can lead to air trapping and auto-PEEP.

97. What should be checked when high peak pressure suggests increased airway resistance?
The therapist should check for bronchospasm, secretions, mucus plugs, kinking, biting the tube, water in the circuit, or partial airway obstruction.

98. How can bronchodilator therapy affect airway resistance in ventilated patients?
Bronchodilator therapy can reduce reversible bronchospasm and help return airway resistance toward baseline.

99. What ventilator change may help when bronchospasm causes air trapping?
Increasing expiratory time may help by allowing the patient more time to exhale.

100. What is the main clinical takeaway about bronchospasm?
Bronchospasm is a reversible airway-resistance problem that requires assessment, treatment with appropriate bronchodilator therapy, and reassessment.

Final Thoughts

Bronchospasm is a clinically important airway reaction that can occur in asthma, COPD, pulmonary function testing, aerosol therapy, airway clearance, mechanical ventilation, and several other settings. It narrows the bronchial airways, increases airway resistance, makes exhalation more difficult, and can lead to air trapping, auto-PEEP, and impaired ventilation.

The key clinical priorities are prevention, recognition, treatment, and reassessment. Respiratory therapists should monitor for wheezing, increased work of breathing, rising peak pressures, prolonged exhalation, and changes in FEV₁ or capnography.

When bronchospasm is present, prompt bronchodilator therapy and correction of the underlying trigger can improve airflow and patient stability.