Anesthesia Alert: Anesthetizing Asthmatic Patients

I once cared for a pediatric patient who had been intubated for respiratory failure caused by acute severe asthma two weeks before they presented for emergency surgery. Immediately after induction of anesthesia and intubation, the patient had a severe asthma attack leading to a bronchospasm. Despite administering IV steroids intraoperatively and albuterol through the endotracheal tube, as well as deepening the anesthetic, the patient’s symptoms did not immediately resolve. I then administered epinephrine, which helped to calm the attack. The experience highlighted the challenge of managing the care of asthmatic patients — and the potentially lifesaving skills needed to do it effectively.

About 8% of the U.S. population has asthma, according to the CDC. While there are many different causes of the chronic disease, the underlying symptoms are the same: airway inflammation and hyperresponsiveness to triggering stimuli. Asthma causes narrowing or spasming of the bronchial smooth muscles, also known as bronchospasm, which in turn limits the amount of oxygen exchanged within the lungs. Imagine trying to breathe through a straw. That’s what an asthma attack feels like.

Most asthma attacks respond to medications such as steroids and bronchodilators, which are aimed at decreasing airway inflammation and improving gas exchange. In severe cases, the patient does not respond to standard treatments. This is a true medical emergency that if left untreated can lead to cardiac and respiratory arrest.

Asthmatic patients are at a higher risk for surgical complications because they have very reactive airways that bronchoconstrict, limiting airflow and gas exchange. Anesthesia providers can help these patients prepare for surgery by obtaining a thorough and detailed health history along with a focused cardiopulmonary physical examination. Providers could have an asthma sufferer undergo a nebulizer treatment before surgery to help decrease the potential for airway complications, including bronchospasms and laryngospasms.

Patients might need to be pretreated with an inhaled beta-2 agonist medication, such as albuterol; inhaled, oral or IV corticosteroids, which act directly in the lungs to inhibit the inflammatory process that causes asthma; oral leukotriene antagonists, which are used to manage allergies and asthma; and IV magnesium, which may help stop an asthma attack by relaxing and opening the airway.

Ultimately, it might be best to postpone elective surgeries of patients with uncontrolled or unstable asthma until their symptoms — wheezing or breathing difficulties despite pretreatment with an inhaler or nebulizer — are better managed. Patients who present for emergency surgery can be treated with bronchodilators and steroids intraoperatively as well as postoperatively to help mitigate risks of airway complications associated with asthma.

The most critical times for asthmatic patients are induction of anesthesia, subsequent airway manipulation — especially with an endotracheal tube — and emergence, because they create a higher risk of respiratory complications such as bronchospasm or even status asthmaticus. Certain anesthetic medications such as morphine and succinylcholine should be avoided, if possible, in patients with asthma due to associated histamine release. Histamine is a potent bronchoconstrictor and can worsen an asthma attack. Some forms of propofol contain preservatives that can also cause bronchoconstriction. Other agents, such as sevoflurane and ketamine, have bronchodilatory effects and can be used safely. IV steroids can also be beneficial as they decrease the airway’s inflammatory response.

Providers can use a laryngeal mask airway, which is less invasive and not as stimulating as an endotracheal tube. They should avoid administering “light” anesthesia to asthmatic patients, who might respond to stimuli of all types, and instead opt for a deeper plane of anesthesia to mitigate airway hyperreactivity. Providers can also consider performing a “deep” extubation — while patients are spontaneously breathing under general anesthesia and not wide awake — to avoid airway irritation and coughing. 

Vigilance regarding bronchospasm is the key to minimizing post-anesthesia complications. Recovery room staff should closely monitor patients with a history of asthma attacks and those who experience airway inflammation, trouble breathing after extubation, wheezing, bronchospasm and desaturation. 

The safe care of asthmatic patients ultimately demands creating a tailored anesthetic plan that decreases the risk of bronchospasm while facilitating interprofessional communication among anesthesia providers, the surgical team and the recovery room staff. OSM