Anesthesia Management in Patients with Asthma

Function

Asthma is characterized by airway hyperresponsiveness and inflammation, with bronchial smooth muscle constriction and airway inflammation contributing to bronchospasm. Common triggers include allergens, such as medications or latex-based medical equipment; respiratory infections; smoking; cold air; exercise; stress; and physical trauma or stimulation of the airway.[6]

Clinically, bronchospasm manifests as shortness of breath, wheezing, coughing, or chest tightness. However, intubated patients in the operating room cannot directly report these symptoms. Instead, clinicians must monitor for a sudden acute rise in peak inspiratory pressures, changes in end-tidal carbon dioxide, and decreasing oxygen saturation. In addition, clinicians must distinguish between bronchospasm and anaphylaxis, which presents with additional symptoms such as hypotension, flushing, rash, or angioedema.[7]

Issues of Concern

The risk of anesthesia-related complications in patients with well-controlled asthma is low. Preoperative determination of the patient's level of asthma control is the key to mitigating perioperative complications. Clinicians should ensure that asthma is well managed before elective surgery.[3][4] Obtaining a detailed history and performing a thorough cardiopulmonary physical examination are essential for this assessment. Preoperative labs, chest radiographs, and tests to assess pulmonary function have not been shown to correlate with perioperative respiratory adverse events and are rarely recommended.[8] However, spirometry may be helpful if the patient's level of asthma control is in question or their peak flow rate is below 80% of their predicted value.

During the preoperative evaluation, clinicians must gather information about recent asthma exacerbations, hospitalizations, and any previous endotracheal intubation or mechanical ventilation due to asthma. When reviewing systems, the patient should report any recent episodes of wheezing, chest tightness, cough, or shortness of breath. Although most patients with well-controlled asthma tolerate anesthesia without complications, patients older than 50 and those with poorly controlled disease are at increased risk.[4]

In addition to a diagnosis of asthma, the following factors increase the risk of perioperative respiratory adverse events in children. Clinicians should assess these factors before administering anesthesia:

• Wheezing with exercise
• Wheezing more than 3 times in the last 12 months
• Nocturnal dry cough
• Upper respiratory tract infection within the last 2 weeks
• History of hayfever
• History of eczema
• Second-hand smoke exposure
• Family history of asthma, hay fever, or eczema
• Age younger than 6
• Higher American Society of Anesthesiologists Physical Status Classification
• History of congenital heart disease
• Prematurity
• Low birth weight
• Obesity 
• Obstructive sleep apnea [9][10] 

A history of an upper respiratory tract infection within the preceding 2 weeks and an age younger than 6 are both risk factors for intraoperative airway complications in all children.[11]

Patients with asthma may require prophylactic or abortive medications, including inhaled ß₂-agonists, such as albuterol; inhaled corticosteroids, such as budesonide; oral leukotriene antagonists, such as montelukast; oral or intravenous (IV) corticosteroids; and IV magnesium.[12] Upon verifying that the patient is using routine asthma medications, the anesthesia provider must determine whether to administer prophylactic therapy such as inhaled ß₂-agonists or systemic corticosteroids (for example, methylprednisolone) before proceeding to the operating room. Preoperative systemic steroids have shown little benefit unless started 2 to 3 days in advance of surgery. A study revealed that administering systemic corticosteroids alongside inhaled ß₂-agonists for 5 days before surgery markedly decreased the incidence of bronchospasm following intubation.[13]

Clinical Significance

Asthma is a common respiratory condition among patients undergoing surgery, and proper preoperative assessment, pharmacotherapy, and safe anesthesia measures are crucial for reducing complications. Perioperative respiratory adverse events can occur at any stage of anesthesia. However, the most critical times for perioperative respiratory complications occur during the induction of general anesthesia, airway manipulation, and emergence. Complications include bronchospasm, laryngospasm, desaturation, coughing, excessive secretion production, and pneumonia. Regional anesthesia can be a better option to avoid airway manipulation when appropriate. Involving expert team members is essential to patient safety. Having an experienced pediatric anesthesia provider manage the airway has been shown to reduce the risk of perioperative respiratory adverse events for children.[14] Patients with uncontrolled asthma have a higher risk of postoperative mortality and pneumonia. A preoperative assessment, including a detailed history, medication evaluation, and possibly pulmonary function tests, is essential when assessing patients with asthma before surgery. By optimizing medical management and using appropriate anesthetic techniques, healthcare professionals can minimize perioperative respiratory complications.[4]

Preoperative Medications

Other than theophylline, patients should continue their maintenance medications during the entire perioperative period, including the day of surgery. Patients with poorly controlled symptoms scheduled to undergo thoracic or upper abdominal surgery, open aortic aneurysm repair, neurosurgery, or head and neck surgeries generally receive a 5-day course of oral glucocorticoids and short-acting bronchodilators. In addition, short-acting bronchodilators are often administered shortly before anesthesia and endotracheal intubation. The anesthesia team must carefully administer warm and humidified gases, achieve appropriate anesthesia depth, and monitor airway management during surgery. Patients with bronchorrhea can receive a combination of a nebulized anticholinergic agent and a moderate-acting ß₂-agonist, such as ipratropium bromide-salbutamol. Postoperative care involves monitoring oxygen levels, providing adequate hydration and analgesia, and correctly prescribing the patient's usual asthma medications.

For patients with well-controlled asthma, routine mechanical ventilation is generally suitable. However, when airflow obstruction is present, prolonged expiratory phases can pose challenges. To prevent dynamic hyperinflation, also known as auto-PEEP or breath-stacking, clinicians must ensure sufficient time for exhalation during mechanical ventilation.

Anesthesia Agents

When anesthesia providers plan for endotracheal intubation, experts recommend a variety of pharmacological agents for premedication, a primary induction agent, and a neuromuscular-blocking agent. Adjunctive medications for premedications include an opioid-like fentanyl, lidocaine, or the α₂-agonist dexmedetomidine. Guidelines suggest different induction agents, including propofol, ketamine, etomidate, isoflurane, and sevoflurane, for patients with asthma undergoing surgery based on their stability and bronchodilatory properties. Induction agents must induce sufficient anesthesia to prevent a physiological response to airway manipulation. Propofol is often the primary agent selected in hemodynamically stable patients. Neuromuscular-blocking agents are the most common cause of intraoperative allergic reactions. As they release the least amount of histamine, vecuronium, rocuronium, and cisatracurium are the neuromuscular-blocking agents of choice for patients with asthma. 

The volatile anesthetics sevoflurane and isoflurane are viable options for inhaled anesthesia induction and have direct bronchodilatory properties. In contrast, desflurane can increase bronchial smooth muscle tone and airway resistance at higher concentrations; therefore, clinicians avoid this in patients with asthma.[15] Although propofol can blunt reflex bronchoconstriction of the airways, its bronchodilation is inferior to volatile anesthetics. However, compared to etomidate and thiopental, propofol has lower airway resistance.[16] Ketamine has direct bronchodilatory effects, blunts airway reflex bronchoconstriction, and is often the agent of choice in hemodynamically unstable patients. However, it also causes increased secretions, which can complicate airway management.[17] Sevoflurane and isoflurane are generally used to maintain anesthesia in patients with asthma. 

Given their heightened airway responsiveness, children with asthma require a more cautious approach. Anesthesia providers must minimize airway manipulation, use specific anesthetic agents that are less likely to trigger bronchospasm, and often premedicate with bronchodilators to prevent airway issues during induction and emergence. When possible, experts recommend IV induction instead of inhaled induction for children at risk for perioperative respiratory adverse events. Guidelines also recommend cuffed endotracheal tubes and less invasive airway devices such as mask ventilation or a supraglottic airway when possible.[18] Noninvasive airway management, such as supraglottic airway placement, is associated with a decreased risk of postoperative hypoxemia and coughing compared to endotracheal tube use in adults.[14] When comparing the supraglottic airway to an endotracheal tube for airway control in children, the incidence of perioperative respiratory adverse events was lower with the supraglottic airway. However, there was no statistically significant difference in bronchospasm or aspiration between the 2 groups. Propofol is a suitable induction agent that avoids volatile agents. Ketamine is suitable for the hemodynamically unstable pediatric patient. For children with poorly controlled asthma, delaying surgery for improved asthma management is ideal. If unable to postpone, experts recommend bronchodilators and steroids before and after surgery. IV magnesium and continuous ß₂-agonist therapy may be necessary. Aminophylline is not a recommended treatment option, and antibiotics are not required for asthma exacerbations unless a known bacterial cause exists.[19][20][21]

Neuromuscular-blocking drugs (NMBDs) improve conditions during intubation by minimizing airway resistance. Clinicians often avoid depolarizing NMBDs in children, given the risk of hyperkalemic cardiac arrest in the setting of a possible undiagnosed myopathy. The use of topical and inhaled lidocaine applied to prevent airway irritation and bronchoconstriction before endotracheal intubation is controversial, as evidence suggests an increased incidence of desaturation using this technique.[16][22] If heart rate or blood pressure control is necessary in acute settings, cardioselective β-blockers such as esmolol and metoprolol are safer options for patients with asthma.[13]

Before patients emerge from general anesthesia, anesthesia providers reverse neuromuscular blockade. Cholinesterase inhibitors such as neostigmine must be used cautiously, as these drugs can increase bronchoconstriction by inhibiting acetylcholine breakdown. Alternatively, sugammadex, which directly binds to non-depolarizing neuromuscular blockers such as rocuronium and vecuronium, may be preferred as it does not increase the risk of bronchospasm. Although deep extubation theoretically reduces the risk of bronchospasm from the ETT, current research offers limited support for this benefit; a recent randomized controlled trial found no significant difference between awake and deep extubation regarding perioperative respiratory adverse events.[23]

Other Issues

All that wheezes is not asthma. When caring for an anesthetized patient with asthma, bronchospasm is likely to be at the top of the list of differential diagnoses for an episode of wheezing. However, the following list presents other entities to consider:

• Anaphylaxis
• Aspiration of stomach contents
• Aspiration of a foreign body such as a tooth or piece of medical equipment
• Upper airway obstruction
• Mainstem intubation
• An endotracheal tube on the carina
• An endotracheal tube obstruction
• An endotracheal tube cuff herniation
• Pneumothorax
• Pulmonary edema
• Pulmonary thromboembolism
• Drug-induced wheezing due to histamine release or anticholinesterase
• Carcinoid syndrome or crisis [19]

Enhancing Healthcare Team Outcomes

Asthma, marked by airway hyperresponsiveness and inflammation, can be triggered by allergens, respiratory infections, cold air, exercise, stress, and airway manipulation. Patients with asthma have an increased risk of pulmonary complications associated with anesthesia, and bronchospasm may arise at any stage of the anesthesia process, making meticulous planning essential to minimize perioperative respiratory complications. The management of bronchospasm is a critical skill set for healthcare providers in patient care throughout the healthcare environment, as it can develop rapidly in response to various stimuli.

A comprehensive preoperative assessment, including pulmonary function testing, a detailed medical history, and a medication review, is vital in evaluating asthma control and optimizing the patient's condition. Patients with the highest risk of bronchospasm and laryngospasm include those who have used asthma medications, experienced symptoms, or sought care for asthma within the past year. The risk is significantly increasing for those who required treatment within the last 30 days or had an upper respiratory tract infection within the last 2 weeks.

To mitigate the risk of pulmonary complications, except theophylline, patients should continue their maintenance medications up to and including the day of surgery. Patients with poorly controlled symptoms undergoing a high-risk surgery should receive supplemental glucocorticoids in addition to a short-acting ß2-agonist 5 days before surgery when possible. In emergent cases, clinicians may administer preoperative short-acting bronchodilators and systemic corticosteroids.

Clinicians and advanced practitioners use their clinical expertise to perform a preoperative clinical assessment to determine the patient's asthma severity and level of disease control. Based on current guidelines, they determine the appropriate asthma management to optimize patients for surgical anesthesia. In addition, anesthesia providers choose the most appropriate anesthetic techniques and agents to avoid excessive airway stimulation and bronchospasm.

Nurses are vital in monitoring patients for symptoms of pulmonary complications and providing education about proper inhaler use and perioperative medication regimens. Nurses ensure the patient performs deep breathing exercises, uses the incentive spirometer, and ambulates as appropriate. Pharmacists provide guidance on the stress dosing of glucocorticoids and educate patients about the various asthma medications, including dosages, proper usage, and the importance of adherence. Respiratory therapists administer bronchodilator therapy and manage ventilator settings, ensuring optimal respiratory function throughout the procedure. By employing a comprehensive preoperative evaluation, appropriate diagnostic testing, medication management, and anesthetic techniques and choices, clinicians can minimize the anesthetic risk for patients with asthma.

Interprofessional communication and care coordination are critical to patient safety, as all team members are responsible for monitoring the patient's respiratory status. Preoperative team meetings facilitate discussions among anesthesia providers, surgeons, nurses, and respiratory therapists, aligning airway management and emergency preparedness strategies. Real-time intraoperative monitoring allows teams to promptly identify and address bronchospasm or airway resistance signs, ensuring immediate intervention. By using their skills, promoting interprofessional communication, and coordinating care, clinicians, advanced practitioners, nurses, pharmacists, and other healthcare professionals enhance patient-centered care, improve outcomes, promote patient safety, and optimize team performance in anesthesia management in patients with asthma.

Nursing, Allied Health, and Interprofessional Team Interventions

Clear and closed-loop professional communication should be maintained between interdisciplinary team members and among all team members.

Nursing, Allied Health, and Interprofessional Team Monitoring

Monitoring must be diligent and consistent between and among team members.