Complications of Airway Management

Incidence, Classification, and Risk Factors

Incidence and Overall Burden

• Complications can occur at any step of airway management, including facemask ventilation, supraglottic airway (SGA) placement, tracheal intubation, and extubation. Common minor events include sore throat and hoarseness; major events include hypoxemia, aspiration, airway trauma, negative pressure pulmonary edema, cardiovascular collapse, and failed airway.¹
• In adults, major airway complications causing death, brain injury, surgical airway, or unplanned intensive care unit admission have been reported in approximately 1 in 20,000 anesthetics.¹
• Pediatric patients have a higher rate of airway and respiratory complications compared to adults. These complications account for most anesthesia-related critical events and a substantial proportion of perioperative cardiac arrests.²
• The rates of difficult and failed intubation are higher in parturients compared with nonpregnant adults. Parturients have a decreased functional residual capacity and higher oxygen consumption, leading to rapid desaturation and potential fetal compromise.³
• Airway complications can be classified into several groups. Table 1 summarizes the classification of airway complications.

Risk Factors

• Risk factors for airway complications can be organized into multiple categories. Airway anatomy, pre-existing cardiopulmonary disease, environmental (situational and procedural) factors, and special patient populations (pediatrics and parturients) have risk factors for potential airway complications (Table 2).

Direct Traumatic Complications

Sore Throat and Hoarseness¹

• Sore throat is the most common postoperative airway complaint, with reported incidences up to 60 percent after endotracheal intubation; symptoms usually resolve within 24–48 hours.
• There is an increased risk with the use of large endotracheal tubes (ETTs), high cuff pressures, traumatic intubation, double-lumen tubes, nasogastric tubes, and coughing during emergence.
• Risk can be reduced by:
  • Using the smallest appropriate ETT diameter
  • Monitoring and limiting cuff pressure
  • Gentle laryngoscopy and minimizing the number of attempts
  • Considering SGA use when appropriate

Dental, Lip, and Oropharyngeal Trauma¹

• Dental injury is a frequent source of airway-related claims and typically affects the maxillary incisors.
• Patients at increased risk often have poor dentition, loose teeth, or prominent upper incisors. Difficult laryngoscopy requiring increased force or multiple attempts increases risk.
• Prevention strategies include preoperative dental assessment, use of protective bite blocks when appropriate, video-assisted laryngoscopy, and early transition to alternative techniques when direct laryngoscopy is challenging.

Laryngeal and Tracheal Injury¹

• Mucosal lacerations, arytenoid dislocation, vocal cord paresis, and subglottic injury can present with hoarseness, dysphonia, stridor, or airway obstruction.
• There is an increased risk with difficult or repeated intubations, oversized tubes or overinflated cuffs, and stylet or bougie trauma from blind advancement.
• Risk can be reduced by:
  • Using an appropriately sized ETT
  • Ensuring proper loading of the ETT stylet
  • Checking cuff pressure after balloon inflation
• Persistent hoarseness or stridor beyond 48 hours warrants evaluation with laryngoscopy.

Barotrauma^1,2

• Potential causes of barotrauma, including pneumothorax and subcutaneous emphysema, include:
  • Excessive bag-mask ventilation pressures
  • Aggressive jet ventilation through transtracheal catheters
  • Obstructed expiratory flow (e.g., severe laryngospasm)
• There is an increased risk in small children, patients with obstructive airway disease, or when high airway pressures are used.

Physiologic and Hemodynamic Complications

Hypoxemia and Hypercapnia

• Hypoxemia is the central mechanism behind most catastrophic airway events across all patient groups.^1,2
  • Causes include airway obstruction, laryngospasm, bronchospasm, apnea with prolonged attempts, esophageal intubation, or equipment malfunction.^1,2
  • Consequences include arrhythmias, myocardial ischemia, brain injury, cardiac arrest, and death.¹
• Rapid desaturation is particularly prominent in:
  • Infants and young children due to high oxygen consumption and small functional residual capacity.²
  • Parturients are affected by physiologic changes of pregnancy, including decreased functional residual capacity and increased metabolic demands.³

Hemodynamic Instability¹

• Hypotension can occur after intubation, particularly in critically ill adults and during emergent intubations.
• The mechanism of anesthesia-related hypotension is typically multifactorial, including:
  • Vasodilation and myocardial depression from induction agents
  • Loss of sympathetic tone and reduced venous return with positive pressure ventilation
  • Preexisting hypovolemia or sepsis
• Alternatively, sympathetic stimulation from laryngoscopy can result in hypertension and tachycardia, which can precipitate myocardial ischemia, heart failure, or intracranial hemorrhage in susceptible patients.
• Strategies for prevention include careful weight-based dosing of induction agents, hemodynamic monitoring and optimization, and prompt hemodynamic support with vasopressors and fluids as clinically appropriate.

Arrhythmias

• Sinus tachycardia often accompanies sympathetic stimulation and hypoxemia.¹
• Bradycardia can occur from hypoxemia, vagal stimulation during airway manipulation, or drug effects (e.g., succinylcholine, high doses of opioids).^1,2
• Children have higher baseline vagal tone; bradycardia and cardiac arrest can develop rapidly during episodes of hypoxemia or laryngospasm. Prompt treatment is essential.²

Respiratory and Pulmonary Complications

Laryngospasm²

• Laryngospasm is a reflex closure of the glottis, usually occurring during light planes of anesthesia with airway stimulation.
  • Symptoms include inspiratory stridor, cyanosis, and chest wall retractions.
  • In children, the incidence ranges from approximately 2% to 25%; it is a leading cause of respiratory-related perioperative cardiac arrest.
• Risk factors include:
  • Airway manipulation during light anesthesia
  • Recent upper respiratory infection
  • Passive smoke exposure, obstructive sleep apnea, or airway anomalies
  • Airway surgeries (e.g., tonsillectomy)
• Prevention strategies include maintaining adequate depth of anesthesia during airway manipulation and stimulation, thorough airway suctioning prior to extubation, and avoiding extubation during stage 2 of anesthesia.
  • Management requires immediate application of 100% oxygen with continuous positive airway pressure, jaw thrust (Larson maneuver), deepening anesthesia (e.g., propofol), and neuromuscular blockade (e.g., succinylcholine) if spasm persists.
  • Please see the OA summary on laryngospasm for more details. Link.

Bronchospasm^2,6

• Bronchospasm occurs when the airway muscles tighten, constricting airflow.
  • Triggers include airway instrumentation, aspiration, anaphylaxis, or underlying reactive airway disease.
  • Symptoms include expiratory wheezing, coughing, increased airway pressures, and hypoxemia.
  • Without timely treatment, airway pressures may rise, and ventilation and oxygenation may rapidly deteriorate.
• Management includes deepening anesthesia, inhaled β-agonists (e.g., albuterol), epinephrine (intravenous or intramuscular), and, when needed, systemic bronchodilators and steroids (e.g., methylprednisolone).
• Please see the OA summary on bronchospasm for more details. Link.

Aspiration of Gastric Contents

• Aspiration is an uncommon but serious complication that can lead to chemical pneumonitis, acute respiratory distress syndrome, or infection.^1,2
  • Risk is increased by emergency surgery, inadequate fasting, obesity, pregnancy, bowel obstruction, and use of SGAs in high-risk patients.^1,3
  • In children, aspiration events often occur at induction or during maintenance when SGAs or facemasks are used and anesthesia is light.²
• Management includes head-down positioning, prompt oropharyngeal suctioning, treatment of laryngospasm or bronchospasm, and ventilatory support; bronchoscopy may be required for large particles.²
• Please see the OA summary on pulmonary aspiration. Link.

Negative Pressure Pulmonary Edema²

• Negative-pressure pulmonary edema results from strong inspiratory efforts against an obstructed upper airway, most commonly due to laryngospasm.
  • It presents with acute hypoxemia, frothy sputum, and bilateral infiltrates on imaging.
• Management is supportive with oxygen, positive pressure ventilation, and, when necessary, short-term mechanical ventilation.
• Please see the OA summary on post-obstructive pulmonary edema. Link.

Failed Airway and CICO Events

Definition and Incidence^4,7

• The 2022 American Society of Anesthesiologists Guidelines define a difficult airway as a clinical situation in which a trained anesthesiologist experiences difficulty with facemask ventilation, SGA ventilation, tracheal intubation, or all three.⁷
• A failed airway is present when adequate oxygenation cannot be maintained despite optimized attempts with facemask, SGA, and tracheal intubation.
• CICO occurs when intubation and oxygenation are unsuccessful.
  • CICO is rare but carries a high risk of brain injury and death, and has been implicated in up to one-quarter of anesthesia-related deaths.
• Contributors to failed airway resulting in harm include:^1,4
  • Repeated attempts at the same technique without a change in strategy.
  • Delayed recognition of failure, delay in calling for help.
  • Lack of familiarity with emergency front-of-neck access techniques.
  • Inadequate preparation of difficult airway equipment and a lack of standardized carts.

Principles of Management^4,7

• Early declaration of CICO status and immediate activation of a difficult airway algorithm are essential.
• A maximum of three attempts (plus one by a more experienced provider) is recommended for each noninvasive technique before escalation.
• In a difficult airway with preserved oxygenation, options include direct laryngoscopy, video laryngoscopy, fiberoptic intubation, SGA placement, rigid bronchoscopy, and use of intubation adjuncts (bougie, stylets)^4,7
• If establishing the airway is challenging but mask ventilation is adequate, returning to mask ventilation is appropriate until the patient can be woken up or another intubation plan can be developed.
• If the CICO situation is encountered and a surgical airway is required, consider:
  • In adults, scalpel cricothyrotomy using a scalpel–bougie–tube or scalpel–finger–bougie–tube technique is generally recommended when personnel are trained.
  • In children, needle cricothyrotomy with transtracheal ventilation is preferred because of anatomic differences in the larynx and trachea.
  • Attempted reversal of neuromuscular blockade is unlikely to restore spontaneous ventilation fast enough to rescue a CICO event and may interfere with emergency invasive access.

Prevention Strategies Based on Patient Population

• Certain patient populations are at risk of different complications. Key patterns for adults, pediatrics, and parturients are listed in Table 3.
• Prevention strategies for these population-specific complications are described below (Table 3).