Airway Burn
Definition
Airway burn is thermal or chemical injury to the mucosa of the airway between the mouth and the alveoli.
Etiology
Inhalation of hot gases
From breathing circuit
Direct exposure to fire
Exposure to smoke or toxic gases
Ignition of the ETT during laser surgery
Typical Situations
Patients with acute burns
Laser surgery in the pharynx, the larynx, or the tracheobronchial tree
Tracheostomy using electrocautery
Rupture of ETT cuff, allowing escape of oxidizer from the lungs to the upper airway
Prevention
Assess fire risk in EVERY case
Hospital laser committee is responsible for monitoring laser safety-related issues
Safety training for hospital personnel working with lasers
Protect the ETT during laser airway surgery
Use “laser-proof” ETT
Fill ETT cuff with saline colored with methylene blue to create a visible marker for cuff puncture
Maintain a low FiO 2 (less than 30%) in air
If higher FiO 2 is required to maintain an acceptable O 2 saturation
Periodically oxygenate with a higher FiO 2 , then decrease below 30% prior to recommencing with surgery
Coordinate this with surgeons
Allow a few minutes to wash out high FiO 2
Consider aborting laser surgery if FiO 2 requirements are high
Use a cuffed ETT in surgery in and about the airway (e.g., tonsillectomy)
Surgeon should suction oropharynx prior to using electrocautery in the airway
During tracheostomy, enter the trachea with scalpel or scissors
Have a clamp available to occlude the ETT in case of ETT fire
Protect patient from exposure to OR fire or smoke
Manifestations
Immediate manifestations
Laser-ignited ETT fire
Visible ignition or burning of the ETT
Smell of burning, smoke, flames in the surgical field
Fire may propagate into the breathing circuit
Later manifestations
Airway edema or airway rupture
Decreased O 2 saturation and Pa o 2
Decreased pulmonary compliance
Pulmonary edema
Bronchospasm
Lung injury/ARDS
Tracheal stenosis
Similar Events
Pulmonary edema from other causes (see Event 20, Pulmonary Edema )
Lung injury from other causes
Pneumonia
Bronchospasm (see Event 29, Bronchospasm )
Partial airway obstruction
Management
For laser-induced ETT fire
Stop the flow of O 2 to the ETT
Clamp the ETT immediately
Disconnect the patient from the breathing circuit
Pour saline or water into airway to extinguish burning material
Extubate the trachea
Ventilate with 100% O 2 by bag valve mask
Reintubate the patient as soon as possible
Rapid development of airway edema may make later reintubation difficult
Consider use of tube exchanger and smaller ETT
If reintubation is not possible, proceed to either cricothyrotomy or tracheostomy
Provide supportive care and mechanical ventilation
Add PEEP as necessary to maintain oxygenation
Consider administering high-dose steroids
Methylprednisolone IV, 0.1 to 1 g
Immediate consultation with an otolaryngologist or a thoracic surgeon to evaluate the extent of the airway burn
Fiberoptic bronchoscopy when the patient is stable
Impound any device thought to be defective for inspection by a biomedical engineer
Complications
Hypoxemia/hypercarbia
Inability to reintubate
Permanent pulmonary injury
Pulmonary fibrosis
Restrictive pulmonary disease
Tracheal stenosis
Pneumothorax
Pneumonia
Death
Suggested Reading
Airway Rupture
Definition
Airway rupture includes traumatic perforation or disruption of any part of the airway.
Etiology
Mechanical or thermal energy rupturing airway walls
Hyperextension of the neck combined with a direct blow to the unprotected trachea
Penetrating injury of the chest or neck
Erosion of the tracheobronchial wall by an ETT or tracheostomy cuff
Aberrant entry of tracheostomy tube (e.g., during placement of percutaneous tracheostomy)
Typical Situations
Following thoracic injury
Blunt trauma in presence of a closed glottis
Frequently no external evidence of injury
Penetrating injury of the chest or neck
During placement of ETT with videolaryngoscopy
During laser surgery to the airway
During or following thoracic surgery
Associated with the use of a double-lumen ETT
With nasal intubation or instrumentation
Intubation of the airway with any rigid object
During rigid or flexible bronchoscopy
During placement of a metal ETT for laser surgery
Stiff airway exchange catheters (e.g., bougie)
During attempts at jet ventilation
Prevention
Avoid excessive force during instrumentation of the airway
Avoid blind passage of ETT through oropharynx during videolaryngoscopy
Prewarm nasal ETT prior to placement
Use nasal spray to vasoconstrict nasal mucosa
Phenylephrine 1% spray
Oxymetazoline 0.05% spray
Cocaine 4% topical solution
Use lubricated nasopharyngeal airways to dilate nasal passage prior to placing ETT
Do not allow the stylet to protrude beyond the tip of the ETT during intubation
Avoid overinflation of the ETT cuff or the endobronchial cuff of a double-lumen ETT
Deflate endobronchial cuff on double-lumen ETT when lung separation is no longer required
Intermittently check the occlusion pressure of the ETT cuff(s)
Especially in presence of N 2 O
Maintain full relaxation of the patient during endoscopy, rigid bronchoscopy, and laser surgery of the airway
Assess depth of insertion of airway exchange catheters to avoid insertion beneath the carina
Manifestations
Lacerations or partial rupture of the airway may easily be missed until some other event or a late complication demonstrates its presence (e.g., bronchial stenosis).
Rupture of nasopharynx
Inability to pass ETT easily through the nasal cavity
ETT not visible in the pharynx on direct laryngoscopy
Blood or bloody secretions from nasopharynx or ETT
Inability to ventilate through nasal ETT passed blindly
Nasopharyngeal swelling and visible hematoma
Rupture of tracheobronchial tree
Respiratory distress
Dyspnea
Hypoxemia
Cyanosis
Hemoptysis
SC emphysema
Mediastinal emphysema
Pneumothorax
CXR may be diagnostic
Laryngeal or tracheal injuries are frequently associated with visible cervical, mediastinal, and SC air without accompanying pneumothorax
Bronchial injury is associated with pneumomediastinum, with pneumothorax, and possibly with overlying rib fractures
Rarely, CXR may show “fallen lung sign,” in which the transected bronchus allows the lung to fall away from the mediastinum, not toward the mediastinum as in a pneumothorax
Air leak from the site of a penetrating injury to the chest or neck
Persistent air leak after placement of a chest tube is suggestive of bronchial rupture or bronchopleural fistula
Difficulty in establishing ventilation after intubation
High PIP
Decreased breath sounds
Similar Events
Other causes of airway obstruction
Pneumothorax (see Event 35, Pneumothorax )
High PIP ( see Event 7, High Peak Inspiratory Pressure )
Hemoptysis (see Event 34, Massive Hemoptysis )
SC air
Management
Nasopharyngeal rupture
Orally intubate the trachea by direct laryngoscopy or videolaryngoscopy before removing nasal ETT
If the ETT is removed first, severe hemorrhage may occur and make intubation difficult or impossible
Obtain otolaryngology consult
Tracheobronchial tree rupture
Suspect airway rupture in major trauma cases with SC or mediastinal air, a pneumothorax, or other major abdominal, cervical, or thoracic injuries
Ensure adequate oxygenation and ventilation
If severe respiratory distress is present, manage the airway FIRST and assess site of rupture SECOND
Intubate the trachea via direct laryngoscopy or videolaryngoscopy
Carefully ventilate with 100% FiO 2
Assess ET CO 2 and bilateral chest expansion
If difficult airway is suspected (see Event 3, Difficult Tracheal Intubation )
Prepare for awake fiberoptic intubation
Prepare for emergency surgical airway
Stat surgery consult for cricothyrotomy or tracheostomy
Assess the site of airway rupture
Perform fiberoptic bronchoscopy in all cases of major thoracic trauma
Will require an experienced bronchoscopist
Should be performed awake with topical anesthesia if feasible
May confirm the diagnosis and exact site of airway rupture
May allow aspirated material or secretions to be removed
If tracheal rupture is diagnosed
Advance the ETT beyond the site of rupture if possible
One lung ventilation may be required to maintain oxygenation
Consider bronchial blocker or double-lumen ETT
Repair the injury
If bronchial rupture is diagnosed
Intubate under fiberoptic guidance
Advance single-lumen ETT into unaffected bronchus or intubate the trachea and place a bronchial blocker into the affected side
Double-lumen ETT may be necessary
Resuscitate the patient as necessary
Diagnose and manage other injuries (see Event 14, The Trauma Patient )
Exclude the presence of a pneumothorax (see Event 35, Pneumothorax )
If nonemergent intubation is required for bronchoscopy or surgery
Treat as a known difficult intubation (see Event 3, Difficult Tracheal Intubation )
Fiberoptic intubation with topical anesthesia is the method of choice
Sedate the patient
Fentanyl IV, 50 μg, repeat as necessary
Midazolam IV, 0.5 mg, repeat as necessary
Ketamine IV, 10 to 20 mg, repeat as necessary
Dexmedetomidine infused at 0.1 to 0.7 μg/kg/hr
Administer supplemental O 2 and, if necessary, manually ventilate with gentle breaths, avoiding high PIP
Surgical correction versus conservative management will depend on the location and extent of injury
Plan management with ENT and thoracic surgeons
In patients with cervical injuries, consider performing fiberoptic bronchoscopy as the ETT is removed to identify tracheal injuries
Complications
Retropharyngeal abscess
Airway obstruction
Hypoxemia
Mediastinitis
Pneumonia distal to bronchial rupture
Tracheal or bronchial stenosis
Cardiac arrest
Suggested Reading
Anterior Mediastinal Mass
Definition
An anterior mediastinal mass is a benign or malignant tumor found in the mediastinum anterior to the pericardium.
Etiology
Compression of vital structures within the chest
Trachea or bronchi
Heart and great vessels
Typical Situations
Benign or malignant tumors
Thymoma
Teratoma
Lymphomas
Thyroid tumors
Cysts of multiple origins
Vascular malformations
Prevention
Carefully evaluate for signs and symptoms of symptomatic airway or vascular compression
Intolerance of supine position
Assess the effect on symptoms of changing patient position (e.g., right or left lateral)
Obtain an anteroposterior (AP) and lateral CXR and CT scan of the thorax to evaluate mass
There is questionable value of flow-volume loops in the upright and supine positions to evaluate dynamic compression of the airway in adults
Prepare for loss of airway or circulation during induction of anesthesia or intubation
Have a rigid bronchoscope available
Discuss the need for standby CPB or ECMO with surgeons
Manifestations
Cardiac
Chest pain or fullness, cough, syncopal symptoms and exercise intolerance
Pulmonary
Dyspnea that might or might not be positional
Hoarseness
Dysphagia
Stridor
Systemic symptoms associated with malignancy
Upper extremity and facial/neck swelling (SVC syndrome)
Incidental finding on CXR or CT obtained for other reason
Intraoperative manifestations
Inability to maintain a patent airway
Difficulty in advancing an ETT
Inability to ventilate through an ETT
Hypoxemia
Hypotension
Similar Events
Bronchospasm (see Event 29, Bronchospasm )
Epiglottitis (see Event 31, Epiglottitis [Supraglottitis] )
Intrathoracic airway obstruction
Tracheal or endobronchial tumor
Extrathoracic airway obstruction
Foreign body, Ludwig angina, epiglottitis, postoperative hematoma from head/neck/carotid surgery
Stridor (see Event 36, Postoperative Stridor )
Management
Requires interdisciplinary approach with consultation with thoracic or general surgery, radiology, oncology, intensive care, and radiation oncology.
General principles
Obtain and examine imaging studies preoperatively
AP and lateral CXR examination
Thoracic CT scan
TTE to evaluate for presence of pericardial effusion and other cardiac, systemic, or pulmonary vascular compression
Ensure adequate IV access
In patients with SVC syndrome, place large-bore IV in lower extremity
Consider arterial line prior to procedure
Anesthesia management
Local anesthesia may be adequate for biopsy, anterior mediastinoscopy, or CT-guided biopsy
For asymptomatic adult patients
IV induction and tracheal intubation
Risk of airway obstruction and cardiovascular compromise is minimal in these patients
For symptomatic adult patients
Experienced bronchoscopist and rigid bronchoscope should be available prior to induction
Consider the need for CPB or ECMO prior to induction
Discuss options with cardiac surgery, cardiology, and perfusionist team
Inhalation induction with sevoflurane maintaining spontaneous ventilation
Assess the ability to ventilate prior to administering a short-acting muscle relaxant
Intubate trachea with small ETT
If unable to give positive pressure breaths, awaken the patient and reassess the situation
If airway obstruction occurs
Check ETT position if intubated
Attempt rigid bronchoscopy and ventilate via bronchoscope
Prepare to institute emergency CPB or ECMO
If circulatory collapse occurs
Change patient to lateral position
If no response to change in position, proceed with immediate sternotomy (to relieve pressure on great vessels)
Complications
Hypoxemia
Inability to advance ETT into the trachea
Inability to ventilate the intubated patient
Airway trauma due to difficult intubation or rigid bronchoscopy
Postoperative stridor
Pulmonary edema due to excessive negative intrathoracic pressure
Cardiac arrest
Suggested Reading
Aspiration of Gastric Contents
Definition
Aspiration of gastric contents is inhalation of gastric contents into the tracheobronchial tree.
Etiology
Passive regurgitation or active vomiting of gastric contents in patients who are unable to protect their airway
Typical Situations
Patients with a “full stomach” or raised intra-abdominal pressure
Patients who are not NPO
Patients who have acute pain or who are on opioids
Bowel obstruction
Gastroparesis (e.g., diabetic patients)
Late pregnancy
Acute alcohol intoxication
Patients with large amounts of gas in the stomach
Prolonged positive pressure ventilation via mask or SGA
Difficult tracheal intubation
Patients with an incompetent gastroesophageal junction
Hiatal hernia
Previous esophageal or gastric surgery
Obesity
Patients who have had or are having bariatric surgery
Any patient with impaired laryngeal reflexes or cough
Depressed level of consciousness
Patients with residual neuromuscular blockade
Topical anesthesia of the larynx or pharynx (e.g., upper gastrointestinal procedures under sedation)
Chronic neurologic disease (e.g., patients with multiple sclerosis or stroke)
Anatomic abnormalities in and around the larynx
Patients who have had ineffective cricoid pressure
Recently extubated patients in ICU or OR
During a cardiac arrest
Prevention
In patients at risk of aspiration of gastric contents
Avoid general anesthesia if possible
Delay nonemergent surgery as long as possible to allow the stomach to empty and to allow time for medications that assist gastric emptying and reduce gastric acidity to be effective
Avoid depression of laryngeal reflexes (e.g., from excess sedation or topical anesthesia)
Administer nonparticulate antacid immediately prior to induction of general anesthesia
Sodium citrate PO, 30 mL
Administer H 2 antagonists at least 30 minutes prior to the induction of anesthesia
Famotidine IV, 20 mg
Ranitidine IV, 50 mg
Administer metoclopramide IV, 10 mg, to stimulate gastric emptying
If general anesthesia is necessary
Assess the patient’s airway carefully prior to inducing general anesthesia
Suction an in situ NGT prior to induction of general anesthesia
If a NGT is left in place, it may produce incompetence of the lower esophageal sphincter
There may still be gastric contents present even after suctioning an NGT
Have a trained and experienced assistant apply cricoid pressure
Maintain cricoid pressure until the ETT position is confirmed (see Event 5, Esophageal Intubation )
Intubate the trachea, inflate the ETT cuff, and confirm placement
Patient is at risk for aspiration at the end of surgery
Apply NG suctioning prior to extubation
Extubate the patient only after recovery of protective laryngeal reflexes
Consider awake intubation
Topical anesthesia of the larynx before securing the airway may ablate protective reflexes at a time that regurgitation or vomiting is likely to occur
Fiberoptic intubation can be performed with the patient sitting, making regurgitation less likely
Consider tracheostomy under local anesthesia if fiberoptic intubation is impossible and a difficult tracheal intubation is anticipated
Manifestations
Gastric contents visualized in the oropharynx
Severe hypoxemia
Increased PIP
Bronchospasm
Copious tracheal secretions
Coughing, laryngospasm, rales, or chest retraction
Dyspnea, apnea, or hyperpnea
CXR findings
Unremarkable in 15% to 20% of cases of aspiration
Pneumonic infiltrates and atelectasis may be present
Similar Events
Hypoxemia from other causes (see Event 10, Hypoxemia )
Obstruction of the ETT
Bronchospasm from other causes (see Event 29, Bronchospasm )
Other causes of high PIP (see Event 7, High Peak Inspiratory Pressure )
Pneumonia
Pulmonary edema (see Event 20, Pulmonary Edema )
ARDS
PE (see Event 21, Pulmonary Embolism )
Management
If gastric contents are visible in the oropharynx or larynx
Suction oropharynx with Yankauer suction tip
Intubate the trachea
Perform immediate tracheal suctioning prior to positive pressure ventilation
Pass a suction catheter down the ETT
Obtain a sample of the pulmonary aspirate for pH, Gram stain, and culture
Do not make prolonged efforts at suctioning the trachea, especially if the patient is desaturating
Ensure adequate oxygenation and ventilation
Positive pressure ventilation with 100% FiO 2
Add PEEP to maintain oxygenation
If particulate aspiration has occurred
Lavage plus suctioning or bronchoscopy will be necessary to remove particulate material and to assess level of contamination
Cancel elective surgery and restrict emergency surgery to the minimum procedure consistent with safety
Provide supportive care
Fluid management with crystalloid rather than colloid
Administer H 2 blockers for stress ulcer prophylaxis
Famotidine IV, 20 mg
Ranitidine IV, 50 mg
Perform intermittent pulmonary toilet (uninjured pulmonary cilia will continue to sweep particles and edema fluid to the bronchi)
Large volume lavage via the ETT is usually not indicated
Consider the administration of antibiotics
Choice of antibiotic should be based on the results of a Gram stain of the pulmonary aspirate
Prophylaxis is indicated if there is a high likelihood of bacterial colonization of gastric contents (e.g., patients on H 2 antagonists and proton pump inhibitors and those with small or large bowel obstruction)
Steroids have not been shown to be of benefit during the period of acute hypoxemia and may impair the long-term healing process of the lung
Bronchodilators may be helpful in relieving large airway closure in less damaged areas of the lungs
Consider ECMO support if oxygenation cannot be maintained
Consider lung transplant
Complications
Pneumonia
ARDS
Sepsis
Barotrauma secondary to high PIP
Death
Suggested Reading
Bronchospasm
Definition
Bronchospasm is a reversible narrowing of the medium and small airways because of smooth muscle contraction.
Etiology
Asthma
COPD with a reversible component of airway narrowing
Airway irritation (e.g., aspiration, bronchiolitis, upper respiratory infection [URI])
Medication side effects (e.g., allergy or anaphylaxis)
Typical Situations
Patients with known asthma, COPD, or recent URI
Mechanical irritation of the airway
Placement of oral or SGA
Placement of ETT
Endobronchial intubation
Chemical irritation of the airway
Pungent anesthetic gases
Soda lime dust
Smoke inhalation
Carcinoid syndrome
Medications known to cause bronchospasm
β 2 -antagonists (labetalol, propanolol)
Anticholinesterases
Drug allergies (e.g., antibiotics, neuromuscular blockers, latex, adenosine, radiocontrast agents)
Aspiration of gastric contents
PE (fat, thrombus, amniotic fluid)
Prevention
Cancel elective surgery for patients who are actively in bronchospasm.
Avoid anesthesia and elective surgery when the patient is at risk of bronchospasm
Acute URI
Recent exacerbation of asthma or COPD
In patients with known asthma or COPD, optimize therapy with bronchodilators and/or systemic steroids prior to anesthesia
Administer bronchodilators on day of surgery
Inhaled β 2 -agonists prior to induction
Albuterol MDI 4 to 8 puffs (90 μg/puff)
Albuterol nebulizer solution 2.5 mg/3 mL
If it is necessary to proceed with surgery in patients with a known risk of bronchospasm
Regional anesthesia will eliminate airway stimulation
Consider SGA with general anesthesia
Consider using ketamine IV, 1 to 2 mg/kg, for anesthetic induction
Consider intraoperative ketamine infusion at 0.25 mg/kg/hr as an anesthetic adjuvant
Deepen anesthesia prior to intubation
Administer additional propofol IV, 30 to 50 mg
Lidocaine IV, 1 to 1.5 mg/kg, 1 to 3 minutes prior to intubation
Ventilate with sevoflurane prior to intubation
Monitor flow-volume loops if available for early detection and treatment of bronchospasm
Manifestations
Increased PIP
Audible wheezing, usually during exhalation
If bronchospasm is severe, there may be an absence of wheezing or gas movement
Upward sloping of capnogram wave
ET CO 2 may be absent or diminished depending on severity of bronchospasm
Decreased Pao 2 and O 2 saturation
Decreased tidal volume especially with pressure-controlled ventilation
Gradient between Paco 2 and ET CO 2 will increase
Increased Paco 2
Hypotension
Similar Events
Aspiration of gastric contents (see Event 28, Aspiration of Gastric Contents )
Kinked or obstructed ETT (see Event 7, High Peak Inspiratory Pressure )
Pneumothorax (see Event 35, Pneumothorax )
Aspiration of foreign body (usually unilateral wheeze vs. diffuse)
Amniotic fluid embolism (see Event 81, Amniotic Fluid Embolism )
Pulmonary edema (see Event 20, Pulmonary Edema )
PE (see Event 21, Pulmonary Embolism )
Endobronchial intubation (see Event 30, Endobronchial Intubation )
Anaphylaxis and anaphylactoid reactions (see Event 16, Anaphylactic and Anaphylactoid Reactions )
Air trapping
Management
Ensure adequate oxygenation and ventilation
Increase FiO 2 to 100%
Briefly ventilate the patient with reservoir bag
Assess pulmonary compliance
If hand ventilation will be an ongoing requirement, call for help
Mechanically ventilate the patient
Optimize RR and I:E ratio to avoid hyperinflation or auto-PEEP
Verify the diagnosis of bronchospasm
Auscultate the chest
Check ETT position
Check patency of ETT
Pass a suction catheter down the ETT
For mild bronchospasm
Increase anesthetic depth with sevoflurane if the patient is not hypotensive
Administer β 2 -agonist to the lungs by MDI; repeat in 10 minutes if there is no response and no tachycardia
A large dose of any aerosolized medication may be required when administered via the ETT
Albuterol: initial dose, 4 to 8 metered puffs (90 μg/puff)
Albuterol and ipratropium bromide combination therapy, initial dose, 8 metered puffs
For moderate to severe bronchospasm
Institute measures as in mild bronchospasm
Consider the possibility of silent aspiration of gastric contents
Suction through the ETT and collect aspirate for analysis of pH
If bronchospasm does not resolve
Inform the surgeon
Administer β 2 -agonist
Albuterol MDI, initial dose 4 to 8 metered puffs (90 μg/puff) q20m
Albuterol nebulized, 2.5 mg/3 mL q20m
Institute IV bronchodilator therapy
Epinephrine IV, 0.1 μg/kg bolus; infusion, 5 to 20 ng/kg/min, titrated to the pulse rate, BP, and bronchodilator response
MgSO 4 IV, 2 g
Administer corticosteroids
Methylprednisolone IV, 125 mg bolus
Reassess ventilation
Avoid high PIP to minimize barotrauma
Alter tidal volume and I:E ratio to maintain oxygenation and minimize airway pressure, allowing permissive hypercapnia if necessary
Check for air trapping
Consider deepening volatile anesthetic or providing paralysis to improve patient-ventilator synchrony
Obtain a high-performance ventilator (such as an ICU ventilator)
Pulmonary compliance/resistance may exceed the performance envelope of the anesthesia workstation
Heliox may improve airflow in patients with severe bronchospasm
Stop the surgical procedure as soon as possible
Transfer patient to ICU for postoperative care if resolution is incomplete
If the patient is NOT intubated (e.g., bronchospasm in PACU)
Consider noninvasive ventilation CPAP or BiPAP
Bronchodilator therapy as previously stated
Evaluate for increased effort to breathe, fatigue, altered mental status, subjective distress, or hypercarbia
Intubate the trachea if treatment fails
Complications
Hypoxemia
Hypercarbia
Hypotension due to increased intrathoracic pressure
Arrhythmias
Barotrauma
Cardiac arrest
Suggested Reading
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