Pulmonary Events

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

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

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

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

Definition

Bronchospasm is a reversible narrowing of the medium and small airways because of smooth muscle contraction.