Airway & Chest Injuries

1. Airway & Chest Injuries Airway (Laryngotracheal) Trauma Moderator: Dr. Shende Presenters: Dr.Ajay, Dr. Shalini www.anaesthesia.co.in anaesthesia.co.in@gmail.com

2. Definition: • Airway trauma is any injury that directly involves the airway in any location from nasopharynx to the bronchioles • It may involve actual damage to the airway or injure bony or vascular structure that distort airway anatomy. Incidence: Laryngotracheal trauma(LTT): 0.03% - 2.8% 70 – 80% die before reaching medical care Of those who reach tertiary care, 21% die in the first two hours of admission. Age: 26 – 34 years Sex: More common in males (75%)

3. Anatomy • Larynx well protected on 3 sides • Posteriorly: vertebral column • Sides: Strap muscles& Sternomastoid • Mandible to sternum • The entire airway is a fairly free & mobile structure, attached superiorly to the hyoid & intrathoracically to the lungs. • Platysma key muscle to define penetrating trauma, cervical fascia unyielding. • Cricotracheal ligament – weak & most likely point of airway separation.

5. Mechanisms of Injury • Trauma – Penetrating Blunt • Thermal & Inhalational injuries • Iatrogenic/ Intubation injuries • Aspiration of foreign body

6. Penetrating Trauma • Complicate 5-10% of trauma cases. • Mortality: 20% • Usually apparent • Causes: Stab, firearm, blast injury, fall on sharp objects • May be high or low velocity injuries • Airway injuries are more common in missile than stab injuries • Zones of penetrating injury of the neck

7. Zone 1: • Cephalad border of clavicle to cricoid cartilage inc the thoracic inlet • 3- 7% • Ass. with great vessel injuries, (subclavian vs, jugular vs, common carotid artery, aortic arch), as well as that of trachea, thyroid, esophagus & pulmonary contusion. • Zone 2: • cricoid to the angle of the mandible • 82% • Airway compromise is most likely to occur if wound involves this area.33% require emergency airway management. Most require surgical exploration. • Ass. with injury to carotid artery, vertebral artery, jugular vein, larynx, pharynx, cranial nerve X, XI, XII, cervical spine • Zone 3 : • Angle of the mandible to the skull base • 15% • Ass. with injury to internal & external carotid arteries, pharynx, cranial nerves VII, IX, X, XI, XII.

8. Blunt Trauma • 1 in 30,000 of ED admissions • Mortality : 40% • Often concealed & not obvious • Causes: Motor vehicle accidents(MVA), direct blows, crush injuries, clothesline injuries, strangulation injuries. • Frontal impact MVA: The victim’s head is forced back, neck is hyperextended & the exposed larynx makes contact with the dashboard & is crushed against the cervical spine. • Direct blows usu. cause fractures of the laryngeal cartilages. • Mc- Thyroid(47%) , foll. by arytenoid(24%) and cricoid(22%). • Tear of the cricotracheal ligament, resulting in complete laryngotracheal disruption(23%). • Intrathoracic airway is prone to injury in blunt trauma chest. These tears are usu found within 2.5cm of the carina at the junction of the membranous & cartilaginous portion of the airway. • Associated injuries: • Cervical spine( 10 – 50 %) • Esophageal injury • Pulmonary contusion/pneumothorax

9. Thermal & Inhalational Injury • Facial & perioral swelling  pharyngeal obstruction • Thermal injury to upper airway  laryngeal obstruction • Chemical injury to lung  impaired gas exchange • Maximal airway edema may not occur for upto 18- 24 hrs but if evidence of upper airway burn is present, it is necessary to secure the airway early. • Burns involving the lower airway are unusual because of the heat absorptive capacities of the upper airway. • Smoke inhalation injury accounts for 50% of fire related deaths, although less obvious than thermal injury. • Smoke – CO, HCN, NH3, SO2, Cl2, phosgene. • Always have a high index of suspicion for cervical/head injury secondary to a fall.

10. Intubation Injuries • Cuff injury (high pressure, low volume) • Incidence 0.1% • Mc :- chronic cicatrix with stenosis • Others: tracheo esophageal fistula, tracheal erosion by tracheostomy tube, tracheo innominate artery fistula, bronchial rupture

11. Classification • According to site of injury : • Supraglottic • Transglottic • Cricoid • Tracheal • According to the mechanism of injury : • Blunt trauma • Penetrating trauma • Superficial • deep • According to severity: • Group 1 : minor endolaryngeal hematoma , edema , laceration without detectable fracture • Group 2 : edema , hematoma , minor mucosal disruption without exposed cartilage & non displaced fracture on CT • Group 3 : massive edema , mucosal disruption , displaced fracture , exposed cartilage , cord immobility • Group 4 : group 3 + two or more fracture lines , skeletal instability or significant anterior commissure trauma • Group 5 : complete laryngotracheal separation • Group 1 , 2 : mild • Group 3 : moderate • Group 4 , 5 : severe

12. Diagnosis • Symptoms • Hoarseness/Change in character of voice • Shortness of breath • Inability to tolerate the supine position • Pain • Dysphagia • Aphonia • Signs • Stridor/Respiratory distress • Tenderness • Subcutaneous emphysema • Anterior neck contusion/Hematoma • Tracheal deviation • Loss of palpable landmarks/abrasion • Hemoptysis • Obvious open wound

13. Specific assessment for airway injury • Radiography: • Chest & cervical radiographs – pneumomediastinum, pneumothorax, air in soft tissues, prevertebral air or hematoma. • CT: Investigation of choice for cartilage injury • Endoscopy: Investigation of choice for mucosal injury. Flexible laryngoscopy, bronchoscopy, & esophagoscopy. • Gastrografin study

14. Associated Injuries • Cervical spine (10 – 50%) • Esophagus (5 -15%) • Vascular (25 – 40%) • Chest • Closed head injury • Facial fractures • Nerves – Brachial plexus, Recurrent laryngeal nerve Other concerns • Risk of Aspiration • Intracranial & intraocular injuries

15. Airway Management • Starts with : Airway Breathing Circulation • Resuscitation • Secondary survey • Periodic assessment from neck to foot

16. Patients requiring immediate intervention: a) airway obstruction b) hypoventilation c) severe hypoxemia (hypoxemia despite supplemental oxygen) d) severe cognitive impairment (GCS <8) e) cardiac arrest/respiratory arrest f) severe hemorrhagic shock A Definitive Airway • Endotracheal intubation • Cricothyrotomy • Tracheostomy • Through wound • Fibreoptic – not very appropriate In such cases, all but the most routine precautions (cricoid pressure & manual in line stabilization) should be overlooked.

17. Patients requiring emergency intervention: • patients who are not apneic but unresponsive require this. Manual opening of the airway & bag mask assisted ventilation can be done until an elective procedure is done. • Should be shifted to OT • Monitors attached • Surgeon scrubbed and ready • Larynx, trachea identified, cleaned and draped. Method determined by: - urgency of situation - patient cooperation - type of injury - significant bleed

18. Desjardins et al, Ryder trauma centre: Resuscitation 2001 • Awake fiberoptic • Rapid sequence fiberoptic • Rapid sequence induction • Awake orotracheal intubation

19. Awake fibreoptic: safest, considered in all awake and cooperative patients • Awake, no severe distress: few minutes available • Full endoscopy cart • Topical anaesthesia: lidocaine spray • Advance FOB till carina: any evidence of injury: pass ETT under vision beyond defect • Thermal injuries: intra oral, laryngeal, tracheal assessment • Edema interferes with DL →role of FOB

20. Combative patient: rapid sequence FOB • Who do not appear difficult to intubate • Rapid sequence induction, in line immobilization ► standard laryngoscopy ► insert FOB beyond larynx to rapidly evaluate for injury

21. Orotracheal intubation: • With paralysis • Without paralysis • problems with blind endotracheal intubation: -further injury, complete obstruction -upper airway examination difficult -false passage -covert partial to a complete tear -burns: edema interferes with DL

22. Patients requiring urgent intervention: Such as those with burns , expanding hematomas, chest injuries, who at the moment appear well compensated will also require intubation but can be given supplemental O2 and monitored continuously until some preliminary assessment is done. When planned for work up: e.g. CT scan- accompanied by anaesthesiologist, airway cart and monitoring facilities.

23. Summary • Laryngotracheal trauma is a life threatening injury with serious complications. • It is easily overlooked unless one has a high index of suspicion • Prompt diagnosis & management is often rewarding in terms of life as well as eventual voice quality & airway patency www.anaesthesia.co.in