Anesthesia Considerations in Thoracic Trauma Patients

1. Anesthesia Considerations in Thoracic Trauma Patients 張婉玲 醫師 嘉義長庚醫院 麻醉科 2009.11.21.

2. Introduction • Mortality from chest injuries is around 10% • The majority of patients with thoracic trauma can be managed conservatively • Require thoracotomy： • Blunt trauma：10 % • Penetrating trauma：15 %～30 %

3. Initial Management Plan • Airway maintenance with cervical spine protection • Breathing: ventilation and oxygenation • Circulation with hemorrhage control

4. Initial Assessment • Primary Survey: –AIRWAY •Always assume a cervical spine injury exists until proven • Jaw-thrust maneuver

5. Initial Assessment • ALWAYS ASSUME FULL STOMACH PRECAUTIONS---RAPID SEQUENCE INTUBATION

6. Indications for intubation: –Airway obstruction –PaO2 < 80 mmHg or SpO2 < 90% with O2 –Shock with SBP < 90 mmHg –Severe head injury or unconscious (GCS <9) –Anticipated surgery with multisystem injury

7. Initial Assessment • Awake intubation: local, topical superior laryngeal nerve blocks • Awake fiberoptic: may be too bloody • Awake cricothyrotomy/tracheostomy • Know your difficult airway algorithm!

8. Initial Assessment • BREATHING –100 % O2 –Always verify correct position of ETT.

9. Initial Assessment • Circulation –Control hemorrhage first! –Crystalloids vs. colloids vs. blood products?

10. Secondary survey • After primary survey complete, attempt to complete a head-to-toe assessment

11. Preop assessment • Cardiac: S/S shock, EKG changes • Respiratory: Breath sounds, crepitus, respiratory patterns/distress, CXR • Neurologic: GCS, LOC; assume C-spine injury until ruled outLateral C-spine Xray, palpate neck • Renal: monitor urine output, amount and color

12. Preop assessment • Gastrointestional: FULL STOMACH!!!! • Endocrine: release of stress hormones (catecholaminesand glucose) • Hematologic: hypovolemicshock; coagulopathies

13. Laboratory/diagnostic tests • CBC, electrolytes, urinalysis, PT/PTT, lactate, baseline ABG (as condition permits) • CXR, lateral C-spine, CT/MRI • 12 lead EKG • FAST: focused abdominal sonography for trauma

14. INJURIES TO IDENTIFY DURING PRE-OPERATIVE ASSESSMENT

15. AIRWAY INJURY/OBSTRUCTION • Intrathoracic tracheobronchial injuries are less common than upper airway injuries. • High mortality. • A definitive airway can usually be secured using a fiber-optic bronchoscope

16. Pneumothorax • Accumulation of air between parietal and visceral pleura • Results in severe V/Q mismatch and hypoxia • S/S: –chest wall hyperresonant to percussion –Breath sounds decreased or absent unilaterally –Subcutaneous emphysema –CXR confirms

17. Tension pneumothorax • Diagnosis of tension pneumothorax is clinical rather than radiological - Absent breath sounds - Hyper-resonant percussion - No chest movement - Tracheal deviation to the injured side - Distended neck veins (may not be seen if the patient is hypovolaemic). - Severe dyspnoea, tachycardia and hypotension

18. Tension pneumothorax • Immediate chest decompression is required. • During anaesthesia • In pressure controlled modes: ↓ tidal volume • In volume controlled modes: ↑ peak airway pressure

20. OPEN PNEUMOTHORAX • >2/3rd the diameter of the trachea. • This results in paradoxical breathing with collapse of the lung on the affected side during inspiration. • This results in increased intra-pulmonary shunt, decreased venous return and progressive hypoxaemia and hypercapnia. • Administration of oxygen, covering the wound and chest drain insertion.

22. Hemothorax • Can be caused from bleeding of intercostal vessels, pulmonary arteries or veins, avulsion of mediastinal vessels or penetrating cardiac injury. • Differentiated from pneumothorax by dullness to percussion with absent breath sounds

25. Hemothorax • The choice and dose of anaesthetic induction agent is determined by the severity of the shock and any preexisting medical co-morbidity • Fluid load before chest tube placement • Thoracotomy may be needed if drainage is more than 250 mls per hour, or the patient’s physiological status continues to deteriorate despite fluid replacement.

26. Flail chest • Results from two or more ribs fracture in two or more places • Accompanied by hemothorax or pulmonary contusion • Patients with 3 or more rib fractures have greater likelihood of hepatic or splenicinjury

27. Flail chest • S/S –Paradoxical chest wall movement • Treatment –O2 –Pain control

28. Cardiac tamponade • Life-threatening emergency • Bleeding into pericardial space, which restricts cardiac filling during diastole and creates a low cardiac output state • Initial symptoms - Dyspnea – Orthopnea – tachycardia

29. Cardiac tamponade • Classic symptoms –Beck’s triad neck vein distention, hypotension, muffled heart sounds –Pulsus paradoxus: > 10 mmHg decrease in blood pressure during spontaneous inspiration • May not be evident in hypovolemia

30. Cardiac tamponade • Echocardiography provides the definitive diagnosis.

31. ANAESTHESIA FOR RESUSCITATIVE THORACOTOMY • Penetrating cardiac injury may rapidly lead to cardiac arrest. • Induction of anaesthesia may lead to a dramatic loss of blood pressure and care should be taken with the choice of induction agent.

32. AORTIC DISRUPTION • A wide mediastinum on chest X-ray may be the only indication that the injury has occurred • Spiral contrast CT is now performed more frequently than angiography

33. TRACHEOBRONCHIAL INJURY • high mortality • In blunt trauma the majority of injuries occur within a 2 – 3 cm of the carina • Signs include haemoptysis, subcutaneous emphysema and persisting pneumothorax or broncho-pleural fistula following chest drain insertion.

34. TRACHEOBRONCHIAL INJURY • Low tidal volume, permissive hypercapnia ventilatory strategies are required until surgical intervention has occurred. • Once intubated fibre optic bronchoscopy is needed to identify the site of the leak.

35. OESOPHAGEAL DISRUPTION • very rare • most frequently occurring in the lower oesophagus

36. DIAPHRAGMATIC RUPTURE • most commonly after blunt abdominal trauma. • Usually on the left side. • Classically the stomach, nasogastric tube or colon is noted to be in the left side of the chest on chest X-ray.

37. Pulmonary contusion • Intra-alveolar hemorrhage and edema resulting from sudden increase in intra-alveolar pressure and rupture of alveolar-capillary interface • Difficult to diagnosis

38. ARDS • Later pulmonary complication • Attributed to direct thoracic injury, sepsis, aspiration, head injury, massive transfusion, oxygen toxicity, and fat embolism • Mortality rate reaching 50%

39. INTRA-OPERATIVE LUNG PROTECTIVE STRATEGIES • LUNG PROTECTIVE VENTILATION • tidal volume 6 - 8 mls/kg • trans alveolar pressure is kept below 35 cm of water (plateau airway pressure of 35 - 45 cm of water).

40. INTRA-OPERATIVE LUNG PROTECTIVE STRATEGIES • INTRA-OPERATIVE LUNG RECRUITMENT • Extrinsic PEEP • a single large tidal breath and holding end inspiration for 20 seconds

41. Myocardial contusion • Associated with blunt trauma • Contusion most often right ventricle since lies directly posterior to sternum • S/S –Dysrhythmias: heart block to Vfib; ST segment elevation –Elevated CPK-MB; ? Troponin elevation –CHF –Anginal pain which may or may not respond to nitrates

42. Anesthetic management • The general principles of trauma anesthesia such as oxygenation, restoration of circulating volume, correction of hypothermia and coagulopathy.

43. Anesthetic management • Induction • Standard monitors • Preoxygenation • direct laryngoscopy + RSI • Invasive monitors as indicated

44. Induction agents • Thiopental 3-4 mg/kg; reduce doses in unstable patients • Ketamine 0.5-1 mg/kg; useful for burn and hypovolemic patients; avoid with head injuried • Etomidate 0.1-0.3 mg/kg; reduce doses with hypovolemia • Propofol 1-2 mg/kg in stable patients; reduce doses in hypovolemia

45. Muscle relaxants • Succinylcholine: 1-2 mg/kg; useful for RSI • Rocuronium: 1 mg/kg

46. ONE LUNG ANAESTHESIA • Double-lumen tubes are often difficult to insert during rapid sequence intubation and are commonlyassociated with malposition.

47. Maintenance • Low-dose volatile agent with fentanyl and nondepolarizing muscle relaxant is usually suitable. • Avoid Nitrous oxide. • Bispectral index monitor

48. Conclusion • Blunt or penetrating thoracic injuries present a particular challenge as a result of complex, dynamic and lifethreatening injuries • The roles of the anesthesiologist and anesthetist are critical.