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Describe the pathophysiology of primary lunch parenchymal injury due to blunt force trauma.
compressive force on chest--> gas-filled alveoli and fluid-filled vessels move at different velocities--> shearing forces as gas-fluid interfaces--> vessel rupture and hemorrhage
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Describe the pathophysiology of secondary lung injury due to an inflammatory response.
damage to alveolar epithelium--> fluid accumulation--> worsening pulmonary function over first 24 hours
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What are physical exam findings with pulmonary contusions?
- respiratory distress- rapid and shallow or prolonged and deep
- auscultation- increased bronchovesicular sounds, crackles
- hemoptysis/ blood-tinged fluid in nose or mouth
- with cardiovascular collapse, can bleed out in lungs
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What initial diagnostics should we pursue with thoracic trauma? (4)
- chest tap based on hx of trauma or PE findings
- pulse oximetry: assess oxygenation
- arterial blood gas analysis: earliest indicator of pulmonary function, more sensitive than radiographs, assess need for supplemental oxygen
- thoracic rads: only once stabilized, interstitial alveolar pattern, patchy or diffuse, initial rads may not reflect severity
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What is the treatment for pulmonary contusions?
- supplemental oxygen
- ventilation if needed (if SpO2 <90% or PaO2 < 60mmHg)
- be cautious with fluid therapy- don't want rapid increases in hydrostatic pressure ("hypotensive resuscitation")
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What are causes of pneumothorax? (5)
- Open- penetrating chest wounds (open to atmospheric pressure- aka sucking chest wound)
- Closed- leak from pulmonary parenchyma- HBC, stepped on, fall from height, kicked
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What is the pathophysiology of an open pneumothorax?
penetrating wounds opens pleural space to atmosphere--> negative intrapleural pressure draws air on inspiration--> positive intrapleural pressure expels air on expiration--> pulmonary collapse
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What is the pathophysiology of a closed pneumothorax? (2)
- compression against a closed glottis--> unable to expel air orally--> sudden increase in alveolar pressure--> dissection of alveolar has along tissue planes into pleural space--> shear injury at gas-fluid interface
- direct puncture by fractured ribs
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What is the pathophysiology of a tension pneumothorax?
rapidly progressive, severe form of close pneumothorax; one way valve allows to leak only during inspiration, but not during expiration--> leads to rapid accumulation of air in pleural space without egress--> fatal unless treated immediately
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What are POSSIBLE physical exam findings with pneumothorax? (5)
- may be none
- restrictive breathing pattern
- open wound
- dull/ absent lung sounds
- cyanosis secondary to low oxygen saturation
- if severe, cardiovascular collapse
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What are radiographic findings with pneumothorax? (3)
- heart elevated from sternum on lateral
- retraction of lung lobes, atelectasis
- unable to ID vascular margins
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What is the treatment for pneumothorax? (3)
- oxygen therapy
- thoracocentesis
- if open, occlude opening then perform thoracocentesis
- place indwelling thoracic drainage catheter
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What are indications for a chest tube placement?
- >3 taps in 24 hours
- > 2 taps in 1 hour
- [most traumatic pneumothorax is self limiting]
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How do you monitor a patient recovering from pneumothorax? (3)
- monitor resp rate and effort through auscultation
- pulse oximetry/ arterial blood gases
- monitor tube if placed
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Most traumatic closed pneumothorax is _____________.
self-limiting (may not even need to be tapped)
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What are common sites of diaphragmatic hernia?
avulsion from rib, muscular tear (weakest part of diaphragm)
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Describe the pathophysiology of diaphragmatic hernia.
abdominal trauma--> abrupt increase in intra-abdominal pressure--> rapid lung deflation with open glottis--> large pleuroperitoneal pressure gradient--> rupture of diaphragm leading to abdominal contents in pleural space--> physically prevents lung expansion
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What is the pathophysiology behind dyspnea with diaphragmatic hernia?
compression of lungs leads to alveolar hypoventilation and low V/Q mismatch--> unaffected lung hyperventilates, resulting in high V/Q mismatch--> hypoxemia and hypercapnea
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What is the pathophysiology behind cardiovascular collapse with diaphragmatic hernia?
increased intrapleural pressure--> compression of great vessels--> decreased venous return and cardiac output
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What specific organ involvement can there be with diaphragmatic hernia? (4)
- Liver entrapment (most common): hydrothorax from venous occlusion and elevated venous hydrostatic pressures
- Gastric entrapment: impaired gastric emptying, rapid air accumulation--> major reduction in tidal volume; surgical emergency
- SI entrapment: mechanical obstruction or intestinal ischemia
- Splenic and liver entrapment: reduced arterial flow--> tissue necrosis
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What are physical exam findings with diaphragmatic hernia? (6)
- respiratory distress with restrictive pattern, dull/ absent lung sounds, cardiac sounds may be present or muffled, gut sounds in thorax
- AUSCUTATION MAY BE NORMAL
- empty abdomen on abdominal palpation
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What can help you with diagnosis of diaphragmatic hernia? (3)
- chest tap: if negative, or you get bile, blood, or foul smelling air, it MIGHT be diaphragmatic hernia
- thoracic rads: unable to see diaphragmatic margins, gas filled structures in thorax
- ultrasound: can see hepatic or splenic herniation, pleural effusion; if severe pul contusions are present, lungs look hepatized
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Describe the treatment for a diaphragmatic hernia. (5)
- oxygen supplementation
- supportive care
- intubation if necessary
- NG tube to reduce gastric distention, the "shake down", 30 degree incline
- maybe surgery
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diaphragmatic hernia is a surgical emergency if... (3)
gastric entrapment, severe, non-responsive respiratory distress, unresponsive shock/ tissue perfusion abnormalities
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