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
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
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
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
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")
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
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
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
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
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
What are radiographic findings with pneumothorax? (3)
- heart elevated from sternum on lateral
- retraction of lung lobes, atelectasis
- unable to ID vascular margins
What is the treatment for pneumothorax? (3)
- oxygen therapy
- if open, occlude opening then perform thoracocentesis
- place indwelling thoracic drainage catheter
What are indications for a chest tube placement?
- >3 taps in 24 hours
- > 2 taps in 1 hour
- [most traumatic pneumothorax is self limiting]
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
Most traumatic closed pneumothorax is _____________.
self-limiting (may not even need to be tapped)
What are common sites of diaphragmatic hernia?
avulsion from rib, muscular tear (weakest part of diaphragm)
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
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
What is the pathophysiology behind cardiovascular collapse with diaphragmatic hernia?
increased intrapleural pressure--> compression of great vessels--> decreased venous return and cardiac output
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
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
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
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
diaphragmatic hernia is a surgical emergency if... (3)
gastric entrapment, severe, non-responsive respiratory distress, unresponsive shock/ tissue perfusion abnormalities