Mechanical Ventilation and Positive Airway Pressure Essay

Submitted By deliababy8
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Respiratory Trauma (Chest Trauma)

Chest trauma is often sudden and dramatic
Major causes of trauma:
Motor vehicle accidents – worse if unrestrained
Deceleration injury from MVAs – ruptured vessels
Penetrating trauma – gunshot, stabbing, impaled
Blunt trauma – dropping free-weights on chest
Medical procedure mistake – pneumo p CVP
Fall from height
Accounts for 25% of all trauma deaths
40-50% of deaths occur on scene
50-60% of deaths occur after reaching a hospital
Fatal consequences: Hypoxia + exsanguination -> vascular collapse -> hypovolemic shock -> cardiac arrest = death

Mechanism of Injury
Head on collision
Falling out a window – how high?
Stab wound – pocket knife or cleaver
Gunshot – what calibre – shotgun?
Is it a peripheral lung injury?
Is a hemothorax involved?
Is it a pneumothorax? Open? Greater risk for tension pneumothorax bc it only occurs with open, bc the pressure becomes greater and the uneffected lung will become affected. Closed?
Is it a great vessel injury?

Blunt Injuries
Blunt injuries: direct blow (e.g. rib fracture) deceleration injury or compression injury
Rib fracture is the most common sign of blunt thoracic trauma
Fracture of scapula (left) will affect the spleen. sternum, or first rib suggests massive force of injury

Chest Wall Injuries
Pulmonary contusion – most common injury
Rib fractures
Flail chest
Open pneumothorax

Pulmonary Contusion (Bruise)
Most common chest wall injury
Pt may be asymptomatic at first
Respiratory failure develops over time (ARDS)
Mostly seen with deceleration injuries
Lung vasculature bleeds
Alveoli become edematous
Edema causes loss of pulmonary compliance
Secretions increase – may lead to hypoxemia and/or respiratory failure
Much more effort is needed to ventilate a contused lung – patients tire out easily, which decreases the surface area, which impairs gas exchange.
Need mechanical ventilation with positive end-expiratory pressure to keep lung inflated
If not treated will lead to ARDS

Rib Fractures
2nd most common thoracic injury
Localized pain, tenderness, crepitus
CXR to exclude other injuries
Analgesia effect is underestimated
Upper ribs, clavicle or scapula fracture: suspect vascular injury
If ribs 1-4 are fractured greater risk of pulmonary contusion or pneumothorax
Patient not taking deep breath r/t pain
Risk of atelectasis and pneumonia
Chest is not splinted to allow normal expansion when breathing
Focus is to decrease pain for breathing
Simple rib fx are left alone to heal
Injuries involving ribs 1-2 or 7 or more ribs usually indicative of an intrathoracic injury, must stay at the hospital.
Poor prognosis with these injuries

Flail Chest
Multiple rib fractures produce a mobile fragment which moves “paradoxically” with respiration.
40% mortality rate
Significant force required
Usually diagnosed clinically
Rx: ABCs and analgesia
Treated conservatively
Best stabilized by mechanical ventilation with PEEP
Surgical fixation only in extreme cases
Pain management
Coughing and deep breathing

Lung Injury
Pulmonary contusion
Parenchymal injury
Trachea and bronchial injuries

Open Pneumothorax
Defect in chest wall provides a direct communication between the pleural space and the environment
Lung collapse and paroxysmal shifting of mediastinum with each respiratory effort = tension pneumothorax which can lead to cardiac tamponade.
“Sucking chest wound”
Rx: ABCs…closure of wound…chest drain... 3 way dressing will create a 1 way valve.

Air in the pleural cavity
Blunt or penetrating injury that disrupts the pleura
Unilateral signs: ↓movement and breath sounds, resonant to percussion
Confirmed by CXR
Rx: chest drain

Tension Pneumothorax
Air enters pleural space and cannot escape
P/C: chest pain, dyspnea
Dx: Respiratory distress, Tracheal deviation (away), Absence of breath sounds,