Author:
William A.Porcaro
Description
- Presence of free air in the intrapleural space
- Spontaneous pneumothorax is due to atraumatic rupture of alveolus, bronchiole, or bleb
- Primary spontaneous pneumothorax (2/3 of incidences):
- No underlying pulmonary pathology present
- Rupture of small subpleural cyst or bleb
- Primarily young, healthy patients (20-40 yr old) with tall, thin body habitus
- Risk factors: Smoking, family history, Marfan syndrome, homocystinuria, thoracic endometriosis
- Evidence of possible increased incidence with changes in weather pattern/atmospheric pressure
- Secondary spontaneous pneumothorax from underlying pulmonary pathology (see Etiology)
- Tension pneumothorax:
- Air continues to enter pleural space through bronchoalveolar disruption and becomes trapped via “ball-valve” mechanism
- Intrapleural pressure increases
- Venous return to right heart decreases, resulting in decrease in cardiac output
- Mediastinum shifts toward uninvolved side, mechanically interfering with right atrial filling
- Ventilation compromise and ventilation/perfusion mismatch result in hypoxemia
Etiology
- Idiopathic
- Airway disease:
- Chronic obstructive pulmonary disease (COPD)
- Asthma
- Cystic fibrosis
- Infections:
- Neoplasm
- Interstitial lung disease:
- Sarcoidosis
- Idiopathic pulmonary fibrosis
- Lymphangiomyomatosis
- Tuberous sclerosis
- Pneumoconioses
- Connective tissue diseases
- Pulmonary infarction
- Endometriosis
- Blunt chest trauma
- Penetrating trauma to neck or trunk
- Iatrogenic:
- Central line placement
- Other vascular access procedures
Signs and Symptoms
History
- Severity of symptoms is generally proportional to size of the pneumothorax
- Chest pain on the ipsilateral side:
- Sharp, pleuritic pain
- Sudden onset
- Dull ache in delayed presentations
- Shortness of breath
- Rarely cough, asymptomatic, or generalized malaise
Physical Exam
- Tachypnea
- Heart rate <120 bpm generally seen in simple spontaneous pneumothoraces
- Jugular venous distention and tracheal deviation to the contralateral side may be evident in tension pneumothorax
- Cardiac and pulmonary exam:
- Asymmetric decreased breath sounds
- Hyperresonance to percussion of ipsilateral side
- Tension pneumothorax:
- Hypotension
- Tachycardia, heart rate >120 bpm
- Diaphoresis
- Cyanosis
- Cardiovascular collapse
- Tracheal deviation
Essential Workup
- Imaging is mainstay of the workup
- DO NOT delay chest decompression if the patient is hemodynamically unstable and there is sufficient clinical evidence of pneumothorax
Diagnostic Tests & Interpretation
Lab
Arterial blood gas offers little over oxygen saturation
Imaging
- Chest radiograph:
- Patients unable to tolerate upright chest radiograph can be taken in decubitus position with the suspected side up:
- Absence of lung markings distal or peripheral to the visceral pleural white line
- Displacement of mediastinum or anterior junction line
- Deep sulcus sign
- On frontal view, larger lateral costodiaphragmatic recess than on opposite side
- Diaphragm may be inverted on the side with deep sulcus:
- A rough estimate of pneumothorax size is sufficient to make clinical decisions
- Expiratory film:
- May demonstrate small pneumothorax but has not been shown to increase yield of detection
- Inverted grayscale mode is not superior to stand ard view digital x-ray for identification of small pneumothorax
- Chest CT:
- Very sensitive for small pneumothorax but has little practical advantage over chest radiograph
- US:
- User experience required
- Rapid at bedside
- Lack of lung sliding and comet-tail artifact signifies pneumothorax
- M-mode confirms pneumothorax with smooth lines above and below pleural line
- With experience, sensitivity surpasses chest radiograph
Diagnostic Procedures/Surgery
ECG:
- Often necessary to rule out cardiac etiologies of chest pain
- Nonspecific changes include T-wave inversion, left axis deviation, and decreased R-wave amplitude
Differential Diagnosis
- Acute abdominal processes
- Aortic aneurysm or dissection
- Asthma exacerbation
- Chest wall pain
- COPD exacerbation
- Myocardial infarction
- Pericarditis
- Pleuritis
- Pneumomediastinum
- Pneumonia
- Pulmonary embolus
Prehospital
ALERT |
| Unstable patients with a suspected tension pneumothorax require immediate needle thoracostomy |
Initial Stabilization/Therapy
- Cardiac monitor
- Pulse oximetry
- Oxygen 100% via nonrebreather face mask
- IV access
- Suspected tension pneumothorax requires either immediate needle thoracostomy or tube thoracostomy
- Needle thoracostomy:
- Immediate placement indicated in unstable patients with a tension pneumothorax
- 14-18G angiocatheter in the second intercostal space at midclavicular line or fourth or fifth intercostal space at anterior axillary line
- NOTE: The length of most stand ard angiocatheters is too short to penetrate the pleural cavity in moderate- to large-framed patients - longer, purpose-specific catheters may be required
ED Treatment/Procedures
- Nontraumatic pneumothorax estimated at <15% collapse and no cardiovascular or respiratory compromise:
- Observe with 100% oxygen support for 4-6 hr
- Repeat chest radiograph and discharge if unchanged
- Simple aspiration:
- Indications:
- Simple pneumothorax with only 15-30% collapse
- Increase in size of a small pneumothorax during observation
- Placement of aspiration catheter (typically 8F) with 3-way stopcock
- Similar success and recurrence rates to chest tube drainage
- Aspirate air until resistance or 3 L of air aspirated
- If the pneumothorax is no longer visible on 2 subsequent chest radiographs at 4 hr intervals, remove catheter
- If a final chest radiograph is normal 2 hr after the catheter is removed, the patient may be discharged
- A second aspiration may be attempted if the pneumothorax does not resolve
- Heimlich valve:
- Indicated when <30% collapse after failure of aspiration
- Attach Heimlich valve to aspiration catheter or chest tube
- Suction:
- Indicated when the Heimlich valve fails
- Attach aspiration catheter to suction at 20 cm H2O
- Observe in ED for 1 hr
- Tube thoracostomy:
- Indications:
- Suspicion of a tension pneumothorax
- Gunshot wound to the chest
- Clinical evidence of a pneumothorax following blunt chest trauma or penetrating chest trauma
- Presence of a pneumothorax of any size in patient receiving positive-pressure ventilation
- Pneumothorax with >30% collapse
- Most cases of secondary pneumothorax
- Definitive therapy after needle thoracostomy
- Tube size:
- Small-caliber (7-14F) tube for primary spontaneous pneumothoraces
- 20-28F for secondary spontaneous pneumothorax
- 28F when there is detectable pleural fluid or an anticipated need for mechanical ventilation
- Check for tube kinks by fully rotating the inserted tube
- All side holes in the tube must be within the chest wall to avoid leak
- Following insertion, the tube should be connected to a water-seal device
- A Heimlich valve may be used instead of a water-seal device in stable patients without a pleural effusion
- Re-expansion edema is a rare complication requiring supportive care
- Possible complications:
- Intercostal vessel bleeding
- Inadequate drainage:
- Kinked tube
- Clogged tube
- Communication outside of pleural cavity with leak
- Re-expansion pulmonary edema:
- Treatment with fluid resuscitation
Medication
- Local anesthetic:
- 1% lidocaine with epinephrine 1:100,000
- Max dose: 7 mg/kg-500 mg
- Consider procedural sedation in stable awake patients
- No indication for antibiotics in a clean procedure
Disposition
Admission Criteria
- Tension pneumothorax
- Chest tube required
Discharge Criteria
- <15% collapse, no expansion while in the ED or successful aspiration with catheter removed:
- Discharge with follow-up in 24 hr and 1 wk for chest radiograph to assure re-expansion
- Reliable patients with the thoracic vent and successful aspiration or secured catheter and Heimlich valve:
- Discharge with 24 and 48 hr follow-up
- At 48 hr follow-up:
- Clamp catheter, observe for 2 hr, and repeat chest radiograph
- Remove thoracic vent or catheter if no re-expansion
- Observe for 2 hr and repeat chest radiograph
- If no re-expansion, discharge with 24 hr and 1 wk follow-up
- Discharge instruction should include prompt return for new onset of chest pain or dyspnea
- Patients without re-expansion at 1 wk require a cardiothoracic surgery consult
Follow-up Recommendations
Pulmonary medicine and /or chest surgery
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