Tension pneumothorax must be identified and treated immediately. In addition to chest pain and breathing difficulties, its symptoms include tachycardia, cyanosis, distended blood vessels on the neck and hypotension.
Consider spontaneous pneumothorax as a cause for acute chest pain and dyspnoea in young smokers as well as in patients with chronic obstructive pulmonary disease.
Classification
Primary spontaneous pneumothorax
Occurs in persons with otherwise healthy lungs. Usually a rupture of a pulmonary alveolus in the apex of the lung causes an air leak.
Occurs most frequently in men aged 20-40 years and in tall, thin persons.
More than 90% of the patients are smokers.
Secondary spontaneous pneumothorax
A complication of another pulmonary disease (pictures 12)
Usually COPD, but also asthma, infections, tumours, interstitial lung diseases
The condition is more severe than the primary form, even life-threatening, because pulmonary function is already affected by pulmonary disease.
Traumatic pneumothorax
Penetrating trauma of the chest, rib fracture, increased intrathoracic pressure in association with another injury
Iatrogenic pneumothorax
Catheterizations, punctures and operations in the chest area; positive pressure ventilation
Tension pneumothorax
A one-way valve is formed in the pleural cavity, whereby air can enter the pleural cavity during inhalation but cannot exit from there. Due to changes in the relative pressures, the ventilation is suddenly impaired.
Usually seen in trauma patients and in connection with mechanical ventilation and resuscitation.
Urgent treatment is essential.
Symptoms
Sharp chest pain, dyspnoea and cough irritation are the main symptoms.
The onset is rapid, and the symptoms are exacerbated by breathing and physical exertion. The pain radiates to the ipsilateral shoulder.
The symptoms may be alleviated within 24 h due to adaptation.
A small pneumothorax may be asymptomatic or cause very mild symptoms.
Clinical signs
Suppressed or missing respiratory sounds, impaired chest mobility, and hollow echoing (hypersonoric) percussion sounds are often observed.
Chest movement may be asymmetric.
The clinical findings can be normal in a small pneumothorax.
Tachycardia, cyanosis, and hypotension can be observed in tension pneumothorax.
Subcutaneous emphysema may be present (a crepitation on pressing the skin).
Signs of injury (haematoma, crepitation from a broken rib, etc.) may be visible on the chest.
Diagnosis
A chest x-ray (preferably posteroanterior, standing) or ultrasound examination is always necessary to confirm the diagnosis.
A rim of air is visible or the lung has collapsed.
A small pneumothorax may be difficult to detect (picture 3). A radiograph taken during expiration may be helpful.
A large emphysematous bulla may resemble pneumothorax and cause misinterpretation.
In special cases a CT scan may be necessary (diagnostic problems, planning of surgery, investigation of aetiology).
Treatment
Conservative treatment
Conservative treatment (follow-up by chest x-ray every 1-3 days) is feasible in spontaneous pneumothorax if the following conditions are fulfilled:
The patient is otherwise healthy.
The patient does not have dyspnoea, the air-filled space is less than half of the pleural cavity (the maximum width is less than 3 cm), and it does not become larger during follow-up.
The pneumothorax should decrease in size in 3-4 days and disappear in two weeks at the latest.
The follow-up can be performed in ambulatory care. The patient should contact the doctor immediately if the symptoms get worse.
If conservative treatment is carried out in hospital, oxygen therapy may hasten the resorption of air from the pleural cavity. (The nitrogen content of pulmonary capillary blood decreases, resulting in as much as a 10-fold increase in the gradient necessary for resorption).
Invasive treatment
Tension pneumothorax is always an indication for immediate treatment. A cannula or needle is pushed into the pleural cavity, thus converting the tension pneumothorax into an open pneumothorax.
Thoracocentesis is indicated in a trauma victim or resuscitated patient with difficulty in breathing and signs suggesting tension pneumothorax even if a confirmatory chest radiograph cannot be obtained.
For urgent treatment of tension pneumothorax any injection needle, as large and long as possible, can be used. If possible, at least 14G and over 5 cm long needle should be chosen.
Traditionally, the 2nd intercostal space in the midclavicular line has been recommended as the puncture location. Alternatively, 4th or 5th intercostal space in the midaxillary line can be used. The puncture is performed close to the upper margin of the lower rib to avoid damaging the nerves and blood vessels under the upper rib.
If pleural drainage cannot be immediately implemented, the cannula may be covered during transportation with a special pneumothorax dressing (e.g. Asherman chest seal) that has a one-way valve to prevent outside air from entering the chest cavity.
Active treatment (drainage or aspiration) is indicated in other types of pneumothorax if one of the following conditions is fulfilled:
The lung is markedly or completely collapsed.
The patient has a chronic pulmonary disease.
The patient has significant dyspnoea (e.g. a previously healthy patient has dyspnoea on slight exercise such as walking).
Mere aspiration may in some conditions be warranted. The outcome of aspiration is good in 70% of patients. The procedure is carried out as follows:
Puncture the pleural space after local anaesthesia between the second and third ribs (the second rib is on the level of angulus sterni) at the midclavicular line, close to the upper margin of the third rib, with a cannula (minimum length 4.5 cm).
Remove the needle from the cannula and connect the cannula to a 50-100 ml syringe (Luer lock).
Aspirate air until resistance is felt or the patient gets a heavy cough, or until more than 2.5 l of air has been aspirated.
Pleural suction is recommended in traumatic pneumothorax, collapsed lung, and in patients with severe dyspnoea. The procedure is performed as follows:
Use a small pleural puncture catheter (French 9-12) if there is no fluid in the pleural space. Other catheters can be used if they have several holes in the last 10 cm of the catheter tip.
A local anaesthetic is infiltrated in the 2nd or 3rd intercostal space in the midclavicular line. The tissue near the rib periost must be anaesthetized particularly well.
Incise the skin and subcutaneous tissue with a lancet as far as the upper margin of the rib. Make the way to the pleural space with a blunt instrument (crile).
Insert the trocar in to the pleural space without force.
Connect the catheter with suction (10-20 cm H2O) immediately or use a Heimlich valve. Do not close the catheter.
Traumatic pneumothorax is often associated with haemothorax. In such cases the pleural space should be drained at the mid- or posterior axillary line in the sixth intercostal space (the nipple is usually situated on the fifth intercostal space) with a larger (French 20-24) catheter. It is safest to make an incision with a lancet and then use the finger to make the way to the pleural space. Usually it is not necessary to drain a haemothorax before transportation to a hospital.
If the lung is not inflated insert another drain.
If an air leak continues despite the suction, the leak should be treated surgically, nowadays usually endoscopically. Open thoracotomy is rarely needed.
After treatment the patient should avoid physical exercise for 2-4 weeks and travelling by air for 2 weeks.
Prognosis
Both primary and secondary pneumothorax tend to recur in 50% of patients.
Surgical treatment should be considered after the second episode at the latest.
References
Henry M, Arnold T, Harvey J; Pleural Diseases Group, Standards of Care Committee, British Thoracic Society. BTS guidelines for the management of spontaneous pneumothorax. Thorax 2003;58 Suppl 2():ii39-52. [PubMed]
MacDuff A, Arnold A, Harvey J; BTS Pleural Disease Guideline Group. Management of spontaneous pneumothorax: British Thoracic Society Pleural Disease Guideline 2010. Thorax 2010;65 Suppl 2():ii18-31. [PubMed]