Definitions
Needle thoracocentesis involves placing a wide-bore cannula into the mid-clavicular line of the second intercostal space, just above the third rib, in order to decompress a tension pneumothorax.1 Normally, the pleural cavity is a potential space that is free from air and contains only a thin layer of fluid. When air enters the pleural cavity it is termed a pneumothorax.2 Tension pneumothorax is a life-threatening condition that occurs when the intrapleural pressure exceeds atmospheric pressure. It is created when injury to the chest or respiratory structures allows air to enter but not to leave the pleural space, resulting in a rapid increase in pressure on the affected side. This causes collapse of the affected lung, compression atelactasis of the unaffected lung, mediastinal shift towards the opposite side of the chest, and compression of the vena cava.2
Resuscitation and trauma usually illustrate a patient in extremis and suggest that the clinical diagnosis is straightforward and that needle chest decompression always produces a rapid and reliable response.3,4 This may be far removed from the real life situation, where the classically taught signs are not often present. Table 14.1 summarises the symptoms and signs that may be useful for diagnosing tension pneumothorax in awake and ventilated patients.5
Table 14.1 Symptoms and signs of tension pneumothorax, adapted from Leigh-Smith and Harris (2005)5
| Diagnosis of tension pneumothorax in awake patients | Diagnosis of tension pneumothorax in ventilated patients |
| Reliable and early | Rapid disease progression Reliable and early |
| •Pleuritic chest pain | •Decrease in SpO2-immediate |
| •Air hunger | •Decrease in BP |
| •Respiratory distress | •Tachycardia |
| •Tachypnoea | |
| •Tachycardia | |
| •Falling SpO 2 | Others |
| •Agitation | •Increased ventilation pressure |
| Disease lateralisation-ipsilateral | •Surgical emphysema |
| •Hyper-expansion | Disease lateralisation |
| •Hypo-mobility | •Ipsilateral |
| •Hyper-resonance | •Hyper-resonance |
| •Decreased breath sounds | •Decreased breath sounds |
| •Added sounds–crackles/wheeze | •Chest hyper-expansion |
| Disease lateralisation-contralateral | •Chest hypo-mobility |
| •Hyper-mobility | •Added sounds |
| Pre-terminal | Inconsistent |
| •Decreasing respiratory rate | •Cyanosis |
| •Hypotension | •Distended neck veins |
| •Decreasing SpO2 | •Tracheal deviation |
| •Decreasing level consciousness | |
| Inconsistent | |
| •Tracheal deviation | |
| •Distended neck veins |
The literature surrounding needle thoracocentesis
The actual incidence of tension pneumothorax is not known, but it is more common in ventilated than awake patients and possibly most common in ventilated patients with visceral pleural injury from chest trauma.4 Emergency needle decompression is widely advocated for use in the emergency management of tension pneumothorax6,7,8 but there needs to be an appreciation of the potential problems associated with the technique; these will be discussed later.
Needle thoracocentesis is often ineffective on its own and requires subsequent tube thoracostomy,9–14 hence why it should be seen as a temporary measure at best. There are also a number of factors that could cause needle decompression to fail; these include:
Needle too short15,16,17
The recommended point for insertion of a needle is between the 2nd and 3rd intercostal space in the mid-clavicular line. Whilst this is easy to access, it does entail penetration of pectoral muscles and a variable quantity of subcutaneous tissue, which may be increased by oedema and subcutaneous emphysema. It has previously been recommended that the minimum length should be 4.5 cm (standard length 14-gauge cannula);17 although up to one third of trauma patients have a chest wall thickness greater than 5 cm at the normal insertion point.18,19
A potential option is to use the 4th or 5th intercostal space in the midaxillary line and this has been recommended by ATLS as it contains less fat and avoids large muscles.4 Unfortunately this site may have an increased risk of lung damage in the supine patient, as gas collects at the highest point and adhesions are most likely in more dependent parts of the lung.20
Obstruction5,11
- Kinking of the catheter
- Blood
- Pleural fluid
- Tissue.
Malposition
- Incorrect identification of landmarks; could lead to cardiac tamponade
- Inadvertent removal by patient
- Catheter too small to drain a large area5
- Missing a localised tension pneumothorax.
Despite these problems, needle decompression is a technique that has proved safe and therapeutic in the prehospital environment,12,22-23and leads to shorter on-scene times compared with tube thoracostomy.23
Equipment
- 14-gauge cannula
- 10 mL syringe (consider filling with sterile saline)
- Alcohol swab
- Asherman seal or other method of stabilising and securing the cannula.
Indications for use
When there are convincing signs of a tension pneumothorax Table 14.1.
Contraindications for use
None in the emergency management of tension pneumothorax.
Potential problems of use
Box 14.1 Potential problems of needle thoracocentesis
| Problem | Solution |
| 1. Obstruction of catheter: blood, fluid or tissue, or kinked catheter. | Try to aspirate, if unsuccessful, insert second needle close to original site. |
| 2. Needle too short. | Consider using 4th or 5th intercostal space in the midaxillary line if authorised to do so. |
| 3. Malposition | Leave in situ and secure. A small pneumothorax may be created by incorrect thoracocentesis, but this is unlikely to be a significant problem. However, if surgery and ventilation are required under anaesthesia, this can be expanded to a tension pneumothorax. If cannula has been removed, cover wound with sterile dressing and notify receiving hospital. |
| 4. Displaced cannula | Insert a second cannula and secure well. |
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