Recommended Site for Needle Decompression in Pneumothorax
For needle decompression of pneumothorax, the recommended sites are the 2nd intercostal space in the midclavicular line (2nd ICS-MCL) for left-sided pneumothoraces, and either the 2nd ICS-MCL or the 5th intercostal space in the midaxillary line (5th ICS-MAL) for right-sided pneumothoraces, using a minimum 7 cm needle (ideally 8.25 cm). 1, 2
Site Selection Based on Side of Pneumothorax
Left-Sided Pneumothorax
- Primary site: 2nd intercostal space in the midclavicular line (2nd ICS-MCL)
- This site is preferred for left-sided pneumothoraces due to lower risk of cardiac injury 2, 1
Right-Sided Pneumothorax
- Either:
- 2nd intercostal space in the midclavicular line (2nd ICS-MCL)
- 5th intercostal space in the midaxillary line (5th ICS-MAL)
- The 5th ICS-MAL has thinner chest wall thickness compared to 2nd ICS-MCL, potentially increasing success rates 2
Needle Length and Equipment
- Use a 14-gauge needle/angiocatheter with a minimum length of 7 cm, ideally 8.25 cm 1
- Failure rates decrease by approximately 7.76% per cm of increased needle length 2, 1
- Standard 5 cm needles have high failure rates due to insufficient length to reach the pleural cavity 3, 4
Proper Technique
- Identify the correct intercostal space
- Insert needle perpendicular to the chest wall, just above the rib (to avoid neurovascular bundle)
- Advance until a rush of air is heard/felt, indicating entry into the pleural space
- Attach a one-way valve to the catheter if available
- Leave catheter in place until definitive chest tube can be inserted 1
Anatomical Considerations
- Chest wall thickness varies significantly between patients, particularly with increased BMI 5
- In overweight and obese patients, the chest wall is thicker at the 5th ICS-AAL than at the 2nd ICS-MCL 5
- Meta-analysis data shows the 5th ICS-AAL/MAL sites have thinner chest walls than the 2nd ICS-MCL 2
Cautions and Complications
- Failure to correctly identify the 2nd intercostal space is a common error 6
- Risk of injury to underlying structures, particularly with improper placement 1
- For left-sided pneumothoraces, avoid the 5th ICS positions due to increased risk of cardiac injury 2, 1
- Insufficient needle length and catheter dislodgment are common causes of procedure failure 1, 4
Evidence Quality Assessment
The most recent meta-analysis (2025) analyzed 51 studies and found that the 5th anterior axillary line (5AAL) and 5th midaxillary line (5MAL) had thinner chest walls than the 2nd midclavicular line (2MCL), but injury rates were higher at 5AAL than 5MAL 2. The American College of Surgeons guidelines recommend using a minimum 7 cm needle (ideally 8.25 cm) to ensure adequate pleural penetration 1.
Some studies have found higher success rates with the 5th intercostal space approaches 7, while others have found better theoretical success rates with the 2nd ICS-MCL approach, particularly in overweight and obese patients 5. The most recent and comprehensive evidence supports a site-specific approach based on which side of the chest requires decompression 2, 1.