Where do you insert the needle for pneumothorax decompression?
“2nd intercostal space (ICS), mid-clavicular line (MCL)” – this has been drilled into all of us since we began training and caring for critically ill patients. Ever since we began as pre-hospital care providers or took our first Advanced Trauma Life Support have we used the 2nd ICS, MCL and assumed it to be optimal.
Well recently some studies have started looking at whether we should consider an alternative location. There is some evidence to suggest that the traditional anterior approach may reduce kinking and in the combat environment, it might be preferred (Beckett A et al. J Trauma 2011). However, if it will never enter into the pleural space then kinking becomes irrelevant. While the utility of needle decompression vs. simple finger thoracostomy followed by chest tube insertion can be debated, in the pre-hospital setting, needle decompression remains within the realm of paramedics and may at times be most practical. Also, unless you’re rapidly prepared to perform a chest tube with sterility in mind, needle decompression may be a better option. Thus, such studies remain important.
A recently published study (from the USC trauma surgeons in Los Angeles who seem to publish everything related to trauma) compared the 2nd ICS , MCL with the 5th intercostal space, anterior axillary line (AAL).
CT chest exams of 120 trauma patients were used in the study. Measurements were taken at both sites and compared. Interestingly, the authors stratified patients into 4 BMI categories then analyzed the data based on these groupings.
- Overall, the 5th ICS AAL was a superior site for needle decompression based on chest wall measurement
- Chest wall thickness was thicker at the 2nd ICS MCL compared to the 5th ICS AAL (by 0.5cm)
- As only 16% of patients had chest walls thicker than the standard 5cm needle commonly used. Compared to 42% probable failures if placed at the 2nd ICS MCL.
- Based on BMI stratification, needle decompression at the 5th ICS AAL would be possible for all but the highest BMI while at the 2nd ICS MCL would likely fail except in the lowest group
Take home message – given this was not a clinical study (only based on CT scans) it’s not quite practice changing. We don’t know the potential risks of cardiac injury using the 5th ICS AAL or whether it can be feasibly performed without kinking. However, this technique could be considered if the 2nd ICS MCL fails, especially in high BMI patients and clearly any benefits outweigh the risks – for instance if the patient has already arrested.
Inaba K et al Radiologic evaluation of alternative sites for needle decompression of tension pneumothorax. Arch Surg 2012;147:813-8
OBJECTIVE: To compare the distance to be traversed during needle thoracostomy decompression performed at the second intercostal space (ICS) in the midclavicular line (MCL) with the fifth ICS in the anterior axillary line (AAL).
DESIGN: Patients were separated into body mass index (BMI) quartiles, with BMI calculated as weight in kilograms divided by height in meters squared. From each BMI quartile, 30 patients were randomly chosen for inclusion in the study on the basis of a priori power analysis (n = 120). Chest wall thickness on computed tomography at the second ICS in the MCL was compared with the fifth ICS in the AAL on both the right and left sides through all BMI quartiles.