Background: 40% of needle thoracostomy were failed in emergency situation. The Advanced Trauma Life Support was
recommended to apply 5-cm of needle into the 2nd intercostal space (ICS) about the midclavicular line (MCL) for immediate
treatment of tension pneumothorax. 9.9-35% of normal chest wall thickness (CWT) from the previous studies were more than
5 cm.
Objective: To analyze the average of Thai patient CWT at the 2nd ICS in MCL.
Material and Method: Prospective data collection of the patients who underwent a chest computed tomography scans during the period between April and September 2009. CTW was measured at the 2nd ICS in the MCL in distant for standard
procedure, shortest distant and injured distant.
Results: The mean CWT patients were 35.2+11.9 mm for the right side and 34.7+11.7 mm for the left side. The mean of
shortest distant was 30.9 mm. The mean CWT was significantly higher in patients with high body-mass index (BMI).
Conclusion: The standard 5-cm needle may be not passed into the thoracic cavity in 11.3 % of studied population. CWT was
showed significant correlation with BMI. 44.5% of patients with BMI more than 30 kg/m2 had CWT more than 5 cm.

Keywords: Needle thoracostomy, Chest wall thickness, Pneumothorax