Ultrasound-guided comparison of needle decompression sites in obese patients: a prospective observational study

The optimal site for needle decompression in tension pneumothorax patients with a body mass index (BMI) over 30 remains debated. This study aimed to identify the most suitable site-second intercostal space at the midclavicular line (2nd ICS in the MCL) or fifth intercostal space at the midaxillary line (5th ICS in the MAL)-by comparing skin-to-pleura distances using point-of-care ultrasound (POCUS). Skin-to-pleura distance measurements at the right 2nd ICS-MCL and the right 5th ICS in the MAL, assessed by three different operators. The primary outcome was to compare the skin-to-pleura distances at the 2nd ICS in the MCL and the 5th ICS in the MAL using POCUS in volunteers with a BMI over 30. The secondary outcome was to evaluate the consistency of different operators in determining the most appropriate site for needle decompression in the management of tension pneumothorax among healthy volunteers with a BMI over 30, using bedside ultrasonography. A total of ninety-one volunteers were enrolled. The skin-to-pleura distance at the 5th ICS in the MAL was found to be statistically significantly greater than that at the 2nd ICS in the MCL in the measurements performed by each operator (Operator 1: p = 0.016; Operator 2: p = 0.002; Operator 3: p = 0.006). The MCL measurements obtained by all three operators demonstrated statistically significant agreement. In obese patients, the 2nd ICS-MCL may be considered the preferred site for needle decompression. Nevertheless, individualized assessment of both sites using bedside ultrasonography is recommended to optimize procedural success and reduce complications.