Needle Thoracostomy: Chest Wall Thickness, Anatomical Location, and Needle Length

Needle Thoracostomy: Chest Wall Thickness, Anatomical Location, and Needle Length

Authors: Schaefer L, Stein E, Schwarz A, Beck G, Krebs J, Boesing C
Journal: Annals of Emergency Medicine, July 2026

Conclusions:

  • In patients with class II and III obesity, chest wall thickness was lower at the 2nd intercostal space midclavicular line than at the 4th/5th intercostal space anterior axillary line.

  • Increasing BMI had a much larger effect on chest wall thickness at the anterior axillary site than at the midclavicular site.

  • With an 83-mm needle, no patients exceeded chest wall thickness at the 2nd ICS-MCL, while about 1 in 5 exceeded it at the 4th/5th ICS-AAL.

  • Practical takeaway: for obese patients needing emergent needle decompression, this study suggests 2nd ICS-MCL with a longer 83-mm needle may maximize pleural access, despite common teaching favoring lateral placement.

Practice Takeaways:

  • The classic 5-cm angiocatheter may be too short in a substantial proportion of obese patients, especially at the lateral/anterior axillary location.

  • In this cohort, the 4th/5th ICS-AAL site was thicker, and thickness rose more sharply with increasing BMI.

  • This paper challenges the assumption that lateral placement is always anatomically easier in obese patients.

  • For suspected tension pneumothorax in obesity, consider:

    • Using a longer needle/catheter when available.

    • Confirming landmarks carefully.

    • Moving quickly to finger thoracostomy or tube thoracostomy if needle decompression fails or the patient remains unstable.

  • This was an ultrasound anatomy study, not a clinical outcomes trial; it measured likely pleural access, not actual decompression success.

  • The finding is especially relevant for EDs and EMS systems that stock both shorter and longer decompression catheters.

Results:

  • Population: 110 patients with class II or III obesity.

  • BMI range: 36–71 kg/m².

  • Chest wall thickness was measured by ultrasound at:

    • 2nd intercostal space, midclavicular line.

    • 4th/5th intercostal space, anterior axillary line.

  • Chest wall thickness was consistently greater at 4/5 ICS-AAL than at 2 ICS-MCL across the BMI range.

  • Effect of BMI on chest wall thickness:

    • 4/5 ICS-AAL: increased 11.3 mm per 10 kg/m².

    • 2 ICS-MCL: increased 4.2 mm per 10 kg/m².

  • Chest wall thickness exceeded a 50-mm needle length in:

    • 22% at 2 ICS-MCL.

    • 82% at 4/5 ICS-AAL.

  • Chest wall thickness exceeded an 83-mm needle length in:

    • 0% at 2 ICS-MCL.

    • 21% at 4/5 ICS-AAL.

Methods:

  • Prospective cross-sectional study of patients with class II and III obesity.

  • Chest wall thickness was assessed by ultrasound at two common needle thoracostomy locations.

  • Investigators compared measurements across BMI categories and evaluated whether thickness exceeded common needle lengths:

    • 50 mm

    • 83 mm

  • Linear mixed-effects models assessed the influence of:

    • BMI

    • Anatomical location

    • Sex

Schaefer, L., Stein, E., Schwarz, A., Beck, G., Krebs, J. and Boesing, C., 2026. Needle Thoracostomy: Implications of Chest Wall Thickness for Anatomical Location and Needle Length. Annals of Emergency Medicine.

 

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