OR / Prep · Trauma & Acute Care Surgery · open
You’re scrubbing into
Intercostal chest drain insertion
Why are we operating?
A tube into the pleural space through the safe triangle, the treatment of pneumothorax, haemothorax and effusion, and the trauma bay's most performed operation.
Indication: Traumatic haemothorax or pneumothorax, tension pneumothorax after needle decompression, and large symptomatic effusions.
Read the imaging first

Practice before you scrub
Find the lung edge
A tall 22-year-old with sudden pleuritic pain and breathlessness at rest. Chest radiograph. (Fictional educational case.)
- Line plus markless space makes the diagnosis; size and reserve choose between observation, aspiration and a drain.
- Tension physiology is treated on examination, never on imaging: the film you wait for is the one in the coroner's file.
The operation in 4 steps
01The safe triangle
The triangle is drawn: anterior border of latissimus dorsi, lateral border of pectoralis major, a line at the level of the nipple, aiming for the 4th to 5th intercostal space in the mid-axillary line.
Why: The triangle exists to miss things: above the nipple line avoids the diaphragm and abdomen, in front of latissimus avoids the long thoracic nerve's territory, and mid-axillary keeps clear of the internal mammary and the heart.
02Blunt dissection into the pleura
Skin incision, then blunt dissection with a clamp over the top of the rib, a controlled pop through the parietal pleura, and a finger sweep confirming lung, not liver, spleen or adhesions.
Why: The finger sweep is the safety step no imaging replaces: it confirms the space is truly pleural and free before a tube is committed. Trocars are not used, they are how drains end up in lungs and livers.
03Tube placement and connection
The drain is guided in with the clamp, directed apically for air and basally for blood, connected to an underwater seal, and the water column checked for swing and bubbling.
Why: The underwater seal is a one-way valve made of physics: air leaves on expiration and cannot return. Swinging confirms the tube is intrapleural; bubbling reports the air leak it is treating.
04Securing and the check film
The drain is sutured and taped, an omental tag dressing applied, and a chest X-ray taken to confirm position and re-expansion.
Why: A drain that falls out at 3 a.m. was secured badly at 3 p.m. The film is the proof of both position and effect, and the baseline every later film is judged against.
Danger zones
Intercostal neurovascular bundle
The bundle cannot be seen from outside; only technique protects it, and a drain forced under a rib rather than over one finds the artery.
Anatomy you need
Count the ribs of the safe triangle and note the subcostal groove: the bundle hides under each rib, which is why the drain goes over the top of the one below.
What can go wrong
Watch it done
Chest tube placement
The emergency medicine teaching of the open technique in the triangle of safety.
Source: EM:RAP Medical Education · Watch on YouTubeChest tube placement
The Boston Children's open-access teaching, longer and slower, with the underwater seal explained.
Source: OPENPediatrics · Watch on YouTube
Conceptual teaching for learners preparing to observe and assist under supervision, not operative instructions. Five minutes from now you should know why this operation exists, what its shape is, and which structures it is designed not to injure.