Chest Drain — Seldinger Technique

Indications

• Pneumothorax — spontaneous pneumothorax needing intervention where aspiration has failed or is not appropriate; pneumothorax in a ventilated patient; symptomatic secondary pneumothorax.
• Pleural effusion — symptomatic effusion; suspected pleural infection / empyema (small-bore ≤14F is first line for pleural infection).
• Traumatic haemothorax / haemopneumothorax — usually needs an open (blunt-dissection) large-bore drain, not Seldinger; follow ATLS.

Contraindications & cautions

Consent & preparation

• Written consent for non-emergency insertion; verbal/best-interests documented in emergencies. Discuss pain, bleeding, infection, organ injury, drain failure/malposition and the (rare) need for surgery.
• Review imaging; ensure current chest X-ray or ultrasound supports the diagnosis and side. Confirm side against imaging and mark — wrong-sided drains are a recognised never-event-class error.
• IV access, baseline observations, analgesia plan. Check platelets/INR if time allows and risk factors exist.
• Position: semi-recumbent at ~45° with the arm abducted behind the head (pneumothorax); for fluid, position guided by comfort and ultrasound findings.
• Full aseptic technique — sterile gloves, gown, drapes, skin prep.

Equipment

Site — the safe triangle

First-choice insertion site is within the triangle of safety. Placing drains outside it — especially posteriorly — increases the risk of intercostal vessel and organ injury.

Step-by-step technique

1. Scan (if fluid) and confirm the site

   Bedside ultrasound at the point of insertion, in the position the patient will stay in. Confirm fluid depth and the absence of underlying lung/solid organ at the chosen space.

2. Anaesthetise generously, down to the pleura

   Infiltrate skin with lidocaine 1% (max 3 mg/kg), then track down to rib periosteum and pleura — the pleura is richly innervated and under-anaesthetising it is the commonest cause of a distressed patient. Aspirate air or fluid to confirm you are in the pleural space; if you cannot aspirate, do not proceed.

   LAST rescue — AAGBI algorithm ↗

3. Nick the skin

   Small scalpel nick at the entry point while the anaesthetic takes full effect; prepare needle, wire and dilator.

4. Introducer needle — just above the rib

   Advance the introducer needle along the anaesthetised track, passing just above the upper border of the rib to avoid the neurovascular bundle. Hold it ~3 cm from the tip to prevent over-insertion, aspirating continuously. Once air/fluid returns, advance only 5–10 mm further.

5. Guidewire

   Steady the needle, remove the syringe, and feed the wire — never more than 30 cm (marks every 10 cm; exact limits vary by kit — check the wire in use). It should pass with little or no resistance; if it doesn't, stop and reassess. Never let go of the wire.

6. Dilate

   Remove the needle over the wire, enlarge the skin nick right up to the wire, then pass the dilator with a gentle rotating advance along the same plane. If it won't pass, the skin nick is usually too small.

7. Insert the drain

   Remove the dilator, thread the drain over the wire to ~12–14 cm (deeper in a larger chest wall) so all side holes sit within the pleural space. Remove wire and stiffener together.

8. Connect and confirm

   Attach the three-way tap, take diagnostic samples with a 50 mL syringe if needed, then connect to the underwater seal. Confirm swinging with respiration and bubbling (air) or drainage (fluid).

9. Stitch and stick

   Secure with a stitch pulled tight enough to dent the drain, a transparent dressing that leaves the site visible, and an "omental tag" of tape on the tubing as a second anchor.

Complications

Aftercare & documentation

• Immediate observations, then at least 4-hourly, guided by NEWS2; chest-drain chart documenting swinging, bubbling, drainage type and hourly volume, site checks.
• Post-insertion chest X-ray to confirm position.
• Document: indication, consent, side and site, ultrasound findings, anaesthetic dose, drain size and depth at skin, complications, samples sent, post-procedure instructions.
• Prescribe analgesia and regular drain flushes (small-bore drains block easily).
• Bottle always upright and below the insertion site; never lift above the chest without clamping briefly for the move (and never leave a bubbling drain clamped).
• Admit to a ward familiar with chest drains; refer to the respiratory/pleural team.

Pitfalls & pearls

• Ask first: does this patient need a drain at all? Aspiration or observation manages many primary pneumothoraces.
• The commonest failed-Seldinger story: inadequate local anaesthetic → patient moves → wire kinks. Anaesthetise the pleura properly and wait for it to work.
• Cut the skin next to the wire — a nick 5 mm away from the wire track is why dilators "won't go in".
• A drain that stops swinging is blocked, kinked, or out. Examine the whole circuit before flushing.
• Fluid drains need a three-way tap in the circuit from the start — retrofitting one is fiddly and breaks the sterile field.
• In trauma with haemothorax, go straight to an open large-bore drain — a 12F Seldinger will block with clot.

References