Wound: drainage

• To remove unwanted material from tissue spaces.

• Obliteration of dead space.
• Elimination of subcutaneous collection of fluid and gas.
• Provide prophylaxis against anticipated fluid or gas accumulations.

Advantages

• Easy to place and maintain.
• Cheap.

Disadvantages

• Increased infection rates compared with wounds not drained.
• Drain can act as a large foreign body.

• Inappropriate use of drain.

Procedure

• Few minutes.

Criteria for choosing test

• Large dead space.
• Subcutaneous collection of fluid.
• Potential for accumulation of fluid or air.

Minimum equipment

• Skin suture instruments.
• Aseptic dressing.
• Skin suture material.

Minimum consumables

• Drain.

Flat drain

• Drain by capillary action and gravity.
• Drainage occurs outside lumen.
• Drainage efficiency is directly related to surface area of drain.
• Fenestration contra-indicated because decreases surface area and impedes flow.
• Soft latex, eg Penrose drain Drain: Penrose  .

Tube drain  

• Rubber or plastic Drain: tube.
• Round with single lumen +/- side holes.
• Drip tubing may be used by cutting hole where plastic has been manually folded (>30% diameter of tube to prevent kinking).
• Advantages:
  • Drainage inside and outside drain.
  • Suction may be applied.
  • Irrigation possible.
  • Less interference with healing than Penrose drains.
• Disadvantage:
  •  Patient discomfort due to stiffness of material.

• Entry site: dorsal recess of wound or above wound.
• Exit site: below wound. 
  Do not place drain through primary incision or suture line.

• Sedation or general anesthesia.

• Prophylactic antibiotics (continue for at least 24 h after removal of drain).

Step 1 - Incise skin

• Make stab incision below wound:
  • Slightly larger than size of drain.

Step 2 - Place drain into wound

Drain placement through exit incision only

• Secure drain in the dorsal recesses of the wound using a penetrating suture tied on the outside of the skin and bring out of ventral exit incision.
• Use Chinese finger trap suture.

Drain placement through both entry and exit incisions

• Place drain into dorsal entry incision and bring out through ventral exit incision.
• Use Chinese finger trap suture. 
  May provide a portal for retrograde contamination.

Step 1 - Dress drain

• Cover drain with sterile absorptive dressing to prevent ascending infections.

Antimicrobial therapy

• Prophylactic antibiotics for at least 24 h after removal of drain.

Follow up

Remove drain

• Capillary ooze only: remove within 24 h.
• Profuse serum discharge: remove within 3-4 days.
• Large areas of dead space: up to 10 days until dead space obliterated. 
  Prolonged use of drains may lead to discomfort, infection and cellulitis.

• Ascending infection.
• Cellulitis.
• Incisional dehiscence.

• Inappropriate use of drain.
• Lack of sterility.

Refereed papers

• Recent references from PubMed and VetMedResource.

Other sources of information

• Manual of Canine and Feline Wound Management and Reconstruction. (1999) Fowler D & Williams J M (eds), BSAVA, Cheltenham.
• Small Animal Wound Management. (2nd edn) (1997) Swaim S F & Henderson R A, Williams & Wilkins, Baltimore.