How to manage wound drains

01 November 2011
Practical
10 mins read
02 November 2011
Volume 2 · Issue 9

Abstract

Wound drains play an important role in the management of wounds that arise in small animal practice. These wounds may result from trauma or following surgical intervention and the employment of drains may be used to improve healing by removing any fluid or air accumulation within tissues and reducing ‘dead space’ both of which are known to prolong wound healing and are associated with increased wound infection and wound dehiscence. Wound drains can be divided by their method of action as either passive or active, the selection of which drain type is suitable is dependent on the nature of the wound, its origin and its position. Correct management of wound drains in situ is a vital component of wound care and incorrect management of these drains can adversely affect wound healing and be detrimental to the patient and their recovery.

Surgical drains are indicated for the prophylactic or therapeutic removal of fluid, air or exudate accumulation within tissue and to obliterate ‘dead space’ left following surgery (Figure 1). The removal of these wound fluids and exudate accumulations are necessary for normal wound healing to occur (Pead and Langley-Hobbs, 2007) and therefore their removal can decrease the risk of wound infection and dehiscence (Ladlow, 2009). Unfortunately, the development of infection by ascending nosocomial pathogens is an associated potential complication with the use of such devices (Johnson, 2002) and it is therefore essential that barrier nursing (wearing appropriate personal protective clothing) is performed to reduce the aforementioned risk to patients with indwelling devices (Johnson, 2002; Andrews and Boag, 2008).

Figure 1. A Bearded Collie with wound breakdown and abscess formation following the removal of a mast cell tumour.

In addition to barrier nursing, during the post-operative period, an aseptic technique is vital when attending to wounds, catheters and surgical drains. With hand washing being the single most effective method of reducing nosocomial infections, a thorough hand washing protocol, such as that recommended by the World Health Organisation (2009), should be carried out prior to (and after) handling the patient and any invasive devices (Gregory, 2005) Hand washing should be performed (with an appropriate antibacterial handwash) even if sterile gloves are to be worn in case there is a break in asepsis (Baines, 1996). Instances of incorrect management and poor aseptic technique will readily negate the benefits of minimizing and preventing bacterial contamination during the pre- and operative stages (Baines, 1996).

Types of available wound drain systems

There are numerous types of wound drain systems available for use in small animal practice. Four of the most common types in use will be covered in this article: Penrose, Jackson Pratt, Redon and Redovac drains. These drains can be classified by their method of action as either passive or active. Passive drains use capillary flow, overflow and gravity to remove fluid from the wound and active drains are those with a vacuum assisted suction via a closed reservoir; usually a collapsible chamber with an intrinsic memory which produces a vacuum on reinflation (Ladlow, 2009). Each of the aforementioned drains will be briefly described and discussed and attention paid to the necessary details for each drain type.

Penrose drains

Penrose drains (Figure 2) are passive drains made from soft flexible latex rubber tubing that relies on capillary action, wound overflow and gravity to drain fluid out of tissues and dead space. It is important to note that passive drains must be placed exiting at the ventral site of the wound to allow for this gravitational pull to enable drainage. As Penrose drains are essentially open to the environment it is essential that they are protected from contamination and the risk of ascending infection reduced by covering them with an absorbent dressing; it may also be necessary to use an emollient cream to protect the skin from becoming inflamed/irritated by the fluid produced.

Figure 2. Penrose drains are passive drains made from soft flexible latex rubber tubing that relies on capillary action, wound overflow and gravity to drain fluid out of tissues and dead space.

As stated, these drains are open to the environment and are therefore unsuitable for the removal of air and without a reservoir they should only be used when the volume of fluid produced is expected to be small. Without a reservoir, monitoring the volume of fluid produced is relatively subjective; a more objective method of measuring fluid drained is to weigh the protective dressing pre and post-absorption of fluid. This method of assessing fluid production is obviously limited and will not be wholly accurate.

These drains are available in a variety of widths (6–50 mm); as a rule, the wider the drain the more effective the drainage (Ladlow, 2009). Theye are suitable for use in, for example, bite wounds or abscesses that require further drainage following treatment.

Jackson Pratt drains

Jackson Pratt (grenade) drains are active suction drains comprising a fat internal silicone tube (with a number of fenestrations along its length to increase surface area through which drainage occurs and prevents blockages) (Figure 3) that exits the body and is attached to an external grenade-shaped reservoir (Figure 4) for the collection of fluid. To activate the vacuum the grenade is squeezed to evacuate the air and its plug closed, thus creating suction along the length of the tube and drawing fluid into the grenade reservoir. Any loss of this vacuum will result in a subsequent loss of suction.

Figure 3. A Jackson Pratt drain — note the fenestrations along its length to increase surface area for drainage.
Figure 4. External grenade-shaped reservoir for the collection of fuid.

The grenade bulb has an external measuring scale to allow for the volume within the reservoir to be recorded. The reservoir should be checked at regular intervals (for loss of vacuum) and can be emptied, as necessary, by opening the plug and squeezing out the contents into a container before resetting the drain. This drain reservoir has two channels at the top: one for attachment of the drain tubing, and a second allowing for the contents of the reservoir to be emptied while still in place (Figure 5).

Figure 5. The two channels at the top of the drain reservoir allowing attachment of the drain and the contents of the reservoir to be emptied while still in place.

This type of drain is suitable in a number of patients and circumstances, for example removal of a mass within the tissues in order to reduce ‘dead space’ and prevent the accumulation of air or fluid. They are available in a variety of tubing and grenade sizes (Ladlow, 2009).

Redon/Red-O-Pack drains

Redon/Red-O-Pack drains are active suction systems consisting of a plastic fenestrated tube (Figure 6) exiting the body and connecting to a cylindrical reservoir chamber which when charged collapses into a concertina formation (Figure 7); as the drain removes fluid, it expands in volume. Again, as with the Jackson Pratt drain it should be checked at regular intervals to measure volume of fluid in the reservoir and to ensure that the drain vacuum is still charged and functional.

Figure 6. Redon/Red-O-Pack drain — note the fenestrations along its length to increase the surface area for drainage.
Figure 7. Cylindrical reservoir chamber — collapses into a concertina formation.

Unlike the Jackson Pratt drain, to empty the drain the reservoir must be disconnected from the tubing as it does not have a separate plug for emptying. These are useful, for example, following the removal of a mass where air or fluid is expected to be produced or where tissues were not able to be fully apposed or following wound breakdown resulting in abscess formation.

Step-by-step guide to managing a wound drain

Passive drain management

  • These drains should always be covered in entirety with a primary absorbent dressing (such as Allevyn or Melolin, Smith and Nephew) placed over the drain to absorb fluid and prevent the risk of ascending nosocomial infection as a result of any strikethrough. Depending on the site of the drain, this absorbent layer may be adhesive or non-adhesive in nature. Non-adhesive dressings will require further dressing layers (such as Soffban and Easifx, BSN Medical, and Vetwrap, 3M) to ensure the primary layer remains in place.
  • These dressings should be removed completely daily and the drain site monitored for any signs of infection and inflammation. Hands should be thoroughly washed and dried and gloves should be worn for the removal of the dressings. Sterile gloves should be worn for the removal of the primary dressing and for inspection of the drain site. The outer layers can be removed by one person, leaving the primary layer in situ to be removed and site inspected by the person wearing sterile gloves.
  • A new primary layer should be applied once the area has been fully inspected. The surrounding skin can be cleaned with sterile swabs and saline if required and emollient cream, e.g. Vaseline (Unilever UK Ltd, Surrey) or Sudocrem (Forest Laboratories UK Ltd, Kent), should be applied if skin irritation is occurring as a result of fluid contact.
  • The choice of primary dressing should be determined by the level of fluid being produced and therefore requiring absorption. If strikethrough occurs, extra layers can be added to the dressing or the dressing may need to be changed more frequently.

    • Active drain management

  • As these drain systems are closed and have a reservoir for collection of fluid, they require minimal dressing; however this does not mean that any less attention should be applied to the prevention of ascending nosocomial infection when handling them.
  • A light adhesive dressing, such as a Primapore (Smith and Nephew) may be all that is required to cover the exit site of the drain as there should be an airtight seal around the drain site which should remain clean, dry and free of any contamination from the drain. Hands should be washed, dried and sterile gloves should be worn to remove this dressing and this site should be checked daily for any sign of infection or irritation and a new dressing applied.
  • As a loss of vacuum due to air entering the reservoir or from the drainage of fluid will result in loss of suction, these drains should be regularly checked to ensure the vacuum is still present. As a general rule, when the drain is 50% full it should be emptied (Ladlow, 2009) to ensure the negative pressure being applied is maintained.
  • Emptying the drain should be performed in an aseptic manner; the opening to the chamber should be wiped with an alcohol wipe (Sterets: Molnlycke Healthcare) and its contents squeezed out into a container. The vacuum should then be reset using both hands to compress the reservoir (Halfacree et al, 2006) before reattaching to the drain tubing.

    • Redovac drains

    Redovac drains are completely closed active suction units. They consist of fenestrated drain tubing which connects into a large rigid plastic reservoir bottle (Figure 8). The reservoir bottle has a pre-established vacuum mechanism which should not be activated (by the release of gate clamps present along the length of the drain tubing) until a seal has formed around the exit site (4–6 hours post operatively) as the vacuum in these bottles cannot easily be recreated (Ladlow, 2009). If the bottle fills with air before a seal has formed, this bottle will need to be replaced or emptied of air using a suction unit or syringe.

    Figure 8. A Redovac drain is composed of a trocar, fenestrated drain tubing and collection unit with a pre-established vacuum.

    These systems have a scale along the side of the bottle which allows for the volume of fluid to be measured accurately and there is also an indicator allowing for the presence of the vacuum to be checked; this is essential to determine the presence of a vacuum as the reservoir bottle does not change shape. These systems are not always suitable/tolerated in cats due to their large size but they have been successfully used in some cases, e.g. septic joint, large wound closure where there has been difficulty in reducing ‘dead space’ and apposing tissue layers, stick injury deep within the tissues and where a moderate to large volume of fluid or air is expected to be produced.

    The exit site of all drains must be covered and the drain can be carried by the patient in a stockingette dressing (e.g. Surgifix, Smith and Nephew, London) for patient comfort or can be placed in a canine back-pack (e.g. Dog Packs, Ruffwear, Oregon, USA) which is well tolerated in the majority of cases.

    Advantages/disadvantages of passive and active drains

    There are advantages and disadvantages to both passive and active drainage system.

    Passive drains

    Advantages

  • Inexpensive.
  • Soft, flexible material resulting in less tissue trauma compared with the tubing from active drains.

    • Disadvantages

  • Suitable for small volumes of fluid only; difficult to measure fluid production and manage dressings if volumes are high.
  • Require gravity to achieve successful drainage; may be unsuitable for wounds on head or dorsum.
  • May allow the passage of air into the wound and are therefore unsuitable for use in wounds that may lead into the thoracic cavity as a pneumothorax could develop (Ladlow, 2009).

    • Active drains

    Advantages

  • More efficient than passive drains.
  • Reduced risk of nosocomial infection as systems are closed to the environment.
  • Easily portable using sutures, stockingette dressing (e.g. Surgifix, Smith and Nephew) (Figure 9) or a canine back-pack (e.g. Dog Packs, Ruffwear).
  • Minimal dressing required, which in wounds producing larger volumes of fluid, may compensate for the cost of the drain against the use of a cheaper passive drain and the dressing materials required for absorption of fluid.
  • Fluid production can be easily measured.
  • Reduced risk of drain occlusion due to constant low pressure vacuum environment.
    • Figure 9. Redovac drain placed following the closure of a large inguinal wound, carried by the patient within a stockingette dressing.

    Disadvantages

  • Loss of vacuum and therefore loss of suction may occur if air enters the reservoir. Drains may require extra sutures to ensure an air tight seal is manufactured; alternatively the drain can be activated 4–6 hours post placement when a fibrin seal will have made the wound air tight (Ladlow, 2009).

    • How to manage wound drains

    Drains in situ may generate some degree of irritation and discomfort therefore measures should be taken to prevent patient interference allowing for the drain to function effectively and to prevent the patient contaminating the area. Patients should be assessed for pain and analgesia provided as necessary to ensure they remain comfortable as the premature removal of drains by patients may in some cases be prevented by the provision of adequate analgesia (Bacon, 2007). Unless contraindicated Buster Collars should also be utilized to prevent contamination or early removal of the drain by the patient.

    The key to effective management of wound drains is to ensure that equipment is prepared in advance and in an aseptic manner. Considering the type of drain and the intervention required will assist in the preparation of the correct materials needed.

    Drain sites should be checked at least daily with full removal of all dressing material to allow thorough inspection of the wound and exit site before the application of a new dressing. Recordings should be regularly made of the volume and nature of the fluid produced allowing for trends and changes to be noted (Whiting et al, 2007). See the Step-by-step guide.

    Removal of drains

    The presence of a drain will produce an inflammatory response and cause fluid production. It is accepted that the volume of fluid produced is approximately 2–4 ml/kg/24 hours, therefore when production of fluid falls below this volume, the drain should be removed. Usually this occurs within 2–5 days. The removal of passive drains should occur following an improvement in the appearance of the exudate and a significant reduction in the volume produced (Ladlow, 2009).

    When drains are removed, the stoma should be left open and covered with a small dressing until sealed (Bacon, 2007).

    Conclusion

    Wound drains play a significant role in small animal practice and it is essential that they are managed with appropriate care and attention to ensure that their effectiveness and assistance in the management of wounds is not annulled by poor management technique.

    Key Points

  • Incorrect management of wound drains will readily negate the pre-operative patient preparation and prevention of bacterial contamination.
  • Drains in situ may generate some degree of irritation and discomfort therefore measures should be taken to prevent patient interference allowing for the drain to function effectively and to prevent the patient contaminating the area.
  • Drain sites should be checked at least daily with full removal of all dressing material to allow thorough inspection of the wound and exit site before the application of a new dressing.
    • surgical wound drain
    Jackson Pratt
    Penrose
    Redon
    Redovac