In our ICU, the hospitalist ordered leech therapy to relieve venous congestion in a reattached finger. What do I need to know about this therapy?-L.C., ARIZ.

Airyn Labarite and Bridget Parsh, EdD, RN, CNS, reply: Medicinal leech therapy (MLT), also called hirudotherapy, was used by the ancient Greeks and Egyptians.1 Today, under the Federal Food, Drug, and Cosmetic Act, commercial medicinal leeches are an FDA-approved therapeutic medical device used to relieve venous congestion and restore blood flow after plastic surgery and reconstructive procedures such as skin grafts and reattachment surgery.2-4

The Hirudo medicinalis leech is a bloodsucking freshwater worm whose salivary glands contain the anticoagulant hirudin, platelet aggregation inhibitors, and highly specific proteases that support venous flow in the setting of venous congestion.1,3 Following reattachment surgery, venous congestion is a post-op complication that can threaten the digit's survival because arterial inflow does not match venous outflow. Clinical manifestations include dusky purple skin, brisk capillary refill, and dark-colored blood after pinprick.5

A leech's bite induces a small amount of bleeding that mimics venous circulation in areas of compromised tissue.6 Because compounds in the leech's saliva have anti-inflammatory and anesthetic properties, the bite is generally painless.1,7 Contraindications to MLT include arterial insufficiency, immunocompromise, and untreated coagulopathy.7-9

Due to the risk of bleeding and blood loss, a complete blood cell count is required before initiating MLT.10 A prophylactic antibiotic is indicated to prevent infection.5

The provider should explain the procedure to the patient and obtain informed consent.9 The area to be treated is then cleansed with soap and water, followed by rinsing with plain water.4

Nursing care during treatment includes applying the leeches, preventing migration from designated treatment areas, and frequent patient assessments during and after treatment for adverse reactions such as excessive bleeding, hypersensitivity reactions, and infection. Typically four or five leeches are placed at the designated treatment area. However, the number of leeches placed varies based on clinical evaluation; for example, one or two leeches may be adequate to treat a small flap or a finger.1

Direct the head of each leech toward the attachment site on the darker area of the replanted digit or in areas with visible venous congestion.10,11 The head of the leech is identified by its searching motions.7 To prevent migration, the leech can be sutured to the skin or a barrier can be fashioned around the treatment area using a petrolatum or transparent adhesive dressing.8,10 Alternatively, dampen a square of gauze with water and cut a 1-cm hole in the middle. Place the gauze on the patient with the hole over the area to be treated and apply the leech. Once the leech attaches, the gauze can be removed.7

If a leech is slow to attach, try pricking the skin to draw a drop of blood in the treated area.12 Gut peristalsis visible within 30 minutes indicates active feeding.10

Once a leech attaches to the designated treatment area, it is left until it separates itself. Leeches typically feed for 30 to 90 minutes, consuming 5 to 15 mL of blood per feeding.10,12

Treatment must be supervised by a nurse or other healthcare professional to ensure the leeches stay at the desired treatment areas and do not detach prematurely.9 Monitor hemoglobin and hematocrit levels as prescribed.10,13

Leeches typically detach from the skin spontaneously when satisfied. They should be placed in a container labeled with the patient's name and disposed of as biohazardous waste according to facility policy and procedure and the distributor's guidelines.7,13 Never reuse leeches or return them to the pharmacy.1,7,8

Leeches that do not detach spontaneously must be removed gently to prevent them from regurgitating contents of the digestive tract into the treated areas.10,13 Encourage a leech to detach by stroking it with a gauze pad moistened with saline, alcohol, or vinegar.13

After leech detachment, the treated area is encouraged to continuously ooze blood, which is a major therapeutic benefit of MLT. Wipe the site every 2 hours with gauze moistened with heparin to remove clots and permit easy visualization of the site.13

During and after treatment, assess the patient for hypersensitivity reactions including anaphylaxis, local infection, and excessive blood loss, which may require blood transfusion in some cases.9,13-15 Other possible complications include leech bite scars.3 Monitor older adults for orthostatic hypotension and vasovagal effects.1

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