Topic Four: Iodine Dressings
Iodine has been used in wound care for over 170 years. It is a natural dark violet, non-metallic element that has a significant function in metabolism within the body. Iodine occurs naturally in the form of iodine ions in seawater, fish, oysters and certain seaweeds and is also found in vegetables that have been grown in iodine-rich soil and dairy products (Sibbald et al., 2011).
In the 4th century BC, before iodine had been discovered, Theophrastus, a pupil of Aristotle, recorded that iodine-rich seaweeds could be used to reduce the pain of sunburn. One of the first antiseptic iodine preparations to be used in wound care was Lugol’s solution containing elemental iodine and potassium in water, which was developed in 1829. This solution was also used to treat wounds in the American Civil War (Sibbald et al., 2011).
Iodine is used to clean and prepare the wound bed and to manage wound infection. Topical treatment is known to provide a prophylactic antibacterial effect in wound care (Wound Care Today, 2017).
There are two types of iodine:
- Povidone iodine (PVP-I) - a chemical complex of polyvinylpyrrolidone (also known as povidone and PVP) and elemental iodine.
- Cadexomer iodine - an iodine and polysaccharide complex, which can be used as antiseptic fillers, particularly in cavity wounds.
(Sibbald et al., 2011; Wound Care Today, 2017)
Povidone
PVP-I has an affinity to cell membranes and will deliver iodine directly to the surface of the cell. Its role as an antimicrobial agent is not clear. However, some research has reported a wide range of activity against gram-negative and gram-positive bacteria, fungi, viruses and protozoa. Others found that using differing concentrations of iodine in this form made little difference to wound pathogens (Jones et al., 2000).
The use of povidone as a topical preoperative skin disinfectant is well established. In patients with burns, topical povidone iodine provides effective antibacterial prophylaxis. The most common form of PVP-1 is an impregnated tulle (Jones et al., 2000).
Cadexomer
There are three common forms of cadexomer iodine, and these are made up of the same formulation and are available as a powder, paste dressing or ointment. The slow release of the iodine in these preparations allows the wound to remain in continuous contact with it. The beads also absorb debris and can, therefore, be used to remove it from the wound bed, making cadexomer iodine a useful debriding agent.
Ointments containing cadexomer iodine have been shown to be effective against a variety of organisms, such as Staphylococcus aureus, β-haemolytic streptococcus and pseudomonas, in a number of different types of wound (Jones et al., 2000).
Mode of Action
The exact antimicrobial mode of action for iodine-based products is not fully understood, but it is believed to be associated with its ability to rapidly penetrate the cell wall of the microorganism.
Indications for use
An International Consensus document (WUWHS, 2008) recommends the use of antiseptic dressings as part of an overall management plan in the following circumstances:
- To prevent wound infection or recurrence of infection in patients at greatly increased risk of infection
- To treat localised infection
- To treat spreading infection when healing is delayed
- Minor burns
- Superficial skin injuries
- Leg ulcers
- Chronic exudate wounds
(WUWHS, 2008; Sibbald et al., 2011)
Contraindications
Iodine dressings must be used under medical supervision in patients with thyroid diseases, known or suspected iodine sensitivity, in pregnant or breastfeeding women or in newborn babies up to the age of six months (Boothman, 2010).
For further information, visit: NICE