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WOUND DRESSING IN DIABETIC FOOT
OVERVIEW OF DRESSINGS AND WOUNDS
FUNCTIONS OF DRESSING
TYPES OF DRESSING
SELECTION OF DRESSING MATERIAL
TOPICAL AGENTS AND ANTISEPTIC CLEANSERS
NEWER OPTIONS IN THERAPY
o PLATELET DERIVED GROWTH FACTOR
o HYPERBARIC OXYGEN
The management of wound and wound dressing is an important aspect of diabetic
foot management, which is neglected many a time. Care of the wound involves
management of the ulcer, care of the exudate and knowledge and rational use of
myriad dressing materials available to provide a cost-effective, simple, and easy
method of dressing tailored to each patient's needs. Proper dressing with cost
effective dressing material, done with scientifically correct method can help in
salvaging diabetic foot. It is necessary to keep in mind the basic physiological facts
about wound healing when planning for the diabetic foot wound dressing.
Management of the ulcer:
It is aimed at achieving an ulcer bed that is clean, free from necrotic tissue, foreign
matter and bacterial infection. This is accomplished by debridement. Debridement
means the removal of dead tissue and the accompanying bacteria and foreign matter
which may be present in the ulcer. Debridement can also be accomplished in an
autolytic manner, meaning the wound itself is encouraged to do this task. In fact the
job of the WBC's and macrophages is to debride the wound. In diabetic patients this
may not be effective or sufficient. The doctor has to assist this natural process.
Some of the measures are as follow. The advantages and disadvantages should be
carefully understood and are by and large not recommended today. The wet to dry
method of using saline gauze to debride, or the use of enzymes like Streptokinase as
topical ointment is an effective but expensive method of debridement of ulcers.
Ointments containing collagenase have also been tried with some benefit. Weak
Hydrogen peroxide, Eusol, acetic acid have been shown to be harmful to the fragile
regenerating epithelium and should therefore never be used.
Surgical debridment is often necessary in large or refractory wounds. This involves
the use of surgical blades or scissors to actively, quickly debride. Sometimes it is the
only effective method to debride the wound.
Once the ulcer is clean, the decision to use the first dressing material on the wound is
made. This layer has to be a non adherent layer to protect the granulating or the
epithlialising layer from being damaged during the subsequent dressing. There are
various ready made non adherent and non absorbing materials available. They all
contain a mesh impregnated with paraffin, soframycin, povidone iodine or various
by products of petroleum. Gauze impregnated with paraffin and autoclaved gives a
cheap and effective non adherent layer. Thus remember that the first layer to be used
is a non absorbent layer.
Care of the exudates:
The next layer to be applied over the non absorbent layer has to take care of the
exudation from the wound. Contaminated and infected wounds pour out a large
amount of exudate. This layer has to absorb and retain the exudates thus
giving the twin advantage of not only keeping the wound moist but also prevent
soiling the surroundings. Change of this layer is necessary whenever it gets soaked.
Heavily soaked dressing can be detrimental to wound healing and also causes
contamination of the bed, linen and becomes a source of infection to spread.
Materials used for this include the commonly used Gamjee pads or much thicker
rolls of absorbent cotton. Advanced wound healing compounds have much higher
absorbent capacity and can be used in special circumstances where cost may not be a
The Third component in wound care is the use of various materials to keep the
exudative layer in place and the advanced wound healing products.
a. The retaining layer, which helps to retain the first two layers viz., the non adherent
and the absorbent layer. This is in the form of adhesive tapes (Zinc oxide tapes,
Micropore tapes, simple bandages, adhesive bandages, elastic bandages, Elastic
woven synthetic elasticated bandages etc.)
b. Advanced wound care products facilitate three basic functions - Debridement,
absorption of unwanted material and retaining itself on the wound. All the three
functions are carried out by chemical compounds produced in such a manner that a
single sheet has the non adherent film which marks the first layer, chemical
compounds which have high water absorbent capability or has the capability to
evaporate the water thus capable of continuous display of the exudates away from the
A list of the available wound care products given below explains the merits of each.
Choice of the appropriate material is made based on the requirements of the wound,
cost and benefits of one over the other.
In summary wound care involves Debridement, keeping wound moist and prevent
further injury, which in diabetic foot means to keep weight off the foot. The other
component involves good glycemic control, adequate and nutritious food, and good
hydration. Fever, exudation, bleeding and vomiting if present can quickly cause
dehydration thus impairing wound healing.
Dressings and the wound:
The basic function of any dressing is to protect the wound from mechanical trauma,
to create a moist environment and prevent exposure to infection. Simple gauze
dressing applied properly can help in preventing and / or controlling infection.
Pathogenic bacterial load of a colony count more than 105 is considered as infection.
The diabetic wounds are often polybacterial. To distinguish the contamination from
the multiple pathogens inhabiting the wound requires some sophistication of the
way specimens are collected and the cultures are made and subcultures studied.
However the contamination of the wound by the organisms can be minimized by
mechanical cleaning during the dressing or by absorption of exudates by the
dressing applied. This reduces the requirement for phagocytic and autolytic
debridement and reduces the source for microbial growth. After major debridement
of any diabetic foot infection the dressing regimen should avoid contamination,
reduce the pain, reduce bacterial growth and absorb exudate. This can be achieved
by applying to the wound any suitable anti bacterial ointment / cream and cover the
wound with non-occlusive, absorbent simple dressing. This can be changed once /
twice a day depending upon quantum of discharge. This should be continued till the
wound is filled with healthy, well vascularised granulation tissue.
In the second and third phase of the wound healing maintaining moist environment
is vital for healing. Occlusive dressings, which maintain moist environment, are
Functions of dressings:
Isolation of wound from external environment.
Limit / reduce tissue edema.
Improve gas exchange between tissues & blood.
Should not promote bacterial growth.
Prevent desiccation and contamination:
We describe below a recapitulation of the types and utilities of dressings.
Primary and Secondary dressings:
All the dressings can be classified as primary or secondary.
Primary dressing is the one, which is in direct contact with the wound.
Secondary dressing is of the material, which hold the primary dressing in place. It
has function of compression, occlusion and additional protection.
Flooding of the wound with wound exudate can have serious implication for the
healing due to maceration. Therefore proper absorbent dressing can help in the
wound healing. Cotton, wool, polyurethane foam, pectin, gelatin, alginate, karaya
gum, carboxymethylcellulose, are the examples of absorbent dressings.
Simple gauze impregnated with paraffin or petroleum jelly is routinely used as non-
adherent dressing. Non-adherent dressings are either occlusive & semi-occlusive;
they could be hydrophilic & hydrophobic consisting of hydrocolloid & hydrogel or
Occlusive / Semi Occlusive dressings:
These dressing provide moist environment for the wound healing and are very
useful in minimally exudating wounds. Various types of adherent film dressings are
examples of this type of dressings. These types of the dressings can promote bacterial
growth and can cause maceration. The advantages of occlusive dressings are that it
reduces pain, facilitates rapid healing, helps the process of autolytic debridement,
helps increased granulation and reduces friction. The disadvantages of occlusive
dressings are maceration, accumulation of pus, adherence to healthy tissue, increased
number of bacteria in the wound and may promote anaerobic growth.
These dressings combine the functions of occlusive and absorbent dressings. These
dressings increase epithelialization by 30 to 36%. The examples are Intrasite Gel /
This includes gelatin, collagen and oxidised cellulose. Collagen granules and sheets
have been used as biological dressing. Calcium alginate dressings from seaweeds
have been used effectively.
Medicated dressings: These are impregnated with chemotherapeutic agents,
antibiotics or other sterilising solutions.
Selection of the Dressing material:
The dressing in diabetic foot wounds should be done with minimal damage to the
wound and using available, cost effective dressing material. The selection of the
dressing material will depend upon the type of the wound, cost of the dressing
material, expected duration of the wound healing and the availability of the trained
person. Any material which prevents bacterial contamination, enhances moist
environment, reduces pain should be used. In diabetic foot infection it must be
remembered that off loading of the affected foot is a very important adjuvant to the
The following protocol can be followed for wound dressings in general terms:
First, a decision regarding modality of the treatment i.e. whether conservative or
operative should be made. If the ulcer / wounds do not require debridement then:
1. There should be appropriate strategy to off load the affected foot.
2. The wound / ulcer needs to be dressed with any dressing material, which can keep the
wound environment moist. The simplest and cheapest is Metronidazole gel. Other
antibacterial creams as per the culture and sensitivity report of the wound can be
used. If sophisticated occlusive materials like Hydrogel, Kaltostat, Collagen sheets,
Collagen Granules are available, and affordable they can be used.
3. The frequency of the dressing will depend on the quantum of the discharge. In the
initial phases the quantum is more, necessitating every day dressing.
4. The dressing should be done till the wound fully epithelializes. If the wound requires
debridement then after total / complete debridement based on anatomical principles,
the wound dressing should be done as follows:
A. On the operation table, simple paraffin gauze soaked in either very dilute 1 to 2%
Povidone Iodine should be used to gently pack / cover the wound.
B. This dressing should be opened after 24 to 48 hours. It should be irrigated with saline.
An antibacterial ointment as per the culture and sensitivity report should be used.
C. This should be continued till the early granulation is seen. This usually takes 7 to 10
Infection: Colonisation by bacteria more than 105 pathogens/gm of tissue where
body defenses are unable to control the spread.
If the wound does not show proper healing then re assessment for above mentioned
factors should be done.
Topical Agents and Antiseptic Cleansers:
Many of the traditionally used agents of this type have been shown to be harmful to
the wound healing. The cleaning of the wound is best achieved by saline or sterile
You can put anything on the wound except the patient's weight. Off load,
off load, off load!!!!!!!!!!
For proper wound healing following factors are of paramount importance:
Total Debridement preferably at the first time
Adequate Blood Supply
Total off Loading of the Affected Foot
Colonisation of bacteria less than 105/gm of tissue where body defenses
control the spread.
This method of wound treatment was followed in All India Institute of
Diabetes in Mumbai from Jan 1986. 4129 cases of complicated diabetic foot
infections have been treated from Jan 1986 to Jan 1999 by the
abovementioned method of dressing. The foot salvage rate of 91.2% was
achieved in this institute, by Bal et al.
water. Vigorous mechanical cleaning should be avoided. Eusol / hydrogen peroxide,
acetic acid etc., should not be used in the diabetic foot wounds. These agents can
damage the delicate granulation tissue. The table below may be perused to see the
availability of the dressing materials.
Agents That Delay Wound Healing
Relative Rate of
Synthetic or fluorinated
Liquid detergent 28
Neomycin sulphate 5
Chlorhoxidlno 2% 7
Povidone-Iodine solution (10%) 10
Dakin's solution (0.25%) 15
Acetic acid solution (0.25%) 12
Hydrogen peroxide (3%) 8
Note: The comparisons were carried on with untreated, air-exposed control wounds.
Data obtained from swine studies conducted on partial thickness wounds.
Relative rate of healing was calculated as
this ratio is multiplied by 100
HT50 is healing time in which 50% of wounds are completely healed.
Newer, Innovative Therapies for Wound Healing:
Platelet Derived Growth Factor:
The new addition to the dressing material is useful but the imported gels are
prohibitively costly. The indigenous PDGF is much less so in comparison to the
imported product. The PDGF helps in epithelialization of the wounds. There is
evidence to show that the wound closure occurs earlier even in wounds of fair sizes.
It is felt that PDGF will make larger wounds more graftable with partial or full
thickness grafts earlier than other methods
Sterile maggots are commercially available in several countries. In wounds with lot
of exudation and dead tissue, maggots can be placed on the wounds and left lightly
covered for a day or two. They eat away all the dead tissue, exudates and leave the
wounds clean for further dressing and healing. They should be pulled out of the
wound area after two or three days.
Hyperbaric Oxygen Therapy:
Hyperbaric Oxygen Therapy (HBO) involves intermittent inhalation of 100% Oxygen
under a pressure exceeding that of the atmosphere. O2 is delivered to the tissues in
dissolved form. During HBO Therapy, quantum of dissolved Oxygen in plasma
increases. At rest, the tissues extract 6ml of O2 per 100ml blood. On air at 1
atmospheric pressure there is 0.3ml of O2 per 100ml blood. At 2ATA on 100% O2
there is 4.3ml per 100ml blood dissolved in the plasma. At 3ATA on 100% O2 there is
6.5ml per 100ml blood dissolved in the plasma. Thus HBO “arterialises” the venous
The therapy is delivered in Monoplace Chambers which admit one patient at a time
with the entire chamber pressurized with Oxygen. It is less expensive but can't take
serious patients. Standard precautions should be observed about preparing the
patients for it. The therapy session lasts for about 60 to 90 minutes. Addition of
Hyperbaric Oxygen results in significant cost savings due to lesser stay in hospital
and shorter course of illness.
How does it work?
When tissue Oxygen tension drops to less than 30 mm Hg, healing by cellular
division is significantly reduced and may even stop. Fibroblasts, angioblasts, and
leucocytes are not capable of functioning in this environment. These wounds usually
develop in compromised hosts. Multiple local and systemic factors may contribute to
inhibition of tissue repair. Adequate supply of dissolved oxygen helps these
mechanisms for the wounds to heal.
It is the larger wounds in the compromised patient where the demand for oxygen
exceeds the supply that the non-healing chronic wound develops. In these patients
adjunctive HBO is beneficial. Hyperbaric oxygen plays no role in enhancing wound
healing in the normal host, unless there is evidence of compromise of vascular flow
in the local wound area. Patients with Class 3, 4, or 5 Wagner lesions are considered
for treatment based upon blood flow assessment. TcPO2 is a reliable and useful
noninvasive method for perfusion evaluation. Periwound TcPO2 greater than 30-40
mmHg on room air is sufficient for the wound to heal without intervention. TcPO2 of
less than 20 mm Hg on room air indicates poor prognosis. If the TcPO2 increase to 40
mmHg on 100% O2 in hyperbaric chamber at 1 ATA indicates perfusion enough for
HBO Thearpy to benefit. HBO treatments in diabetic foot are performed at 2-2.5 ATA
for 60-90 minutes of Oxygen breathing. If presence of limb threatening infection or
compromised surgical flaps the treatment is given twice daily. Once the infection
comes under control and soft tissue envelope improves, the treatment schedule is
changed to once daily. Utilization review is usually after 30 treatments and 10
treatments post grafting.
Brief outline of how to deal with ulcers:
1. Assess ulcer (general wound parameters) Anatomic considerations and measure
wound discussed before
2. Address underlying pathologic conditions by
3. Doing sharp debridement reaching up to healthy bleeding tissue. Eliminate
undermining and assure hemostasis.
4. Apply topical antibiotic ointment (Silver Sulfadiazine. Polymyxin and Bacitracin,
Zinc, Mupuricin 2%.)once daily for 2 weeks.
5. Select non-adherent, non-occlusive absorbent dressing (dressing change once
6. As soon as wound is granulated and well vascularized occlude with synthetic
dressing that keeps would moist. Make sure dressing is changed at least once
daily, and patient follows up is once weekly. Advise patient to notify if they notice
the clinical signs of infection.
7. Once wound has healed plan strategy for protection ie education, offloading, moist
environment and protective footware.