The Role of Carbon Dioxide Therapy in the Treatment of Chronic Wounds

Patients and Methods

From January 2005 to December 2007, a total cohort of 70 patients (45 men and 25 women, age: 45-75 y, average: 66 years) with chronic lower limb lesions (Table I) were enrolled in the study at the Plastic Surgery Unit of the Universitary Hospital in Siena. The cutaneous lesions, some of which were caused by trauma, had persisted for an average of 12 months (range 4-24 months) and were variably associated with diseases of the arterial trunks, chronic venous insufficiency and alterations of glucose metabolism (Table II). The general and/or local conditions of all patients initially contraindicated reconstructive procedures. The patients were selected by aetiology and wound extension and randomly divided into two homogeneous groups of 35 (A and B). Group A was treated using advanced dressings and CO₂ therapy, while group B was treated using advanced dressings alone.

All the cutaneous lesions were treated with the routine methods, involving surgical and/or chemical debridement culture analysis for targeted antibiotic therapy, and the use of dressings according to the features of each lesion (hydrogels, hydrocolliods, alginates, activated characoal). Neither vacuum therapy nor other treatments (such as growth factors), which have been shown to directly influence microcirculation, were used in any case (14-15). Ulcers were considered as healed when re-epithelialisation occurred and, in the other cases, the study was conducted (using dressings only in both groups) for a period of 60 days, at the end of which the percentage variation in the size of the lesion was measured and recorded using a transparent millimetre grid.

In group A, subcutaneous administration of CO₂ was performed, with the patient awake and without any kind of anesthesia, twice a week for six weeks, beginning on the first day of treatment (12 treatments in total), using a Carbomed CDT Evolution device produced by L.E.D. (Latina, Italy), with 30G/13 mm needles according to the following method:

Treatment of the vascular axes: the machine was set at a speed of 80 cc/min for the first 3 treatments and subsequently at 100 cc/min; programme 13 was used; the quantity of gas administered subcutaneously was 50 cc per area. In all cases the injection sites were bilateral, in the lower limbs (even when the lesion only affected one limb) at the: femoral triangle (proximal terminal perforating veins), middle third of thigh, adductor canal (lower third of the thigh), Boyd perforator; popliteal fossa and middle third of leg (Figure 1).

Treatment of the lesion: Flow was set at a speed of 30 cc/min, programme 14 was used; the quantity of gas per sector was 5 cc. Injections were made in the healthy area around the wound, at least 2 cm from the damaged skin (Figure 2). If cicatrization was achieved during treatment, CO₂ was continued therapy according to the methods described, as scheduled.

On the first day of treatment and one week after the last session (or after 60 days in the non-healed cases), the microcirculation in the affected limbs of all patients (groups A and B) was studied using a Doppler laser and Perimed PeriFlux System 5040 (Stockholm, Sweden) to determine TcPO₂. Measurements were made at baseline and 30 min after the administration of CO₂, examining patients in a supine position and at a constant environmental temperature (22°C), for a duration of 30 min per trace. To determine the values of TcPO₂ (in mmHg) the probe was set at a temperature of 44°C and calibration was performed according to the barometric pressure values. The ulcers were considered healed when full and stable (almost 30 days) re-epithelialisation was achieved with or without surgical procedures. In cases in which the lesion failed to heal, wound dressings and clinical observation were continued for a period of 60 days, after which the percentage variation in the size of the lesion was measured and recorded. Photographic documentation was acquired and the data were analyzed using a paired Student's t-test: a p-value of below 0.05 was considered statistically significant.

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Figure 1.

Treatment at the origin of and along the main vessels. Injection sites: 1) Femoral triangle (proximal terminal perforating veins); 2) middle third of thigh; 3) adductor canal (lower third of the thigh); 4) Boyd perforator; 5) popliteal fossa; 6) middle third of leg.