Carbon Dioxide: Maybe Not the Only One but an Efficient and Secure Gas for Treating Local Adiposities

Abstract

Currently, carbon dioxide therapy represents an evidencebased and mini-invasive method for treating local adiposities. Many studies [1–3] performed on both women and men have already demonstrated its effectiveness in decreasing local fat in several anatomical areas. Recently, Balik et al. [4] compared the effects of both CO2 and breathable air injection on subcutaneous tissue in a sample of 28 experimental rats. They concluded that the mechanical effects are the same for both gas injections and the changes in microcirculation documented on laser Doppler flow examination are not statistically significant. With respect their article, we would like to make a few comments. We evaluated in a cohort of 48 [5] and 42 patients [6] the effects of CO2 therapy from a histological (through biopsies of tissues performed after the therapy) and a biochemical point of view by showing changes in the laser Doppler signal in association with the assessment of the concentration of transcutaneous oxygen tension (tcPO2). Both these methods are mandatory to evaluate CO2 effects on the microvascular network [3, 7]. Lee [8] confirmed our findings with a study protocol evaluating some anthropometrical parameters on 101 patients (divided per age) after treatment with CO2 injected in several body areas. Furthermore, the gas injection mode of Balik’s study is not comparable to the described protocols for the treatment of local adiposities by CO2 therapy. Medical CO2 injection treatments in previous clinical studies were administered through certified equipment that guarantees both constant gas delivery and electronic flow control. The paraphysiological hyperoxia that underlies the metabolic CO2 effects needs to be evaluated by following a particular treatment timing. This was not done in Balik’s study and therefore the inefficacy of these methods is not clear in the discussion. The data related to tissue oxygenation certainly need further biochemical studies. Moreover, microvascular effects were not completely and correctly evaluated and not demonstrated by using the previously cited association of laser Doppler flow and tcPO2. In addition, it is important to point out that in our studies, tcPO2 data are constant and highly significant (P \ 0.01), whereas laser Doppler flow evaluations are significant (P \ 0.01) but not constant [5]. These results depend on some technical situation (i.e., patient immobility, constant temperature) not easily reproducible in animal models. The histological data presented by Balik et al. showed direct lipoclasic effects of the studied gas. We also found these effects in our studies but they could not be assessed in humans. It is clear that before demonstrating the effectiveness of an alternative gas (e.g., ambient air) in reducing local adiposities, it is necessary to test its security and absence of toxicity. Because of the proven safety and daily use in laparoscopic surgery [9, 10], CO2 has been injected on voluntary patients after informed consent and the approval of the local ethics committee. The aim of our study was to evaluate both the effectiveness and safety of CO2 injection treatments. In our opinion, CO2 therapy combines the characteristics previously cited (Fig. 1). C. Brandi M. Campana (&) F. Russo A. Brafa G. Nisi L. Grimaldi C. D’Aniello Department of General and Specialistic Surgery, Plastic and Reconstructive Surgery Unit, ‘‘Santa Maria alle Scotte’’ Hospital, University of Siena, Viale Bracci 1, 53100 Siena, SI, Italy e-mail: matteocamp@gmail.com