The Connection Between Breathing, Skin, and Fat Tissue

Title: Carbon Dioxide Therapy in the Treatment of Localized Adiposities: Clinical Study and Histopathological Correlations

Authors: Brandi C, D'Aniello C, Grimaldi L, Bosi B, Dei I, Lattarulo P, Alessandrini C.

Journal: Aesthetic Plast Surg. 2001 May-Jun;25(3):170-4. doi: 10.1007/s002660010116. PMID: 11426306.

Link to full text: Carbon Dioxide Therapy in the Treatment of Localized Adiposities: Clinical Study and Histopathological Correlations

Abstract: The authors report their experience using carbon dioxide (CO2) therapy for the treatment of 48 female patients presenting adipose accumulations, located on the thighs, knees, and/or abdomen; a Carbomed Programmable Automatic Carbon Dioxide Therapy apparatus was used. In light of the effects of CO2 on the microcirculation recently described in the literature, we expected this gas, which we administered subcutaneously, to positively affect the physiological oxidative lipolytic process. The aim of our study was to evaluate the effect of this therapy on localized adiposities. As such, we describe the method we used and report the results observed in the areas treated (in terms of reduction in maximum circumference) as well as side effects. Furthermore, we assessed the effect of subcutaneous administration of CO2 on the microcirculation by showing changes in the Laser Doppler signal and in the concentration of transcutaneous oxygen tension (tcPO2). Pre- and posttreatment biopsies of tissues were performed in seven patients in order to study the changes induced by the use of CO2 on both adipose and connective tissues. All data obtained were statistically analyzed; values of P < 0.05 were considered significant.

Title: An overview of the role of carboxytherapy in dermatology

Authors: Bagherani N, Smoller BR, Tavoosidana G, Ghanadan A, Wollina U, Lotti T.

Journal: J Cosmet Dermatol. 2023 Sep;22(9):2399-2407. doi: 10.1111/jocd.15741. Epub 2023 Mar 31. PMID: 36999460.

Link to full text: An overview of the role of carboxytherapy in dermatology

Abstract: Background: Carboxytherapy is defined as intradermal and/or subcutaneous microinjections of sterile purified carbon dioxide into different parts of the body for therapeutic aims. The vasodilatation effect and intradermal collagen reorganization associated with carboxytherapy have advantages for aesthetic dermatology and cosmetology.

Objective: In the current article, we have reviewed some of the most important indications of this modality in dermatology and aesthetic dermatology.

Method: Our review is a narrative one which has gathered some of the most important indications of carboxytherapy in dermatology and cosmetology.

Results: Carboxytherapy has successfully been applied for some dermatologic and cosmetic conditions among which skin aging, cellulite, localized fat deposits, striae distensae, infraorbital hyperpigmentation, scar, lymphedema, androgenetic alopecia, alopecia areata, psoriasis, morphea, and vitiligo are the most important.

Conclusion: Carboxytherapy can be considered as a safe, minimally-invasive modality used for rejuvenation, restoration, and recondition of the skin.

Title: Carboxytherapy: effects on microcirculation and its use in the treatment of severe lymphedema. A review

Authors: Varlaro V., Manzo G., Mugnaini F., Bisacci C., Fiorucci P., De Rango P., Bisacci R.

Journal: Acta Phlebologica 2007 August;8(2):79-91

Link to full text: Carboxytherapy: effects on microcirculation and its use in the treatment of severe lymphedema. A review

Abstract: Carboxytherapy refers to the administration of CO2 for therapeutic purposes. It has been shown that, because of the interaction between CO2 and regulating factors of tissue perfusion, Carboxytherapy acts on the microcirculation at the level of metarterioles, arterioles and precapillary shpincteres by increasing tissue flow velocity and consequently, by improving lymphatic drainage. Analysis of literature data shows a wide range of today applications for this treatment involving either phlebology or non-phlebology fields. Specifically, the positive effect on the increase of lymphatic drainage has more recently made Carboxytherapy useful for treatment of lymphatic stasis. Basic hemodynamic, histologyc and biochemical principles that explain the effects on microcirculation bed and lymphatic drainage are here analyzed to show how Carboxytherapy can be useful in the treatment of diseases such as severe lymphedema.

Title: The Influence of Carboxytherapy on Scar Reduction

Authors: Stolecka-Warzecha A, Chmielewski Ł, Deda A, Śmich A, Lebiedowska A, Wilczyński S.

Journal: Clin Cosmet Investig Dermatol. 2022 Dec 23;15:2855-2872. doi: 10.2147/CCID.S389380. PMID: 36582848; PMCID: PMC9793937.

Link to full text: The Influence of Carboxytherapy on Scar Reduction

Abstract: Introduction
Although it is not a new method, a carboxytherapy, which is based on intradermal or subcutaneous administration of controlled doses of CO2, is gaining more and more recognition among aesthetic medicine doctors, dermatologists and cosmetologists around the world. The consequence of applying carbon dioxide directly into tissues is associated with an immediate expansion of blood vessels, improvement of local blood supply, and, thus, tissue metabolism. It does also support natural regenerative processes. Oxygen and growth factors released from blood, within the area which undergoes treatment, stimulate fibroblasts to produce collagen and formation of new blood vessels also known as neovascularization. In addition to biochemical mechanisms, CO2 injection into the dermis or subcutaneous tissue leads to a mechanical effect exerted by pressure and flow of CO2 which is injected. It is of particular importance in scar treatments.

Methods
Twelve mature scars were subjected to the carboxytherapy which was performed in people aged 23–45 years. A small amount of heated, medical CO2 was injected till the moment a scar turns white. The applied flow rate equalled 100 mL/min (cc/min). Before and after a series of four treatments, the level of hydration, elasticity and colour of the skin were measured. A structured-light 3D scanner was used to determine an exact morphology of the examined scars. The 3D scanning device is seen as a sensitive and precise method of qualitative and quantitative assessment of a morphology of scars.

Results
The results of the measurements performed showed a reduction in the surface of the analyzed changes, as well as proved the ability of CO2 to rebuild collagen fibres. The decrease in value of parameters, which have been obtained thanks to the kutometric examination, indicates softening and loosening of connective tissue. It does confirm the effectiveness of carboxytherapy.

Title: Effect of leg immersion in mild warm carbonated water on skin and muscle blood flow

Authors: Ogoh S, Washio T, Suzuki K, Ikeda K, Hori T, Olesen ND, Muraoka Y.

Journal: Physiol Rep. 2018 Sep;6(18):e13859. doi: 10.14814/phy2.13859. PMID: 30221833; PMCID: PMC6139710.

Link to full text: Effect of leg immersion in mild warm carbonated water on skin and muscle blood flow

Abstract: Leg immersion in carbonated water improves endothelial-mediated vasodilator function and decreases arterial stiffness but the mechanism underlying this effect remains poorly defined. We hypothesized that carbonated water immersion increases muscle blood flow. To test this hypothesis, 10 men (age 21 ± 0 years; mean ± SD) underwent lower leg immersion in tap or carbonated water at 38°C. We evaluated gastrocnemius muscle oxyhemoglobin concentration and tissue oxygenation index using near-infrared spectroscopy, skin blood flow by laser Doppler flowmetry, and popliteal artery (PA) blood flow by duplex ultrasound. Immersion in carbonated, but not tap water elevated PA (from 38 ± 14 to 83 ± 31 mL/min; P < 0.001) and skin blood flow (by 779 ± 312%, P < 0.001). In contrast, lower leg immersion elevated oxyhemoglobin concentration and tissue oxygenation index with no effect of carbonation (P = 0.529 and P = 0.495). In addition, the change in PA blood flow in response to immersion in carbonated water correlated with those of skin blood flow (P = 0.005) but not oxyhemoglobin concentration (P = 0.765) and tissue oxygenation index (P = 0.136) while no relations was found for tap water immersion. These findings indicate that water carbonation has minimal effect on muscle blood flow. Furthermore, PA blood flow increases in response to lower leg immersion in carbonated water likely due to a large increase in skin blood flow.

Keywords: Carbonated water; Doppler ultrasound; near-infrared spectroscopy; popliteal artery.

Title: Carbonate ion-enriched hot spring water promotes skin wound healing in nude rats

Authors: Liang J, Kang D, Wang Y, Yu Y, Fan J, Takashi E.

Journal: PLoS One. 2015 Feb 11;10(2):e0117106. doi: 10.1371/journal.pone.0117106. PMID: 25671581; PMCID: PMC4324962.

Link to full text: Carbonate ion-enriched hot spring water promotes skin wound healing in nude rats

Abstract: Hot spring or hot spa bathing (Onsen) is a traditional therapy for the treatment of certain ailments. There is a common belief that hot spring bathing has therapeutic effects for wound healing, yet the underlying molecular mechanisms remain unclear. To examine this hypothesis, we investigated the effects of Nagano hot spring water (rich in carbonate ion, 42°C) on the healing process of the skin using a nude rat skin wound model. We found that hot spring bathing led to an enhanced healing speed compared to both the unbathed and hot-water (42°C) control groups. Histologically, the hot spring water group showed increased vessel density and reduced inflammatory cells in the granulation tissue of the wound area. Real-time RT-PCR analysis along with zymography revealed that the wound area of the hot spring water group exhibited a higher expression of matrix metalloproteinases-2 and -9 compared to the two other control groups. Furthermore, we found that the enhanced wound healing process induced by the carbonate ion-enriched hot spring water was mediated by thermal insulation and moisture maintenance. Our results provide the evidence that carbonate ion-enriched hot spring water is beneficial for the treatment of skin wounds.

Title: Carbon dioxide and MAPK signalling: towards therapy for inflammation

Authors: Gałgańska H, Jarmuszkiewicz W, Gałgański Ł.

Journal: Cell Commun Signal. 2023 Oct 10;21(1):280. doi: 10.1186/s12964-023-01306-x. PMID: 37817178; PMCID: PMC10566067.

Link to full text: Carbon dioxide and MAPK signalling: towards therapy for inflammation

Abstract: Inflammation, although necessary to fight infections, becomes a threat when it exceeds the capability of the immune system to control it. In addition, inflammation is a cause and/or symptom of many different disorders, including metabolic, neurodegenerative, autoimmune and cardiovascular diseases. Comorbidities and advanced age are typical predictors of more severe cases of seasonal viral infection, with COVID-19 a clear example. The primary importance of mitogen-activated protein kinases (MAPKs) in the course of COVID-19 is evident in the mechanisms by which cells are infected with SARS-CoV-2; the cytokine storm that profoundly worsens a patient's condition; the pathogenesis of diseases, such as diabetes, obesity, and hypertension, that contribute to a worsened prognosis; and post-COVID-19 complications, such as brain fog and thrombosis. An increasing number of reports have revealed that MAPKs are regulated by carbon dioxide (CO2); hence, we reviewed the literature to identify associations between CO2 and MAPKs and possible therapeutic benefits resulting from the elevation of CO2 levels. CO2 regulates key processes leading to and resulting from inflammation, and the therapeutic effects of CO2 (or bicarbonate, HCO3-) have been documented in all of the abovementioned comorbidities and complications of COVID-19 in which MAPKs play roles. The overlapping MAPK and CO2 signalling pathways in the contexts of allergy, apoptosis and cell survival, pulmonary oedema (alveolar fluid resorption), and mechanical ventilation-induced responses in lungs and related to mitochondria are also discussed. Video Abstract.

Keywords: ERK1/2; Hypercapnia; Hypercarbia; Hypocapnia; JNK; p38.

Title: The inflammatory reflex

Authors: Tracey KJ.

Journal: Nature. 2002 Dec 19-26;420(6917):853-9. doi: 10.1038/nature01321. PMID: 12490958.

Link to PubMed: The inflammatory reflex

Abstract: Inflammation is a local, protective response to microbial invasion or injury. It must be fine-tuned and regulated precisely, because deficiencies or excesses of the inflammatory response cause morbidity and shorten lifespan. The discovery that cholinergic neurons inhibit acute inflammation has qualitatively expanded our understanding of how the nervous system modulates immune responses. The nervous system reflexively regulates the inflammatory response in real time, just as it controls heart rate and other vital functions. The opportunity now exists to apply this insight to the treatment of inflammation through selective and reversible 'hard-wired' neural systems.

Title: Effects of repeated carbon dioxide-rich water bathing on core temperature, cutaneous blood flow and thermal sensation

Authors: Nishimura N, Sugenoya J, Matsumoto T, Kato M, Sakakibara H, Nishiyama T, Inukai Y, Okagawa T, Ogata A.

Journal: Eur J Appl Physiol. 2002 Aug;87(4-5):337-42. doi: 10.1007/s00421-002-0626-0. Epub 2002 Jun 7. PMID: 12172871.

Link to full text: Effects of repeated carbon dioxide-rich water bathing on core temperature, cutaneous blood flow and thermal sensation

Abstract: We examined the effects of repeated artificial CO(2) (1,000 ppm) bathing on tympanic temperature (T(ty)), cutaneous blood flow, and thermal sensation in six healthy males. Each subject was immersed in CO(2)-rich water at a temperature of 34 degrees C up to the level of the diaphragm for 20 min. The CO(2)-rich water was prepared using a multi-layered composite hollow-fiber membrane. The CO(2) bathing was performed consecutively for 5 days. As a control study, subjects bathed in fresh water at 34 degrees C under the same conditions. T(ty) was significantly lowered during CO(2) bathing (P < 0.05). Cutaneous blood flow in the immersed skin (right forearm) was significantly increased during CO(2) bathing compared with that during fresh-water bathing (P < 0.05), whereas cutaneous blood flow in the non-immersed skin (chest) was not different between CO(2) and fresh-water bathing. Subjects reported a "warm" sensation during the CO(2) bathing, whereas they reported a "neutral" sensation during the fresh-water bathing. The effects of the repeated CO(2) bathing were not obvious for core temperature and cutaneous blood flow, but the thermal sensation score during the CO(2) bathing was reduced sequentially by repeated CO(2) bathing (P < 0.05). These thermal effects of CO(2) bathing could be ascribed largely to the direct action of CO(2) on vascular smooth muscles and to the activity of thermoreceptors in the skin. Serial CO(2) bathing may influence the activity of thermoreceptors in the skin.

Title: Effect of carbon dioxide-enriched water and fresh water on the cutaneous microcirculation and oxygen tension in the skin of the foot

Authors: Hartmann BR, Bassenge E, Pittler M.

Journal: Angiology. 1997 Apr;48(4):337-43. doi: 10.1177/000331979704800406. PMID: 9112881.

Link to full text: Effect of carbon dioxide-enriched water and fresh water on the cutaneous microcirculation and oxygen tension in the skin of the foot

Abstract: The effects of immersion of the lower leg and foot in fresh water and in carbon dioxide (CO2)-enriched water (1200 mg CO2 per kg water; succinate+sodium bicarbonate: Actibath, KAO Tokyo) on cutaneous circulation, vasomotion and oxygen tension (PO2) were measured by laser Doppler flowmetry and transcutaneous oximetry. On the first of two consecutive days patients were randomly assigned to have the lower extremities immersed in either fresh water or CO2-enriched water under standardized conditions (temperature, 34 degrees C; depth, 35 cm; immersion time, twenty minutes) with concurrent measurement. On the second day patients were switched to the other bath type. For both sets of measurements probes were attached symmetrically to the dorsum of each foot. Included in the study were 18 patients with mild, bilateral, peripheral, occlusive arterial disease (intermittent claudication, femoral or iliac type). During immersion in CO2-enriched water the Doppler laser signal and vasomotion amplitude rose by 300%, while PO2 increased by 10%. These increases were still apparent during the latter part of the measurement period, following withdrawal of the limbs from the bath, while patients were seated and supine. During immersion in fresh water and thereafter the Doppler laser signal was unchanged and the PO2 increase was considerably less marked. The authors were thus able to demonstrate vasodilation and increased oxygen utilization (Bohr effect) resulting from topical CO2 application, and hence, that the use of topical CO2 has an objective basis.

Title: Effect of Carbon Dioxide Therapy on Diabetic Foot Ulcer

Authors: Shalan N., Al-Bazzaz A., Al-Ani I., Najem F. and Al-Masri M.

Journal: Journal of Diabetes mellitus 5, no. 4 (2015): 284-289.

Link to full text: Effect of Carbon Dioxide Therapy on Diabetic Foot Ulcer

Abstract: Ulceration of diabetic foot represents one of the most concerning complications associated with uncontrolled blood sugar in diabetes mellitus. The aim of this study is to evaluate the condition of twenty-two diabetic patients with different degrees of ulceration in their feet after daily secessions of carbon dioxide therapy. Blood flow to the affected foot was measured by Doppler; also the size, color, degree of ulceration and sensation of the ulcerative area were all evaluated. Results showed improvement of blood flow to the affected foot as well as improvement in the sensation and color of the ulcerative area. It was concluded that carbon dioxide therapy of diabetic foot was promising and needed thorough investigation to be brought widely into application.
Keywords: Diabetic Foot Ulcer, Carbon Dioxide Therapy

Title: Carbon dioxide therapy in the treatment of cellulite: an audit of clinical practice

Authors: Lee GS.

Journal: Aesthetic Plast Surg. 2010 Apr;34(2):239-43. doi: 10.1007/s00266-009-9459-0. Epub 2010 Jan 29. PMID: 20111965; PMCID: PMC2847160.

Link to full text: Carbon dioxide therapy in the treatment of cellulite: an audit of clinical practice

Abstract: Background: The clinical practice of using carbon dioxide therapy for localized adiposities was audited over a 4-year period.

Methods: Patients receiving physical, dietary, or drug concurrent therapy were excluded from the audit. Original measurements in terms of mean +/- standard error of the mean (SEM) were compared with those obtained after five sessions.

Results: This series included 101 women who underwent abdominal therapy. Significant reduction (p < 0.05) in mean upper, mid, and lower abdomen circumference was experienced by all three age groups: respectively, 1.8 +/- 0.5, 1.6 +/- 0.4, and 2.1 +/- 0.3 cm in the 20- to 29-year- old group, 1.6 +/- 0.4, 2.3 +/- 0.3, and 2.1 +/- 0.3 cm in the 30- to 39-year-old group, and 2.0 +/- 0.4, 2.5 +/- 0.4, and 2.6 +/- 0.4 cm in the 40- to 50-year-old group. For 57 women who underwent localized thigh therapy (27 in the 20- to 29-year-old group, 18 in the 30- to 39-year-old group, and 12 in the 40- to 50-year-old group), thigh circumference was significantly reduced in the right versus left thigh: respectively, 1.6 +/- 0.3 versus 1.5 +/- 0.2 cm, 1.1 +/- 0.3 versus 1.1 +/- 0.3 cm, 1.6 +/- 0.3 versus 1.5 +/- 0.4. Weight loss was significant for older women who underwent abdominal therapy: 1.3 +/- 0.2 kg in the 30- to 39-year-old group (n = 43) and 1.3 +/- 0.2 kg in the 40- to 50 year-old group (n = 29). Older women who underwent thigh therapy also recorded significant weight reduction: 0.9 +/- 0.4 kg in the 30- to 39-year-old group (n = 18) and 1.6 +/- 0.3 kg in the 40- to 50-year-old group (n = 12). The results for 10 men were not significant.

Conclusion: These results agree with those reported originally and demonstrate that carboxytherapy is safe and effective.

Title: Carbon dioxide therapy: effects on skin irregularity and its use as a complement to liposuction

Authors: Brandi C, D'Aniello C, Grimaldi L, Caiazzo E, Stanghellini E.

Journal: Aesthetic Plast Surg. 2004 Jul-Aug;28(4):222-5. doi: 10.1007/s00266-004-2068-z. PMID: 15599534.

Link to PubMed: Carbon dioxide therapy: effects on skin irregularity and its use as a complement to liposuction

Abstract: For a successful conventional or superficial liposuction, it is necessary to consider the competence of the surgeon who is to administer the procedure necessary for this type of surgery as well as the physical and psychological evaluation of the determined patient. A poor result often is related to the persistence of adipose tissue irregularity in the form of fatty tissue accumulation. This complication, common to this type of surgery, has called for research to determine methods for its treatment. Carbon dioxide (CO2) therapy refers to the transcutaneous and subcutaneous administration of CO2 for therapeutic purposes. This treatment originated at the Royal Spas of France in 1932 with the treatment of patients affected by obliteration of arteriopathies. Recent studies have demonstrated the effect of subcutaneous CO2 therapy performed to improve local parameters of circulation (performed by Doppler, laser-Doppler, and trans-cutaneous partial pressure of oxygen determination), and to reduce localized adiposities (verified reporting variations in maximum circumference and performing histologic studies). With these results, the absence of toxicity, and the relevant side effects related to this treatment taken into consideration, the Plastic Surgery Unit of Siena has been committed to researching the role that CO2 therapy can play in the treatment of skin irregularity and as a complement to liposuction. The authors report their experience using Carbomed programmable automatic CO2 therapy apparatus and 30GA1/2 0,3X13 microlance needles for the treatment of patients with adipose tissue accumulations located on the thighs and knees. In their study, 42 patients were divided into three groups: A, B, and C. In Group A, only liposuction was performed. In group B 3 weeks after liposuction CO2 therapy was administered in two weekly subcutaneous applications of CO2 for 10 consecutive weeks. In group C, CO2 therapy alone was administered with the same contingencies used for group B (two weekly subcutaneous applications of CO2 for 10 consecutive weeks). The objective was to assess the effectiveness of CO2 therapy for skin irregularity and as a complement to liposuction for adipose tissue accumulation by reporting variations in circumference and skin elasticity monitored by the Cutometer SEM 474 in all treated areas. The data obtained were analyzed statistically. Values of p less than 0.05 were considered significant. The authors report their experience and the results achieved from the study.

Title: Immersing Feet in Carbon Dioxide-enriched Water Prevents Expansion and Formation of Ischemic Ulcers after Surgical Revascularization in Diabetic Patients with Critical Limb Ischemia

Authors: Hayashi H, Yamada S, Kumada Y, Matsuo H, Toriyama T, Kawahara H.

Journal: Ann Vasc Dis. 2008;1(2):111-7. doi: 10.3400/avd.AVDoa08001. Epub 2008 Oct 24. PMID: 23555347; PMCID: PMC3595724.

Link to full text: Immersing Feet in Carbon Dioxide-enriched Water Prevents Expansion and Formation of Ischemic Ulcers after Surgical Revascularization in Diabetic Patients with Critical Limb Ischemia

Abstract: Objective: We investigated the effect of immersion of feet in CO2-enriched water for preventing expansion and formation of ischemic ulcer in critical limb ischemia of diabetic patients after surgical revascularization.

Materials and methods: Eligible patients were allocated CO2 group (CO2 immersion plus standard care) or control group (standard care alone) and were followed up for 3 months after surgical revascularization. The end point is defined as an expansion of a target ulcer (more than 101% of original size) or the formation of new ulcers during the follow-up period.

Results: Fifty-nine patients out of originally enrolled 66 patients with type II diabetes were included in intention-to-treat population. The cumulative prevention rate for ischemic ulcer after 3 months was 97.1% in the CO2 group, while, in the control group, it was 77.8%, i.e., significantly lower than the CO2 group (P = 0.012, log-rank test). The transcutaneous oxygen pressure increased significantly only in the CO2 group, from 56 ± 14 to 63 ± 15 mmHg (P < 0.01, Wilcoxon signed rank test), in 3 months.

Conclusion: These results suggest that addition of CO2 immersion to standard care of critical limb ischemia in diabetic patients improves early postoperative outcome after vascular surgery.

Keywords: adjunctive treatments; carbon dioxide; critical limb ischemia; revascularization; transcutaneous oxygen pressure.

Title: A novel system for transcutaneous application of carbon dioxide causing an "artificial Bohr effect" in the human body

Authors: Sakai Y, Miwa M, Oe K, Ueha T, Koh A, Niikura T, Iwakura T, Lee SY, Tanaka M, Kurosaka M.

Journal: PLoS One. 2011;6(9):e24137. doi: 10.1371/journal.pone.0024137. Epub 2011 Sep 8. PMID: 21931656; PMCID: PMC3169585.

Link to full text: A novel system for transcutaneous application of carbon dioxide causing an "artificial Bohr effect" in the human body

Abstract: Background: Carbon dioxide (CO(2)) therapy refers to the transcutaneous administration of CO(2) for therapeutic purposes. This effect has been explained by an increase in the pressure of O(2) in tissues known as the Bohr effect. However, there have been no reports investigating the oxygen dissociation of haemoglobin (Hb) during transcutaneous application of CO(2)in vivo. In this study, we investigate whether the Bohr effect is caused by transcutaneous application of CO2 in human living body.

Methods: We used a novel system for transcutaneous application of CO(2) using pure CO(2) gas, hydrogel, and a plastic adaptor. The validity of the CO(2) hydrogel was confirmed in vitro using a measuring device for transcutaneous CO(2) absorption using rat skin. Next, we measured the pH change in the human triceps surae muscle during transcutaneous application of CO(2) using phosphorus-31 magnetic resonance spectroscopy ((31)P-MRS) in vivo. In addition, oxy- and deoxy-Hb concentrations were measured with near-infrared spectroscopy in the human arm with occulted blood flow to investigate O2 dissociation from Hb caused by transcutaneous application of CO(2).

Results: The rat skin experiment showed that CO(2) hydrogel enhanced CO(2) gas permeation through the rat skin. The intracellular pH of the triceps surae muscle decreased significantly 10 min. after transcutaneous application of CO(2). The NIRS data show the oxy-Hb concentration decreased significantly 4 min. after CO(2) application, and deoxy-Hb concentration increased significantly 2 min. after CO(2) application in the CO(2)-applied group compared to the control group. Oxy-Hb concentration significantly decreased while deoxy-Hb concentration significantly increased after transcutaneous CO(2) application.

Conclusions: Our novel transcutaneous CO(2) application facilitated an O(2) dissociation from Hb in the human body, thus providing evidence of the Bohr effect in vivo.

Title: Possibilities and limits of CO2 balneotherapy

Authors: Resch KL, Just U.

Journal: Wien Med Wochenschr. 1994;144(3):45-50. German. PMID: 8017066.

Link to PubMed: Possibilities and limits of CO2 balneotherapy

Abstract: CO2 baths are considered an integral feature of balneotherapy. Natural springs containing a concentration of CO2 probably sufficient to be clinically effective (> 1 g/l) as well as artificially enriched baths are applied. Phenomena like a marked erythema (at concentrations above 0.5 g/l) imply clinical efficacy beyond unspecific effects of baths (water immersion, thermal effects). Prolonged effects are postulated to exceed "direct" effects, thus forming the rationale for serial applications of CO2-baths. CO2 is believed to cause an acute induction of local vasodilation and a shift of the O2 binding curve, resulting in a facilitation of the delivery of O2 to the tissue. A positive impact of CO2-baths on the flow properties of blood has been reported. A wide variety of indications is mentioned in the literature, while clear evidence from controlled trials exists only for a minority of them, mainly for chronic circulatory disturbances based on atherosclerotic diseases such as peripheral arterial occlusive disease, trophic ulceration, microangiopathies of various origins, and mild hypertension. Some evidence supports the idea that CO2 baths might represent an efficient therapeutic means in the rehabilitation of coronary heart disease, myocardial infarction and stroke, and in the treatment of chronic venous insufficiency, certain inflammatory diseases, and functional disturbances.

Title: Comparison of the effects of carbonated baths with those of carbon dioxide baths, "dry baths"

Authors: Lecomte J, Lagneaux D.

Journal: Acta Belg Med Phys. 1990 Jan-Mar;13(1):11-4. French. PMID: 2110708.

Link to PubMed: Comparison of the effects of carbonated baths with those of carbon dioxide baths, "dry baths"

Abstract: Therapeutic activities of CO2 water bathes are explained by a synergism between many factors. The first ones are related to immersion it-self: hydrostatic pressure and Archimedes force inducing orthosympathetic inhibition and muscular relaxation. The second ones depend on the pharmacological properties of carbon dioxide acting directly on the blood vessels of the skin, causing vasodilation and heat sensation. As "dry" carbon dioxide bath is devoid of the physical factors which are necessary for a successful therapeutic activity, such an administration has no interest in balneotherapy.

Title: A Prospective Clinical and Instrumental Study on the Effects of a Transcutaneous Cosmeceutical Gel that is Claimed to Produce CO₂

Authors: Leibaschoff GH, Coll L, Roberts WE.

Journal: Surg Technol Int. 2018 Jun 1;32:33-45. PMID: 29566423.

Link to PubMed: A Prospective Clinical and Instrumental Study on the Effects of a Transcutaneous Cosmeceutical Gel that is Claimed to Produce CO₂

Abstract: Carboxytherapy is the therapeutic use of carbon dioxide (CO2) in its gaseous state. Since 1933, carboxytherapy has referred to either the subcutaneous injection of CO2 or percutaneous application in a warm bath. The present clinical study was performed to determine if there were any changes in the dermis after the application of a transcutaneous gel, which is claimed to produce CO2, and, if so, how these changes compared to those with CO2 injection. Ten patients received transcutaneous treatment with the gel on one side of the face and the other side without any product was used as a control. We used videocapillaroscopy with an optic probe (VCSO) to evaluate the changes in the microcirculation of the skin. VCSO was performed for the treated right and untreated left ear lobes in each patient. VCSO was performed before treatment was started (VCSO1) and after 7 days of treatment (VCSO2). A comparison of VCSO1 to VCSO2 showed an increase in the microcirculation, an increase in vertical and horizontal capillaries, and a reduction in the area of ischemia. These results are similar to those observed in other studies with CO2 injection. In conclusion, use of this transcutaneous CO2 gel produced changes in the dermis similar to those observed with subcutaneous injection of CO2.

Title: Effectiveness of carboxytherapy in the treatment of cellulite in healthy women: a pilot study

Authors: Pianez LR, Custódio FS, Guidi RM, de Freitas JN, Sant'Ana E.

Journal: Clin Cosmet Investig Dermatol. 2016 Aug 22;9:183-90. doi: 10.2147/CCID.S102503. PMID: 27578994; PMCID: PMC5001663.

Link to full text: Effectiveness of carboxytherapy in the treatment of cellulite in healthy women: a pilot study

Abstract: Background: Carbon dioxide therapy, better known as carboxytherapy, relates to percutaneous infusion of medical carbon dioxide with therapeutic approaches, and its use in the treatment of localized fat has demonstrated good results. Gynoid lipodystrophy, also known as cellulite, affects 80%-90% of women after puberty, especially in the buttocks and thighs. Its etiology is complex and involves multifactorial aspects. Its treatment and evaluation require the use of new technologies (more effective and low-cost approaches). The objective was to investigate the effectiveness of carboxytherapy in the treatment of cellulite in the areas of buttocks and posterior thigh.

Patients and methods: Ten women, 29±6.1 years, were selected and all of them received eight treatment sessions, with an interval of 7 days between sessions. Standardized digital photographs were used to assess the severity of cellulite, and panoramic images were collected by ultrasound diagnosis. The evaluations were performed before the first treatment (baseline) and 7 days after the last treatment session of carboxytherapy.

Results: After the treatment, there was a significant reduction (P=0.0025) of the cellulite from degree III to degree II, and this improvement had correlation with the improvement in the organization of the fibrous lines and the disposal of adipose tissue lines of the treated regions observed through the panoramic ultrasound images diagnosis.

Conclusion: Carboxytherapy is an effective technique of treatment of cellulite in the buttocks region and posterior thighs of healthy women.

Keywords: carbon dioxide; cellulite; gynoid lipodystrophy; localized fat; panoramic ultrasound; skin.

Title: Carboxytherapy in dermatology: A systematic review

Authors: Ahramiyanpour N, Shafie'ei M, Sarvipour N, Amiri R, Akbari Z.

Journal: J Cosmet Dermatol. 2022 May;21(5):1874-1894. doi: 10.1111/jocd.14834. Epub 2022 Feb 14. PMID: 35124882.

Link to PubMed: Carboxytherapy in dermatology: A systematic review

Abstract: Introduction: The overall effects of Carboxytherapy, defined as the administration of carbon dioxide, have been studied for many years. It has been suggested that by improving oxygenation, interacting with the tissue perfusion regulators, and disrupting the adipose cell membranes, the method can lead to notable improvements in different esthetic and pathological conditions. Therefore, we aimed to systematically review the available studies evaluating the potential benefits of carboxytherapy in dermatological conditions and how it objectively stands against scientific scrutiny.

Methods: We searched the PubMed, Scopus, Embase, and Web of Science databases, including the studies exploring the method's efficacy in managing any dermatological condition.

Results: A total 27 of studies were identified (with a pooled sample of over 700 cases), most of which were clinical trials. Facial wrinkles, periorbital hyperpigmentation, skin laxity deficiency, scars, striae distensae, localized lipolysis and cellulite, alopecia, chronic diabetic wounds, and psoriatic plaques comprised the package of the dermatological conditions that were studied. Except for a few studies, the method mainly demonstrated significant improvements on all of the mentioned conditions. The inter- and post-operational adverse events were mild and transient, including erythema, pain, crepitus, and ecchymoses.

Discussion: Carboxytherapy can provide those practicing in the field with sustainably favorable results. However, the numbers of cases on whom the fat-reducing capabilities of the method were studied and experienced varying degrees of recurrence caught our eye. In addition, we observed a notable disparity between the outcome measures utilized in the studies. The modest sample size in each condition also added to the injury, as the conditions on which the method was evaluated are pretty common in the general population. Therefore, for a definite conclusion, more randomized controlled trials with the shortcomings mentioned well addressed need to be conducted.

Keywords: carbon dioxide therapy; carboxytherapy; dermatology.

Title: Carboxytherapy in esthetic medicine – A review

Authors: Zelenkova, H. and Wollina, U.

Journal: A review." Cosmoderma 3 (2023).

Link to full text: Carboxytherapy in esthetic medicine – A review

Abstract: Carboxytherapy is a minimally invasive method used not only in esthetic medicine. It is defined as the transcutaneous or subcutaneous application of carbon dioxide gas. The treatment exerts effects on various levels including improvement of tissue oxygenation, vasodilatation, stimulation of fibroblasts, and antimicrobial activity. In this review, we will focus on facial and neck esthetics, localized adiposities and cellulite, and scars and stretch marks. We discuss reported evidence for these indications and safety issues. We also mention possible combinations with other treatments. In general, a repeated application is necessary to achieve desired results.
Keywords: Esthetic medicine, Carboxytherapy, Indications, Safety

Title: Carboxytherapy--a new non-invasive method in aesthetic medicine

Authors: Koutná N.

Journal: Cas Lek Cesk. 2006;145(11):841-3. Czech. PMID: 17168416.

Link to PubMed: Carboxytherapy--a new non-invasive method in aesthetic medicine

Abstract: Basic information about carboxytherapy and its new use in non-invasive aesthetic medicine and in dermatology is presented in the article.

Title: Comparison of the effects of carboxytherapy and radiofrequency on skin rejuvenation

Authors: Pinheiro NM, Crema VO, Millan BM, Carvalho FA, Mendonça AC.

Journal: J Cosmet Laser Ther. 2015 Jun;17(3):156-61. doi: 10.3109/14764172.2014.1003238. Epub 2015 Jan 30. PMID: 25549818.

Link to PubMed: Comparison of the effects of carboxytherapy and radiofrequency on skin rejuvenation

Abstract: Background: Carboxytherapy (CA) refers to the cutaneous and subcutaneous administration of CO(2) for therapeutic purposes. Radiofrequency (RF) is a method that uses electric current for heating layers of the skin. Both techniques are indicated for the treatment of skin laxity.

Objective: The aim of this study was to compare the effects of CA and RF on human skin.

Methods: After eight patients underwent abdominoplasty, each of them received a single treatment of CA and a single treatment of RF on the right and left infra-umbilical regions, respectively. In the infra-umbilical region, CA was performed on the right and RF was performed on the left side. Untreated skin was used as a control. The sample collection period lasted 120 days. CA was administered at a velocity of 40 mL/min, and the total quantity of CO(2) infused was approximately 20 mL. RF was carried out at a temperature higher than 40°C on the epidermis for 5 min.

Results: CA and RF led to collagen remodeling; however, this result was more evident and lasted longer with RF. With CA an increase in elastic fibers was observed, whereas with RF no alteration was observed.

Conclusion: Our results suggest that RF is more efficient than CA in stimulating collagen synthesis.

Keywords: carbon dioxide; carboxytherapy; radiofrequency; rejuvenation; skin aging.

Title: Increase in collagen turnover induced by intradermal injection of carbon dioxide in rats

Authors: Ferreira JC, Haddad A, Tavares SA.

Journal: J Drugs Dermatol. 2008 Mar;7(3):201-6. PMID: 18380201.

Link to PubMed: Increase in collagen turnover induced by intradermal injection of carbon dioxide in rats

Abstract: Introduction: Results from clinical observations have demonstrated that percutaneous infiltration of carbon dioxide improves the appearance of the skin in adjacent areas. No studies have been found in the literature that showed evidence of histological changes caused by carbon dioxide injections.

Objectives and methods: A blind cross-sectional pilot study was performed in the Departments of Pharmacology and Morphology of the Federal University of Ceará, with the aim of histologically investigating whether intradermal and/or subcutaneous injection of medicinal carbon dioxide would increase collagen turnover in rats. Ten male Wistar rats were used, aged 3 months (2 animals) and 14 months (8 animals). The 2 younger rats were used as controls. Four of the older rats received injections of saline solution (0.9%), and were also considered to be controls. In the remaining 4, carbon dioxide was injected into the subcutaneous cellular tissue and intradermally. Biopsy samples were collected before and after treatment with carbon dioxide.

Results: Collagen turnover increased in the treated animals in comparison with the controls. Compression of collagen bundles in the tissue samples where intradermal injection was used was more intense than in the subcutaneous treatment. The histological characteristics of the samples with carbon dioxide injected intradermally were similar to the characteristics of the younger rats (controls).

Conclusions: The results obtained corroborate clinical observations of aesthetic improvements in the facial skin with carbon dioxide injections. Future research should address the comparison between intradermal and subcutaneous injections, the volume of gas used, and the frequency of treatment sessions.

Title: CO2 release to the atmosphere from thermal springs of Sperchios Basin and northern Euboea (Greece): The contribution of "hidden" degassing

Authors: D'Alessandro W, Li Vigni L, Gagliano Antonina L, Calabrese S, Kyriakopoulos K, Daskalopoulou K.

Journal: Applied Geochemistry, Volume 119, 2020, 104660, ISSN 0883-2927, https://doi.org/10.1016/j.apgeochem.2020.104660.

Link to ScienceDirect: CO2 release to the atmosphere from thermal springs of Sperchios Basin and northern Euboea (Greece): The contribution of "hidden" degassing

Abstract: Greece is a region characterised by intense geodynamic activity that favours the circulation of hydrothermal fluids in the crust transporting volatiles from either the deep crust or the mantle to the surface. Elevated heat flow values are detectable at Sperchios Basin and North Euboea (central Greece), two areas defined by a system of deeply rooted extensional faults and Quaternary volcanic activity. This setting contributed to the formation of numerous hydrothermal systems, which are mostly expressed as CO2-rich thermal springs with intense bubbling. The CO2 output from six bubbling pools has been determined by flux measurements with the use of the floating chamber method. The highest bubbling CO2 output has been found at Thermopyles and Psoroneria (0.6 and 0.84 t/d, respectively), where the outgoing channels have an elevated flow (>250 l/s) of gas-charged water (>15 mmol/l of CO2). Although no bubbling is noticed along the stream, the CO2 content decreases by an order of magnitude after few hundreds of metres, indicating an intense degassing from the water. Taking into account the water flow and the amount of CO2 lost to the atmosphere, the CO2 output of the outgoing channels is quantified in 12.5 t/d for Thermopyles and 9.23 t/d for Psoroneria. Output estimation has also been made for the other springs of the area. The diffuse CO2 release from the outgoing channels has always been higher respect to that of the visible bubbling, suggesting that most of the degassing is "hidden". Furthermore, the loss of CO2 from the water has determined a shift in dissolved carbonate species as demonstrated by the pH increase along the channel that led eventually to an oversaturation in carbonate minerals and therefore travertine deposition. The total CO2 output to the atmosphere of the study area is estimated at ~27 t/d, with the major contribution deriving from the degassing along the outflow channels of the thermal springs. Such output is comparable to that of the single active volcanic systems along the South Aegean Active Volcanic Arc and highlights the importance of "hidden" degassing along CO2-oversaturated streams.

Title: Natural skin surface pH is on average below 5, which is beneficial for its resident flora

Authors: Lambers H, Piessens S, Bloem A, Pronk H, Finkel P.

Journal: Int J Cosmet Sci. 2006 Oct;28(5):359-70. doi: 10.1111/j.1467-2494.2006.00344.x. PMID: 18489300.

Link to full text: Natural skin surface pH is on average below 5, which is beneficial for its resident flora

Abstract: Variable skin pH values are being reported in literature, all in the acidic range but with a broad range from pH 4.0 to 7.0. In a multicentre study (N = 330), we have assessed the skin surface pH of the volar forearm before and after refraining from showering and cosmetic product application for 24 h. The average pH dropped from 5.12 +/- 0.56 to 4.93 +/- 0.45. On the basis of this pH drop, it is estimated that the 'natural' skin surface pH is on average 4.7, i.e. below 5. This is in line with existing literature, where a relatively large number of reports (c. 50%) actually describes pH values below 5.0; this is in contrast to the general assumption, that skin surface pH is on average between 5.0 and 6.0. Not only prior use of cosmetic products, especially soaps, have profound influence on skin surface pH, but the use of plain tap water, in Europe with a pH value generally around 8.0, will increase skin pH up to 6 h after application before returning to its 'natural' value of on average below 5.0. It is demonstrated that skin with pH values below 5.0 is in a better condition than skin with pH values above 5.0, as shown by measuring the biophysical parameters of barrier function, moisturization and scaling. The effect of pH on adhesion of resident skin microflora was also assessed; an acid skin pH (4-4.5) keeps the resident bacterial flora attached to the skin, whereas an alkaline pH (8-9) promotes the dispersal from the skin.

Title: The Shampoo pH can Affect the Hair: Myth or Reality?

Authors: Gavazzoni Dias MF, de Almeida AM, Cecato PM, Adriano AR, Pichler J.

Journal: Int J Trichology. 2014 Jul;6(3):95-9. doi: 10.4103/0974-7753.139078. PMID: 25210332; PMCID: PMC4158629.

Link to full text: The Shampoo pH can Affect the Hair: Myth or Reality?

Abstract: Aim: Dermatologists most frequently prescribe shampoos for the treatment of hair shed and scalp disorders. Prescription of hair care products is often focused on improving scalp hair density, whereas the over-the-counter products focus on hair damage prevention. Little is taught in medical schools about the hair cosmetics, so that the prescriptions are based only on the treatment of the scalp and usually disregards the hair fiber health.

Materials and methods: In this work, we review the current literature about the mode of action of a low-pH shampoo regarding the hair shaft's health and analyze the pH of 123 shampoos of international brands.

Results: All shampoo pH values ranged from 3.5 to 9.0. 38.21% of all 123 shampoos presented a pH ≤ 5.5 (IC: 29.9-47%) and 61.78% presented a pH > 5.5. 26 anti-dandruff shampoos were analyzed. About 19.23% presented pH ≤ 5.5.(IC: 7.4-37.6%). 80.77% of all anti-dandruffs shampoos presented a pH > 5.5. The dermatological shampoo group (n = 19) presented 42.10% with pH ≤ 5.5 (IC: 21.8-64.6%), and 57.90% with pH > 5.5. Among the commercial (popular) products (n = 96), 34.37% presented pH ≤ 5.5 (IC: 25.4-44.3%) and 65.62% presented pH > 5.5. 15 professional products (used in hair salons) were analyzed, of which 75% had a pH ≤ 5.5 (IC: 18-65, 4%), and 25% had a pH > 5.5. 100% of the children's shampoos presented a pH > 5.5.

Conclusions: Alkaline pH may increase the negative electrical charge of the hair fiber surface and, therefore, increase friction between the fibers. This may lead to cuticle damage and fiber breakage. It is a reality and not a myth that lower pH of shampoos may cause less frizzing for generating less negative static electricity on the fiber surface. Interestingly, only 38% of the popular brand shampoos against 75% of the salons shampoos presented a pH ≤ 5.0. Pediatric shampoos had the pH of 7.0 because of the "no-tear" concept. There is no standardized value for the final pH. The authors believe that it is important to reveal the pH value on the shampoo label, but studies are needed to establish the best pH range for both the scalp and the hair fiber's health.

Title: Evaluation of pH of Bathing Soaps and Shampoos for Skin and Hair Care

Authors: Tarun J, Susan J, Suria J, Susan VJ, Criton S.

Journal: Indian J Dermatol. 2014 Sep;59(5):442-4. doi: 10.4103/0019-5154.139861. PMID: 25284846; PMCID: PMC4171909.

Link to full text: Evaluation of pH of Bathing Soaps and Shampoos for Skin and Hair Care

Abstract: Background: Normal healthy skin has potential of hydrogen (pH) range of 5.4-5.9 and a normal bacterial flora. Use of soap with high pH causes an increase in skin pH, which in turn causes an increase in dehydrative effect, irritability and alteration in bacterial flora. The majority of soaps and shampoos available in the market do not disclose their pH.

Aims and objectives: The aim of this study was to assess the pH of different brands of bathing soaps and shampoos available in the market.

Materials and methods: The samples of soaps and shampoos were collected from shops in the locality. The samples of different brands are coded before the analysis of the pH. Solution of each sample was made and pH was measured using pH meter.

Results: Majority of the soaps have a pH within the range of 9-10. Majority of the shampoos have a pH within the range of 6-7.

Conclusions: The soaps and shampoos commonly used by the population at large have a pH outside the range of normal skin and hair pH values. Therefore, it is hoped that before recommending soap to patient especially those who have sensitive and acne prone skin, due consideration is given to the pH factor and also that manufacturers will give a thought to pH of soaps and shampoos manufactured by them, so that their products will be more skin and hair friendly.

Title: Effects of carboxytherapy on skin laxity

Authors: Oliveira SMD, Rocha LB, da Cunha MTR, Cintra MMM, Pinheiro NM, Mendonça AC.

Journal: J Cosmet Dermatol. 2020 Nov;19(11):3007-3013. doi: 10.1111/jocd.13337. Epub 2020 Feb 24. PMID: 32091181.

Link to PubMed: Effects of carboxytherapy on skin laxity

Abstract: Background: Carboxytherapy is capable of inducing tissue repair which results in an increase in elastic and collagen fibers.

Objectives: To evaluate the effects of carboxytherapy upon human skin collagen and elastic fiber synthesis.

Methods: Case study of nine volunteers who received a single application of carboxytherapy in the left infraumbilical region, with infusion rate of 100 mL/min and 0.6 mL/kg weight over an area of 25 cm2 . After 60 days on average, the skin was collected for histological analysis and stained with picrosirius red for collagen and Verhoeff for elastic fibers. The percentage of fibers found was marked by the Image J® program and recorded in a Microsoft Excel spreadsheet. Statistical analysis was performed using SPSS (version 20), with a significance level of 95%.

Results: An increase in the collagen and elastic fibers sample was observed in the treated group. Morphometrically, a significant increase in the percentage of collagen in the Carboxytherapy group (41.44 ± 4.50%) was observed compared with the control group (37.44 ± 3.87%) with P = .04; for elastic fibers, the percentage showed no significant difference between the control group (10.55 ± 4.33%) and the carboxytherapy group (10.44 ± 3.71%).

Conclusions: Carboxytherapy with the parameters used in this study was able to stimulate collagen and elastic fiber synthesis, with significant differences in the morphometry for collagen fibers.

Title: CO2 laser physics and tissue interactions in skin

Authors: Fulton JE, Shitabata PK.

Journal: Lasers Surg Med. 1999;24(2):113-21. doi: 10.1002/(sici)1096-9101(1999)24:2<113::aid-lsm6>3.0.co;2-7. PMID: 10100648.

Link to PubMed: CO2 laser physics and tissue interactions in skin

Abstract:
Background and objectives: The theoretical model of CO2 laser tissue interaction appeared to be too simplistic. To explain the reactions seen in skin, a more complex model was needed. We hoped to correlate the clinical-histologic patterns of CO2 laser tissue interactions.

Study design/materials and methods: The Ultrapulse CO2 laser was used on normal and pathologic skin conditions. Clinical observations were correlated with histologic examinations of biopsies.

Results: It was possible to demonstrate cavitation at the dermal-epidermal junction 2-3 diameters beyond the actual spot of CO2 laser contact with the skin. Dermal heat damage was seen as homogenization of collagen 1-2 diameters beyond the spot of laser contact. This flow of energy laterally at the dermal-epidermal junction and vertically down the skin follicles was both clinically beneficial and detrimental. Beneficially, superficial skin lesions separated at this junction and were easily removed. The heat coagulation of the dermis facilitated lesion removal without bleeding. The clinician had a better view of the pathology and could find focal zones of deeper pathology that could be easily re-treated. Detrimentally, this extended damage delayed wound healing and led to persistent erythema.

Conclusion: These clinical-histologic correlations have provided a better understanding of CO2 laser tissue interactions in skin. It has been possible to take advantage of these findings to remove pathologic skin conditions more efficiently.

Title: The Effects on Skin Blood Flow of Immersing the Ischemic Legs of Patients with Peripheral Arterial Disease into Artificially Carbonated Water

Authors: Makita, S., Ohira, A., Naganuma, Y. et al.

Journal: Int J Angiol 15, 12–15 (2006). https://doi.org/10.1007/s00547-006-2063-0

Link to Springer: The Effects on Skin Blood Flow of Immersing the Ischemic Legs of Patients with Peripheral Arterial Disease into Artificially Carbonated Water

Abstract: It is known that carbon dioxide causes vasodilatation. Therefore, immersing the extremities into carbonated water would be expected to increase skin blood flow, given that carbon dioxide can permeate through the skin surface. We immersed the ischemic legs of patients with peripheral arterial disease (PAD) into water artificially carbonated by a new device. Sixteen Fontaine grade II PAD patients were randomly divided into two groups: eight patients whose legs were immersed into artificially carbonated water (CO2 group), and eight patients whose legs were immersed into tap water as a control (CTL group). The water temperature was set at 35°C, and the immersion (10 min) was repeated daily for 3 weeks in both groups. During immersion, the average percent skin blood flow increase was larger in the CO2 group than in the CTL group (426 vs. 173%, p < 0.001), and increased gradually with each immersion in the CO2 group (272% at the first immersion, 343% after 2 weeks, and 359% after 3 weeks, p < 0.01). Leg symptoms at rest, such as a sensation of cold and/or numbness, were significantly alleviated in the CO2 group compared to the CTL group (2.5 points, CO2 group vs. 8.7 points, CTL group after 3-weeks based on a 10-point relative scale, p < 0.01). Immersion into artificially carbonated water appears to be a convenient treatment option for treating limb ischemia.