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Meta-analysis finds very uncertain evidence for CO therapy in wound healingCarbon Dioxide Therapy May Help Stubborn Wounds Heal Faster

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Key Takeaway
Interpret CO therapy evidence for wound healing as very uncertain; larger trials are needed.

This meta-analysis assessed highly concentrated carbon dioxide (CO) therapy (bathing and non-bathing methods) for treating diabetic foot ulcers and pressure injuries. The analysis included 127 wounds/participants from studies that were not further specified. The primary outcome was complete ulcer healing, with secondary outcomes including microvascular perfusion, skin temperature, VEGF, TNF-α, and wound area reduction.

For complete ulcer healing, the pooled relative risk was 5.33 (95% CI 0.23-126.05), indicating a very wide confidence interval that crosses 1, making the result very uncertain. For microvascular perfusion, the standardized mean difference was 0.61 (95% CI 0.23-0.99), suggesting a moderate improvement with low certainty. Other secondary outcomes were not reported with effect sizes.

The authors note several limitations: heterogeneity among studies, imprecision of estimates, and small sample size. They emphasize the need for further large-scale trials. Adverse events, serious adverse events, and discontinuations were not reported. The certainty of evidence was rated very low for complete healing and low for microvascular perfusion.

Clinicians should interpret these findings with caution. The evidence does not support definitive efficacy of CO therapy for wound healing due to very low certainty. The association is based on limited data, and no causal conclusions can be drawn.

Chronic wounds are painful and stubborn. They can stop you from walking, working, or sleeping well. For people with diabetes, a small sore on the foot can turn into a major problem. Doctors often struggle to get these wounds to close. Now, a new review suggests a gas you already know, carbon dioxide, might help when used in a highly concentrated way.

The review looked at five small trials with 127 wounds. The goal was simple. Can bathing a wound in carbon dioxide, or applying it in other ways, help it heal faster. The results are promising but early. This is not a cure, and it is not ready for every clinic. But it points to a new path for a tough problem.

Chronic wounds affect millions of people worldwide. Diabetic foot ulcers and pressure injuries are two of the most common. These wounds often fail to heal because of poor blood flow, infection, and ongoing inflammation. Standard care includes cleaning, special dressings, offloading pressure, and sometimes surgery. Even with good care, healing can take months. Some wounds never close. That is why researchers keep testing new tools.

Here is the twist. Carbon dioxide is not new to medicine. It is already used in some therapies to improve blood flow. But this review tested a highly concentrated form. The idea is to bathe the wound in CO2 or apply it directly to the skin. The hope is that this gas can open tiny blood vessels and reduce swelling. That could give the wound the oxygen and nutrients it needs to heal.

Think of a wound like a blocked factory. The workers want to build new tissue, but the supply lines are clogged. Carbon dioxide may act like a key that unlocks the doors. It can help relax blood vessels and improve microvascular perfusion, which is the flow through tiny vessels. Better flow means more oxygen and nutrients reach the damaged area. That can support cell growth and reduce inflammation.

The review included five randomized controlled trials. These are the gold standard for testing treatments. The studies looked at both bathing methods, where the wound is soaked in CO2-rich water, and non-bathing methods, like direct gas application. The trials focused on people with chronic wounds, including diabetic foot ulcers and pressure injuries. The researchers followed strict steps to find and check the studies, using standard tools to reduce bias.

The findings were mixed but encouraging. In two trials, carbon dioxide therapy increased the chance of complete ulcer healing. The numbers were wide and uncertain, but the direction was positive. In another two trials, the therapy improved microvascular perfusion, which means blood flow in tiny vessels got better. Some individual studies also reported warmer skin, lower inflammation markers, and smaller wound areas. These are all signs that the wound environment is improving.

But there is a catch. The evidence is still low to very low certainty. That means we cannot be sure the results are reliable. The studies were small, and the methods varied. Some used bathing, some used non-bathing. The wound types and treatment times differed. This makes it hard to compare results. More large, high-quality trials are needed to confirm the effect and find the best way to use it.

This does not mean carbon dioxide therapy is ready for every clinic.

Experts in wound care are watching this area closely. The review followed standard methods and used tools to rate the certainty of the evidence. That adds credibility. But the field needs more data. Researchers should test larger groups, use consistent methods, and track long-term outcomes. The goal is to know who benefits most and how to apply the therapy safely.

If you or a loved one has a chronic wound, talk to your doctor about all options. Carbon dioxide therapy is not yet a standard treatment. It may be available in some clinics as part of research or specialized care. Do not try this at home. Standard wound care, like keeping the wound clean and offloading pressure, remains essential. Ask your care team about new therapies and clinical trials.

The review has limits. It included only five trials with 127 wounds. The wound types and treatment methods were not the same across studies. Some results were very uncertain. This is common in early research. It means the therapy could help, but we need better data to know for sure.

What happens next. Researchers should run larger trials across different hospitals and wound types. They should compare bathing and non-bathing methods and test the best dose and timing. Approval for routine use will depend on strong evidence of safety and benefit. For now, carbon dioxide therapy is a promising idea, not a proven standard. Stay informed and talk with your doctor as new data arrives.

Study Details

Study typeMeta analysis
EvidenceLevel 1
PublishedJan 2026
View Original Abstract ↓
BACKGROUND: Wound healing poses a persistent clinical challenge, especially in chronic wounds like diabetic foot ulcers and pressure injuries. Highly concentrated carbon dioxide (CO) therapy has emerged as a non-invasive approach to promote healing, but its effectiveness remains uncertain. OBJECTIVE: To evaluate the efficacy of highly concentrated CO therapy, bathing and non-bathing methods, on wound healing outcomes. METHODS: This systematic review and meta-analysis followed PRISMA guidelines and was registered in PROSPERO (CRD420251035698). Six databases were searched, identifying 10,348 records. Five randomized controlled trials met the inclusion criteria, involving participants with wounds treated using highly concentrated CO through bathing or non-bathing methods. Two reviewers independently extracted data and assessed risk of bias using the Cochrane RoB 2.0 tool. Meta-analyses were conducted with fixed- or random-effects models, and the certainty of evidence was evaluated using the GRADE approach. RESULTS: Five trials ( = 127 wounds/participants) were included. Meta-analysis of two trials indicated that CO therapy increased the likelihood of complete ulcer healing (RR = 5.33; 95% CI [0.23-126.05];  = 81.3%), though the evidence was very uncertain due to heterogeneity and imprecision. Another meta-analysis of two trials found moderate improvement in microvascular perfusion (SMD = 0.61; 95% CI [0.23-0.99];  = 0%), rated as low certainty. Individual studies reported improvements in skin temperature, VEGF, TNF-α, and wound area reduction. CONCLUSION: Highly concentrated CO therapy shows promise in enhancing wound healing. However, further large-scale, high-quality trials across diverse settings are needed to validate its clinical applicability.
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