What is the appropriate application and pressure setting for barotherapy (pressure therapy) in a patient with conditions such as chronic wounds, lymphedema, or edema?

Barotherapy (Pressure Therapy): Application and Settings

Defining Barotherapy in Clinical Context

Barotherapy refers to two distinct therapeutic modalities: negative pressure wound therapy (NPWT) for wound management, and compression therapy for venous insufficiency, lymphedema, and edema. These are fundamentally different applications with opposite pressure vectors and distinct clinical indications.

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Negative Pressure Wound Therapy (NPWT)

When to Use NPWT

NPWT should be considered only for post-operative surgical wounds in diabetic foot ulcers, not for chronic non-surgical wounds. 1

• Strong recommendation AGAINST using NPWT for chronic non-surgical diabetic foot ulcers - all available evidence shows no clear benefit over standard care, with studies suffering from high risk of bias 1, 2
• Consider NPWT for post-operative wounds to reduce wound size, though effectiveness remains to be fully established 1
• NPWT may be used in necrotizing infections only after complete surgical debridement 2

Critical Prerequisites Before NPWT Application

Complete surgical debridement removing all necrotic and infected tissue is absolutely mandatory before applying NPWT. 2

• NPWT should never be applied to infected wounds until complete surgical removal of necrosis has been accomplished 2
• Initial debridement must continue into healthy-looking tissue before NPWT application 2
• Residual necrotic tissue or uncontrolled infection are absolute contraindications 2

NPWT Pressure Settings

Use 75-80 mmHg for vulnerable anatomic areas or wounds with exposed structures; standard pressure is 125 mmHg for routine wounds. 2

• Lower pressures (75-80 mmHg) prevent tendon desiccation when tendons are exposed 2
• Continuous pressure is preferred over intermittent for most applications 2
• Dressing changes should occur every 2-3 days, with an average of 5 changes required for optimal granulation 2

Special Considerations for Exposed Tendons

A large, fenestrated non-adherent interface layer must be placed directly over exposed tendon before foam application. 2

• The interface layer prevents tendon damage during dressing changes and should extend beyond immediate wound margins 2
• Foam should never contact exposed tendon directly 2
• Use specialized commercial foam-based NPWT kits rather than improvised methods 2

Common Pitfalls with NPWT

• Four RCTs and multiple cohort studies demonstrated high risk of bias with major methodological flaws in non-surgical diabetic foot ulcers 2
• Potential adverse effects include wound maceration, dressing retention, and paradoxically, wound infection 1, 2
• Using NPWT before complete necrosis removal prevents effective therapy 2

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Compression Therapy (Positive Pressure)

Pressure Settings by Clinical Indication

For venous ulcers (C6 disease) and ulcer prevention (C5 disease), use 30-40 mmHg inelastic compression; for less severe venous disease (C2-C4), start with 20-30 mmHg. 3

Venous Insufficiency and Ulcers

• 30-40 mmHg inelastic compression is superior to elastic bandaging for wound healing in venous ulcers 3
• 20-30 mmHg minimum effective pressure for C2-C4 disease 3
• For patients with ankle-brachial index (ABI) 0.6-0.9, reduce to 20-30 mmHg 3, 4

Lymphedema and Chronic Edema

• 20-30 mmHg initially for lymphedema management 4, 5
• 30-40 mmHg for more severe lymphedema 4
• Compression is essential for proper wound therapy when peri-wound lymphedema is present 6, 7

VTE Prophylaxis

• 15-30 mmHg below-knee graduated compression stockings for long-distance travelers at increased VTE risk 4
• Intermittent pneumatic compression preferred over graduated compression stockings for hospitalized patients when pharmacological prophylaxis is contraindicated 4

Critical Pre-Treatment Assessment

Always check ankle-brachial index (ABI) before applying compression - this is the most dangerous error to avoid. 3

• When ABI <0.6, compression is absolutely contraindicated as it indicates arterial disease requiring revascularization first 3, 4
• Approximately 16% of venous leg ulcer patients have unrecognized concomitant arterial disease 3
• ABI between 0.6-0.9 requires reduced compression pressure (20-30 mmHg) 3, 4

Optimal Compression Technique

Apply "negative graduated compression" with higher pressure at the calf rather than the distal ankle for venous insufficiency. 3

• Higher pressure at the calf achieves improved ejection fraction in refluxing vessels compared to traditional graduated compression (higher at ankle) 3
• Avoid bandages that are too tight at the knee, as this paradoxically worsens venous return 3
• Inelastic compression is superior to elastic bandaging for venous ulcers 3

Compression for Specific Conditions

Chronic Wounds with Edema

• Mobilization of lymph fluid from the peri-wound area with reasoned compression is essential for proper wound therapy 7
• Proper wound care demands attention to related lymphedema, as lymphedema negatively affects wound healing 6, 7
• Compression therapy combined with debridement and other wound care strategies is fundamental 1, 7

Post-Thrombotic Syndrome

• The American Society of Hematology suggests against routine use of compression stockings for prevention of post-thrombotic syndrome in DVT patients 4
• Compression stockings may still benefit selected patients with DVT-related edema and pain for symptom management 4

Adherence Optimization

Treatment failure most commonly results from non-compliance rather than inadequate compression. 3

• Provide detailed application instructions and proper fitting education 3
• Proper fitting is essential - stockings should be measured and fitted to the individual patient 4
• Patient education on proper application and removal techniques improves adherence 4

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Pressure Offloading for Diabetic Foot Ulcers (CLTI)

Patients with chronic limb-threatening ischemia (CLTI) and diabetic foot ulcers should receive pressure offloading when possible to promote tissue growth and wound healing. 1

Evidence-Based Offloading Strategies

• Nonremovable pressure offloading devices are superior to removable devices for wound healing in diabetic foot ulcers 1
• Total-contact cast demonstrates higher and faster wound healing rates than half-shoe or removable cast walker 1
• Forefoot pressure offloading shoes or cast shoes are effective in promoting wound healing 1

Post-Healing Prevention

Patients with PAD and previous diabetic foot ulcers should be referred for customized footwear that accommodates, protects, and fits the shape of their feet. 1

• Custom-made footwear with improved and sustained pressure offloading reduces plantar ulcer recurrence at 18 months in patients with high adherence 1
• Foot shape- and barefoot pressure-based orthoses are more effective than standard care in reducing submetatarsal head plantar ulcer recurrence when worn as prescribed 1

Patients Without Diabetes

• Patients with CLTI and foot ulcers who do not have diabetes may be considered for pressure offloading, though evidence is limited to diabetic populations 1
• Podiatrists or foot-trained professionals should evaluate these patients for appropriate pressure offloading therapy 1

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Adjunctive Therapies with Limited Evidence

Hyperbaric Oxygen Therapy (HBOT)

Consider systemic hyperbaric oxygen therapy for diabetic foot ulcers, though further trials are required to confirm cost-effectiveness and identify optimal patient populations. 1

• Two methodologically good quality RCTs demonstrated improved wound healing within 12 months 1
• Ulcer healing with HBOT was associated with baseline transcutaneous oxygen pressure levels, not with ABI or toe blood pressure 1
• Many patients cannot complete the full HBOT regimen due to poor overall health 1
• Limited or no access to HBOT in some countries, and expensive with significant patient burden 1

Topical Oxygen Therapy

Do not use topical oxygen therapy - conflicting evidence from equally rigorous blinded RCTs shows no consistent benefit. 1

• One large blinded RCT showed higher proportion of healed DFUs at 12 weeks with continuous oxygen diffusion 1
• Another equally large blinded RCT over similar timeframe showed no benefit 1

Other Adjunctive Therapies

• Electromagnetic therapy, therapeutic ultrasound, and laser therapy were similar to controls for ulcer alleviation 1
• Electrical stimulation accelerated wound healing but showed no superiority for complete wound healing, with skin irritation as the most common adverse effect 1
• Frail elderly patients had more adverse events with electrical stimulation 1