Can the Kendall SCD 700 sequential compression system be used on an elderly diabetic man with a chronic painful ankle ulcer and suspected critical limb ischemia?

Sequential Compression Devices in Critical Limb Ischemia: Contraindicated

The Kendall SCD 700 sequential compression system is absolutely contraindicated in this patient with suspected critical limb ischemia and should not be used. Sequential compression devices are designed for venous disease, not arterial insufficiency, and applying external compression to an ischemic limb can worsen tissue perfusion and accelerate tissue loss.

Why This Device Is Dangerous in Arterial Disease

Mechanism of Harm

• Sequential compression devices work by increasing venous return and reducing venous stasis through external pressure (typically 30-45 mmHg for the Kendall SCD systems) 1
• In critical limb ischemia, the fundamental problem is inadequate arterial inflow—not venous stasis 2
• Applying external compression to an already ischemic limb further reduces the already compromised arterial perfusion pressure, potentially converting a salvageable limb into one requiring amputation 2

Critical Diagnostic Requirements Before Any Compression

• The American College of Radiology explicitly warns that compression therapy requires checking the ankle-brachial index (ABI) first, as applying compression when ABI <0.6 is contraindicated because it indicates arterial disease requiring revascularization 1, 3
• When ABI is <0.6, compression is absolutely contraindicated 1, 3
• Critical limb ischemia is defined by ankle pressure <50 mmHg, toe pressure <30 mmHg, or transcutaneous oxygen pressure (TcPO₂) <30 mmHg 2
• In diabetic patients, ABI may be falsely elevated (>1.40) or non-compressible due to medial arterial calcification in up to 30% of cases, requiring toe pressures or TcPO₂ for accurate assessment 2, 4, 5

What This Patient Actually Needs

Immediate Diagnostic Workup

• Confirm critical limb ischemia hemodynamically with ABI, ankle pressure, toe pressure, or TcPO₂ measurement 2
• If ABI is non-compressible or >1.40 (common in diabetics), obtain toe pressure or TcPO₂ 2, 4
• Obtain cross-sectional imaging (CT angiography or MR angiography) from aorta to pedal vessels to plan revascularization 2

Urgent Revascularization

• The primary treatment for critical limb ischemia is revascularization to restore arterial inflow—not compression therapy 1, 2
• Surgical bypass using great saphenous vein is preferred for suitable candidates with adequate conduit, especially for complex below-knee disease 2
• Endovascular therapy (angioplasty ± stenting) is appropriate for high surgical risk patients or those lacking suitable vein conduit 2
• Without revascularization, critical limb ischemia progresses to major amputation within 6 months 2

Wound Management Adjuncts

• Moist wound dressings to maintain optimal wound environment 2
• Off-loading footwear to reduce pressure on ulcerated areas 2
• Prompt debridement of necrotic tissue 2
• Broad-spectrum antibiotics if infection is present (infection accelerates tissue loss by increasing metabolic demand) 2

Common Pitfall to Avoid

The most dangerous error is assuming this is a venous ulcer and applying compression therapy without first excluding arterial disease. Approximately 16% of venous leg ulcer patients have unrecognized concomitant arterial disease 3. In this elderly diabetic man with a painful ankle ulcer and suspected critical limb ischemia, the clinical picture strongly suggests arterial insufficiency, not venous disease. Diabetic neuropathy can mask pain severity, leading to extensive tissue loss with minimal discomfort, so the presence of pain actually suggests significant ischemia 2.

Device-Specific Considerations

While the Kendall SCD 700 is effective for venous thromboembolism prophylaxis in appropriate patients (achieving peak venous velocities of 37.4 cm/s and applying sequential compression from ankle to thigh) 6, these hemodynamic benefits are irrelevant and potentially harmful in arterial disease. The device's 45 mmHg compression pressure would further compromise already inadequate arterial perfusion in this patient 6.