Contraindications and limitations may include the following:

• Non-compressible vessels
• Presence of hemodialysis access
• Presence of ulcers, casts, staples or bandages
• Incomplete palmar arch
• Ischemic digits
• Raynaud’s syndrome
• IV or catheters that limit access /visualization of arterial structures
• Patients' inability to cooperate with or tolerate the examination