Contraindications and limitations may include the following:

• Neck Braces
• Endotracheal tube harness
• Patients with short, thick, muscular necks
• Recent surgery in region of exam (penetration and visualization may be limited secondary to the presence of edema, hematoma, surgical staples, dressings)
• Calcified/complex plaque and acoustic shadowing may limit penetration of the ultrasound beam, limiting the Doppler and B-mode image assessment
• Patients with chronic obstructive pulmonary disease (COPD) or arthritic necks may require head of the bed elevation or sit upright during exam
• Involuntary movement or inability to remain still during examination
• Studies performed at the bedside may be limited due to patient access and room dimensions