Unintentional intra-arterial injection

Background

Accidental intra-arterial cannulation and administration of medications can result in severe pain, paresthesias, swelling. In severe case, direct vascular and tissue injury can progress to compartment syndrome, gangrene and even auto-amputation. This is significant and potentially severe complication of medication administration that every provider should be able to recognize. Must consider this scenario any time patient begins complaining of paresthesias or pain distal to IV site. Self-inflicted cases are also being described in patients with IVDA

Risk Factors

• Obesity
• Hypotension
• Procedurally difficult situations (ie. agitated patient, back of ambulance)
• Aberrant vascular anatomy

Pathophysiology

Is often multifactorial and dependent upon type of medication administered. Theories include NE induced vasospasm, crystal formation, venous constriction, lipid solubility, direct cytoxicity, endothelial damage and high osmolality. All pathways suggest the primary mediator of tissue injury is thrombosis

Medications known to cause severe injury if administered IA:

• Benzodiazepines
• Barbiturates
• Propofol
• Penicillins
• Amphetamines
• Phenothiazines
• Phenytoin
• Heroin
• Tubocurarine
• Atrcurium
• TPN
• NaHCO3
• Hypertonic Dextrose (D50)

Clinical Features

There is a lot of variance in presentation and a spectrum of severity.
Symptoms:

• Immediate: pain on injection, numbness, weakness
• 30 min-24 hours: decreased cap refill, pallor, skin mottling, cramping, paresthesias motor deficit
• 24- 48 hours: swelling, edema, contractures, signs of compartment syndrome
• 1-2 weeks: clinical evidence of rhabdo, necrosis, gangrene, autoamputation

Severity of symptoms and presentation can be assessed using the Tissue Severity Score (patient receives 1 point for every finding that is abnormal)

• Skin color
• Capillary refill
• Distal sensation
• Distal extremity temperature

A score of >2 is associated with higher likelihood of requiring amputation despite early treatment and management.

Management

1. Maintain catheter in place: 1) start slow infusion of isotonic solution to keep patent, 2) to be used for arteriogram and administration of vasodilators
2. Thoroughly evaluate medications administered through this catheter
3. Evaluate severity of injury (soft compartments, neuro-vascular exam)
4. Anticoagulation with heparin initial loading dose 60IU/kg recommended
5. Treat pain and symptoms

Evidence of Vasospasm:

1. IA

Disposition

Much of management depends on extent of injury and timing. Admission for serial neurovascular exams and compartment checks is recommended with early elevation and aggressive pain management.