The intraosseous needle

This has come up at least three times now.  Question 8 from the first paper of 2000, Question 15.1 from the first paper of 2012,  again in Question 15 from the second paper of 2014 and as a part of Question 30 from the first paper of 2018. The typical style of question has been "What is this item ? (colour picture of typical-looking IO needle). Discuss the complications / indications / insertion sites / etc etc." Half the marks seem to be awarded for recognising the object.

Indications

• Failure to gain IV access in a life-threatening situation where IV access is critically important

Contraindications

• Underlying fracture
• Underlying prosthesis
• Severe osteoporosis
• Osteogenesis imperfecta
• Contaminated site
• Inability to identify landmarks
• Insertion at a site of recently attempted IO access
• Unfamiliarity with the device (you might hurt yourself)

Age is no longer a contraindication.

Sites of insertion

• Humerus
• Just above the medial malleolus
• Anterior tibia
• Sternum

Confirmation of position

How do you know you are in the right spot?

• Aspiration of bone marrow
• Ability to flush fluid with no evidence of extravasation
• Ultrasound- colour flow within the intraosseous space (though this is so far experimental)
• Circumferential pressure around to the IO site: if the needle is extravasating into soft tissues, the gravity-fed fluid infusion rate will slow considerably when those soft tissues are compressed by a blood pressure cuff.

Complications of intraosseous vascular access

• Osteomyelitis
• Fracture
• "through and through" penetration
• Extravasation
• Compartment syndrome due to extravasation
• Injury to staff (slipped needle)
• Damage to surrounding structures
• Microscopic fat emboli

With sternal approach:

• Mediastinal injury
• Pneumothorax
• Greater vessel injury