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.
- Failure to gain IV access in a life-threatening situation where IV access is critically important
- 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
- Just above the medial malleolus
- Anterior tibia
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
- "through and through" penetration
- Compartment syndrome due to extravasation
- Injury to staff (slipped needle)
- Damage to surrounding structures
- Microscopic fat emboli
With sternal approach:
- Mediastinal injury
- Greater vessel injury