10.5 Intraosseous Anatomy

Question 1

A 10-year-old child has been brought to A&E with a history of diarrhoea and vomiting for the past 3 days.

How would you assess dehydration in children?

Answer 1

1. Parental observation
   Parental report of vomiting, diarrhoea, or decreased oral intake is sensitive in
   identifying dehydration in children.

2.Physical examination
Weight loss, capillary filling time, pulse, respiration, blood pressure, sunken
eyes, lethargy, and dry mucous membranes.

3. Laboratory assessment
   Serum bicarbonate < 17 mmol/L may improve sensitivity of identifying
   children with moderate to severe hypovolemia.

Severity of dehydration is classified according to these clinical parameters
into mild, moderate, and severe.

Combination of physical examination findings are the most specific and sensitive tool for accurately diagnosing dehydration in children and categorising its severity.

overdiagnosis of dehydration may lead to unnecessary tests and treatment, whereas
underdiagnosis may lead to increased morbidity.

Question 2

A 10-year-old child has been brought to A&E with a history of diarrhoea and vomiting for the past 3 days.

How would you assess dehydration in children?

Answer 2

1. Parental observation
   Parental report of vomiting, diarrhoea, or decreased oral intake is sensitive in
   identifying dehydration in children.

2.Physical examination
Weight loss, capillary filling time, pulse, respiration, blood pressure, sunken
eyes, lethargy, and dry mucous membranes.

3. Laboratory assessment
   Serum bicarbonate < 17 mmol/L may improve sensitivity of identifying
   children with moderate to severe hypovolemia.

Severity of dehydration is classified according to these clinical parameters
into mild, moderate, and severe.

Combination of physical examination findings are the most specific and sensitive tool for accurately diagnosing dehydration in children and categorising its severity.

overdiagnosis of dehydration may lead to unnecessary tests and treatment, whereas
underdiagnosis may lead to increased morbidity.

Question 3

Attempts at cannulation by medical personnel have failed.

What else could you do?

Answer 3

European resuscitation council (ERC) recommends the use of intraosseous
(Io) route if establishing peripheral venous access is delayed.

Question 4

What are the sites of insertion?

Answer 4

• Tibial—anterior surface, 2–3 cm below the tibial tuberosity
• Femoral—anterolateral surface, 3 cm above lateral condyle
• Humeral—posterolateral surface
• Iliac crest—in older children

Question 5

Describe the procedure of inserting an io needle in the tibia.

Answer 5

Identify site and landmarks

• Identify the tibial tuberosity, just below the knee, by palpation.
• Locate a consistent flat area of bone 2 cm distal
  and slightly medial to the tibial tuberosity.

Asepsis
Procedure
* Insert needle at 90 degrees to skin.
* Advance until a ‘give’ is felt as cortex penetrated.
* Attach the syringe and aspirate for sample.
* Flush to confirm positioning.
* Attach 20 mL syringe and push infusion in boluses.

Question 6

What do you do after insertion of the io needle?

Answer 6

Once inserted, correct placement is confirmed before delivery of drugs
by aspirating from the needle;

presence of Io blood indicates correct placement,

but absence of aspirate does not necessarily imply a failed attempt.

1. Aspiration of contents (not always possible)
2. Flushing without subcutaneous swelling

Question 7

What drugs can be given?

How can you infuse fluids?

Answer 7

All drugs but should be flushed by 5–10 mL of saline to reach circulation.

The following methods are used to overcome venous resistance.
* Use of pressure bag
* 20 mL syringe and a 3-way tap for easy and rapid aspiration and infusion

Question 8

List some common complications associated with intraosseous route.

Answer 8

• Extravasation
• Fracture and growth plate injuries
• Osteomyelitis
• Compartment syndrome
• Local haematoma
• Fat emboli

Question 9

What are the contraindications for io access?

Answer 9

Absolute
* Fracture of that particular bone

Relative
* Cellulitis overlying the insertion site
* Previous attempt on the same bone
* Osteogenesis imperfecta because of a higher likelihood of fractures
* Osteoporosis

Question 10

What are the different needle sizes available?

Answer 10

Different-sized needles are available for adult and paediatric use.

The newer EZ-IO type has three types of needles:

15 mm 3–39 kg

25 mm > 39 kg

45 mm > 39 kg,
for those having excessive tissue over the targeted insertion site

Question 11

What structures do you pass through as you insert the intraosseous needle?

Answer 11

• Skin
• Subcutaneous tissue
• Periosteum
• Cortical bone
• Cancellous bone
• Medullary cavity

Question 12

What can be given through the io needle?

Answer 12

All resuscitation fluids, drugs, and blood products can be given via
the Io route.

Studies have shown the administration of
ceftriaxone, chloramphenicol, phenytoin, tobramycin, and vancomycin
may result in lower peak serum concentrations.

Question 13

What are the parts of a long bone?

Answer 13

• Epiphysis:
  filled with cancellous bone and covered by the cortex,
  a hard thin casing.
• Diaphysis:
  shaft of the bone composed of a thick,
  hard cortex with a hollow interior space
  (the medullary cavity).
• Epiphyseal plate:
  the junction between the
  epiphysis and the diaphysis
  where bone growth occurs.