Overview
Definition:
Intraosseous (IO) access is a method of obtaining intravenous (IV) access by inserting a needle into the bone marrow cavity
This allows for rapid infusion of fluids, medications, and blood products directly into the systemic circulation, bypassing the venous system
It is a critical technique for emergency resuscitation when peripheral IV access cannot be achieved quickly.
Epidemiology:
IO access is utilized in emergent settings, particularly in pediatric and adult resuscitation
Its use is increasing with improved devices and training
While specific incidence data for all settings is scarce, it is a cornerstone of advanced life support protocols globally, including in Indian emergency departments and trauma centers.
Clinical Significance:
IO access provides a reliable and rapid route for drug and fluid delivery in critical situations such as hypovolemic shock, cardiac arrest, severe trauma, and difficult venous access scenarios
It is particularly vital in pediatric patients where peripheral veins can be challenging to cannulate under duress
Proficiency in IO placement is essential for surgical residents involved in trauma and emergency care.
Indications
Urgent Access Needed:
Failure to obtain peripheral venous access within 90 seconds in a life-threatening situation
Conditions include severe hypovolemia, hemorrhagic shock, cardiac arrest, profound hypotension, and severe burns.
Pediatric Patients:
Preferred route for vascular access in infants and children during cardiopulmonary arrest or severe trauma when peripheral IV is not immediately achievable.
Adult Patients:
Used in adults when peripheral IV access is impossible due to obesity, edema, burns, trauma, or anatomical difficulties
Also useful in scenarios with extreme peripheral vasoconstriction.
Specific Scenarios:
During mass casualty incidents, battlefield medicine, and in resource-limited environments where advanced vascular access is challenging
Can be used for initial resuscitation followed by conversion to central venous access if prolonged therapy is needed.
Contraindications:
Absolute contraindications are few but include fractures at the insertion site, infection overlying the bone, and significant bone disease (e.g., osteogenesis imperfecta)
Relative contraindications include previous attempts at the same bone and severe osteoporosis.
Placement Techniques
Manual Insertion:
Utilizes a sternal or tibial IO drill with a sharpened stylet
The drill is advanced into the bone cortex until it enters the marrow cavity, indicated by a sudden loss of resistance
The stylet is removed, and a catheter is advanced
Examples include the Jamshidi needle or Cook needle.
Automatic Devices:
Examples include the FAST (Fluid and Advanced Site Therapy) IO device and the Pyxis IO
These devices are designed for rapid, single-handed insertion with a spring-loaded mechanism
They offer ease of use and speed, especially under high-stress conditions.
Site Selection Adults:
Proximal humerus (anterolateral), distal tibia (medial aspect, 1-2 cm superior to the medial malleolus), and sternum are common sites
The humerus offers rapid flow rates due to its vascularity.
Site Selection Pediatrics:
Distal tibia (anterior or medial surface, 1-2 cm superior to the medial malleolus) is the most common and safest site for infants and children
Proximal humerus and distal femur are alternatives.
Procedure Steps:
Identify and palpate the landmark
Prepare the site aseptically
Insert the IO needle or device perpendicular to the bone surface
Advance until bone marrow is aspirated or resistance decreases significantly
Remove the stylet
Connect to a pressure infusion bag or syringe
Flush to confirm patency and assess for extravasation
Secure the device.
Medications And Fluids
Fluid Resuscitation:
Rapid administration of isotonic crystalloids (e.g., Normal Saline, Lactated Ringer’s) or colloids (e.g., albumin) is crucial in shock states
Flow rates can be enhanced using a pressure bag or rapid infusion pump.
Emergency Medications:
Adrenaline (epinephrine), amiodarone, lidocaine, atropine, vasopressin, and sodium bicarbonate can be administered via IO access during cardiac arrest, with doses typically similar to IV administration, though absorption may be slightly slower.
Anesthetics:
Local anesthetics like lidocaine can be infused into the IO space prior to medication or fluid administration to reduce pain associated with IO access, especially in conscious patients.
Antibiotics And Other Drugs:
Antibiotics, sedatives, analgesics, and other intravenous medications can be safely administered through IO access for prolonged management, though continuous infusion monitoring is important.
Pediatric Considerations:
Drug dosages for pediatric patients are crucial
For example, epinephrine 0.01 mg/kg (1:10,000) for cardiac arrest, and fluid boluses of 20 mL/kg
Exact weight-based calculations are vital.
Complications
Local Complications:
Pain at the insertion site is common, especially in conscious patients
Extravasation of fluids or medications leading to subcutaneous or soft tissue damage
Infection at the insertion site, including osteomyelitis, is rare but serious.
Fracture:
Fracture of the long bone at the insertion site, particularly in children with fragile bones or if the insertion is not performed carefully
Compartment syndrome is a rare but potentially devastating complication.
Systemic Complications:
Fat emboli are theoretically possible but rarely reported
Growth plate injury is a concern in pediatric patients if placed too close to the epiphyseal plate, though this risk is minimized with proper landmark identification
Bone marrow suppression or leakage into surrounding tissues are other rare possibilities.
Prevention Strategies:
Strict aseptic technique during insertion
Proper landmark identification to avoid growth plates or fracture sites
Use of specialized IO devices designed for minimal trauma
Careful assessment for extravasation
Prompt removal of the IO catheter once peripheral or central venous access is established.
Key Points
Exam Focus:
Know the primary indications for IO access in both adult and pediatric populations
Be familiar with common insertion sites and contraindications
Understand the types of devices available (manual vs
automatic)
Recall key medications and fluids that can be administered
Recognize potential complications and their management.
Clinical Pearls:
IO access is NOT a last resort
it is a first-line option when IV access is delayed
The humerus is often the fastest site for drug delivery in adults due to its rich vascular supply
Always flush with saline to confirm placement and check for extravasation
Pain management is crucial for conscious patients receiving IO infusions.
Common Mistakes:
Attempting IO in the presence of absolute contraindications
Incorrect landmark identification leading to malplacement or complications
Failure to flush or adequately secure the device
Delaying conversion to IV access when possible, leading to prolonged IO use and potential complications
Not adequately managing pain associated with IO infusion.