Chapter 55. Intraosseous Infusion

Obtaining peripheral vascular access in the critically ill patient may be difficult and time-consuming. The vascular collapse that may accompany severe dehydration or a cardiac arrest can be profound and delay administration of essential therapies. Pediatric patients, in particular, may present a challenge due to the small size of their peripheral veins and the increased subcutaneous tissue. Administration of endotracheal medications may not provide rapid and reliable drug absorption during a cardiorespiratory arrest.1,2

Intraosseous (IO) access was first described in 1922 by Dr. Drinker. He referred to the medullary cavity as a “non-collapsible vein” that can be used for obtaining rapid vascular access. IO access for pediatric use was introduced in 1941. The first IO blood transfusion was documented in1942. The IO route of venous access did not become popular for many reasons. The equipment at the time was crude and did not improve until the 1970s. The technique of a saphenous venous cutdown was soon developed as an alternative method for obtaining vascular access. The development of plastic, disposable, and single use intravenous (IV) catheters revolutionized the technique of IV access.

IO access is an alternative route for blood, drug, and fluid administration. This previously abandoned technique was reintroduced in the mid-1980s in response to the need for more immediate vascular access during cardiopulmonary resuscitation.3,4 This procedure has focused on pediatric patients due to the increased difficulty and necessity of access in critically ill children. Studies have demonstrated that peripheral venous access during pediatric cardiac arrest constituted the most expeditious manner of obtaining vascular access (mean time of 3.0 minutes). However, it was only successful in 17% of patients. This was in stark contrast to the 83% success rate for IO lines, 81% for peripheral venous cutdowns, and 77% for central venous lines.5,6 The time required to place an IO line was 4.7 minutes compared to 8.4 minutes for a central venous line and 12.7 minutes for a peripheral venous cutdown. The insertion of an IO line was recently studied in the prehospital arena, where it was shown to be safe and effective.7,8 IO infusion is also quick, safe, and effective in compromised neonates.9

IO access has been increasingly used in the resuscitation of adult patients when vascular access is unobtainable.10,11 For prehospital providers, IO access has proved to be an invaluable procedure. One national prehospital study noted success rates for IO placement at 91%, with the majority of patients being adults.12 In adults over the age of 80 years, success rates neared 97%. The newer powered devices make penetrating the adult cortical bone much less difficult.12

Long bones are composed of a dense outer cortex and inner soft, spongy (cancellous) bone (Figure 55-1). The nutrient artery supplies the bone with a rich vascular network. It pierces the cortex and divides into ascending and descending branches that further divide into arterioles and then capillaries. Venous drainage from the capillaries into the medullary venous sinusoids, located at the proximal and distal portions of the long bone, flows into the central venous channel located in the shaft of the long bone.13

The IO needle is inserted through the cortex and into the bone marrow (medullary) cavity of a long bone. Numerous anatomic sites can be used to access the medullary cavity. The most traditional site, which is favored in pediatric patients, is the flat anteromedial surface of the proximal tibia (Figure 55-2). The distal tibia just above the medial malleolus is the preferred site in adult patients (Figure 55-3). In the adult, it is easier to penetrate the cortex of the medial malleolus than the thicker cortex of the proximal tibia. Other sites for IO access include the flat anterior surface of the distal femur (Figure 55-4) and the anterolateral surface of the proximal humerus (Figure 55-5).14

Crystalloid infusion studies through an IO line in animals have demonstrated an infusion rate of approximately 10 to 20 mL/min with gravity and up to 40 mL/min under pressure.15,16 Fluids and medications administered through an IO line are immediately absorbed into the systemic circulation. Sodium bicarbonate infusion, even during a cardiac arrest, was shown to have superior buffering capacity when administered via an IO line than by a peripheral IV line.17 Medications and fluids that may be administered by the IO route are listed in Table 55-1.18,19 The medication concentrations, dosages, and infusion rates through an IO line are the same as those through a peripheral IV line. Succinylcholine has been effectively infused by the IO route for muscle paralysis prior to endotracheal intubation.20

The placement of an IO line is indicated when vascular access is rapidly required for the resuscitation of a patient and standard vascular access is unobtainable or delayed. It may be operationally useful to define a specific time frame or a specified number of peripheral IV attempts before proceeding to IO access. Situations that may require the placement of an IO line are cardiac arrest, shock, sepsis, trauma, severe dehydration, extensive burns, status epilepticus, or any condition that requires urgent administration of fluids, medications, or blood products.18 Current American Heart Association Advanced Cardiac Life Support guidelines recommend IO access if IV access is unobtainable within 90 seconds or two attempts and for the administration of medications over endotracheal medication administration.

In addition to resuscitation, IO access can provide blood samples for typing, crossmatching, and laboratory analysis. Electrolytes, creatinine, blood urea nitrogen (BUN), glucose, calcium, and arterial blood gas values from blood samples obtained through an IO needle are similar to those from samples taken via traditional routes.21,22 Laboratory values may be less accurate after five or more minutes of active resuscitation, or if drugs or fluid have been infused through the IO site.22

Placement of an IO line is contraindicated in diseased or osteoporotic bone. The placement of an IO line through areas of cellulitis, abscesses, or burns should be avoided.23 Fractures in the ipsilateral bone increase the risk of an extravasation-induced compartment syndrome and nonunion of the fractures.24 Failed placement of an IO line in the same bone is a relative contraindication. Do not use a bone that has had a previous orthopedic procedure, contains hardware, or may contain hardware (i.e., pins, plates, screws, and artificial joints). An IO line should not be inserted if the patient is morbidly obese as the needle is too short to enter the medullary cavity or if the patient is so obese that the bony landmarks cannot be palpated.

There are contraindications specific to sternal IO access. Do not attempt sternal IO access in patients who weigh less than 50 kg, are small in stature, have a small sternum, have congenital sternal malformations, or have chest wall malformations. The blunt trauma patient with a suspected sternal fracture or soft tissue injury over the sternum should not be considered for sternal IO access. A history of a sternotomy or osteoporosis is also a contraindication.

• Sandbag or towels
• Povidone iodine or chlorhexidine solution
• Local anesthetic solution, 1% or 2% lidocaine
• Syringe, 5 to 60 mL
• Primed intravenous tubing with normal saline
• Tape
• Plastic protective cup
• Leg board for immobilization
• IO access device

IO needles are available in a number of sizes and styles (Figure 55-6). Only specifically designed IO needles should be used for this procedure. Spinal needles often bend and do not penetrate the cortex of the bone. Their long length causes increased resistance to fluid flow. Standard hypodermic needles also often bend and do not penetrate the cortex of the bone. Both these types of needles may break while being inserted and injure the healthcare provider.

Available models of manually inserted IO devices include the hand-driven threaded-needle SurFast and Cook Intraosseous needle (Cook Critical Care, Bloomington, IN), the Jamshidi bone marrow needle (Baxter Healthcare, Valencia, CA), and the MedSurg Industries Illinois sternal/iliac aspiration needle (MedSurg Industries, Rockville, MD). The typical unit consists of a detachable handle, an IO needle, an obturator, and a sleeve to prevent the needle from penetrating too deeply. The IO needle ranges in size from 12 to 20 gauge. The IO needles available today are variations of the basic unit and include adjustable-length shafts to decrease the risk of penetrating too deeply, a variety of tips on the obturator (e.g., lancet, pencil point, and trocar), threaded versus nonthreaded shafts, needle side ports to increase flow rates, numerous lengths, and numerous handle types.

New powered and spring loaded injection devices have evolved. Two currently available devices are the EZ-IO Intraosseous Driver (Vidacare, San Antonio, TX) and the Bone Injection Gun (BIG, Wais Medical, Kress USA Corporation). The EZ-IO uses a battery-powered driver to insert the needle to a preset depth (Figure 55-7).14 The BIG incorporates a loaded spring to inject the IO needle, and the desired depth of injection may be adjusted (Figure 55-8).25 Both devices are available in adult and pediatric needle sizes. The EZ-IO and the BIG have numerous advantages when compared to the manual devices. They are easier to use, quicker to establish IO access, require less or no force to insert the IO needle, and do not bend during insertion.

Sternal access devices include the MONOJECT™ I-Type Sternal-Iliac Aspiration Needle (Covidien, Mansfield, MA), the First Access for Shock and Trauma (FAST1™ and FASTX™, Pyng Medical, Richmond BC), and Life/form® Adult Sternal Intraosseous Infusion System (Nasco, Modesta, CA). The F.A.S.T.1™ is a multiple-component kit to be used for sternal IO access in the adult patient. A special introducer limits the depth to which the needle can be inserted. This prevents injury to the underlying great vessels, heart, lung, and mediastinum. This system was evaluated in Special Forces military settings, and found to be equally useful and safe in terms of IO access.27 Sternal IO access devices are used less often than the previously described powered devices due to the possible interference with resuscitation attempts and their incomplete removal on occasion requiring surgical removal.

Explain the procedure, its risks, and benefits to the patient and/or their representative if time permits. This procedure is often performed in emergencies; therefore, informed consent can often be waived. Currently, the primary site of choice for IO line placement is the proximal tibia. Alternate sites include the distal tibia, distal femur, proximal humerus, and the sternum. Even with sternal access, it is possible to perform a cricothyroidotomy and cardiopulmonary resuscitation (CPR).25 The proximal humerus allows more central access, while the proximal tibia is often accessible without disrupting airway management and CPR.14

Place the patient supine with the lower extremity supported behind the knee with a towel or sandbag. Identify by palpation the landmarks required to perform the procedure. Palpate the bony landmarks with the nondominant hand. The bony landmarks for the proximal tibia approach are the tibial tuberosity and the flat anteromedial surface of the proximal tibia. The site of IO needle placement is approximately 2 cm below the tuberosity on the flat anteromedial surface of the proximal tibia (Figure 55-2). The bony landmark for the distal tibia approach is the junction of the medial malleolus and the flat anteromedial surface of the distal tibia just posterior to the greater saphenous vein18 (Figure 55-3). This is the preferred site in the adult patient. The bony landmarks for the distal femur approach are the medial and lateral condyles of the femur and the patella. The IO needle should be positioned approximately 2 cm above these structures (Figure 55-4). This site is utilized less often due to the abundance of muscle and soft tissue structures. The bony landmarks for the humeral approach are slightly anterior to the lateral midline of the arm, with care to avoid the bicipital groove (Figure 55-5). The arm should be adducted and internally rotated for optimal positioning.14

Prepare the patient. Clean any dirt and debris from the skin. Apply povidone iodine or chlorhexidine solution to the skin and allow it to dry if time permits. This procedure is extremely painful. If time permits, the use of a local anesthetic solution in the conscious or semiconscious patient will be greatly appreciated. Infiltrate local anesthetic solution into the skin, subcutaneous tissues, and periosteum overlying the bone puncture site. Additionally, in the alert patient, consider infusing 3 to 5 mL of 2% lidocaine intravenously both initially and at regular intervals to minimize patient discomfort.11

Manually Inserted IO Devices

Examine the IO needle to ensure that it appears to have been manufactured properly. Reidentify the landmarks with the nondominant hand. Stabilize the extremity with the nondominant hand (Figure 55-9A). Grasp the IO needle firmly with the dominant hand. The handle of the IO needle should be firmly planted in the palm of the dominant hand. Insert the needle perpendicularly or slightly angulated (at a 10° to 15° angle) to the long axis of the bone (Figure 55-9). The IO needle should always be directed away from the growth plate to avoid injuring it. Direct the needle caudad in the proximal tibial approach and cephalad in the distal tibial and distal femoral approaches.

Advance the IO needle through the skin and subcutaneous tissue until the bone is contacted. Advance the IO needle through the bone. A twisting or rotary motion with the simultaneous application of downward pressure should be used to cut through the cortex of the bone (Figure 55-9A). A significant reduction in the resistance to forward motion will be encountered when the cortex is penetrated and the needle enters the medullary canal. This distance is rarely greater than 1 cm in most patients. An index finger may be placed 1 cm from the bevel of the IO needle prior to advancement. This will help prevent overpenetration into and through the cortex on the opposite side of the bone.28 Alternatively, adjust the sleeve so that only 1 cm of the IO needle is exposed. Stop advancing the IO needle when it enters the medullary canal.

Remove the stylet when the medullary canal is entered (Figure 55-9B). Attach a 5 or 10 mL syringe onto the hub of the IO needle (Figure 55-9C). Aspirate blood from the medullary canal to confirm proper placement of the IO needle. Any samples obtained may be sent to the laboratory for subsequent analysis. The aspiration of more than 2 to 3 mL of blood may not be possible in cardiac arrest situations. Attach IV tubing to the hub of the IO needle and begin the infusion of fluids. Medications can be administered through the injection port of the IV tubing. Place a sterile dressing around the skin puncture site and apply pressure for 5 minutes.29

IO Access Using the EZ-IO

The EZ-IO is a reusable, nonsterile, battery powered driver that uses sterile, disposable, single patient use IO needles. The IO needles are available in three lengths (15, 25, and 45 mm). Choose the proper IO needle for the patient, their body habitus, and the insertion site. Assess the tissue depth by palpation. Choose an IO needle so that at least one black line on the IO needle shaft will be above the patient's skin when the tip is against the bone. The IO needle tip is designed to cut the bone and create a hole the same size as the needle.

Identify the IO insertion site and prepare for the procedure. Clean and prep the skin at the site and surrounding area. The procedure requires aseptic technique. Select the appropriate size IO needle. Open the cover of the case that holds the sterile IO needle. Insert the bit on the EZ-IO driver into the base of the IO needle (Figure 55-10A). Leave the cap on the IO needle until it is ready to be inserted. Open the EZ-Connect tubing and flush it with a syringe containing 10 mL of sterile normal saline. Leave the syringe attached to the tubing after it is flushed.

Reidentify the landmark for the insertion site. Inject local anesthetic solution subcutaneously and down to the periosteum. Remove the cap from the IO needle. Insert the IO needle perpendicular or at a 90° angle to the skin (Figure 55-10B). Advance the IO needle through the skin and subcutaneous tissues until the tip is against bone. At least one black line on the needle shaft should be visible above the patient's skin. If a black line is not visible on the needle shaft, withdraw the needle and replace it with a longer IO needle. Press the trigger to start the driver shaft and IO needle rotating. Apply gentle and minimal downward pressure to advance the IO needle into the medullary canal. Stop advancing the driver when a loss of resistance is felt.

Grasp and firmly hold the hub of the IO needle. Remove the driver (Figure 55-10C). Do not allow the IO needle to move while removing the driver. Twist the stylet counterclockwise and remove it while securely holding the IO needle hub (Figure 55-10D). Attach the EZ-IO stabilizer (Figures 55-7B & 55-10E), if using it, followed by the primed EZ-Connect tubing. Aspirate bone marrow to confirm proper needle placement. Do not attach a syringe directly to the IO needle hub. A syringe attached to the hub can result in a fracture of the hub. Always attach the EZ-Connect tubing then aspirate and inject through it and not directly through the IO needle hub. Begin using the IO access.

IO Access Using the BIG

The BIG is an automatic, spring loaded device that does not require a power source. It is available in two sizes, adult and pediatric. The insertion site is different for adults and children. Always start at the tibial tuberosity as the initial landmark. For adults, move 2 cm medially toward the inner leg and then 1 cm proximally toward the patient's head. For children, move 1 to 2 cm medially toward the inner leg and then 1 to 2 cm distally toward the patient's foot. Mark this final location as the insertion site. It may also be inserted in the proximal humerus in the adult patient.

Prepare for the procedure. This procedure requires aseptic technique. Clean and prep the skin at the insertion site and surrounding area. Open the package and remove the sterile BIG. Rotate the base of the unit to adjust the IO needle penetration depth according to the pediatric patient's age: 0 to 3 years at 0.5 to 1.0 cm, 3 to 6 years at 1.0 to 1.5 cm, and 6 to 12 years at 1.5 cm (Figure 55-11A). Use the adult BIG for patients over the age of 12 years. Reidentify the landmark for the insertion site. Inject local anesthetic solution subcutaneously and down to the periosteum.

Position the BIG at the insertion site with the base perpendicular or at 90° to the skin (Figure 55-11B). Firmly grasp the BIG with the nondominant hand. Squeeze and pull out the red safety latch while firmly holding the BIG against the insertion site (Figure 55-11C). Do not discard the safety latch as it will be used later to secure the IO needle. Grasp the upper part of the BIG with the dominant hand (Figure 55-11D). Place two fingers under the wings and the palm on the top of the BIG (Figure 55-11D). Continue to firmly hold the base against the patient's skin with the nondominant hand.

Insert the IO needle. Trigger the BIG by gently pressing down with the palm. The device will eject the spring loaded IO needle into the bone. The IO needle should be standing upright, firmly in the bone, and stable. If not, it has been placed into muscle or soft tissue. Gently lift and remove the BIG device without catching on the IO needle hub (Figure 55-11E). Attach the safety latch onto the cannula between the patient's skin and the IO cannula hub (Figure 55-11F). Secure the safety latch to the skin with tape (Figure 55-11F). Gently remove the stylet-trocar, leaving the cannula in place (Figure 55-11G). If the stylet-trocar is “stuck” and not easily removable, do not pull or try to forcefully remove it. The IO needle did not penetrate all the way into the medullary cavity and is embedded in the cortex. Insert the square end of the safety latch into the hub of the IO needle and gently twist to remove the IO needle. Repeat the procedure at another site. Attach the IV tubing onto the hub of the cannula (Figure 55-11H). Aspirate bone marrow to confirm proper placement (Figure 55-11H). Flush the IV tubing and cannula with 5 to 10 mL of sterile saline. Begin using the IO access.

Assess whether the IO needle is correctly positioned within the medullary cavity. First aspirate blood from the marrow cavity. This may not be possible because of poor circulation in patients with a cardiac arrest. A second sign of correct placement is to assess whether the IO needle will stand erect without support. Finally, flush the IO line. The ability of the fluid to flow without inducing soft tissue swelling can also be used to confirm proper placement. Ultrasonic visualization of flow within the medullary cavity using color flow Doppler can also confirm proper placement.45 A reassessment must be performed again at regular intervals to ensure that extravasation does not occur.30 Circumferential pressures of the involved extremity may be used for serial examination.30 A C-arm fluoroscopic imaging device may be used at the bedside to confirm accurate placement of the IO needle.31

Secure the IO needle. Secure the manually inserted IO needle by taping it in place. It may be easier to apply 4 × 4 gauze squares on two sides of the IO needle to support it and then tape the needle and gauze in place. Secure the EZ-IO needle in the same manner. Tape the safety latch of the BIG to the skin to secure it. Tape the IV tubing securely at several points. This will prevent traction on the tubing from pulling the IO needle out of the bone. Tape a plastic cup over the IO needle to avoid inadvertent disruption during patient resuscitation or positioning. Immobilize the extremity, if necessary, to help secure the IO line.

Remove the IO line once the resuscitation is complete and another form of secure vascular access has been obtained. Manually inserted IO devices can be removed by gently twisting it and pull it straight out. Do not rock the device. To remove the EZ-IO, attach a 5 or 10 mL Luer lock syringe onto the IO needle hub. Rotate the syringe clockwise and pull it straight out. It may take several rotations of the syringe before the IO needle can be removed. Do not rock the IO needle or syringe. To remove the BIG cannula, insert the square end of the safety latch into the hub of the cannula and gently twist and pull to remove it. Bleeding at the insertion site can be controlled with a sterile pressure dressing followed by cleansing the skin and a simple bandage.

The most common complication of IO infusions are subcutaneous and subperiosteal extravasation of fluid due to technical difficulty.4 Under ideal circumstances, the type of IO needle used should not affect extravasation rates.30,32 Extravasation is usually due to under- or overpenetration of the cortex. There have been cases of tibial fracture due to overpenetration of the cortex.33,34 A compartment syndrome may occur when there is extravasation or when IO lines are placed in fractured bones.26 Necrosis and sloughing of the skin at the insertion site of the IO needle are due to extravasation of fluid or medication.35

Localized infections may occur after IO needle placement. Cellulitis or the formation of subcutaneous abscesses occur in 0.7% of patients.24 Osteomyelitis has been reported in less than 1% of patients with IO needles.25 Risk of osteomyelitis increases with prolonged IO use, administration of hypertonic fluids, and bacteremia.25,36

Injury to the growth plate is a commonly mentioned complication; however, the literature does not support this.37,38 Additionally, in recent animal studies, the rate of the IO infusion and the osmolarity of the infused fluid did not adversely affect the bone marrow or bone development.42 Fat embolism has also been mentioned as a possible complication.41 Consider a fat embolism if the patient becomes hypoxic or experiences respiratory difficulty shortly after beginning an IO fluid infusion or bolus. The use of an IO line for the infusion of emergency drugs and fluids does not increase the magnitude of fat embolization during CPR.39,40 Animal studies have shown no significant increase in fat emboli in lung tissue when IO infusion is used.39

The flow rate of fluid through an IO line is slower than that through a peripheral intravenous line. This may be due to a small marrow cavity, a fibrous marrow cavity, and/or the replacement of red marrow with yellow marrow. Fluid flow rates can be significantly increased by applying a pressure bag onto the intravenous fluid bag or using a level-one infuser. The placement of a second IO line may be required to further increase the amount of fluid that can be infused.

The complications specific to the EZ-IO include hub fracture after insertion and separation of the needle from the hub upon removal. Too much downward pressure upon IO needle insertion can result in it penetrating the back of the bone. The other general complications are described above.

The complications associated with the BIG are primarily from incorrect use. Never remove the safety latch until the BIG is against the patient's skin over the insertion site. Removal of the safety latch activates the device. The IO needle can be forcefully ejected and injure someone if the BIG is squeezed after the safety latch is removed. Never place a finger over the distal end of the BIG. Always grasp the BIG properly. Grasping it upside down can result in the IO needle penetrating the Emergency Physician's hand. Incorrectly adjusting the penetration depth can result in the IO needle penetrating the back of the bone. The other general complications are described above.

The placement of an IO line is a viable option in the resuscitation of a patient when traditional vascular access techniques have failed. The procedure is technically straightforward and has been demonstrated to be successful in the hands of trained healthcare workers, including prehospital personnel. Complications have been related mostly to technical mistakes and can be avoided if care is taken to correctly identify landmarks, avoid the growth plate, regulate the depth of IO needle placement, and ensure the early removal of the IO line.