95CHAPTER 14 Pediatric Vascular Access and Centeses needles (e g , the Cook intraosseous infusion needle, Cook Medi cal) can be used by manual insertion Usually, a 15 or 18 gauge needle is chosen, wit[.]
CHAPTER 14 Pediatric Vascular Access and Centeses needles (e.g., the Cook intraosseous infusion needle, Cook Medical) can be used by manual insertion Usually, a 15- or 18-gauge needle is chosen, with the latter being used in infants If these are not available, lumbar puncture needles can be used; however, they bend easily.6,17 In neonates, a 19- or 21-gauge butterfly needle can be used.17 Needles with a stylet are preferred to prevent clogging of the needle with bony particulate Three mechanical devices appropriate for pediatric patients have been introduced: the Bone Injection Gun (BIG, PerSys Medical), New Intraosseous (NIO, PerSys Medical), and the EZIO (Teleflex; Fig 14.1) The BIG and NIO are spring-loaded devices, whereas the EZ-IO is a small, battery-powered drill These devices penetrate the bone marrow more quickly and are used more frequently than the manual method in many settings, including prehospital.18,19 Finally, the FASTResponder (Pyng Medical), a specialized sternal injection gun, is used primarily in the adult population but has been cleared for use in adolescents who are 12 years of age and older in the United States, Canada, and most of Europe Other equipment required for IO needle placement and infusion include antiseptic solution (chlorhexidine or povidoneiodine), sterile gloves and drapes, a syringe with saline or heparinized • Fig 14.1 EZ-IO battery-powered drill (Courtesy Vidacare Corporation.) 95 saline flush, a T-connector or stopcock, IV fluid and tubing, and IO dressing components (gauze and tape) and/or securement device Optional supplies include a syringe for laboratory specimen collection, towel or IV bag for extremity stabilization, pressure bag, and materials for local anesthesia (syringe with 25-gauge needle and 1% lidocaine) Technique The IO needle can be placed into the bone marrow at one of several sites: the proximal tibia, distal femur, distal tibia, proximal humerus, iliac crest, and sternum In preparation for IO insertion, the selected body site needs to be stabilized In an extremity, this can be achieved by placing a towel or IV bag underneath it Additionally, the operator’s nondominant hand is used to stabilize the extremity However, it is essential to ensure that the hand is clear of the area behind the insertion site to minimize the risk of needlestick injury The anatomic landmarks and intended insertion site should be identified, and the overlying skin prepped with an antiseptic solution If the patient is conscious, topical anesthesia is indicated The proximal tibia is the most commonly used location for IO access In children, the insertion site is located on the tibial plateau, approximately cm medial and to cm distal to the tibial tuberosity In young children, this location offers the thinnest cortex while having the highest vascular content in the area and avoids injury to the proximal epiphyseal plate For adolescents and adults, the insertion site is cm medial and cm proximal to the tibial tuberosity (Fig 14.2) Accessing the midshaft increases the risk for fracture To obtain IO access in the distal femur, the needle should be positioned in the midline, approximately to cm proximal to the patella In the distal tibia, the needle is placed cm proximal to the medial malleolus, midway between the anterior and posterior surfaces The distal tibia may be easier to access in older children (.6 years), as the proximal tibial cortex has become thicker Although it is less preferred, the distal fibula can also be accessed cm above the lateral malleolus For the proximal humerus, the patient’s hand is positioned on the abdomen with the elbow adducted; the insertion site is the greater tubercle, to cm proximal to the surgical neck of the humerus The anterior superior iliac spine is the insertion site for IO access on the iliac crest The sternum has historically been an access point used by the military in combat More recently, sternal IOs have been developed for use in civilians, including adolescents and adults A Tibial tuberosity Insert needle into medial flat surface of the anterior tibia Growth plate • Fig 14.2 Insertion of the intraosseous needle into the anterior tibia 96 S E C T I O N I I Pediatric Critical Care: Tools and Procedures needle is injected a set depth into the manubrium using an injection gun It can provide effective access, even while cardiopulmonary resuscitation (CPR) is in progress However, CPR must be paused for placement—ideally, during a pulse and rhythm check Sternal IO lines should be avoided in infants and children due to the risk for cardiac or major vessel puncture as well as inadequate drug delivery due to the small sternal marrow cavity IO needles can be placed manually or using mechanical devices With manual needles, the needle insertion angle is controversial: some suggest inserting the needle at a 60- to 75-degree angle away from the epiphyseal plate of long bones, while others recommend using a 90-degree angle to prevent the needle from sliding along the bone The needle is advanced using firm pressure and a twisting motion until a “give” (loss of resistance) is felt, indicating entry into the marrow space The bony cortex, which thickens with age, requires considerable force to penetrate The stylet is removed, and a syringe is attached to the needle in an attempt to aspirate marrow Correct placement of the needle should always be confirmed to avoid complications such as extravasation There are several ways to confirm that the needle is correctly placed: (1) aspiration of bloody fluid; (2) observation that the needle stands upright in the bone without support; (3) lack of resistance when saline solution is infused; and (4) absence of noticeable swelling of the soft tissues or extravasation of fluid Sometimes marrow cannot be aspirated even if the needle is correctly placed; in that case, one must rely on the other means of confirmation Placement of IO needles with mechanical devices has success rates equal to or higher than manual methods, with the added benefit of ease of use and less risk to the user.4,10 However, the high cost of this equipment may be a limitation, especially in small facilities or resource-limited settings In children, prehospital providers prefer the IO drill to the spring-loaded injection gun.20,21 The appropriate mechanical device is selected based on age/weight of the patient and the intended IO insertion site The EZ-IO is approved for use in patients who weigh greater than or equal to kg; the appropriate needle length is chosen based on weight, site, and presence of excessive tissue Operators should ensure that at least mm of the catheter remain visible outside of the skin Longer needles may be considered in obese patients where the tibial tuberosity is not palpable and body mass index exceeds 43.22 This device is approved for pediatric use in the proximal tibia, distal femur, distal tibia, and proximal humerus In contrast, the BIG Pediatric and NIO-Pediatric (NIO-P) are intended for use only in the proximal tibia, with the former cleared for use in term neonates to children 12 years of age and the latter in children to 12 years of age Respective adult versions can be used for patients older than 12 years Detailed instructions for use of mechanical IO insertion devices are discussed on ExpertConsult.com Maintenance Once correct placement of the needle is confirmed and secured, fluids and medication can be administered with a syringe via a stopcock or T-connector, or a standard IV infusion set can be connected to the needle The site should be observed visually and by palpation for signs of extravasation immediately after placement and every to 10 minutes during use If evidence of extravasation is observed, the needle should be removed to avoid compartment syndrome To remove, while holding the hub of the catheter (or needle) itself or attaching a Luer-Lok syringe, traction is applied while rotating the catheter clockwise, pulling it out of the bone without bending or rocking Following pressure hemostasis, a dressing is applied using aseptic technique IO access is intended only for short-term use in emergency resuscitative situations; long-term use increases the risk of extravasation, compartment syndrome, and infection.23,24 Therefore, once IO access is secured, efforts should be directed toward obtaining definitive IV access Once alternative access is obtained, the IO needle should be removed Complications Significant complications of IO insertion and infusion are rare The most common complication is extravasation of fluid The causes of extravasation include incomplete penetration of the bony cortex, movement of the needle such that the hole is larger than the needle, dislodgment of the needle, penetration of the posterior cortex, and leakage of fluid through another hole in the bone, such as a previous IO site or fracture Extravasation of a small amount of fluid is usually not problematic However, with larger volumes, compartment syndrome can develop, which may require fasciotomy and even amputation Use of the IO line for prolonged periods or with pressure bags increases the risk for this complication If extravasation occurs, the needle should be removed and the extremity diligently observed for signs of compartment syndrome Experience to date suggests that the complications of the new mechanical insertion devices are similar to manual IO needle use Other rare complications include infection and bone fracture Osteomyelitis, cellulitis, and sepsis have been reported in conjunction with IO infusion.25,26 Risk for infection is increased when IO access is prolonged, and these devices are used in patients with bacteremia Summary IO infusion is a valuable means of obtaining temporary emergency vascular access in the critically ill infant or child, as it has a high success rate Using appropriate technique and vigilantly monitoring the insertion site for extravasation can usually prevent complications Arterial Catheter Placement The dynamic and rapidly evolving nature of pediatric critical illness often requires frequent blood sampling and continuous blood pressure monitoring in order to thoroughly assess acid-base status, oxygenation, and ventilation as well as to plan timely interventions aimed at improving systemic oxygen delivery (Do2) The arterial catheter serves as an invaluable tool to achieve these goals in addition to providing a visible pressure waveform that may contribute additional diagnostic information (see Chapters 26 and 33) Therefore, the ability to place an arterial catheter is a fundamental skill in pediatric critical care medicine Indications There are several indications for an arterial catheter: • Need for continuous invasive blood pressure measurements to assess the patient’s hemodynamic status and allow for timely assessment of interventions aimed at improving hemodynamics, such as fluid administration and titration of vasoactive infusions 96.e1 Instructions for Use of Mechanical Intraosseous Insertion Devices When using the EZ-IO drill, the operator must first ensure that the driver and needle set are securely seated magnetically After removing the safety cap, the operator positions the driver at the insertion site with the needle set at a 90-degree angle to the bone, pushes the needle set through the skin until it touches bone, and squeezes the trigger, applying moderate, steady downward pressure until the bone cortex is penetrated The trigger should be released when a sudden “give” is felt upon entry into the medullary space in children to ensure that it does not penetrate the posterior cortex (although it may be advanced to cm into the space for adolescents) If excessive force is used, the driver may stall and not penetrate the bone After IO placement, the power driver is detached and the stylet removed After confirming catheter stability and placement, a primed extension set is attached to the catheter hub, and the apparatus is flushed When using the spring-loaded injection gun, such as the BIG Pediatric or NIO-P, one must dial in the desired needle penetration depth based on the patient’s age For the BIG Pediatric, the red barrel is firmly held at the insertion site with the nondominant hand at a 90-degree angle while the dominant hand pulls out the safety latch After placing two fingers of the dominant hand on the wings and the palm on top and applying consistent and gentle downward pressure, the device is activated with the dominant hand The device is removed by pulling upward with a slight side-to-side motion, leaving the cannula in place The trocar is pulled out; then, the safety latch can be slid around the cannula and taped for stabilization For the NIO-P, hold the red barrel with the nondominant hand and place the designated location arrow on the tibial tuberosity with the arrow pointed toward the knee Rotating the cap 90 degrees with the dominant hand will unlock the device, which is pressed against the skin with the palm of the dominant hand, while placing two fingers on the trigger wings Continuing to apply downward pressure with the palm, the trigger wings are pulled upward to activate Following insertion, the base of the needle stabilizer is maintained while lifting up and disconnecting the device from the cannula and removing the trocar and securing the line CHAPTER 14 Pediatric Vascular Access and Centeses • Need for frequent sampling of arterial blood for laboratory analysis Access to arterial blood through an indwelling catheter eases the task of obtaining blood samples painlessly Catheter-derived arterial samples also eliminate skewing of results caused by physiologic changes related to the stress and discomfort of vascular puncture Most notably, an indwelling arterial catheter allows for frequent assessment of arterial blood gas measurements, thereby providing the most accurate information on a patient’s acid-base status as well as measurement of partial pressure of arterial oxygen • Need for continuous monitoring of cerebral perfusion pressure in patients with traumatic brain injury or other causes of increased intracranial pressure (see Chapter 60) • Need for arterial access to facilitate therapeutic procedures, such as exchange transfusions and continuous arteriovenous hemodiafiltration Contraindications Few absolute contraindications for placement of arterial catheters exist The skin at the site of arterial access must be intact prior to insertion of a catheter Evidence of infection of the skin or underlying structures is a contraindication to catheter placement at that site Other disruptions in skin integrity, such as burns, are relative contraindications Severe coagulopathy and systemic anticoagulation increase the risk of hemorrhage from unsuccessful arterial punctures during attempted arterial catheter placement and from the site of arterial catheter insertion These risks must be weighed against the potential benefits of improved monitoring when facing the decision of whether to place an arterial catheter in this patient population A catheter should not be placed in an extremity with compromised perfusion Evidence of adequate collateral circulation is desirable prior to placement of an arterial catheter The traditional means of assessing collateral circulation to the hand is the Allen test The radial and ulnar arteries are compressed until the distal extremity is blanched Pressure over one artery is then released; capillary refill should return to the distal extremity within seconds The test is repeated, releasing pressure from the other contributing artery A normal Allen test does not guarantee adequate collateral circulation, and an abnormal test does not necessarily indicate that complications will occur.27 Additionally, the Allen test is considered less reliable for patients in shock It is common for arterial catheters to be placed without assessing collateral circulation in emergent circumstances Procedure Supplies and equipment required for arterial catheterization are listed in eBox 14.1 Technique The initial step in placing an arterial catheter is site selection The radial, posterior tibial, and dorsalis pedis arteries are optimal sites owing to easy accessibility and typically good collateral circulation Placement of the catheter in distal arteries of the extremities also allows for ease of site observation and hemorrhage control with direct pressure Preductal placement in the right radial artery is preferred in infants with ductal-dependent cardiac lesions Catheters also can be placed in the axillary or femoral arteries if no peripheral sites are suitable Insertion of a catheter into the 97 axillary artery is more difficult technically than the other sites mentioned and is associated with a risk of brachial plexus injury due to hematoma compressing the neurovascular bundle.28 Many physicians have been reluctant to place arterial catheters for longterm use into the femoral artery—particularly in infants and young children—for fear of complications, most notably severe ischemia of the limb A retrospective study of 234 pediatric burn patients who underwent 745 femoral artery catheterizations revealed a 1.1% rate of loss of distal pulse; limb ischemia was associated with younger age, smaller patient size, and increased severity of the burn injury.29 Patients who suffered limb ischemia were managed with immediate catheter removal and systemic heparinization Three underwent thrombectomy, with one requiring amputation of a digit Traditionally, it is taught that the brachial arteries should not be used for arterial catheters because of the lack of collateral blood flow and risk of distal extremity ischemia In a review of arterial catheter placements performed at a pediatric cardiac surgical center, 386 brachial artery catheters were placed in infants weighing 20 kg or less with no report of permanent ischemic damage and only three with temporary perfusion loss.30 Despite these results, the complete lack of collateral circulation at the brachial artery requires careful consideration of risks and benefits before placement of a brachial artery catheter Additionally, the superficial temporal arteries should not be used owing to poor collateral flow and the potential for retrograde flow, which could result in showering of emboli into the cerebral circulation Next, the selected site must be properly immobilized prior to placement of the indwelling catheter If placing a radial artery catheter, the wrist is hyperextended 30 degrees to develop a straighter course and more superficial position of the radial artery Typically, the radial pulse is best palpated in a position just proximal to the wrist crease The technique for radial arterial catheter placement has been summarized in the “Videos in Clinical Medicine” series in the New England Journal of Medicine.31 The intended site for arterial catheter placement requires preparation with an aseptic solution and draping of sterile towels Infiltration of lidocaine (1% without epinephrine) should be considered in most patients unless infiltration will obscure landmarks or the patient is deeply sedated Alternatively, a topical anesthetic cream can be used for local anesthesia Systemic narcotics or anxiolytics may be administered but demands caution in patients who are not receiving mechanical ventilation Percutaneous placement of the catheter can be accomplished using one of several techniques In the over-the-needle technique, similar to placement of a peripheral IV catheter, the needle is inserted through the skin at a 30-degree angle When a flash of blood is obtained in the hub, advance the needle another to mm Holding the needle steadily, the catheter is advanced over the needle into the lumen of the vessel Blood should flow continuously into the catheter hub prior to attempting to advance the catheter Once the catheter is inserted through the skin to the hub, pressure is applied over the artery proximal to the catheter and a flushed Luer-Lok connector is attached to the hub Correct placement of the catheter is verified by easily aspirating arterial blood into a syringe The catheter is then flushed and secured with suture or tape A chlorhexidine-impregnated patch is usually placed at the site of catheter insertion (to decrease catheter-associated bloodstream infections), and an occlusive dressing with a transparent adhesive film is applied over the catheter as a protective barrier.32 The second percutaneous technique, transfixation, involves using the over-the-needle technique; however, when a flash of 97.e1 • eBOX 14.1 Supplies and Equipment for Arterial Catheterization • Appropriate size catheter (24 gauge for infants, 22 gauge for toddlers and older) • Sterile gloves • 10% povidone-iodine or chlorhexidine solution • Sterile towels • Syringe with 1% lidocaine and 25-gauge needle for local infiltration • Topical anesthetic cream • Luer-Lok connector with heparinized flush • 3-0 silk suture • Instrument tray with needle holder and scissors • Cloth tape • Plastic, nonocclusive dressing • Connecting tubing • Transducer • Fluids containing heparin (1 U/mL) and papaverine ... “give” (loss of resistance) is felt, indicating entry into the marrow space The bony cortex, which thickens with age, requires considerable force to penetrate The stylet is removed, and a syringe... with the added benefit of ease of use and less risk to the user.4,10 However, the high cost of this equipment may be a limitation, especially in small facilities or resource-limited settings... in obese patients where the tibial tuberosity is not palpable and body mass index exceeds 43.22 This device is approved for pediatric use in the proximal tibia, distal femur, distal tibia, and