This chapter presents the indications, advantages, and procedures for vascular access techniques in children: IO, central venous, US-guided peripheral venous, and umbilical venous access in the newborn.
IO access has the advantage of cannulating a noncollapsible structure that connects to the central circulation. IO access is indicated when there is an emergent need for vascular access and other sites are difficult, high risk, or excessively time consuming. Mechanical IO insertion devices have insertion times of only seconds with consistently >90% success rates.1-8 Insertion devices include simple hand-twist needles, hand-held power drills, and spring-loaded devices.
There are few contraindications to IO placement (Table 114-1), and the rate of serious complications from IO insertion is ≤1%. The most common complication is extravasation at the insertion site. By comparison, central venous catheters have complication rates of at least 3.4%.1,2 Although the indications for IO access are often thought to be limited to unstable patients who need immediate access, IO access is a viable alternative to central venous access in some patients without adequate peripheral access.9
TABLE 114-1Contraindications to IO Placement
MEDICATIONS AND FLUIDS ADMINISTERED BY THE IO ROUTE
Any medication or fluid that can be given through an IV can be administered by the IO route. Paralytics, anticonvulsants, analgesics, benzodiazepines, and vasopressors such as epinephrine have comparable IO and IV infusion rates. Blood and blood products can be given by the IO route.3 Medications for rapid-sequence intubation can be administered by the IO route, although the time to effect may be delayed.4 In a study of sheep given IV or IO succinylcholine, the IV route induced respiratory arrest in a mean of 30.8 seconds, whereas the IO route took 57.5 seconds.5
The principal limitation of IO access is a relatively low maximum flow rate. Resistance to flow within the bone marrow cavity limits the flow rate of IO needles, and flow rates per kilogram tend to be higher in young patients who have a greater percentage of low-resistance red marrow compared to adults. The speed of administration of IO infusions can be improved with pressure devices.
LABORATORY TESTING OF BONE MARROW ASPIRATE
The comparison of marrow aspirate with peripheral blood has been explored in small trials of hematology and oncology patients undergoing routine marrow sampling (Table 114-2). Two of these human studies have shown a close correlation of marrow aspirate to venous blood in regard to hemoglobin, sodium, chloride, bilirubin, pH, bicarbonate, urea, and creatinine concentrations.6,7 In another study, bone marrow taken for medical diagnosis ...