This is a prospective diagnostic accuracy study investigating the sensitivity and specificity of methods used to confirm correct placement of an intraosseous (IO) catheter. Intraosseous catheters allow medical providers to rapidly administer fluids and medications to critically ill patients when intravenous (IV) access is not present or difficult to achieve. It is standard of care to confirm the correct placement of an IO catheter prior to using it to administer medications or fluids. Three IO placement confirmatory tests will be performed on all research subjects using a standardized protocol. There will be two index tests (the method utilized by most of the medical community evaluating the stability of the catheter, ability to aspirate blood or bone marrow and ability to administer fluids without visible or palpable extravasation as well as the method of demonstrating color flow Doppler only within the intraosseous space during bedside ultrasound exam) and one reference test (ability to visualized a pulsatile waveform when the IO catheter is attached to a pressure transducer). Primary outcome measures of the study will be the determination of correct or incorrect IO catheter placement from the confirmation methods. This data will be used to investigate the primary endpoints of sensitivity and specificity of the confirmation tests as well as inter-operator variability interpreting the raw data from the confirmation methods. Secondary outcomes include complications from the IO catheter. The goal of this study is to see if a more sensitive and specific method of IO catheter confirmation can reliably be performed by different physicians and reduce the amount of complications associated with the catheters. Additional subgroup analyses will be performed in regards to the research subjects BMI and the anatomic site selected for IO catheter use (proximal tibia or humeral head).

Inclusion Criteria:

• Patients greater than 18 years of age
• Full code
• Require placement of an intraosseous catheter for emergent resuscitation due to lack of reliable intravenous access
• Capable of undergoing all three intraosseous placement confirmatory methods

Exclusion Criteria:

• Age less than 18 years old
• Pregnant patients
• Prisoner/incarcerated
• Patients unable to undergo all three intraosseous placement confirmatory methods

There is only one arm because all participants will be undergoing the same protocol. To evaluate inter-operator variability for methods 2 and 3, co-investigators will be reviewing saved images recorded by the physicians who placed the intraosseous (IO) catheter. Saved images include the color flow Doppler image for method 2 and the pressure waveform for method 3. Two co-investigators will review saved images from method 2, blinded and independently. Two other co-investigators will review saved images from method 3, blinded and independently. If the results of the two co-investigators for method 2 or method 3 is discordant then a third blinded reviewer will review the saved image for the method with discordant results.