Background: The most commonly used (and recommended) site for intraosseous (IO) access in pediatric patients is the proximal tibia. The primary objective of this study was to determine the accuracy of emergency IO placement in pediatric patients by both prehospital providers and emergency department providers.
Methods: The authors determined accuracy of tibial IO placement using post-mortem CT. They reviewed 92 cases referred by the state medical examiner for post-mortem CT and found 31 where a tibial IO had been placed. Successful IO placement was defined by needle placement between the proximal 5% to 30% of the tibia with the needle tip in the medullary cavity. Needle length was determined by measuring via CT or appearance of the needle hub color.
Key Results: Among 31 cases, there were 42 total tibial IO insertions. The authors found that:
· Infants < 6 months of age accounted for 30/42 IO placements. Overall success in this age group was 47%. There was variability in success by IO needle size (56% for 15 mm needle and 0% success for 25 mm needle).
· Success rate amongst patients 6 months to 2 years of age was 83% (n=6)
· Success rate among patients > 2 years of age was 100% (n=6)
· The most common reason for failure varied by needle size. For 15 mm needle it was that the needle was outside the bone (45%, n=11) or embedded in the cortex (45%, n=11), while for the 25 mm it was perforation of the tibia (83%, n=6).
· Rates of failure were not significantly different between EMS and ED personnel (30% failure rate for ED personnel, 46% failure rate for EMS).
Conclusions: While there is some risk of bias as this study only examined non-survivors, the failure rate of proximal tibial IO placement in pediatric patients, in particular those < 6 months of age, was alarming. Size mattered: 15 mm needles were much more likely to be successful that 25 mm needle (which was unsuccessful in 6/7 patients under 2 years of age). These results are in line with a prior cadaver study by Maxien et. al. demonstrating a high rate of malposition (64%) of IO in infants < 1 year.
These findings raise the question of whether how can we improve success rates: manual insertion over drill? Mandatory needle sizes? Increased training? Alternative site such as the distal femur?
What this means for EMS: Pediatric IO placement has a high failure rate, especially in infants < 6 months of age. At minimum, to improve success rate a 15 mm needle should be chosen in this age group. Further research is needed to address whether alternative sites or methods may be preferable.
Article Summary by Maia Dorsett, MD PhD FAEMS FACEP, @maiadorsett
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