Page 40 - JSOM Winter 2025

While the SAM IO has the same needle lengths as the EZ-IO, pre-existing device preferences or perceived agency expec-
the needle hub assembly for the SAM IO is longer, allowing for tations. Participants may have anticipated that their service
the potential of better hand grip and manual use for insertion. may consider switching IO devices, influencing their choices.
The hub of the drivers is shaped differently, namely, hexagon Observational or performance bias may also have been
versus polygon. This study design excluded the assembly and confounding factors, as participants knew they were being
stabilization times, which most likely addresses Kay et al.’s observed, which may have altered their behavior to favor
prolonged insertion time. a particular device. Having only one evaluator and trainer
may attributed to some bias. The discrepancy between con-
One potential advantage of the SAM IO is that it does not fidence in field use and future preference suggests that while
rely on battery power, making it well-suited for long-term stor- the SAM IO is perceived as functional and reliable, other
age. The device is less expensive than the EZ-IO G3 ($179.00 factors or biases influencing user preference warrant further
vs. $659.99) list price, 21,22 and its plastic design makes it suit- investigation.
able for austere environments and situations where weight is
a consideration. The IO needles are also less expensive than Furthermore, participant bias due to their familiarity with the
the EZ-IO ($89.99 vs. $126.99) 21,23 list price and have an IO EZ-IO may have influenced their insertion times to reflect their
adapter to accommodate other driver IO needles. On the other preference for a particular device. As the SAM IO becomes
hand, EZ-IO is a familiar tool for vascular access. The EZ-IO more common in field practice, perceived personal preferences
requires only a one-finger squeeze of the trigger while focus- may shift, and conducting a similar study in the future may
ing on the tactile feel for needle insertion versus the repeti- offer different outcomes. Additional studies should examine
tive manual-trigger hand squeezing, potentially complicating field success rates in human subjects, blinded insertion results
the tactile feel for new users concentrating on rhythmically evaluators, and incorporate a washout period from the training
squeezing the actuator. sessions. Our study made an intentional methodological choice
to isolate the mechanical insertion efficiency and reduce the in-
Limitations ter-operator variability introduced by the setup time and stabi-
The study had several limitations. Most importantly, the par- lization techniques, acknowledging the real-life field scenarios.
ticipants could not be blinded to the device, so the study design Future studies should include field-based outcomes, longitu-
was selected to simulate cortical bone resistance and anatom- dinal usage trends in confidence, learning curves, and brand
ical landmarks while acknowledging this fails to replicate the loyalty composite metric of preparation, insertion, and stabili-
complexity and variability of live human subjects. Further- zation to reflect better the end-to-end process, real-life clinical
more, realizing the logistical and ethical restraints, this model implications with cognitive load tasks, and time constraints.
was used to control device mechanics to minimize participant
variability.
Conclusion
In addition, the SAM IO training was introduced with the In the largest randomized controlled trial to date, we found
EZ-IO training, which likely influenced the insertion speed that the EZ-IO had a statistically significant faster insertion
due to ease of use and familiarity with the more ubiquitous time when compared to the SAM IO. However, the time dif-
EZ-IO. To mitigate some of the learning curve bias for all par- ference was unlikely to be clinically meaningful. Most partic-
ticipants, hands-on training was conducted until the partici- ipants preferred the EZ-IO, but most were comfortable using
pants reported they were comfortable using both IO devices, the SAM IO in their field EMS setting.
then randomization occurred. Post-training randomization
posed limits on potential real-life memory effects, although Author Contributions
the study’s primary focus was on mechanical device compar- RS contributed to data collection, data analysis, critical review
isons. Needle selection was based purely on the availability and evaluation of results, primary authorship of the paper, re-
of the needles, and clearly, the longer needle should take a view, and editing. RCP contributed to conceptualization, data
slightly longer time to insert. However, needle size compar- analysis, critical review and evaluation of results, primary
isons in both analyses showed no statistically significant authorship, review and editing of the paper, and study super-
difference. vision. SET contributed to conceptualization, data analysis,
critical review and evaluation of results, review, and editing.
The authors did hang six 1L bags of normal saline from the JAM contributed to data analysis, critical review, evaluation
same height, used the same manufacturer’s infusion set, and of results, review, and editing.
compared the emptying times of both the EZ-IO and SAM IO
45mm catheters. All emptied within 3 seconds of each other. Disclaimer
No formal test was conducted beyond this. We concluded that The statements, opinions, and data contained in all publications
the flow rates were similar and variation could be attributed are solely those of the individual authors and contributors. The
to slight fluid volumes in the bags, but no further flow rate information, content, and conclusions do not necessarily repre-
testing was conducted. Further studies should be undertaken sent the official position or policy of the University.
to confirm actual flow equivalency between the needle sizes.
Disclosures
Only 8.5% of the participants had prior experience with the The authors have nothing to disclose.
SAM IO compared to 100% with the EZ-IO; interestingly, their
time performance was similar to the rest of the cohort. All our Funding
study participants had years of experience using the EZ-IO in This study received no external funding. It was supported by
simulation and field practice. Lastly, response bias may have departmental resources and conducted as part of internal EMS
influenced participants’ survey choices and participation with education and quality improvement activities.

38 | JSOM Volume 25, Edition 4 / Winter 2025