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Three Part Question

[In patients requiring IO access] is [a screw tipped IO needle better than a standard needle] at [rapidly easing insertion and ensuring correct placement]?

Clinical Scenario

A 50 year old alcoholic man presents to the emergency department by ambulance. He is known to have been fitting for the last 20 minutes. He has a SaO2 of 90% on oxygen mask and tolerates an oral airway. You are unable to obtain IV access and his vigorous movements will make central venous access difficult and possibly dangerous. You decide to place an intraosseous needle in the sternum. You use your standard IO needle but struggle to get through the bone cortex. Your consultant suggests buying some screw tipped cannula to aid insertion. You wonder if they would be any better.

Search Strategy

Medline 1966-01/04 using the Ovid interface.
[exp Infusions, intraosseous OR IO.mp. OR intraosseous.mp.] AND [screw.mp.]

Search Outcome

Altogether 35 papers were found of which one was relevant to the 3 part question

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Jun H et al, 2000, USA	Medical students received instruction on use of screw tip IO, or normal bone marrow aspiration needle. They were then tested on simultated IO infusion on ribs and turkey thighs. 2 attempts, one following demo, one practised.	Randomised experimental study. 42 medical students were randomised as to which needle they used first	1st attempt (written instruction and demo)		Experimental model was bone only (rather than bone plus flesh) Poor model for "adult" bone Difficult to know whether skills will degrade to "unpractised" level with time Comparison was against "standard bone marrow" needle rather than "standard IO needle"
			Time to placement	Less for standard (33 secs vs 54 secs p=0.19)
			Ease of insertion (10 point VAS)	Less for standard (3.2 vs 6.3 p<0.001)
			Success rate	83% for standard vs 76% for screw tip p=NS
			2nd attempt (practised)
			Time to placement	Less for screw tip (32 secs vs 27 secs p=NS)
			Ease of insertion (10 point VAS)	Less for standard (2.5 vs 5 p<0.001)
			Success rate	79% for standard vs 95% for screw tip. P<0.05

Comment(s)

A previous study by the above authors demonstrated no benefit for standard IO needles vs. standard bone marrow needles for IO access. In clinical practice IO infusion is a relatively rare event, often performed by junior staff with little prior experience of the procedure, the levels of training/experience used in this study are probably realistic. The time differences for insertion are not clinically important. The ease of insertion scores are important and show a clear benefit for the standard needle, however the most important clinical outcome is successful placement of the IO needle. The study shows an improvement in successful placement of the screw tipped needle once the students had practised the technique. The authors conclude that there is no benefit to screw tip needles. We believe that the potential improvement in successful placement with little difference in time to successful placement is clinically important.

Clinical Bottom Line

Screw tip IO needles are more difficult to insert but have a higher success rate.

Level of Evidence

Level 3 - Small numbers of small studies or great heterogeneity or very different population.

References

1. Jun H, Haruyama AZ, Chang KS, et al. Comparison of a new screw tipped intraosseous needle versus a standard bone marrow aspiration needle for infusion. Am J Emerg Med 2000;18:135-9.