Gap ExMC 4.16: Lack of technique or procedure to draw injectable medication into a syringe without bubble formation or bubble removal prior to medication delivery (CLOSED)
Last Published:  04/20/22 11:43:20 AM (Central)
Responsible Element: Exploration Medical Capability (ExMC)
Status: Closed
Closure Rationale

Gap Closure Synopsis
There will be situations during exploration space flight where an ill crew member will require a liquid medication that must be administered via intravenous methods, in particular, a single dose via needle-syringe-like method. Typically in terrestrial medicine, such doses can be drawn from a liquid vial to appropriate amounts followed by the removal of air within the syringe. The separation of the air from the liquid medication is simplified via the forces of gravity. This is not applicable to space flight where such forces will be minimal if not absent. This situation will hinder the separation of air from the liquid medication and, quite possibly, increase the likelihood of air bubbles or micro-bubbles being mixed with the liquid medication. This will subsequently lead to the administration of bubbles into a crew member’s vasculature which could be deleterious to the crew member’s health. This gap was established to identify, evaluate, and integrate any system or procedure that would allow minimally trained CMOs to minimize bubble formation in liquid medications prior to their administration to crew.

In 2008, JSCs Space Medicine Training Group (Training) and Pharmacy with help from ExMC evaluated the effectiveness of needleless vial adaptors for the administration of liquid drugs aboard the ISS. The evaluation and a supplemental study have been documented in two reports within the NASA Memorandum “C-9 and Other Microgravity Simulations” - Summary Report (NASA/TM-2009-214794). These data along with results from the University of Kentucky’s NASA Reduced Gravity Student Flight Opportunities Program Final Report (“Bubble Free Injection Syringe”) provide sufficient closure to this gap by 1) evaluating techniques for the reduction/removal of air bubble formation during the drawing of liquid drugs using a syringe and 2) identifying a successful method for minimizing the formation of air bubbles during such a process in a microgravity environment.

The initial evaluation of needleless vial adaptors in parabolic flight identified a concern with single-dose medication vials <5 milliliters (mL). The drug manufacturer’s air bubble within their vials traps fluid along the sides and base of the vial despite effective air/fluid separation before medication withdrawal. In terrestrial medicine, any fluid that is not immediately at the septum of the vial can be “chased” by the user using the needle already inserted such that it can interface with the liquid bubble and thus, be drawn into the syringe. The vial adaptors tested for this study limited the range of the needle to “chase” the fluid bubble. In addition, the needle length was also a limiting factor in acquiring fluid in vials with a volume of <3mL. Because of this limitation to “chase” the fluid and acquire the proper dose from the vial, the team looked at blunt cannulas to evaluate their effectiveness in acquiring fluid volumes from smaller-unit-dose vials of medications.

The subsequent parabolic study by Training, Pharmacy, and ExMC showed that some air will inevitably be mixed into medications as they are drawn into the syringe. This occurs, in part, to the dead space within both the vial adaptors and the blunt cannulas. This can be counteracted by a simple maneuver by crew to isolate the fluid within the syringe prior to medication administration. To better facilitate this maneuver, it is recommended to select a syringe with a volume larger than the volume of medication required. The study also indicated that the hardware selected for withdrawing the liquid medication in a microgravity environment has the ability to reach the entire interior surface of the vial to facilitate “chasing” of the medication. Lastly, the results from the University of Kentucky’s parabolic study complemented these recommendations.

Rationale for Closure

Although complete removal of air bubbles and microbubbles from liquid medications will be difficult regardless of the gravitational environment, Training, Pharmacy, ExMC and the University of Kentucky sufficiently demonstrated systems and techniques that maximize air bubble removal to sufficient levels for the administration of liquid medications to crew during space flight. These systems and techniques are applicable for different doses of medication and can be effectively executed by astronaut Crew Medical Officers (CMOs) during exploration class space missions.

Task and Supporting Reports Completed

1. Hailey, M., and Bayuse T., Effectiveness of Needleless Vial Adaptors for Drug Administration in a Microgravity Environment. C-9 and Other Microgravity Simulations -- Summary Report, pg 55, 9/1/2010, NASA Johnson Space Center.

2. Moore, D., Anderson, et al. Free Injection Syringe University of Kentucky’s NASA Reduced Gravity Student Flight Opportunities Program Final Report. 2010.

Closure Documentation:
1)  Initial State

Preparation of injectable medications in a non-micro gravity environment simplifies removal of air bubbles within the syringe. This luxury is lost in micro gravity as isolation of bubbles becomes difficult due to the absence of a force greater than the surface tension of the medication. The consequence of injecting an air bubble into a crewmember could be harmful.

This gap’s focus is on development of a technology or technique to prepare an injectable medication without air bubbles for safe delivery into a crewmember.

Target for Closure
No Target for Closure available.
Risk Risk of Adverse Health Outcomes and Decrements in Performance Due to Medical Conditions that occur in Mission, as well as Long Term Health Outcomes Due to Mission Exposures
You are here! Gap ExMC 4.16: Lack of technique or procedure to draw injectable medication into a syringe without bubble formation or bubble removal prior to medication delivery (CLOSED)

Multi-Disciplinary Research Plans

No Documentation Available