FILTER NEEDLES AND GLASS AMPULES

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FILTER NEEDLES AND GLASS AMPULES

Q. Are special filter needles required when drawing up medication from a glass

ampule? Are there hidden risks to patients, ie, sharp glass particles, if a

filter needle is not used?

A. Fred L Meister, PharmD, replies:

Bacterial contamination has always been the major concern associated with the

intravenous administration of medications and is a well-known cause of morbidity

and mortality. Additional risk factors, however, have been identified and must

also be considered.

The potential risks associated with administration of medications supplied in

glass ampules is much greater than realized by most practitioners. Opening a

glass ampule produces a shower of glass particles, many of which enter the

ampule and contaminate the contents. Some of the particles have been shown to

carry bacteria, though the significance of this has not been determined.

The number of glass particles found in opened ampules varies, but most reports

indicate approximately 100 particles, ranging in size from 10 to 1,000 µm, per

10-mL ampule. The particle count increases as the size of the ampule increases

(ie, a 20-mL ampule will contain more glass particles than a 10-mL ampule). When

the content of a 10-mL ampule is aspirated through an 18-gauge, 1.5-inch needle,

the particle count is reduced by approximately one third (ie, approximately 65

particles remain in the aspirate), and the maximum particle size is reduced to

less than 400 µm.

The potential risks associated with intravenous administration of glass

particles are based on animal studies, though similar risks would apply equally

to humans. It has been shown that glass particles cause inflammatory reactions

(eg, phlebitis) and granuloma formation in pulmonary, hepatic, splenic, renal,

and intestinal tissue. This represents a significant risk of an adverse patient

outcome.

The effective removal of glass particles from an opened ampule can be

accomplished by aspirating through a 19-gauge, 5-µm filter needle. Using this

method decreases the average total number of particles in the aspirate to

approximately ±1, and the particle size to less than 200 µm. Using a 0.22-µm

in-line filter offers little or no additional benefit, and is more costly and

labor intensive—once the ampule content is aspirated into a syringe, the filter

needle must be replaced with a standard needle prior to transferring or

administering the medication.

Based on the available information, a filter needle is recommended when

aspirating a medication from a glass ampule.

References

1. Turco S, NM. Glass particles in intravenous injections. N Engl J Med.

1972;287:1204-1205.

2. Carbone-Traber KB, Shanks CA. Glass particle contamination in single-dose

ampules. Anesth Analg. 1986;65:1361-1363.

3. Waller DG, CF. Ampules, infusions and filters. Br Med J.

1986;292:714-715.

4. Kempen PM, Sulkowski E, Sawyer RA. Glass ampules and associated hazards. Crit

Care Med. 1989;17(8):812-813.

5. Sabon RL, Cheng EY, Stommel KA, Hennen CR. Glass particle contamination:

influence of aspiration methods and ampule types. Anesthesiology.

1989;70(5):59-62.

6. Falchuk KH, L, McNeil BJ. Microparticulate-induced phlebitis: its

prevention by in-line filtration. N Engl J Med. 1985;312:78-82.

Fred L. Meister is a clinical pharmacologist at Hoag Memorial Hospital

Presbyterian in Newport Beach, Calif, and an assistant clinical professor at the

University of California, San Francisco.