Glass contamination in parenterally administered medication

This paper reports a study examining glass particle contamination in two ampoule sizes under three different experimental conditions (n = 18 in each group).

While existing literature is clear that glass contamination occurs on opening single-dose glass ampoules, the clinical significance of intramuscular administration of glass particles is equivocal. Current nursing practice standards do not adequately address this issue in terms of aspiration or filtration techniques that can minimize risk to patients.

A computer microscope was used to compare the number and size of glass particles aspirated into a syringe between two needle sizes [18 gauge (G) (130 microm lumen diameter) and 21 gauge (90 microm lumen diameter)] without filters and 19G (110 microm lumen diameter) filtered needles. Data were collected in 2002.

At least one glass particle was found in 22% of the 1-mL ampoules, and 56% and 39% of the 2-mL ampoules, using 18G and 21G needles, respectively, had glass contaminants. Many of the 2-mL ampoules produced multiple glass particles on opening. Use of 19G filtered needles resulted in no glass particles. There was a significant difference in mean particle size between the 18G and 21G groups of 2-mL ampoules.

Our results support the existing literature in that larger bore unfiltered needles increased the risk of aspirating more glass and other particles than smaller bore or filter needles. These data add further support to the use of filtered needles in administering IM medications to patients who receive ongoing scheduled IM injections.