Ampoules, infusions, and filters

Intravenous drug delivery in neonates: lessons learnt

Intravenous drug administration presents a series of challenges that relate to the pathophysiology of the neonate and intravenous infusion systems in neonates. These challenges arise from slow intravenous flow rates, small drug volume, dead space volume and limitations on the flush volume in neonates. While there is a reasonable understanding of newborn pharmacokinetics, an appreciation of the substantial delay and variability in the rate of drug delivery from the intravenous line is often lacking. This can lead to difficulties in accurately determining the pharmacokinetic and pharmacodynamic relationship of drugs in the smallest patients. The physical variables that affect the passage of drugs through neonatal lines need to be further explored in order to improve our understanding of their impact on the delivery of drugs by this route in neonates. Through careful investigation, the underlying causes of delayed drug delivery may be identified and administration protocols can then be modified to ensure predictable, appropriate drug input kinetics.

Glass ampoules: risks and benefits

BACKGROUND AND OBJECTIVES

Glass ampoules have been widely used in packaging injection drugs. Glass has important characteristics that allow it to be widely used in fabrication of recipients for drugs and other sterile substances. However, contamination of solutions with glass microparticles on breaking open glass ampoules, the presence of metals, percutaneous injury, and biological contamination justify the need of educational materials to orient the manipulation of ampoules.

CONTENTS

Glass microparticles generated in the snap-opening of ampoules, as well as metals that contaminate their contents can be aspirated and injected through several routes. Exogenous contaminations by glass and metals can reach several sites in the organism. They trigger organic reactions that may give rise to injuries. Opening ampoules can expose professionals to the risk of percutaneous injuries. These lesions increase the biological risk as they are the gateway for viruses and bacteria. Ampoules opening systems (VIBRAC and OPC) have been developed to reduce the incidence of such accidents. Alternative materials to glass may represent an interesting strategy to increase safety. The use of prefilled syringes may represent an evolution regarding safety.

CONCLUSIONS

Team training and information provided by the pharmaceutical industry on the use of ampoules are fundamental in the prophylaxis of accidents and contaminations. The search for safer materials to replace glass is also important.

Glass contamination in parenterally administered medication

AIM

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

BACKGROUND

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.

METHODS

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.

RESULTS

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.

CONCLUSION

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.

Hazards of parenteral treatment: do particles count?

After prolonged parenteral nutrition a 12 month old infant died with pulmonary hypertension and granulomatous pulmonary arteritis. A review of necropsy findings in 41 infants who had been fed parenterally showed that two of these also had pulmonary artery granulomata, while none of 32 control patients who died from sudden infant death syndrome had similar findings. Particulate contaminants have been implicated in the pathogenesis of such lesions and these were quantified in amino acid/dextrose solutions and fat emulsions using automated particle counting and optical microscope counting respectively. Parenteral feed infusions compounded for a 3000 g infant according to standard nutritional regimens were found to include approximately 37,000 particles between 2 and 100 microns in size in one day's feed, of which 80% were derived from the fat emulsion. In-line end filtration of intravenous infusions may reduce the risk of particle associated complications. A suitable particle filter is required for use with lipid.

Particulate contamination in spinal analgesia

A microscopic investigation was undertaken to quantify the amount of particulate contamination in the injectates of bupivacaine 0.5% in spinal analgesia. No differences were found between samples prepared with either a glass syringe or a disposable plastic syringe, nor could differences be documented between groups where atraumatic opening of vials, perforation of vial stoppers or opening of glass ampoules was performed. The use of commercially available bacterial filters was followed by a significant increase in the amount of particulate contamination, probably filter debris. The clinical use of such filters in spinal analgesia is therefore questionable.

Other potential clinical uses of oral rehydration

An increasing awareness that bowel absorptive function can be maintained or returned to normal soon after trauma or abdominal injury and the formulation of glucose/electrolyte solutions specifically designed to be rapidly absorbed from the small bowel are responsible for the current trend of early oral rehydration and decreasing use of intravenous fluids in surgical patients. Much of this article is devoted to observations and results of clinical trials on surgical patients in Aberdeen Royal Infirmary and Dr Gray's Hospital, Elgin. To date, the results of early oral rehydration after surgery have been sufficiently encouraging to create changes in the routine fluid resuscitation and management protocols in several areas of surgical practice at these centres.