Patient safety movement calls for
reexamination of multidose vial use
From the June 14, 2000 issue
PROBLEM: The Centers for Disease Control (CDC) recently
reported that a contaminated multidose vial (MDV) of saline
was the likely source of transmitting hepatitis C virus (HCV)
to at least three patients1.
Although the vial was not available for testing, the CDC concluded
that saline flushes from a 20 mL MDV were the only exposure
associated with the infection. Investigators suspect that
the MDV was contaminated either from reuse of a needle or
syringe or improper decontamination of the rubber membrane.
There were 41 patients admitted to the hospital unit during
the suspected outbreak, but only one had a documented history
of HCV. While 15 patients died before the investigation, death
certificates did not mention HCV as an underlying cause. Five
of the remaining patients tested positive for HCV and the
genotype was the same. CDC identified the source patient and
three confirmed cases (and one unconfirmed case) of transmission
to patients with no known HCV risk factors.
In 1990, Plott et al. demonstrated that 25% of practitioners
misused MDVs by reentering the vial with a needle that had
already been injected into a patient2.
However, actual vial contamination rates vary in the literature,
from no detectable contamination identified by Christensen
et al., to a 23% contamination rate noted by Bothe3-4.
Yet, ongoing reports of infections transmitted through contaminated
MDVs clearly suggest that their use poses a tangible risk.
While common preservatives used in MDVs may be highly effective
for most bacteria, they are not antiviral agents. Also, there
is a vulnerable window of time (about two hours) during which
contaminating organisms may remain viable in MDVs before the
preservative fully exerts its effect5. Even after the preservative
inactivates the organism, endotoxins may be present and cause
pyretic or febrile reactions. While faulty aseptic technique
is often the primary cause of vial contamination, other influential
factors include the design of the vial, storage conditions,
the frequency of entering the vial, the environmental air
injected into the vial, and its use for patients with highly
contagious diseases. The patient's underlying health also
influences the risk of transmitting the infection. Further,
there is little guidance regarding an appropriate expiration
date after initial entry of the MDV. Practices are variable,
from discarding the vial within 24 hours, to reliance on the
manufacturer's expiration date and visual inspection.
SAFE PRACTICE RECOMMENDATION: The reuse of MDVs is
a balancing act between cost containment and patient safety.
Certainly, there are a few settings in which the cost benefit
outweighs the risk because potential contamination is significantly
reduced. For example, the reuse of a MDV for a single patient,
such as insulin for a diabetic patient, carries little risk
of patient cross contamination. In the pharmacy, the risk
of contamination is minimal when MDVs are used for compounding
in an aseptic environment, using proper technique, with no
potential for patient-to-patient contamination. MDVs of expensive
drugs also may be safely stored in the pharmacy and dispensed
to units in ready-to-administer syringes. Yet on patient care
units, multiple staff members use the relatively inexpensive
drugs and solutions commonly found in MDVs for many different
patients. In fact, many (e.g., saline and lidocaine) require
multiple entries into the vial for a single patient encounter.
Further, many MDVs look alike and have been confused with
other drugs packaged similarly. With such ripe opportunity
for contamination, single unit packages in ready to use form
are preferred. At a recent CDC conference, attendees were
strongly encouraged to use prefilled syringes or single dose
vials for inexpensive but widely used substances (e.g., saline,
bacteriostatic water, heparin, lidocaine) to reduce the risk
of contamination. Don't wait until you have a nosocomial outbreak
to heed this advice.
References: 1). Multidose vial linked
to nosocomial HCV outbreak. Hosp Infect Control, May 2000;
68-69. 2). Plott et al. Iatrogenic contamination of multiple-dose
vials in simulated use. Arch Dermatol 1990; 126:1441-4. 3).
Christensen EA, et al. Assessment of risk of microbial contamination
by use of multidose containers of injectable products. J Hosp
Infect. 1992; 20:301-4. 4). Bothe J. Study shows contamination
in multiple-dose vials. AORN J. 1973;17:111-14. 5). Wilson,
JP et al. Updating your multiple-dose vial policy: The background.
Hosp Pharm. 1998;33: 427-32.