Multidose vial linked to nosocomial HCV outbreak
Three patients infected in surgical ward
A contaminated multidose vial of saline was the likely source of transmission of hepatitis C virus to at least three patients in a Florida hospital, underscoring that infection control professionals should consider switching to single-dose containers of such widely used solutions, an investigator with the Centers for Disease Control and Prevention reports.
"We conclude that the outbreak was caused by patient-to-patient transmission of hepatitis C from one source patient to probably three other patients," said Gerard Krause, MD, an officer with the CDC Epidemiology Intelligence Service. "We identified saline flushes as a risk factor for infection. Most likely, the saline solution or the saline solution vial became contaminated by either re-use of a needle or syringe or by improper decontamination of the rubber membrane. Subsequent flushes from the same vial would then have resulted in transmission of the virus."
The CDC began an outbreak investigation last August after it appeared that three patients hospitalized on the same ward in November 1998 had developed HCV. The patients had onset of symptoms less than eight weeks after being admitted to the Miami facility, which the CDC did not identify. There were 41 patients hospitalized on the ward over the suspected outbreak period, but only one had a documented history of HCV, Krause told attendees at the CDC’s 4th Decennial International Conference on Nosocomial and Healthcare-Associated Infections, held in March in Atlanta.1
Some of the patients could not be located, and 15 had died. However, none of the death certificates listed hepatitis as an underlying cause of death, he said. Overall, 21 patients were contacted and tested for hepatitis C virus infection. Five (24%) of the 21 were positive for HCV, and the genotype of all five viral samples was the same. The cluster represented the patient with chronic HCV who already was infected prior to admission, three confirmed cases of nosocomial transmission, and one possible case. None of the patients had risk factors for HCV, such as a history of injecting drug use or blood transfusions prior to 1992.
Investigators reviewed invasive procedures and phlebotomy, but saline flush of heparin locks was the only exposure that was associated with infection. The solution was not available for testing, and the ward nurses said they practiced standard precautions, but the vials emerged as the most likely source of the outbreak, investigators concluded. The saline solution was kept in 20 ml multidose vials that were shared by all staff. Approximately three ml were used for each saline flush. Saline flushes were done before and after IV medication was administered.
"The only substance that was shared by all patients for intravenous use was saline solution used to flush heparin locks," Krause told conference attendees. "Hospitals may want to consider the use of prefilled syringes or single-dose vials for inexpensive but widely used substances such as saline solution. This would reduce the possibility of accidental contamination of injectable drugs. The [Miami] hospital has stopped the use of multidose saline vials in favor of single-dose vials."
Inspect, discard vials regularly
In general, multidose vials can be safely used in today’s budget-conscious health care settings, but policies should include regular review and discard procedures, says Patrick Joseph, MD, CEO of California Infection Control Consultants in San Ramon, CA.
"With any of these vials, the first guideline is the expiration date, and that always has to be followed," he says. If a sole provider, such as a nurse practitioner or a physician, is using the vial, it is reasonable to keep it until expiration, he says. "So, if I happen to have a multidose vial of lidocaine in my office — and I am the only person using it and the expiration date is a year from now — then I am very comfortable keeping that for a year," Joseph says.
On the other hand, when there are multiple uses by a hospital staff, many ICPs set up a time frame for vial discard, he says. A common practice is to write the date on the vial when it is opened and then to discard it at some set time thereafter. "Although 30 days is often used, there is nothing magic about 30 days," he says. Though such policies look good on paper, they can be difficult to follow because workers must remember to date the vial and discard it at the designated time, he adds.
"We have seen numerous hospitals and clinics cited because they’ve had that policy but there has been just poor compliance," Joseph says. Another approach is to use as few multidose vials as possible and then to discard all vials on a given day, he adds. "We have done that in several hospitals successfully, and the cost is minimal," he says. "You discard all multidose vials on the first day of the month — even if it was opened the day before. You recognize that there are some that you are discarding that have really only been opened a few days, but the total cost at the end of the year is really pennies, and you have is a policy that permits compliance."
Multidose vials of very expensive products should be kept in the pharmacy and dispensed in syringes, he adds. "And there are a couple of those, particularly the recombinant genetic products, that are stable for a long time after opening," he says. "We don’t put those on the ward. So, this [policy] really only applies to ward stock, and ward stock multidose vials are generally relatively low-priced."
Most biologic products such as vaccines and purified protein derivative (PPD) are dispensed by the pharmacy, he says. "In those circumstances where vaccines and PPD may be ward stocks — since that stuff is a little bit more expensive — it might be reasonable to develop a bottle-dating policy for biologics," he says. "[Then regularly] discard all non-biologics, which would include the multidose vials of potassium, insulin, lidocaine, and the other things usually found on a nursing ward."
1. Krause G, Whisenhunt S, Trepka M, et al. Patient-to-patient transmission of hepatitis C virus associated with use of multidose saline vials in a hospital. Abstract S-TH-06. Presented at the Centers for Disease Control and Prevention 4th Decennial International Conference on Nosocomial and Healthcare-Associated Infections. Atlanta; March 5-9, 2000.