Authors: Roland K. Smith A-M, Sheperd L
Department of Pathology and Molecular Medicine
Kingston General Hospital, Kingston ON
One of the recognized risks associated with the transfusion of blood products is bacteremia due to blood products contaminated by bacterial pathogens. The rate of RBC bacterial contamination has been reported to be as high as 1 in 72,000 units with a fatality rate of 1 in 1 million.
One of the strategies to minimize the risk of an adverse event from RBC bacterial contamination is the storage of RBC units at cold temperatures. The Canadian Standards Associations (CSA) requires that RBC components be stored between 1-6 degrees Celsius in refrigeration units where the temperature is regularly monitored. Furthermore the transport of RBC units outside the Blood Bank must be done via a validated transport system, and the temperature of units cannot exceed 10 degrees Celsius at the end of 24 hours.
At Kingston General Hospital, crossmatched blood is sent to the operating room (OR) suite daily in anticipation of the day’s surgical transfusion needs in amounts according to the hospital’s surgical blood ordering schedule (SBOS). There are two small refrigeration units located in the OR suite that comply with CSA standards for the temporary storage of blood products. The transportation method of blood products to and from the OR has been validated internally as compliant with CSA standards.
Occasionally blood products are removed from the OR refrigerators and are stored temporarily in coolers within Individual OR rooms for easy access during surgery. These coolers have not been validated for storage, and no records are kept regarding which blood products are stored in coolers, for how long, and the temperature of unused units that are returned to the OR refrigerators. All unused blood products are collected from the OR refrigerators each evening and returned to the Blood Bank. If the temperature of the returned product is within the acceptable range (1-10 degrees Celsius) then it is returned to storage for potential future use. What is currently unknown is whether the temperature of the RBC units has strayed outside of acceptable limits at any time during temporary storage outside the OR refrigerators and Blood Bank. If RBC units whose temperature has exceeded acceptable limits are returned to Blood Bank storage and are reissued for transfusion at a later date, there may be an increased risk of an adverse reaction due to bacterial contamination.
1. To assess the total number of non-transfused RBC units returned from the OR that have exceeded acceptable temperature limits during storage and/or transport and thus may not be safely-re-stored in the Blood Bank for future use.
2. If a significant rate of over-heated RBC units are found, then the rate for each individual OR will be assessed as an initial means of improving storage practices.
Starting November 1, 2005, all consecutive RBC units sent to the OR were provided with a Safe-T-Vue Nonreversible Temperature Indicator (William Laboratories, Inc., Enfield, CT, USA)provided by Discovery Diagnostics (Claremont ON, Canada). These indicators permanently change colour from white to red when the temperature of the unit exceeds 10 degrees Celsius. The indicators were applied according to the manufacturers’ instructions and the following protocol:
- The indicators were stored in the Blood Bank refrigerator at least 2 hours priori to use.
- The indicators were applied to the RBC units without removing the units from the refrigerator.
- The RBC units were kept in the refrigerator while the following data was recorded: date, unique RBC unit number, patient ID number, destination OR room
- The RBC units were then packed in a pre-cooled transport container previously validated for red blood cell transport.
- During the routine morning temperature check of the OR refrigerators, the indication of the stored RBC units were examined. Any with red indicators were removed and replaced with new cross-matched units.
- When the non-transfused units were returned to the Blood Bank, the colour of the temperature indicator on each unit was recorded. If the indicator was missing or damaged, it was recorded as such.
- RBC units with red indicators were discarded.
- Data was collected from November 1, 2005 to March 20, 2006 inclusive
- A total of 1397 consecutive RBC units were issued from the Blood Bank to the OR with the temperature indicators. data from none of the units had to be excluded.
- Of the 1397 units sent to the OR, 336 (24%) were transfused and 1061 (76%) were returned to the Blood Bank for a crossmatch-to-transfusion ratio of 4.2:1.
- Of the 1061 non-transfused RBC units returned from the OR, 816 (76.9%) had a white indicator, 199 (18.8%) had a red indicator, 4- (3.8%) were missing their indicators, and 6 (0.5%) had damaged indicators.
- The rate of red indicators from each OR (lettered A, B, C, D, F, G/H, J, K) ranged from a low of 0.0% (room F) to a high of 38.2% (room J).
- The overall rate of non-transfused RBC units returned from the OR at KGH that have exceeded storage temperature requirements i unacceptably high at 18.8% and require corrective action. This may involve communication with the OR and surgical staff regarding proper conditions for blood storage and internal validation of OR coolers.
- There are significant differences in the rate of over-heated RBC units between the various OR rooms. Possible contributing factors include the likelihood of different surgical procedures to require blood urgently and the personal practices of different surgeons and anesthetists. Storage practices in the rooms with the highest rates will be reviewed in detail.
We wish to thank Discovery Diagnostics for providing the Safe-T-Vue Non-Reversible Temperature Indicators (William Laboratories, Inc.) for this study.