Probe blames condensation for fatal blood
No one person responsible: panel
Bacteria that killed a patient after a blood transfusion earlier this month could have seeped into the blood bag from condensation on a foam container during transport to Tuen Mun Hospital, an investigation has found.
Following release of the report yesterday, which said no individual should be held responsible for the 'rare' incident, the Blood Transfusion Service said it would suspend use of its mobile collection vehicles, provide timers at venues and redesign blood packaging. The hospital said it would revise its antibiotics prescription and blood test protocols.
The investigation panel was set up to find out how the blood given to Wong Yun-cheun became contaminated with the bacteria Pseudomonas fluorescens. Wong, 52, went into shock after the January 3 transfusion. He was given antibiotics late on January 4 but died on January 7.
The four-member panel's chairman, Yuen Kwok-yung, University of Hong Kong chair professor and head of its department of microbiology, announced the findings and recommendations a day after the report was submitted to the Hospital Authority, which runs the transfusion service.
The contamination occurred on or before December 20, the day after the bag of red cells was sent from the transfusion service to the hospital, the report said. Foam boxes in which the blood was kept had coolants to keep the temperature at or below 20 degrees Celsius. But condensation could have formed.
'This condensation could drip into the blood bags through microscopic defects in tubing. The bacteria will swim through the leaky area into the blood bag and cause the contamination,' Professor Yuen said.
The microscopic defects could have been introduced during thermal sealing of the tubing, which he described as 'the most high-risk' procedure in separating blood into its various components.
He said the seepage of bacteria-laden condensation into the bag was 'the most likely possibility' for the contamination. Tests of the condensate showed 'heavy growth of Pseudomonas fluorescens'. Also, every millilitre of blood remaining in the near-empty blood bag after transfusion to the victim contained 500 million bacteria, he said.
'It took 18 days for the bacteria to multiply to such an extent, so we can estimate that the time of contamination of this blood bag was on or before December 20,' he said.
DNA fingerprinting showed that the bacteria strain from the condensate was identical to that found in the patient and the donor blood bag.
There was a 'theoretical possibility' that the hands of the staff collecting blood at the mobile vehicle could have been contaminated by the bacteria from condensate in the blood bin. 'But this is much less likely.'
In the past 10 years, there have been no deaths out of the more than 3.4 million units of blood products transfused in the city.
Secretary for Food and Health York Chow Yat-ngok said he hoped the Hospital Authority would implement the recommendations quickly.
Hospital Authority director of quality and safety Leung Pak-yin said the authority accepted the recommendations and would examine them in detail for implementation.
Patients' Rights Association spokesman Tim Pang Hung-cheong said the recommendations were 'straightforward'.
Hand-washing facilities in mobile donation vehicle
Use of stopwatches to time disinfection
Minimise thermal sealing/stripping of tubing
Avoid condensation in foam containers
Clarify guidelines on indication of transfusion
Audit transfusion reactions and their management
Elective transfusion should be held in morning or early afternoon
Use one dose of antibiotic for unexplained shock and fever after a transfusion
Urgent test on donor blood and phone report sent to clinician