Ensuring biobank safety with remote freezer monitoring

Nottingham Tissue Biobank stores and distributes different types of human tissue that can be used in a variety of surgical procedures. The service sits within the University of Nottingham, and its main user is the Nottingham University Hospitals NHS Trust, comprising Queen's Medical Centre and City Hospital. The mainstay of the tissue bank is femoral heads collected with consent from live donors during complete hip replacements. These are then stored at -80 °C in ultra-low temperature (ULT) freezers at Queen’s Medical Centre, and tested extensively in line with the rigorous requirements stipulated by the Human Tissue Authority (HTA), the UK’s independent regulator of human tissue and organ donations. At the end of a six-month testing period, the femoral heads can be released for use as bone grafts in various orthopaedic surgeries – such as shoulder, hip and ankle revisions – performed at either of the two hospital sites within the trust.

Accurate, real-time monitoring of the ULT freezers is crucial to ensure that all the tissue is kept at a safe temperature while in storage. In the past, the hospital relied on auto-diallers – which would send the team a notification in case of a complete power outage – and in-freezer thermometers that required manual checks. However, this meant that the biobank did not have any way to remotely monitor the live status of freezers or doors, and it was extremely difficult to verify whether or not auto-dialler alerts were genuine and, therefore, if intervention was required. This forced staff members to frequently go on site out of hours to check the thermometer readings and freezer doors in person.

Dr Jane McClaren is the Manager of the Nottingham Tissue Biobank, and is also the service’s HTA Designated Individual and Senior Technical Specialist. She explained the motivation behind the decision to purchase new monitoring equipment: “Bone graft is considered to be the gold standard in encouraging bone repair, so it's exceptionally important that we can protect these valuable samples by monitoring and recording temperature fluctuations, environmental conditions and door opening events around the clock. Our previous probes were not providing us with the real-time, in-depth information we needed, so we decided to look for another solution.”

The team purchased Haier Biomedical’s wireless monitoring system which consists of PT100 sensor/ RF transmitters and an RF gateway for wireless monitoring of the internal conditions of their freezers, as well as status sensors for keeping track of door opening events. The probes and sensors act as an early warning system, sending alerts via email and text message to staff if there is a deviation from the pre-set acceptable temperature range or doors are left open. This enables team members to investigate the cause of the alert straight away through Haier Biomedical’s web-based software, avoiding the need to visit the freezers in person to verify any issues. Remote monitoring with these devices is far more convenient and reliable than the previous system, lightening the burden of work on the biobank service and reassuring team members that its bone tissue is being stored under optimal conditions. The web-based software also provides straightforward data integration and viewing of historical data, ensuring that the biobank has a full audit trail to satisfy regulatory requirements, as well as helping staff to pinpoint the causes of alarms and rectify any issues as soon as possible.

The tissue bank has also recently acquired a Haier Biomedical 51 L Under-counter ULT Freezer for storing bone tissue at its satellite location at City Hospital. This unit is being used for the short-term storage of a small number of femoral heads intended for use in upcoming elective orthopaedic surgeries, streamlining the distribution process and ensuring that valuable bone tissue is ready when and where it is needed. Jane continued: “We compared several brands of biomedical freezers, and found that Haier Biomedical’s cold chain offerings were the best by miles in terms of cost and spec. The ULT freezer we eventually chose was a perfect fit for our requirements and budget, so it was a no brainer when choosing our new supplier. The unit is very stable, and we haven’t experienced any errors, so we can trust it with our precious biological samples.”