Colorado fertility lab now protecting frozen embryos with new thermal imaging system.
UCHealth University of Colorado Hospital,
05 February 2020

A fertility lab at UCHealth University of Colorado Hospital has become the first customer in the world to add a new thermal imaging system to protect frozen embryos, eggs and sperm for people coping with infertility.

The University of Colorado clinic has never suffered a tank failure. But, Colorado leaders wanted to do everything they could to protect frozen embryos and be sure that a similar catastrophic loss would never happen here.

“We are acutely aware that these tissues in our care represent the hopes and dreams for many people dealing with infertility, for those who stored sperm or eggs before cancer treatments and for young women preserving their eggs for future use,” said Dr. Liesl Nel-Themaat, director of the Colorado lab.

After the tank failures elsewhere, Nel-Themaat and her colleagues began exploring options to further safeguard the nitrogen-cooled tanks at the lab in Aurora. And, the center recently became the first in the world to install a system called Cryo Sentinel.

Each of the tanks already has a built-in temperature gauge, as is standard for tanks at most fertility clinics. But, when the failures occurred in Ohio and California, alarms did not sound until most of the cooling nitrogen had evaporated, hours too late to protect frozen embryos, sperm and eggs.

Cryo Sentinel uses an entirely different system to provide real-time data on the external temperature of the tanks. Multiple infrared cameras aimed at the tanks can immediaely sense temperature changes and sound an alarm if a tank is failing up to 20 hours earlier than the other temperature gauges.

“The Cryo Sentinel triggers an alert the moment the tank integrity is compromised, providing ample time to move any eggs, embryos or sperm to safety,” Nel-Themaat said.

Nel-Themaat can monitor the status of the tanks from anywhere in the world. She routinely checks on them every night before she goes to sleep.

“I’m checking on our patients’ babies every night,” she said.

New technology that can safeguard precious frozen tissues means a great deal to patients, many of whom have already dealt with tough health challenges. Some have been diagnosed with cancer at a young age and choose to store eggs or sperm before going through additional cancer treatments. Others have coped with fertility issues and the decision to go through in vitro fertilization or IVF can be emotionally and physically exhausting.

The prospect of losing precious embryos, eggs or sperm – that represent dreams of future children – is simply unthinkable.

How the Cryo Sentinel system protects frozen embryos

  • Thermal imaging cameras monitor tanks that protect frozen embryos, eggs and sperm.
  • The tanks are cooled with liquid nitrogen. At room temperature, nitrogen is a gas. When it’s cooled below about negative 320 degrees Fahrenheit (or negative 196 Celsius), it becomes a very cold liquid.
  • If the liquid nitrogen doesn’t stay cool enough, it evaporates and would no longer protect frozen embryos.
  • If nitrogen evaporates, the internal temperature in the tank doesn’t cool immediately, and thus, the alarm doesn’t trigger right away.
  • The tanks are like insulated coffee flasks. If the inner vacuum fails, it first causes the outside of the tank to cool.
  • The Cryo Sentinel’s thermal imaging cameras can detect this external cooling right away and immediately trigger alarms.
  • Liesl Nel-Themaat and others can check live videos of their cyrostorage room at any time, from anywhere in the world.
  • If there’s a change in temperature, lab employees can immediately check the tanks, which are also called Dewars.
  • If a tank failed, lab workers would have plenty of time to protect frozen embryos, eggs and sperm to transfer them to a properly functioning tank.
  • Said Nel-Themaat: “We are constantly trying to making things better and safer, and to improve our outcomes.”
  • Cryo Sentinel initially went through extensive testing at a fertility center in Georgia. The Colorado center received the first commercially available system.


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