Colorado fertility lab first in the world to protect frozen embryos with new thermal imaging system

Jan. 31, 2020
Kheli and Kirk Sears with their middle son, Tilman. He was born thanks to IVF. The University of Colorado fertility lab now has a new system to protect frozen embryos.
Kheli and Kirk Sears struggled with infertility, then, with help, gave birth to their second son, Tilman, now 2. Photos by Elizabeth Peterson Photography for UCHealth.,

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

That’s a great relief to patients like Dr. Kheli Sears, a veterinarian, who successfully got pregnant with her second son thanks to help from specialists at the University of Colorado’s Advanced Reproductive Medicine program. Sears has additional embryos stored in the lab and is relieved to know that nitrogen-cooled tanks now have an extra layer of protection.

Two years ago, thousands of people were devastated when tanks failed at two fertility clinics – one in Cleveland and the other in San Francisco.

Kheli and Kirk Sears with their three sons.
Kirk and Kheli Sears with their three sons, Tilman, 2, left, George, 6, center, and Cody, 5-months, right. Photo by Elizabeth Peterson.

“I couldn’t even fathom what that would be like,” Sears said. “Some of those people probably didn’t have children and their embryos at least gave them hope. It’s gut wrenching. It probably felt like losing a child.”

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.

A new system called Cryo Sentinel protects frozen embryos at UCHealth University of Colorado Hospital. Here Dr. Liesl Nel-Themat, who manages the lab, stands with tanks that hold frozen embryos and a new system which uses thermal imaging to monitor the temperatures of the tanks.
Dr. Liesl Nel-Themaat oversees the lab at UCHealth University of Colorado Hospital, which now boasts a new thermal imaging system to protect frozen embryos. Photo courtesy of Dr. Liesl Nel-Themaat.

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 immediately 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.

‘It’s a boy’

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.
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.

Kheli Sears had been through so much – including a painful miscarriage – before having her second child that she chose not to learn the sex of the baby that she and her husband conceived through IVF. With her first, conceived easily the first month she and her husband tried, Kheli and Kirk, who is also a veterinarian, loved knowing they were having a boy. George is now 6.

After coping with infertility issues following George’s birth, Kheli feared another loss and couldn’t bear to know whether she was having a boy or a girl.

“Until we had Tilman in our arms at the delivery, I didn’t think we were going to have a sibling for George,” Kheli said.

Nurses had asked about her birth plan.

“All I care about is that this baby comes out healthy,” she said.

And she wanted her husband to give her the news about whether their baby was a boy or a girl.

The moment arrived at UCHealth Memorial Hospital Central in Colorado Springs. Tilman made his debut on Jan. 8, 2018.

Tilman Sears soon after birth.
Tilman Sears soon after birth. Photo courtesy of Kheli Sears.

“He came flying out with two pushes. The doctor walked in at 8 a.m. and he was out by 8:13 a.m.,” Kheli said.

She looked at Kirk to hear the big news. Overcome with emotion, he was unable to speak at first. Then, choking through tears, he said, “It’s a boy!”

Kheli was crying too.

“When I saw Tilman, I just thought, ‘This is a miracle.’ Yes, he was created thanks to medicine, but he’s no different.

“He was this pudgy, perfect little being with two dimples, just like my husband. He was my husband’s little twin. He was beautiful and I fell in love with him instantly,” Kheli said.

Excited to start their family

Kheli and Kirk had both studied veterinary medicine at Texas A & M (although Kirk had gone to Texas Tech in Lubbock for undergrad and is very much a Red Raider fan, not an Aggie, thank you very much.)

Kheli grew up in California where she attended University of San Diego for undergrad, then vet school for three years in the Caribbean, followed by a fourth year at Texas A & M. Kirk already had graduated and was busy doing an internship in New York City and a residency in Pennsylvania. A Texan through and through, Kheli is sure Kirk stood out while living up north.

George Sears, 6, with his little brother, Tilman, now 2.
George Sears, 6, hugs his little brother, Tilman, 2. Photo by Elizabeth Peterson.

“He probably wore cowboy boots, said ‘howdy’ and was a slow talker,” Kheli says with a grin.

Both she and Kirk are small-animal veterinarians, who primarily care for dogs and cats. They’re animal lovers, of course, and at the moment have a Golden retriever-Labrador mix named Heidi Beth and a cat Frankie, named after Franklin Delano Roosevelt.

“He’s very official. He’s white and gray with blue eyes. He’s handsome and he knows it,” Kheli said.

Kirk is a specialist in internal medicine and tends to pets with challenging health issues. Funny enough, the two doctors hadn’t met through school. Rather, after their training, each was working in Dallas and they happened to be living in the same apartment complex. That’s where their romance began.

Eager to start a family after getting married, they soon had George. They figured it would be nice to have a second child a couple of years later.

At that point, Kheli and Kirk had moved from Texas to Colorado, where he was starting a new job.

Fertility challenges and a solution through IVF

Unfortunately, that’s when the fertility challenges began.

By then, Kheli was 35. She had heard talk among friends that it was harder to get pregnant after 35, but had mostly dismissed those thoughts. Then month after month passed without a positive pregnancy test.

Dr. Alex Polotsky
Dr. Alex Polotsky

Kheli consulted with her obstetrician, who suggested she see Dr. Alex Polotsky at the Colorado Springs IVF & Fertility Center. Polotsky also sees patients in Denver’s Stapleton neighborhood at CU Advanced Reproductive Medicine.

Polotsky conducted various tests and determined that there was no specific reason that Kheli and Kirk were having trouble conceiving.

He diagnosed what’s known as “secondary infertility,” or difficulty conceiving after having had a first baby naturally.

Polotsky likes giving patients options and letting them determine how aggressively they want to proceed.

Kheli and Kirk decided to first try intrauterine insemination or IUI, what some people informally refer to as the turkey baster method. Doctors inseminated Kheli three times and she was thrilled to get a positive pregnancy test.

Sadly, tough news arrived within weeks.

“An ultrasound showed an empty sac. The baby had never formed.

“It was more of a chemical pregnancy, but still heartbreaking,” she said.

Kheli had a miscarriage and she and Kirk were at a crossroads. Her eggs and his sperm were healthy. They decided to boost their chances of success by having doctors create embryos outside the womb, the procedure known as IVF.

Kheli said the process was tough and she has a great deal of empathy for women who go through multiple rounds of fertility treatments. She traveled from Colorado Springs to University of Colorado Hospital for the additional treatments. First, she took medication to stimulate her ovaries to produce as many eggs as possible.

Then, Polotsky harvested her eggs. Kheli had produced a large number: 47.

Tilman's dad throws him in the air. His mom gave birth to him after going through IVF.
Kirk Sears throws son, Tilman, up in the air. His mom gave birth to him after coping with unexplained infertility and going through IVF. Photo by Elizabeth Peterson.

“My ovaries were healthy,” she said.

Then, the team fertilized Kheli’s eggs with Kirk’s sperm and gave the couple the option of having their embryos tested for any genetic defects.

Both Kheli and Kirk are Christians. They are also scientists, and after extensive discussions with each other and their team, they decided to proceed with testing so doctors could implant a healthy embryo, most likely to lead to a successful pregnancy.

Kheli and Kirk Sears with their son, Tilman.
Kheli Sears couldn’t bear to learn if her second baby would be a boy or a girl after going through a miscarriage and infertility. Then, through IVF, she and her husband, Kirk, had Tilman, now 2. Photo by Elizabeth Peterson.

“We believe all children are beautiful in God’s eyes. We would not have selected against something like Down syndrome,” Kheli said.

The test results were quite revealing.

“We obtained 47 eggs. That is a lot,” Polotsky said. “We got 13 embryos genetically tested to determine whether they were chromosomally normal. Of those, Kheli had three normal embryos.”

Doctors implanted one and Kheli was successful in getting pregnant the first time.

“It’s really interesting,” she said. “They implant a 5-day-old embryo. There’s no sedation because it doesn’t hurt. They defrost the embryo, then take a long pipette and inject it into the uterus. You watch on a screen. It’s very small.”

Kheli got to save an image of her future son when he was only a tiny cluster of cells on a screen.

After the procedure, she had to wait about two weeks to learn if the implantation had worked.

Infertility challenges common

Polotsky said that as many as one in eight couples struggles with infertility.

“It’s a very common condition. It’s something that unfortunately is very prevalent and should be approached as a medical condition,” said Polotsky, who is also the Chief of Reproductive Endocrinology and a professor at the University of Colorado School of Medicine.

He said infertility is almost always emotionally and physically challenging, but thankfully many patients have good options and can successfully have children. The Colorado program boasts a 72% embryo transfer success rate for patients of all ages and a 78% success rate for women under age 35.

Regardless of the path that individuals or couples choose, Polotsky and Nel-Themaat advise them to work only with reputable clinics that report data in a transparent way to a governing board for clinics called the Society for Reproductive Technology (SART). SART membership ensures University of Colorado’s Advanced Reproductive Medicine abides by the strictest reporting standards.

Tilman, left, George and Cody.
Kheli and Kirk Sears first had their son George, 6, center. Then they struggled with infertility and had Tilman, left, through IVF. Baby, Cody, then arrived 19 months later. Photo by Elizabeth Peterson.

With respect to the causes of infertility, increased age is certainly the chief factor, but Polotsky said it’s relatively common for couples not to know exactly what’s wrong.

“Some folks have unexplained infertility. We might not be able to scientifically prove the reason, but we can do something to overcome the difficulties,” he said.

“In Kheli’s case, it worked out well. I told them that IVF was not something they absolutely had to do. It was their choice. They could continue trying on their own. One of the cornerstones of our philosophy is that patients should be in the driver’s seat as much as possible,” he said.

“I’m truly blessed to work with such a superb team,” Polotsky said. “All of our doctors, nurses and other staff together make what we do worthwhile. And, if you do it right, you’ll be successful for patients. We love it when they come back with their babies.”

He saluted Nel-Themaat for finding the new Cryo Sentinel system.

“We really wanted to go to an extra step to protect the tanks. This issue is very, very critical to our patients. When Dr. Nel-Themaat found out about this opportunity, it was a no brainer to provide this extra protection. In this day and age, we should not have alarms malfunctioning,” Polotsky said.

IVF success and a bonus baby

For the Sears family, some beautiful surprises followed Tilman’s healthy birth. First, they got to move back to Texas and they now live in Lubbock, where Kirk can cheer for Texas Tech up close. Second, Kheli unexpectedly became pregnant before Tilman turned a year old. Now Kheli and Kirk are the happy parents of three boys: George, 6, Tilman, 2, and Cody, who is nearly five-months-old.

George is in his first year of kindergarten. He loves school and being a big brother.

“He has a huge heart. He’s sensitive and funny. He’s getting into sports and likes baseball and soccer,” Kheli said.

George also loves his family. Kheli lost her father a year ago. Darryl Greenamyer was a legendary test pilot and much beloved in the aviation world. George is very curious about his grandfather and has a keen interest in airplanes.

Tilman loves balls.
Tilman loves balls. He’s already throwing a spiral with a football and hitting a ball off a tee. Photo by Elizabeth Peterson.

Tilman, on the other hand, is obsessed with balls.

“He’s going to be our athlete. He’s hitting a ball off of a tee and he can throw a spiral already,” Kheli said.

Like most other 2-year-olds, Tilman is very independent.

“He’s ‘Mr. do-it-myself,’” she said.

He calls his big brother, Bubba, and his little brother Coco Baby.

As for Cody, he’s Mr. Easy.

The Sears family benefited from fertility treatments.
Kheli and Kirk Sears feel blessed with their family of three boys. Photo by Elizabeth Peterson.

Kheli marvels at what a gift her surprise baby has been.

“He’s such an angel baby. He’s only 19 months younger than Tilman. He came out easy as can be. He sleeps. He eats. He plays with his brothers. He’s just a happy boy,” she said.

Each child arrived in the world in his own way.

Kheli and Kirk still have two frozen embryos stored – and safely monitored – in the Colorado lab. They haven’t decided yet what to do with the embryos, but are grateful for the help they received.

“What Dr. Polotsky and his colleagues do is really amazing. Most people don’t understand what women go through when they can’t conceive,” Kheli said.

She marvels at her family’s good fortune after struggling to have a second child.

“I feel so blessed. Each child is truly a miracle.”

About the author

Katie Kerwin McCrimmon is a proud Coloradan. She attended Colorado College thanks to a merit scholarship from the Boettcher Foundation and worked as a park ranger in Rocky Mountain National Park during summers in college.

Katie is a dedicated storyteller who loves getting to know UCHealth patients and providers and sharing their inspiring stories.

Katie spent years working as an award-winning journalist at the Rocky Mountain News and at an online health policy news site before joining UCHealth in 2017.

Katie and her husband, Cyrus — a Pulitzer Prize-winning photographer — have three adult children and love spending time in the Colorado mountains and traveling around the world.