When Gaston Langezaal enters the Mt. Washington Pediatric Hospital parking lot each morning, his wet, black nose begins to twitch with excitement.

But from the moment Gaston’s human, Jennifer Langezaal, buckles a blue working-dog vest around his chest, the 7-year-old retriever mix is singularly focused on his duties: bringing comfort, healing and joy to sick and seriously injured children.

“Having a dog around just makes the whole day better,” said Dr. Julia Rosenstock, a Mt. Washington Pediatric attending pediatrician. “There are so many things that a kid won’t do for us that they’ll do for a dog.”

Like all of Mt. Washington Pediatric’s therapy dogs, Gaston graduated from the Canine Companions service dog training program in New York. The program teaches dogs to ignore the urge to run after a squirrel or bark at the mailman and instead channel their energy into opening doors, turning on lights and navigating tricky situations with a person with special needs.

The program, which trains dogs at six sites around the country, enrolls 18-month-old retrievers who h`ave been nurtured by specially trained college students, prison inmates or puppy raisers, said Jessica Reiss, Canine Companions program director for the northeast region.

The dogs receive six to nine months of additional training, learning 40 verbal commands and the ability to pick up objects as small as a credit card or as heavy as a frying pan, said Reiss. Most of the graduates become service dogs, dedicated to one person with medical needs, but some of the most gregarious dogs become facility dogs, like those at Mt. Washington Pediatric.

Gaston’s canine colleagues include two golden retriever mixes: 3-year-old Bata, a recent facility dog training school grad, and Babs, who at 10 is the elder statesdog of the group.

With his graying muzzle and calm demeanor, Gaston’s responsibilities include aiding some of the hospital’s most vulnerable patients.

Gaston lay perfectly still on a recent afternoon as Langenzaal, a child life therapist, placed 9-week-old Cameron Beres across his silky flank.

Cameron, who was born two months early, spent several weeks at the Greater Baltimore Medical Center’s NICU. He was transferred to Mt. Washington to be weaned off of oxygen and a feeding tube before joining his parents and older brother at home.

Dressed in dinosaur print pajamas, Cameron snoozed peacefully on Gaston’s side, his chest expanding to the rhythm of the dog’s breathing. Langezaal hovered close by, poised to catch Cameron if the baby started moving.

Gaston’s eyes were partially closed, but it would be a mistake to assume that the dog was drowsing.

“It is a lot of effort for a dog to keep himself that still,” said Langezaal, explaining that Gaston had spent many months learning to suppress his instincts to scratch an itch or lift his head when someone walks in the room. “I know he’s working very hard.”

Resting on a therapy dog helps newborns learn to regulate their breathing and heart rates, said Dr. Rosenstock. The experience helps shape the baby’s rapidly growing brain and can help prepare them to adjust to family pets when they are released from the hospital.

Cameron’s grandparents, Michael and Paula Beres, said they often find the baby resting on a dog when they arrive to hold and feed him each day.

Canine Companions, a nonprofit funded through donations, provides dogs free of charge to hospitals, rehab centers and other facilities. The organization retains ownership of the dogs to ensure they are treated properly, although each dog lives with a dedicated handler who works at the facility to which they are assigned, Reiss said.

It took two years and many site visits before Mt. Washington was approved for its first facility dog, Yuba, in 2012. “There was a lot for us to learn,” said Lindie Ashman, Mt. Washington’s child life manager and the hospital’s liaison with the Canine Companions program.

Yuba retired in 2019, but his presence is still felt at Mt. Washington. A memory box containing his photo, ID tag and a plaster cast of his paw hangs on a hospital wall.

Canine Companions usually gives the dog to its handler at retirement, so the dogs can spend their golden years enjoying a well-deserved rest.

Many former patients feel a deep nostalgia for the therapy dogs they bonded with at Mt. Washington, said Dr. Rosenstock. “The first thing they ask when they come back is, ‘Where are the dogs?’” she said.

Seven-year-old Bert Edelman has been working with Babs and Gaston for more than half his life.

Bert, who has Down syndrome, has undergone heart surgery and three hip surgeries, said his mother, Megan Edelman. He receives physical therapy at Mt. Washington and graduated from an intensive program for children with feeding challenges.

“He’s been in therapy since he was born in one way or another,” said Megan Edelman. “It can really feel like work, and it’s hard to have to watch your kid working all the time. The dogs make it feel like fun and not work.”

After leaving little Cameron in the nursery, Gaston and Langezaal headed to a physical therapy room to meet with Bert, who was doing exercises to improve his balance, coordination and stamina.

“Gaston!” said Bert, clasping the dog’s face in an exuberant hug. As the adults cautioned Bert to pet Gaston gently, the dog licked the boy’s cheek.

“Should we take Gaston for a walk?” physical therapist Kathryn Jendras asked Bert, who bounced up and down with excitement.

Bert raced into the hall clutching Gaston’s leash. His sneakers pounded the hallway as Gaston’s nails clicked along beside him.

“Don’t go too fast! He can’t keep up with you,” said Jendras, as Bert giggled and tried to run faster.

Back in the physical therapy room, Jendras assigned Bert a challenge: Navigate a short obstacle course, then pick an item from a toy doctor’s bag to perform a play exam on Gaston.

Bert flew through the tasks — climbing a step, balancing on round discs, and teetering along a balance beam — then lifted Gaston’s velvety black ears to peer inside with a plastic otoscope.

“Working with the dogs has been a big confidence booster for him,” said Edelman. “He loves it when they give him kisses.”

While Gaston’s work is more patient and tedious, his younger colleague, Bata, is assigned more high-energy jobs.

On this same day, Bata spent the morning playing fetch with the children in the eating program that Bert had attended. Several of the children had significant mobility challenges and struggled to throw the ball, but Bata chased each throw with equal excitement, ears flapping as he flew down the hall.

Later Bata joined a group of older kids, including two teens with traumatic brain injuries, for adaptive curling, as they used a metal stick to push discs down the same hallway. Bata gripped a thick rope in his teeth to pull the discs on a wooden cart as the kids cheered.

Between assignments, Bata and Gaston hang out in adjoining crates in their handlers’ offices, gnawing on chew toys or napping. The walls around their crates are covered with photos of them with patients and drawings and cards that children made for them.

Staff members assess each patient to see which are amenable to working with a dog. If children are in isolation due to an infection or immunodeficiency, staff members encourage them to write cards to the dogs or arrange a no-contact game of fetch.

While the dogs use their well-honed skills to play complicated games with the children as part of occupational, physical or speech therapy, a big part of their duties is simply providing emotional support. When children undergo a delicate and uncomfortable procedure, they often elect to recline their head on a dog’s back. The dogs press their faces against those of the children, breathing quietly.

On this chilly December afternoon, Gaston ended his work day by comforting 9-year-old twins, Kamille and Kent Pabich, who were getting blood drawn. When Kamille tucked her face into her mother’s shoulder as the needle entered her vein, Gaston turned his big brown eyes to Langezaal, as if mirroring the girl’s actions.

Gaston often seems emotionally exhausted after a challenging procedure, Langezaal said.

At the end of the work day, she takes off Gaston’s vest and drives him back to their home in Sparks.

Then it’s time for a walk in the woods, a bowl of kibble and a long snooze on the couch before the next work day begins.

“I try to give him some time to be a dog,” said Langezaal.