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Can a Dog Be a Doctor's Best Friend?

A case report in which a dog served as a perioperative nursing assistant.

Key points

  • Mastocytosis is a rare disease involving an overreaction of the mast cells, which can lead to anaphylactic shock and even death.
  • A service dog was specially trained to detect when the mast cells were releasing chemicals at harmful levels.
  • During surgery on a 6-year-old girl, this service dog served as a perioperative assistant, calming her and monitoring her vital signs.
 Copyright © Shannon Tew and Brad M. Taicher
Service dog in the surgical suite.
Source: Copyright © Shannon Tew and Brad M. Taicher

A colleague recently sent me a journal report that I had missed because it appeared in a medical journal that I usually do not review. The article was by Shannon Tew and Brad M. Taicher at the Duke University Medical Center, in Durham, North Carolina. It is a case report of a surgery in which a service dog acted in the role of a perioperative assistant during a surgery.

According to the Mayo Clinic College of Medicine and Science, a perioperative assistant is usually a nurse who provides help in various stages of surgery. Their duties include caring for patients and helping them to stay calm until they are under anesthesia. Before, during, and after the surgery, they may also monitor various vital signs in the patient along with performing other tasks.

A Rare Medical Condition

This case report involves a 6-year-old girl who underwent urinary tract surgery. She was suffering from a form of mastocytosis. It is a rare condition that affects around 200,000 people in the United States. The condition involves an excess number of mast cells gathering in the body's tissues.

Mast cells are produced in the bone marrow, the spongy tissue found in the hollow centers of some bones. They are an important part of the immune system and help fight infection. When mast cells detect certain substances, they can trigger an allergic reaction in which they release histamine and other chemicals into the bloodstream. Histamine makes the blood vessels expand, and the surrounding tissue becomes itchy and swollen. It can also create a build-up of mucus in the airways. People with mastocytosis have an increased risk of developing a severe and life-threatening allergic reaction that is known as anaphylaxis or anaphylactic shock.

The reason that anaphylaxis is so dangerous is that it causes major responses involving the whole body. The reaction can be marked by a constriction of the airways and swelling of the throat, leading to difficulty breathing. The histamines released during an allergic reaction may cause the blood vessels to expand enough so that it can cause a dangerous drop in blood pressure. Fluid can leak into the lungs, and it also can cause heart rhythm disturbances.

A Special Kind of Service Dog

People with various forms of mastocytosis find that the mast cell reaction can be triggered by a variety of different things including temperature changes, fever, exercise, fatigue, and especially by stress. In this case, the young girl had had frequent instances when the mast cells went into overdrive, and these, unfortunately, were severe enough that they resulted in several episodes of hospitalization. Therefore, to assist her, she obtained a service dog, JJ, who was trained to alert when she detects the scent of the chemicals associated with increased levels of mast cell activity.

JJ is a terrier mix who was rescued from an animal shelter when she was very young. JJ began 14 months of training to become a service animal and lived with the patient for 18 months leading up to the surgical procedure. She was trained using operant conditioning with positive reinforcement to alert to specific stimuli. While she was initially trained to detect hyperglycemia and hypoglycemia, when it became clear that her skills would be needed to help this little girl with mast cell problems, her training was modified so that she was taught to respond to scent samples from the clothing the girl had been wearing when she had a significant reaction. Once JJ was reliably alerting to positive samples from the clothing, the dog was then exposed to samples provided by two other patients with mastocytosis, and she reliably alerted to these as well.

JJ had two levels of alerting indications. Her response to sensing minor mast cell surges involved circling behavior. Her response to more serious reactions involved barking and tugging at her caretaker's clothing.

From Home to the Hospital

JJ's work as a perioperative assistant in this instance began when her young charge arrived at the hospital and was placed in a preoperative holding area. In this case, JJ was present as an important source of comfort, specifically to minimize stress, since this was a known trigger for her mast cell activities.

Perhaps most unique in this situation is that JJ also accompanied her mistress into the operating room. Here, she was handled by her trainer and her task, as with a human perioperative assistant, was to monitor any changes in the patient's condition. At one point during the surgery JJ displayed circling behavior, indicating a minor reaction, but fortunately not severe enough to trigger any clinical evidence of difficulties or changes in vital signs.

The surgery went well, and the girl was then transported to an isolation room in the postanesthesia care unit, along with the service dog whose job then shifted back to being a therapy dog and helping to keep her calm. Approximately 30 minutes into her stay there, JJ again showed circling behavior, alerting to a minor reaction; however, a physical exam showed that no additional intervention was necessary. Since JJ was trained using scent samples from the patient, the best guess is that her alerts were responses to molecules released by the girl's mast cells as their activity level increased at these times.

The clinicians summarize JJ's activity this way: "This service dog was used not only in a family-centered care model, but also as an additional perioperative monitor. During the cystourethroscopy, JJ’s alerts only suggested less serious reactions, but these instances coincided with times in which a patient was most likely to be subject to increased stress, namely, anesthetic induction and emergence."

This case history involved a young child suffering from a rare disease who was lucky enough to have a service dog to monitor her well-being at home and to accompany her to the hospital and serve in the role of a perioperative nursing assistant when she was faced with the frightening circumstances associated with surgery. Her jobs were twofold—monitor the physical state of her young charge and attend to her psychological needs by comforting her as well. The dog's work would continue once her little mistress returned home.

Copyright SC Psychological Enterprises Ltd. May not be reprinted or reposted without permission.


Shannon Tew and Brad M. Taicher (2016). A Dog Is a Doctor’s Best Friend: The Use of a Service Dog as a Perioperative Assistant. Case Reports in Pediatrics, Volume 2016, Article ID 9013520,

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