Tohma Morrison

Legendary Pulmonary Medicine

Tohma Morrison
Legendary Pulmonary Medicine


Pulmonology at Texas Children's Hospital is ranked highest in the nation for its treatment of lung and respiratory disorders.

Dr. Gunyon M. Harrison joined Texas Children's Hospital in 1954 as a pediatric resident, admitting the hospital's first patient. With a specific interest in cystic fibrosis and lung disease in general, he founded our first CF clinic in 1956. By the late 1960's he had established himself as one of the first pediatric pulmonologists in the U.S.

Today, we have eight specialized programs to treat the full range of respiratory conditions, and we see more than 13,500 patients annually. We are also home to one of the largest pediatric lung transplant programs in the country, accounting for 30% of all pediatric lung transplants in the nation. 


It was the 1940s outbreak of a mystery disease – identified as poliomyelitis, or as its more commonly known, polio – that set Dr. Gunyon M. Harrison on a path to a 46-year distinguished career in pulmonology at Texas Children’s Hospital. 

Pioneering pulmonologist Dr. Gunyon M. Harrison works with a patient in the Junior League Clinic at Texas Children’s Hospital. 

Pioneering pulmonologist Dr. Gunyon M. Harrison works with a patient in the Junior League Clinic at Texas Children’s Hospital. 

As a young medical student, Dr. Harrison found himself replying to a flyer posted on a bulletin board at Duke University School of Medicine to learn more about acute poliomyelitis. Dr. Harrison’s response to that flyer eventually landed him at Texas Children’s Hospital where he pursued his interest in not only polio, but in diseases of the lung. His particular interest and knowledge in Cystic Fibrosis (CF) expanded in the first few years of his career, and in 1956, Dr. Harrison was diagnosing and treating 12 CF patients ranging in age from two to ten years old in the newly opened Junior League Diagnostic Clinic of the outpatient department at Texas Children’s Hospital. 

It was in 1960, thanks to a grant by the national Cystic Fibrosis Foundation, that Dr. Harrison was selected as the medical director of the region’s first Cystic Fibrosis Center to be located in Texas Children’s Hospital. This designation marked the opening of the chest section at Texas Children’s Hospital, which was operated by just one physician for almost 17 years – Dr. Harrison. 
In those early years, many first and greats were achieved: 

Created one of the largest fellowship training programs for pediatric pulmonary medicine in the U.S.

Dr. Harrison championed the creation of the Children’s Summer Respiratory Camp Foundation to manage the first CF camp in the nation

Dr. Dan K. Seilheimer became the first full-time staff member in the chest service in addition to only Dr. Harrison

Directly attributed to Dr. Harrison and his efforts at Texas Children’s Hospital, the average survival age for a CF patient increased from an average of 5 years to 18 years. 

The Cystic Fibrosis Foundation grant established the Cystic Fibrosis Research Center at Texas Children’s Hospital

In a move to centralize many of the CF treatment services in the Houston area, the “chest section” officially became Pulmonary Medicine at Texas Children’s Hospital. 

After a groundbreaking discovery where Dr. Arthur L. Beaudet was one of the scientists who pinpointed the location of the CG gene to chromosome seven, researches at Baylor College of Medicine and Texas Children’s Hospital, worked to innovate approaches to the diagnosis, management, and treatment of CF. One of those approaches resulted in the use of amniocentesis to test the cells of an unborn child for CF. With this, Texas Children’s Hospital was the first treatment center in the U.S. capable of performing prenatal diagnosis of CF. 

The late 1980s to early 1990s, brought about significant advances in introducing more than 20 new antibiotics to fight chronic infections. Another part of treating CF is managing care at home. In 1988, Dr. Seilheimer created a 4-part, comprehensive “Family Education Project.” The project and information was so well received and enthusiastically welcomed by CF patients and their families, the program was given an Excellence Award by the Society for Public Health Education in 1994. 

Another notable achievement includes the creation of the Asthma Center in 1993.

In 2000, Dr. Harrison retired after more than 40 years of caring for patients.

As the resident on duty on February 2, 1954, Dr. Harrison admitted Texas Children’s Hospital’s first patient, three-year-old Lamaina Leigh Van Wagner. 


Children from across the nation come to us for treatment in pulmonary hypertension, cystic fibrosis, asthma and other complex pulmonary conditions. 

Children from across the nation come to us for treatment in pulmonary hypertension, cystic fibrosis, asthma and other complex pulmonary conditions. 

Building on the incredible legacy of Dr. Harrison, the Texas Children’s Pulmonary Medicine team strives to provide every service available for patients with respiratory disorders. We treat children with a variety of complex and chronic pulmonary issues in our programs:

  • Aerodigestive Program
  • Asthma Center  
  • Muscular Dystrophy Association Clinic
  • Cystic Fibrosis Center
  • Interstitial Lung Disease Clinic
  • Lung Transplant Program
  • Pulmonary Hypertension Program
  • Sickle Cell Program

Today our team includes:

  • 23 pediatric pulmonary faculty
  • 7 clinical locations in the Houston area
  • 3 transplant respiratory physicians   
  • 9 fellows each year
  • 5 research coordinators


One year after Dr. Harrison retired, the pediatric lung transplant program began in 2001. Led by Dr. George Mallory, Texas Children's has one of the largest and most successful pediatric lung transplant programs. Since 2002, over 150 patient have received new lungs, and in 2013 the team transplanted more children in need of new lungs than any other center in the world. Also, with a median wait time of less than four months, it offers a shorter wait time than most other pediatric programs. Learn more about our transplant program. 

Pulmonology at Texas Children’s Hospital