Despite an incidence of nearly 200,000 per year in the United States and a mortality rate in excess of 35%, acute lung injury is not a well-known condition. A variety of disorders or injuries, including sepsis, pneumonia, and severe trauma, can result in acute lung injury or its more serious form, the acute respiratory distress syndrome (ARDS). Regardless of cause, a characteristic feature of acute lung injury and ARDS is pulmonary edema, in which liquid leaks from the blood vessels into the airspace of the lungs. Pulmonary edema makes breathing difficult and can lead to dangerously low levels of oxygen in the blood. In the most common treatment, a mechanical ventilator is connected to the patient’s airway and helps expand the lungs to assist breathing. Unfortunately, in the process of helping patients breathe, mechanical ventilation often aggravates the underlying lung condition and causes an additional over-distension injury of the lungs.
Dr. Carrie E. Perlman, Assistant Professor of Biomedical Engineering at Stevens Institute of Technology, is an expert in lung mechanics. Funded by the National Institutes of Health, Dr. Perlman is applying her skills and considerable knowledge toward development of a new approach to the treatment of acute lung injury, one that will lessen over-distension and improve recovery.
“Improving clinical healthcare continues to be one of the most urgent and complex challenges faced by society. In response to this prevalent need, Stevens has moved to the forefront of efforts to advance medical technology,” says Dr. Michael Bruno, Dean of the Charles V. Schaefer, Jr. School of Engineering and Science. “Dr. Perlman’s scientific contributions will establish a foundation for future healthcare innovation.”
How mechanical ventilation exacerbates acute lung injury and ARDS is not fully understood. However, ventilation is thought to over-distend a structure called the alveolus. The alveolus is the smallest air-space in the lungs and the site of oxygen entry into the bloodstream. The alveolar walls are thin membranes that contain elastic tissue and are coated by a liquid layer with surface tension at its interface. When air enters the lungs, it must work against both tissue elasticity and surface tension to expand the alveoli.
“Our goal is to protect the alveoli from over-distension. In one approach, we are designing a custom ventilation pressure waveform to minimize alveolar stretch,” says Dr. Perlman. “Our second approach involves manipulating alveolar surface tension. As surface tension is a major determinant of the pressure required to inflate the lungs, altering it may be key in protecting the alveolus.”
Working with Dr. Perlman to tackle this problem are Ph.D. candidates Angana Banerjee Kharge and You Wu. Dr. Perlman introduced them to the study of pulmonary mechanics and both were attracted by the clinical applications of the research.
“My previous research experience focused on medical electronics,” says Ms. Wu. “Working with Dr. Perlman, I am gaining expertise in a new area, biomechanics, yet still using my electrical engineering background in designing custom instrumentation for my experiments.” Ms. Wu, who is developing safer ventilation strategies for patients with pulmonary edema, recently presented a talk on her work at the prestigious American Thoracic Society International Conference in Philadelphia.Ms. Kharge, in her doctoral research, is using a new technique to make the first measurements of surface tension in edematous alveoli. “As I am interested in medical device design, I particularly appreciate the clinical relevance of my research with Dr. Perlman,” says Ms. Kharge. Ms. Kharge, too, presented her findings at the American Thoracic Society meeting, where she found clinicians to be surprised and intrigued by her results.
As the most recent addition to the laboratory, Jeff Bellanich began his thesis for a Master’s degree in biomedical engineering at the same time as he was completing his final undergraduate semester. Under the guidance of Dr. Perlman, Mr. Bellanich is performing computational modeling that will be used to guide experimental studies. “I joined Dr. Perlman’s lab after taking one of her courses,” says Mr. Bellanich. “I like the way she works and teaches, and so chose her as my thesis advisor.”
Dr. Perlman has conducted in-depth studies of the mechanics of alveolar expansion, in the healthy lung and with edema. She earned her bachelor’s degree in mechanical engineering from MIT and a Ph.D. in biomedical engineering from Northwestern University. She has worked as a medical device design engineer for an industrial design firm. Prior to joining Stevens, Dr. Perlman was a postdoctoral fellow in physiology at Columbia University.
To learn about additional healthcare-related activities at Stevens, please contact Dr. Peter Tolias.
To learn more about the Department of Chemistry, Chemical Biology, and Biomedical Engineering or the Program in Biomedical Engineering at Stevens, please contact Dr. Philip Leopold or Dr. Arthur Ritter or contact Undergraduate Admissions or Graduate Admissions via www.stevens.edu.