Ventilator Management DRIVES RESPIRATORY RESEARCH
By Francie Scott
At the heart of every research project is a question for which a curious clinician wants to find an answer.
What causes post-obstructive pulmonary edema? What are the dead space-to-tidal volume ratios in ARDS patients? Is there a correlation between physiologic dead space and surviving ARDS?
“Every time you finish a project, you have 20 new thoughts for other research projects. You never finish,” explained James Alonso, RRT, a clinical research associate at the Cardiovascular Institute in San Francisco and a staff therapist at San Francisco General Hospital.
Alexander Adams, MPH, RRT, a senior research associate at Regions Hospital in St. Paul, Minn., echoed Alonso’s sentiments.
“This is just a great job,” he said. “It’s always exciting. There are different questions and different problems” on every project.
For Adams, the scope for research projects is infinite. Just for starters, he noted, “We don’t treat ARDS well enough. We don’t know how to wean well enough.” He also said monitoring techniques need to be improved.
A few lucky RTs make a living doing research, but most volunteer their time and plod away at different projects. Many eventually complete an abstract and present it at a medical conference.
Respiratory research frequently focuses on the ventilator. RTs and their physician colleagues may test new ventilator modes and evaluate the merits of different management strategies. An outstanding example this year is the low tidal volume study developed by the ARDS Network and the National Heart, Lung and Blood Institute.
Alonso and his colleagues, including Michael Matthay, MD, Richard Kallet, MS, RRT, and Brian M. Daniel, RRT, participated in the multi-center ARDSnet study, which showed that ARDS patients managed on low tidal volumes experienced lower morbidity and mortality. They would enroll patients who met criteria and call the ARDS Network to find out to which group the new patient was randomized. One group got tidal volumes of 6 mls per kilo and the other group got tidal volumes of 12 mls per kilo.
Overall, participation in the ARDSNet study, which involved 850 patients at 24 university hospitals, taught the San Francisco crew the value of multi-center studies that provide a panorama rather than a snapshot. If clinicians follow the ARDSnet protocols nationwide, they could save approximately 15,000 lives per year simply by manipulating knobs on ventilators.
“It’s very exciting just to contribute something,” Kallet said of the experience. He serves as clinical research coordinator at San Francisco General and the Cardiovascular Institute.
Daniel considers the ARDSnet study among the highlights of his career in research. “We always had some suspicion that we could be potentially causing harm using high tidal volumes in patients,” he said.
The San Francisco group is preparing to join a new multi-center ARDSnet project in evaluating a lung protection strategy that calls for setting PEEP levels at or above the lower inflection point on the pressure volume curve. A Brazilian physician, Marcelo Britto Passos Amada, introduced the strategy in an article published in the New England Journal of Medicine (1998; 338:347-354). ARDSnet investigators hope to replicate this study.
Clinicians at San Francisco General developed a simple method for determining the lower inflection point using a pulmonary mechanics monitor. Amada and other clinicians have relied on a cumbersome method using a “super syringe,” explained Mark Siobal, BS, RRT, technical director of respiratory care at San Francisco General.
Adams and his mentor, prominent pulmonary physician John J. Marini, MD, also center much of their research on the ventilator. In Adams’ words, “the goal is to open the lung and keep it open.” The St. Paul group recently conducted a series of pig studies exploring the merits of high frequency ventilation for treatment of ARDS. Adams noted the strategy was compatible with the ARDSnet protocol since high frequency ventilators deliver gentle breaths.
Strategies to protect the lung from ventilator-induced injuries also interest Adams and Marini, and they are considering a series of studies that would help clinicians identify patients who are vulnerable to ventilator-induced injury. Another project under way in the Regions Hospital lab is evaluating the merits of prone positioning in the ICU. Like many standards of practice, prone positioning is a common strategy but is not validated by randomized controlled clinical trials.
ON CENTER STAGE
Kallet and his colleagues at San Francisco General will have the distinction of presenting 11 papers at the International Symposium sponsored by AARC in Las Vegas in December. He contributed to 10 of the papers. Last year Kallet won the Best Original Paper Award given by the American Respiratory Care Foundation for his report on “Acute Pulmonary Edema following Upper Airway Obstruction.” Kallet and his colleagues learned that post-obstructive pulmonary edema is caused by a hydrostatic mechanism.
The San Francisco clinicians reached their conclusions when they drew fluid samples from patients suffering from post-obstructive pulmonary edema and compared protein concentrations between plasma and edema fluid.
In other projects, the San Francisco team explored the merits of late steroid rescue therapy in ARDS patients (an ARDSnet assignment), compared the work of breathing on pressure control and volume control ventilator modes and reported on using intra-esophageal pressures to calculate cardiac filling pressures in a case series of 11 ARDS patients. Team members also evaluated a bicarbonate drug substitute that doesn’t produce carbon dioxide, and they expect to submit that study to a peer-reviewed journal.
Alonso’s pet project is a study examining physiologic dead space in early ARDS. He has enrolled 140 patients during the past three years. “Hopefully, it will show something,” he said.
RTs cite different reasons for seeking careers in research. Daniel enjoys “being on the steep learning curve when it comes to looking at disease process.” His work often takes him into the world of molecular biology, “not something I studied at school,” he said.
For Alonso, the most satisfying aspect of research is “learning things that you weren’t sure were theory or reality.” Alonso contributed material to nine of the 11 papers to be presented at the AARC meeting in Las Vegas.
Most RTs enter research as volunteers. They collect data for a clinical trial led by a physician with a grant from the National Institutes of Health or pursue one of their own ideas.
“If you want to do research, pave your own path,” Alonso advised.
Adams encouraged budding research-ers to “stay observant” and to return to school for subjects like statistics.
Daniel recommended research as a field because it “rounds off the person by giving them an opportunity to get down to the real nuts and bolts of disease management.”
Many researchers find a good mentor an essential ingredient in the success of their careers. Kallet, for example, praised the doctors he worked with in the early years of his career, some of whom continue to guide him. There were times when he “felt like Forrest Gump,” in the shadow of their knowledge and experience, he conceded.
“These people really shaped me,” Kallet explained. “How I think and the discipline I have to do research. It’s like a crucible.”
For all the excitement and drama associated with learning new clinical truths, much of an investigator’s life is devoted to a daily grind of repeating experiments and following false leads.
“If you knew how much trouble and effort it would take in the beginning, you would probably never start (some projects),” Kallet confessed. But “the passion you have at the beginning carries you through hard times. I don’t let go of stuff. I’m like a pit bull at times.”
Most full-time researchers find their job is a way of life. They follow each project, often working long hours. Kallet, for example, estimates he works between 45 and 50 hours per week. Although he has flex time, he may well have to enroll a patient in a study about the time he intended to leave on a short day. He could get home at 1 a.m., carrying his beeper and answering pages throughout the night. Alonso also finds the “erratic” hours difficult at times.
Researchers take their work home at night, at least in their heads. Details and questions swirl through their minds. “Always thinking about (projects) is what makes it a career, not just a job,” Adams said.
Francie Scott is an ADVANCE senior editor.