California Pacific Currents 2004
Early Warnings of Mortality in ICU Patients: The Work of Thomas J. Nuckton
Thomas J. Nuckton, MD, MS, a specialist in pulmonary and critical care medicine who joined the California Pacific Medical Center Research Institute in 2004, has a wide range of research interests—from clinical outcomes in critical care to sleep medicine to near drowning and hypothermia. Dr. Nuckton is currently pursuing several research questions, including: Are there accurate indices that physicians can use to measure how their patients with acute respiratory distress syndrome (ARDS) will fare? What can inform physicians caring for the critically ill in intensive care units about the prognoses of such a diverse group of patients? Dr. Nuckton describes his research among ICU patients succinctly: “What I do is study predictors of mortality early in disease processes in the ICU.”
Searching for Predictors
Earlier in his career, as a fellow at the Cardio-vascular Research Institute at the University of California, San Francisco, Dr. Nuckton and his colleagues began a search for a warning system to predict outcomes for patients with ARDS, a severe injury or inflammation in the lungs that causes fluid to build up in the air sacs, blocking transfer of oxygen to blood.
Dr. Nuckton knew that despite years of research no single, pulmonary-specific measure had been found to predict the risk of death for patients with ARDS. Even the level of oxygen in the blood—often used as a predictor for people on ventilators—did not seem to apply to all ARDS patients. So Dr. Nuckton and his colleagues decided to look at another measure: the dead-space fraction.
Higher Fraction, Lower Survival Rates
Dead-space fraction, Dr. Nuckton explains, measures how much of the lung is not exchanging gas efficiently. The study team measured dead-space fraction in 179 patients within 12 hours of their development of ARDS. They found that as dead space increased, the likelihood that a patient would survive decreased significantly.
Dead-space fraction, says Dr. Nuckton, “turned out to be an exceptional predictor of mortality.” The study was published in the New England Journal of Medicine. Dr. Nuckton plans to continue this kind of research in the intensive care unit at the California Pacific Medical Center, which he calls “one of the best ICUs in northern California.”
Toward Better Outcomes
“I want to identify the most important indicators for predicting outcomes early after admission to the ICU,” Dr. Nuckton says. That kind of information is crucial, according to Warren Browner, MD, MPH, Scientific Director of the Research Institute and Vice President Academic Affairs. “What’s especially important,” he says, “is the ability to stratify patients in the intensive care unit according to their chances of developing severe complications. That way we can compare care in different ICUs, and we can also figure out whether a new treatment is effective.”
Dr. Nuckton’s creativity in searching for ways to identify risk to patients is one of the traits that attracted Dr. Browner to his work. Serving as one of Dr. Nuckton’s mentors, Dr. Browner will assist him in designing clinical research projects that may one day improve outcomes for critically ill patients.
Adding Remote Monitoring
Several studies have suggested that patient outcomes improve when ICUs provide round-
the-clock care by critical care specialists (intensivists)—a level of care available at California Pacific Medical Center’s ICU but not yet offered in many other medical settings. A potential solution may be a remote, high-tech surveillance program called the electronic Intensive Care Unit, or eICU®, system. Sutter Health has established this system in its Sacramento data center, from which doctors and nurses now monitor ICU beds in five northern California hospitals. Another eICU® system will soon open at California Pacific with the aim of discovering if the system can enhance the already high level of care. A third is being planned for an East Bay location.
Under the system, intensivists and specially-trained nurses use voice, video, and data systems to monitor the condition of ICU patients at various locations, some down the street, some as many as 100 miles away. From their stations in the monitoring center, the team can help ensure that patients’ treatment plans are followed. And they can intervene during emergencies when a patient’s attending physician is unavailable.
Now, the question is: How well is remote surveillance working? “We don't know yet,” remarks Dr. Nuckton. “It’s one of the things we will be researching.” Along with colleagues at Sutter Health, Dr. Nuckton will be part of a research project to explore how the system works—for patients, doctors, and staff. It is a subject that fits with his interest in studying outcomes in the ICU.
Dr. Nuckton does have research interests outside the ICU, and one of his projects has taken him to the San Francisco bay—literally. Dr. Nuckton was involved in designing and implementing the “Alcatraz/San Francisco Swim Study” in which he and his colleagues studied a group of enthusiasts who swim regularly in the Bay. The objective was to learn about hypothermia and its effects upon swimmers who spent up to 45 minutes in cold water. With year-around average water temperatures between 50 and 60 degrees Fahrenheit, the San Francisco Bay provided an ideal environment for this project.
Findings from the study suggest that swimmers may experience hypothermia while they are in the water, but they may also be at risk for “afterdrop,” a condition in which body temperature continues to decrease even after leaving cold water. Dr. Nuckton’s results provide insight for rescue personnel and hospital emergency departments. Mathematical models used in the study have been applied to a shipwreck survivor who was rescued by the United States Coast Guard.
Answering Clinically Relevant Questions
With a diverse research background that includes both clinical outcomes and basic physiology research, Dr. Nuckton strives to answer clinically relevant questions. He sees California Pacific as an ideal place for this type of research. “The environment here,” he says, “is dynamic and supportive. It’s a pleasure to work with others who have a spirit of discovery while maintaining a commitment to outstanding clinical care.”
eICU® is a registered trademark of VISICU, Inc. www.visicu.com.