 
Grant from Nursing Professor Judged to Be in Top 1 Percent of Submissions |
Almost a million people in the United States receive tube feedings annually. For those who need mechanical ventilators to breath adequately, small amounts of fluid from an overly full stomach may be pushed up into the throat and inhaled into the lungs. If this happens often, the patient can develop pneumonia.
As many as 20 percent to 25 percent of tube-fed patients have been reported to develop pneumonia, with an associated mortality rate that exceeds 50 percent. At present, there is no agreement about the best way to determine when these repeated inhalations of gastric contents into the lungs are occurring.
Dr. Norma A. Metheny, professor of nursing, has received a three-year, $1,040,515 grant from the National Institutes of Health/National Institute of Nursing Research (NIH/NINR) to study the problem. Dr. Thomas E. Dahms, professor of anesthesiology, is a co-investigator. Metheny's grant was in the top one percent of all grant applications submitted this year to NINR, based on its level of innovation, clinical significance and potential for improving everyday patient care.
"Our project focuses on bedside methods to help detect this event before pneumonia develops," Metheny said. "In this way, we hope to help reduce the morbidity and mortality associated with aspiration of tube feedings."
This is the first study that will test three different methods to detect aspiration of tube feedings. All three methods rely on testing for substances not normally present in fluid suctioned from the lungs. This is possible because suctioning is routinely performed every few hours, as necessary. The two most commonly recommended bedside methods involve testing for dye and glucose in these fluids. The dye method calls for adding blue food coloring to the tube feeding formula to make it easier to see if it is present in the suctioned fluid. The glucose method is based on the premise that fluid suctioned from the lungs normally contains very little glucose, whereas many feeding tube formulas are rich in glucose. So, if unusually high amounts of glucose are found, it is a likely indication that formula has entered the lungs. The third method, an enzyme test, tries to detect an enzyme that is normally in the stomach, but not in the lungs. If the enzyme is found in the fluid suctioned from the lungs, it is evidence that gastric contents are present.
It is difficult to study these methods in humans because of the inability to achieve sufficient control of the variables. However, by using an animal model, use of the three methods can be evaluated fully. Because rabbits' lungs are similar to human lungs, the results may be applicable to humans. The rabbits are fully anesthetized and do not suffer. Metheny plans to involve humans in a future study after testing the methods in an animal model.
"We hope to determine which method, under what conditions, is best," Metheny said. "At the conclusion of our study, we want to be able to say to nurses: 'When you test for aspiration in mechanically ventilated tube-fed patients, this is the best way to do it.' "
  |