Tool helps predict respiratory failure
A new prediction tool can help doctors better identify patients who are at highest risk for respiratory failure after surgery and therefore prevent the often deadly condition, suggest data from a large multi-center study published in the May issue of Anesthesiology.
Affecting nearly 200,000 Americans a year, acute respiratory distress syndrome (ARDS) is a sudden failure of the lungs caused by several issues ranging from smoke inhalation to pneumonia or blood infection. High-risk patients can develop ARDS after surgery. ARDS is difficult to treat once it develops and is fatal at least 20% of the time.
"It’s well-documented that those who develop this syndrome stay in intensive care longer and in the hospital longer, and the impact of the syndrome can persist for many years," said Daryl J. Kor, MD, lead author of the study and associate professor of anesthesiology at Mayo Clinic, Rochester, MN.
Doctors might be able to take measures during surgery to prevent the condition, such as using blood products conservatively, restricting the volume of fluids administered, and using different methods to ventilate the lungs. However, only about 3% of patients considered at risk actually develop ARDS, and testing preventative measures is costly, time-consuming, and might be less than ideal for patients not at high risk. Therefore, researchers in this study focused on identifying patients most likely to develop ARDS after surgery.
"It’s certainly true in this case that an ounce of prevention is worth a pound of cure," Kor said. "But our ability to predict who is at risk has been limited. By identifying those who are at highest risk with better accuracy, we can begin to take steps toward preventing this dangerous and costly surgical complication."
The prediction tool could help doctors assign risk levels to patients by determining if they have one or more of the following predictors identified as most associated with the development of ARDS:
• blood infection (sepsis);
• liver disease;
• high-risk surgery on the heart or aorta;
• emergency surgery;
• admission from a location other than home (such as a nursing home or other hospital);
• an increased respiratory rate;
• two measures that show the patient has lower-than-normal oxygen levels in the blood.
The more factors that apply to the patient, the greater the risk of developing ARDS and the more important it is to use preventive measures, Kor said.
In the study, researchers performed a secondary analysis of data from a trial at 22 medical centers, identifying 1,562 patients who prior to surgery were considered at risk for ARDS. Of those, 117 (7.5%) developed ARDS. Based on their findings, researchers revised an existing prediction tool (used for ARDS prediction in a patients undergoing elective surgery) so it was far more effective at identifying patients who were at greatest risk for ARDS after a wide variety of surgical procedures.
The findings might alter the way patients at high risk of the syndrome are cared for in the operating room, Kor says. "For example, we may be a bit more conservative in the way we transfuse blood products," he says. "We may also ventilate their lungs in a little different way than we might if their risk score was low."
