Index Points to Risk of Post-Op Pneumonia
Warning could reduce danger of potentially deadly complication
MONDAY, Nov. 19, 2001 (HealthDayNews) -- A new index that pays more attention to a patient's overall medical history instead of focusing on his heart health could warn doctors who is most at risk of developing pneumonia after major surgery.
Past studies have led doctors to believe that patients were most at risk if they had cardiovascular problems, but a new study has found that other illnesses or drugs can raise a red flag about pneumonia.
Armed with that information, says the study, physicians could decide whether the risk of this complication -- which, depending on the operation, occurs in 9 percent to 40 percent of patients -- merits special precautions after the procedure or canceling the surgery altogether.
An early warning system for postoperative pneumonia could be crucial, since the mortality rate lies between 30 percent and 40 percent, depending on the type of surgical procedure.
The findings, which appear in the Nov. 20 issue of the Annals of Internal Medicine, use data from the National Veterans Affairs Surgical Quality Improvement Program.
Researchers from Illinois and Massachusetts gathered data from the medical records of 316,071 patients who had major noncardiac surgery at 100 different VA medical facilities between September 1995 and August 1999. Most of the patients were men between 50 and 80 years old.
The study looked at several potential risk factors, including age, alcohol intake, recent chemotherapy, neurologic status, type of surgery, and whether the patient was a smoker. Each risk factor was assigned a point value, for example, 17 points for an age of 80 or over and 3 points for having smoked within the last year.
Out of the patients studied, 1.5 percent developed pneumonia following their surgery. Of those, 21 percent died with 30 days of their surgery.
The goal of the index "is to try to pick out those patients who are at high risk of developing pneumonia and then take measures to prevent that," says William Henderson, a study co-author and senior biostatistician with the National Veterans Affairs Surgical Quality Improvement Program.
The researchers found that patients at greatest risk for postoperative pneumonia were older than 60, had recently used a steroid drug such as prednisone, had chronic lung disease, or had a history of major stroke.
Certain types of surgeries, including emergency surgery or procedures involving the brain, neck, chest, upper abdomen or arteries in the abdomen and legs, also carried a greater risk. Patients receiving general anesthesia, rather than spinal anesthesia, were also likelier to get postoperative pneumonia.
Other heightened risk factors the researchers found included: recent alcohol or tobacco use; recent weight loss; impaired mental or physical function; or requiring at least four units of transfused blood prior to the surgery.
Only two in 1,000 patients with a point value of 0-15 point developed pneumonia, compared to 15 percent of patients who had more than 55 points.
Dr. Valerie Lawrence, a professor of general medicine at the VA Medical Center and the University of Texas Health Sciences Center and the author of an accompanying editorial, says that the majority of research into postoperative problems has focused on cardiac complications.
"We have felt like we had much more evidence to guide us in terms of the risks of cardiac problems than we've had to guide us in the risk of pulmonary complications," says Lawrence. "There's been a gap in the literature."
The focus on cardiac risks has meant that relatively little attention has been paid to pulmonary complications, which she says are just as big a problem.
"Once we've identified risk factors and have deemed people to be at high risk, then we need to do the next level of homework and find ways to reduce that risk with interventions before or after surgery," she says.
"If it was an entirely elective procedure it might sway me towards discussing with the patient or the surgeons either not doing the surgery or using a modified surgical approach that would result in a shorter operation," says Lawrence.
If the procedure was not elective, she adds, the index could help physicians better prepare a patient and his family for any possible complications. "It also helps [clinicians] be more prepared and more vigilant in your care."
Henderson says that several private hospitals and health maintenance organizations have shown interest in the findings. Future studies will test a system like this one in 10 university hospitals.
What To Do
For an overview of pneumonia, check out the American Lung Association.