Pulmonary complications, including pneumonia and respiratory failure, are a common - and dangerous - problem for patients following major surgery.
To address this issue, a comprehensive systematic review and meta-analysis in the April 18, 2006 issue of The Annals of Internal Medicine provides clinicians with new guidelines to use prior to surgery in assessing a patient's risk of developing pulmonary problems postoperatively.
"Independent of surgical complications, such as infections and bleeding, there are three major types of medical risks that accompany major surgery," explains the study's lead author Gerald W. Smetana, MD, an internist in the division of general medicine and primary care at Beth Israel Deaconess Medical Center (BIDMC) and Associate Professor of Medicine at Harvard Medical School. "These include cardiac risks such as a heart attack, the risk of blood clot formation, and pulmonary risks."
Nearly 30 years ago risk indices and guidelines were developed to assess post-surgical cardiac risks, he adds, but until now, the issue of pulmonary risk factors had not been formally addressed.
"Many physicians will be surprised to learn that we found pulmonary complications to be as prevalent as cardiac complications," says Smetana. The reason, he says, is that patients' lung volumes are lower following both surgery and the administration of general anesthesia. As a result, small areas of lung become vulnerable to collapse, thereby increasing patients' chances of developing pneumonia, suffering respiratory failure or experiencing a worsening of existing lung disease, such as emphysema.
Smetana, together with coauthors Valerie Lawrence, MD, and John Cornell, PhD, of the South Texas Veterans Health Care System, performed a systematic review of nearly 1,000 medical studies published between 1980 and 2005 in order to develop the guidelines for the American College of Physicians. After calculating summary estimates of risk, the authors divided their findings into patient-related risk factors and surgery-related risk factors, according to Smetana.