A way to improve outcomes of patients undergoing hip or knee replacements, according to a new study by researchers at Hospital for Special Surgery, is to change the kind of anesthesia. They found that the use of neuraxial anesthesia (also known as spinal or epidural anesthesia) reduced the risk of pulmonary compromise by twofold in knee replacement patients and over threefold in hip replacement patients.
“When one considers the modest decrease in risk of adverse outcomes associated with the use of a number of widely used medications such as anti-cholesterol drugs, the effect sizes seen in this study are really impressive, ” said Stavros Memtsoudis, M.D., Ph.D., director of Critical Care Services at Hospital for Special Surgery, New York City. The findings of this study appear in the May issue of Anesthesiology.
He added, “The influence that the type of anesthetic can have on perioperative outcomes has been vastly underestimated. Indeed, our study suggests that the type of anesthesia chosen may have important impacts on all kind of medical and economic outcomes in orthopedic surgical patient. It is not something to be taken lightly.”
As reported by Science Codex in their story about the research, neuraxial anesthesia involves injecting medication into fatty tissue that surrounds the nerve roots in the spine (known as an epidural) or into the cerebrospinal fluid that surrounds the spinal cord. Currently, the majority of joint replacements in the United States are performed under general anesthesia. Anesthesiologists at the Hospital for Special Surgery use regional anesthesia for over 90% of hip and knee replacements. Several small studies, conducted in the past, showed that, compared with general anesthesia, regional anesthesia reduces intraoperative blood loss and the need for blood transfusions.
In this new study, researchers conducted a retrospective review of hip and knee replacements performed between 2006 and 2010 in the United States using data collected by Premier Perspective. This database contains discharge information from approximately 400 acute care hospitals located throughout the United States.
Information on the type of anesthesia used was available in 71.4% of 528, 495 patients. Eleven percent received neuraxial anesthesia, 14.2% received combined neuraxial and general anesthesia, and 74.8% received general anesthesia. Thirty-day mortality was significantly higher in patients who received general anesthesia, 0.18%, compared with those who received neuraxial, 0.10%, or neuraxial-general, 0.10%.
“Other studies have suggested some benefit of neuraxial over general anesthesia, but they looked at very limited outcomes, primarily at risk of bleeding and blood transfusions. What this study does for the first time is really explore the impact of anesthesia on a wider range of important outcomes, ” said Memtsoudis.
“We found lower rates of complications including pulmonary compromise, pneumonia, infections, and acute renal failure when neuraxial anesthesia is used. The choice of anesthesia seemed to basically affect every organ system.” He noted that the findings of this comparative effectiveness research could be applied to over one million patients undergoing joint arthroplasty in the United States each year.
