Are you overlooking your OR in the battle against pressure ulcers?
Some believe it's a key area of concern
If you're curious about the origination of pressure ulcers in hospitals, consider these data presented at a recent conference at Emory University in Atlanta:
· 1.5 million hospitalized patients develop pressure ulcers each year in the United States.
· An estimated 30% to 40% of all hospital-acquired pressure ulcers actually start in the operating room.
· About one in 12 patients undergoing surgery lasting more than three hours will develop at least one pressure ulcer within four days of surgery.
Some may dispute the precision of the numbers, but there's no escaping the question they raise: Is the OR a prime source for pressure ulcers? If so, just how widespread is the problem? What is the major source of it? What can be done to minimize the risk? Can a new type of support surface overlay alleviate the problem?
Several reasons make surgery a risk factor for pressure ulcers, according to experts:
· Anesthesia and heavy sedation prevent patients from repositioning themselves to relieve the chronic pressure of lying still on the OR table.
· Poor circulation and low blood pressure caused by shearing forces can pinch off capillaries in underlying dermal tissue, leading to ischemia.
· Moisture from blood, perspiration, and saliva, and the use of restraints, tape, and traction weaken the skin and increase the risk of pressure ulcer formation.
· Thermal blankets used to prevent hypothermia may intensify tissue damage.
Still, evaluating how the surgery process contributes to pressure ulcer formation has proved difficult for a number of reasons. Often, patients who get pressure ulcers after surgery are otherwise healthy and mobile before their operations. Because of that, preoperative assessments typically ignore pressure ulcer risks - and surgery itself is rarely, if ever, considered one of those risks.
In addition, pressure ulcer signs typically won't appear until hours or even days after the surgical procedure. It's also difficult for clinicians to determine whether the genesis of an ulcer occurs during prolonged immobility on an OR table, or during postoperative care, when patients often are immobile for far longer periods.
"Because pressure ulcers may not develop into serious sores until days after surgery, the connection back to the operating room is difficult to establish," explains Sharon Aronovitch, PhD, RN, CETN, an education, research, and medical-legal consultant in Delmar, NY. "As a result, the occurrence of OR-acquired pressure ulcers is often underreported."
How big is the problem?
In the simplest analysis, pressure ulcers develop from a straightforward progression of events: Pressure on tissue leads to vascular compression and distortion, which causes ischemia and a disruption of normal tissue integrity. The resulting tissue and vascular deficits trigger tissue deterioration. Almost invariably, dermal breakdown and a pressure sore arise.
Common wisdom among wound care professionals holds that when the pressure applied to tissue is concerted, especially over a bony prominence such as the hip, heel, or sacrum, it takes very little time to induce the physiological process leading to a pressure sore. So it stands to reason that people undergoing surgical procedures and who are immobile for prolonged periods would be ideal candidates for developing pressure ulcers. Definitive answers to the questions of how many and what subsets of surgical patients develop pressure ulcers as a result of their surgeries are not yet available.
Nancy Stotts, RN, EdD, professor of nursing at the University of California in San Francisco, suspects that the underlying problem is large. At the same time, she notes the dearth of solid data revealing just how extensive it is. "There are many allusions in the literature about pressure ulcers resulting from surgery and the factors involved, such as long periods of time on a hard surface, friction and shear from moving patients onto and off of the OR table, and the various positions surgery patients are put in," she says. "But there's just not much literature showing what the actual incidence of the problem is."
A literature review conducted by Stotts did reveal that the risk of pressure ulcer development varies considerably depending on the type of surgery. (See related story, p. 63.)
According to Aronovitch, prevalence estimates - meaning the number of cases in existence at a given time - in the literature range from 12% to 27%, and some studies report even higher numbers. Such a wide range of numbers invites skepticism and underscores the need for additional research.
In her own national survey, Aronovitch found an 8.5% overall prevalence of OR-acquired pressure ulcers from surgeries scheduled for three hours or more. The widely quoted overall prevalence rate in acute care facilities stands at about 11%. She notes that other studies show significantly increased risk of ulcer development in surgeries lasting more than 2.5 hours, and still others have concluded that the risk increases after only two hours.
When Aronovitch examined other risk factors, such as age, vascular disease, and increased length of surgery, she found they did not play a major role in the development of OR-acquired pressure ulcers. In fact, the prevalence rate for patients between 20 and 40 years of age was 9.3%, and for patients undergoing surgeries lasting more than three but less than four hours, the rate was still nearly 6%. "Therefore, all surgical patients should be considered at risk," says Aronovitch. Data for the study were collected for 1,128 patients at 51 different facilities who underwent surgical procedures lasting at least three hours.
What are the risks?
Prolonged immobility on a relatively hard surface is but one factor contributing to the development of OR-acquired pressure ulcers. Surgical patients are exposed to hazards not normally faced by patients on medical wards, according to Aronovitch and others. These include the following:
· Warming blankets under a surgical patient stimulate the demand for additional blood flow to areas where flow is already compromised and hastens impending tissue damage.
· Anesthesia may cause a malfunction in homeostatic compensatory mechanisms that dilate and constrict blood vessels in response to cardiac or blood volume changes.
· Anesthesia can decrease muscle tone, which may result in a greater deleterious effect on tissue over bony prominences.
· Increased pressure of abdominal viscera or masses on the inferior vena cava may decrease blood flow return to the heart, lowering blood pressure.
"The key to intraoperatively acquired ulcer development is unrelieved pressure due to immobility," Aronovitch says in her study. "Surgical patients are immobile, not only during surgery, but frequently for long periods of time before and after surgery. Some patients cannot be turned for extended periods of time due to the use of balloon pumps or other devices post-surgery. Normally, even patients on very sophisticated pressure relief devices are turned every two hours to prevent ulcers, but frequently, surgical patients are not repositioned for hours, or even days."
Pressure ulcer risk factors such as patient age and nutritional status are routinely considered during admission assessments and at regular intervals at many hospitals, but surgical procedures are rarely considered in the equation, says Vincent Dunlop, RN, critical care and critical trials coordinator at St. Paul's Hospital in Vancouver, BC, Canada. "We never look at the entire spectrum of care when a patient enters the hospital for surgery," he says. "Until we actually see the problem develop, we usually don't deal with it."
Dunlop cautions that the many estimates about the incidence and prevalence of OR-acquired pressure ulcers require careful scrutiny and should be critiqued in light of their assumptions and variables. Some studies, for instance, consider only high-risk populations, such as patients with hip replacement surgery, in which the number of pressure ulcers is bound to be higher than the average hospital population. Some studies count stage I ulcers in their tabulations, while others only consider stage II or worse.
"In essence, we need a lot more studies or we need hospitals to constantly do their own quality control checks," says Dunlop. "That would allow us to actually make comparisons between different surgical population groups, such as cardiovascular surgery, neurosurgery, and orthopedic surgery."
Many say 3 hours is plenty of time
The evidence may still be foggy, but some distinct patterns are arising from the haze. "When we trace back, we can see a trend with people who are in the OR and see a link between surgery and pressure ulcers," says Aronovitch. Despite the indications, OR personnel typically claim that the problem does not lay at their end of the process, she adds. It's understandable for OR staff to believe surgeries aren't implicated in pressure ulcers because visible compromises to skin integrity may not appear for 18 to 24 hours postoperatively.
But Aronovitch and others are convinced that three hours on the OR table is plenty of time to cause initial dermal breakdown, and she hopes additional research will open more eyes and begin a wider dialogue on the subject.
Stotts, despite her own suspicions and those of many others, acknowledges that clinicians don't know how often pressure ulcers arise from the surgical process. Only solidly designed and executed prospective research will answer the question.
"There's probably some contribution from all aspects: the surgical procedure itself, positioning on the OR table, and postoperative care," she says. "One problem in the OR is that the padding and positioning is different for different types of surgery, and longer surgeries probably involve more risk regardless of how a patient is positioned," Stotts says. "I believe that pressure ulcers in the surgical population is a problem, and I think the operating room contributes to it. How much that contribution amounts to is not real clear to me."
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