WRAP IT UP The pneumatic contractions of sequential compression devices simulate muscle movement to prevent circulatory stasis.

Short cases and speedy ambulation put same-day surgery patients at a relatively low risk for deep-vein thrombosis and pulmonary embolism during the perioperative process. But that's no reason to skip measures that can prevent the potentially fatal complications, say experts, who maintain that these extra steps may provide a silent benefit against a silent hazard.

Who's at risk?
Impaired circulation and pooled blood can result in the formation of a blood clot, or thrombus, in a large vein, such as those in the legs. If an embolus should break from that clot and block the pulmonary artery in the lungs, the result can be fatal.

While this vascular complication presents unpredictably, it is possible to identify the patients who are at greater risk of suffering it. "All patients who are scheduled for outpatient surgery should have a DVT risk factor assessment at the time of booking, and it should be documented," says Lynn Razzano, RN, MSN, ONCC, a clinical nurse consultant with the Physician-Patient Alliance for Health and Safety in Westborough, Mass.

These assessments will typically arrive by way of physicians' pre-op consultations, says Sharon Butler, MSN, BSN, RN, a clinical nurse IV at Stanford University Hospital and Clinics in Palo Alto, Calif. "Unless they come through the ER, all surgical patients would've spoken before the day of surgery with a physician, who would have determined their risk factors well in advance" and ordered the implementation of special preventative measures in pre-op if they're deemed necessary.

Several different models exist for classifying patients' risk for DVT and PE, including checklists, grids and automated warnings programmed into electronic medical records systems.

The logic of preventative efforts
Anti-DVT prophylaxis is patient- and risk-factor specific. The type and anticipated length of surgery, along with a patient's individual risk profile, are often the primary drivers of the preventative efforts that are implemented. However, the ability to classify patients as low-risk populations for DVT should not foster a false sense of confidence, experts note.

"You might ask, 'If they're low-risk, why are we taking these steps with this patient? If they don't need it, why are we using this? The cost of healthcare is outrageous enough already,'" says Ms. Butler. "The answer is, there's still the risk that the young, healthy patient will suffer an unfortunate result, and we'll have to bear the knowledge that we had the resources to do something about it, that we could have averted it."

"We'll zone in on the high-risk patients, but we must exercise caution with all the others, too," says Ms. Razzano. "It's a common mistake, assuming a patient is low-risk and nothing is needed."

But the unexpected is not unknown to surgery. "Starting anesthesia means starting the clotting cascade," she says. "Even with short cases, like knee scopes, there's no guarantee you'll be in and out in just 15 or 20 minutes. Failure to exercise preventative measures could be setting up a catastrophe."

Preemptive measures begin with mechanical compression: the application of thromboembolic deterrent stockings (also known as compression stockings or TED hose) and/or sequential compression devices (SCDs), whose pneumatic sleeves create intermittent contractions in the legs to assist blood flow and prevent circulatory stasis.

Both options are simple but effective. "Most institutions default to applying compression to everyone, because DVT really is a silent thing, and in most cases SCDs aren't going to hurt the patient," says Ms. Butler. According to researchers, compression may be the most all-around effective prophylaxis against DVT. A pathological assessment known as Virchow's Triad attributes thrombosis to the confluence of 3 conditions: vessel wall injury, stasis in blood flow and changes in coagulation. Stockings remedy vessel damage and stasis, while SCDs combat stasis and coagulability. "Used together, stockings and SCDs cover all three points," says Ms. Razzano.

For compression to be effective, though, it must be in use, and it is most effective if used continuously throughout the perioperative journey. Stockings or SCDs should be applied in pre-op, before the induction of anesthesia. "We're the first step in seeing the patient. If we don't get it started in the beginning, it won't have the full impact later," says Cheryl A. Marsh, BS, RN, CNOR, a nurse clinical educator at Lyndon B. Johnson General Hospital in Houston, Texas. "Once it's placed on the patient in pre-op, it should stay on throughout the process. Use it as soon as it is applied. Make sure it's attached after the patient arrives in the OR. When the patient gets up to ambulate after surgery, are they reapplied when they return?"

Compression should continue until the patient is discharged, and this care should be documented, says Ms. Razzano, who also recommends that patients wearing stockings be discharged with them on. Some manufacturers even offer take-home compression units with disposable sleeves for post-surgical DVT prophylaxis.

DVT ALERT
Common Risk Factors for Circulatory Complications

GET THE FLOW GOING Don't forget to reconnect and restart SCDs after patient transport or other interruptions to ensure continuous use.

• obesity, especially if body mass index is 30 or greater
• sedentary behavior, including long hospitalizations, prescribed bed rest, or long air or auto travels in the weeks prior to surgery
• joint, pelvic or other procedures that require post-surgical immobilization or restricted mobility
• laparoscopic procedures, since the pressure of the inflated peritoneum can obstruct blood flow from the legs
• surgeries under general anesthesia
• age over 40 years
• smoking
• the use of estrogen hormonal replacement therapy or contraceptives
• blood clotting disorders
• varicose veins or edema
• pregnancy
• a history of congestive heart failure or other cardiac or pulmonary disorders
• a personal or family history of DVT

A pharmaceutical approach
While mechanical compression's low-impact, high-effect methods make it the primary preventative measure for most patients, certain patients undergoing certain surgeries may also benefit from a dose of anti-coagulants. "Administering drugs is patient- and procedure-dependent," says Ms. Butler, "but the gold standard for high- and even moderate-risk patients is an injection of low-molecular-weight heparin."

Orally administered warfarin (Coumadin) or rivaroxaban (Xarelto) are also available to prevent coagulation, but the medication route must be followed with caution, particularly in the ambulatory setting.

"Anti-coagulant drugs don't prevent clots, they prevent blood from being sticky," says Ms. Razzano. "Some surgeons don't want to give an anti-coagulant before surgery because they don't want a bleeding situation." She cites sports medicine physicians who stand by pre-surgical aspirin only, and only administer other anticoagulants to high-risk patients as part of a combined compression-and-drugs approach.

The risk of DVT remains for as long as two weeks after surgery, which is why post-op education is critically important among ambulatory patients, a population that might not see symptoms until well after their same-day discharges.

Patients should know these signs. While DVT can occur even without symptoms, the existence of pain, swelling, tenderness, discoloration, redness or warmth in the legs, ankles or feet are cause for concern, as are chest pain or shortness of breath.

Patients should also be advised to stay hydrated and ambulate frequently, avoiding prolonged sedentary behavior or lengthy travel during their recoveries, says Ms. Razzano. "Promote and focus on ambulation, but make sure they keep their stockings on," she says.