pulmonary disorders
Pulmonary Embolism (PE)
Prevention of Pulmonary Embolism
Prevention of pulmonary embolism means prevention of deep venous thrombosis (DVT); the need depends on the patient’s risks, including Type and duration of any surgery Comorbid conditions, including cancer and hypercoagulable disorders Presence of a central venous catheter Prior history of DVT or PE Bedbound hospitalized patients and patients undergoing surgical, especially orthopedic, procedures benefit significantly from venous thromboembolism prophylaxis, and most of these patients can be identified before a thrombus forms (see table). Preventive measures include low-dose unfractionatedheparin, low molecular weightheparin,warfarin,fondaparinux, direct oral anticoagulants (eg,rivaroxaban,apixaban), compression devices, and elastic compression stockings. Choice of drug or device depends on various factors, including patient demographics, the perceived risk, contraindications (eg, bleeding risk), relative costs, and ease of use. The American College of Chest Physicians has published comprehensive evidence-based recommendations for prophylaxis of acute DVT, including the duration of prophylaxis, in surgical and nonsurgical patients and during pregnancy ( Prevention references , The type of surgery as well as patient-specific factors determine the risk of DVT. Independent risk factors include Age≥60 years Prior DVT or PE Cancer Anesthesia≥2 hours Bed rest≥4 days Male sex Hospital stay ≥ 2 days Sepsis Pregnancy or the postpartum state Central venous access Body mass index (BMI) > 40 The Caprini score is commonly used for DVT risk stratification and determination of the need for DVT prophylaxis in surgical patients (see table). The need for DVT prophylaxis is based on the risk assessment score (see table). Appropriate preventive measures, ranging from early ambulation to use ofheparin, depend on the total score. Medication therapy to prevent DVT is usually delayed until after surgery to help avoid intraoperative bleeding. However, preoperative prophylaxis is also effective. In general surgery patients,low dose unfractionatedheparinis given for 7 to 10 days or until the patient is fully ambulatory. Immobilized patients not undergoing surgery should also receive low dose unfractionatedheparinuntil they are ambulatory. dosing for Prevention depends on the specific drug ( -induced thrombocytopenia or some other situations, such as after major orthopedic surgery ( Prevention references ). It is a selective Warfarinis usually effective and safe at a dose adjusted to maintain an INR of 2 to 3 in patients who have undergone total hip or knee replacement.Warfarinuse is increasingly being supplanted by the use of direct oral anticoagulants. Thedirect oral anticoagulantsrivaroxabanandapixabanarefactor Xainhibitors. They can be used for prevention of acute DVT/PE in patients undergoing total knee or hip arthroplasty. Inferior vena cava filters, intermittent pneumatic compression (also known as sequential compression devices [SCD]), and graded elastic compression stockings may be used alone or in combination with medications to prevent PE. Whether these devices are used alone or in combination depends on the specific indication. (IVCF) may help prevent PE in patients with DVT in the leg or pelvic vasculature, but IVCF placement may risk long-term complications. More recent evidence raises questions regarding the efficacy of retrievable filters in patients receiving anticoagulation ( Prevention references ). A filter is most clearly indicated in patients who have Proven DVT and contraindications to anticoagulation Recurrent DVT (or emboli) despite adequate anticoagulation Possibly marginal cardiopulmonary function, causing concern for their ability to tolerate additional small emboli Because venous collaterals can develop, providing a pathway for emboli to circumvent long-standing IVCFs, and because filters occasionally thrombose, patients with recurrent DVT or nonmodifiable risk factors for DVT may still require anticoagulation. An IVCF is placed in the inferior vena cava just below the renal veins via catheterization of an internal jugular or femoral vein. Most IVCFs used currently are removable. Occasionally, a filter dislodges and may migrate up the venous bed, even to the heart or pulmonary vasculature. A filter can also become thrombosed, causing severe venous congestion (including acute phlegmasia cerulea dolens) in the leg, lower body ischemia, and acute kidney injury ( Prevention references ). Intermittent pneumatic compression(IPC) with SCDs provides rhythmic external compression to the legs or to the legs and thighs. It is more effective for preventing calf than proximal DVT. It is insufficient as sole prophylaxis after hip or knee replacement but is often used in low-risk patients after other types of surgery or in medical patients who have a low-risk of DVT or who are at high risk of bleeding. IPC can theoretically trigger PE in immobilized patients who have developed occult DVT while not receiving DVT prophylaxis. Graded elastic compression stockingsare likely less effective than external pneumatic leg compression. After surgical procedures with a high incidence of DVT/PE, low dose unfractionatedheparin, low molecular weightheparin, or adjusted-dosewarfarinis recommended. Afterorthopedic surgery of the hip or knee,additional options include the direct oral anticoagulantsrivaroxabanandapixaban. These medications are safe and effective and, unlikewarfarin, they do not require laboratory tests to monitor the level of anticoagulation. Fortotal hip arthroplasty,patients should continue to take anticoagulants for 35 days postoperatively. In selected patients at very high risk of both DVT/PE and bleeding, temporary placement of an IVCF is an option for prophylaxis. In patients undergoing elective neurosurgical procedures,the risk of DVT/PE is also high. Because of concern about intracranial bleeding, physical methods (SCDs and elastic stockings) have often been used in patients undergoing neurosurgery; however, low molecular weightheparinappears to be an acceptable alternative. Although no specific guidelines exist, the combination of SCDs and low molecular weightheparinmay be more effective than either alone in patients who are at high risk. to prevent DVT/PE ( Prevention references ). For patients at very high risk, a temporary IVCF may be considered. Inacutely ill medical patients,low dose unfractionatedheparin, low molecular weightheparin, orfondaparinuxcan be given. SCDs, elastic compression stockings, or both may be used when anticoagulants are contraindicated. For patients with ischemic stroke, low dose unfractionatedheparinor low molecular weightheparincan be used; SCD, elastic compression stockings, or both may be beneficial. 1.Kearon C, Akl EA, Ornelas J, et al. Antithrombotic Therapy for VTE Disease: CHEST Guideline and Expert Panel Report [published correction appears inChest2016 Oct;150(4):988].Chest2016;149(2):315-352. doi:10.1016/j.chest.2015.11.026 2.Stevens SM, Woller SC, Kreuziger LB, et al. 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