Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_3648_Библиотеки_им_академика_М_И_Перельмана

Warfarin is a vitamin K antagonist that inhibits factors II, VII, IX, and X.It is monitored using prothrombin time (PT) and international normal­ized ratio (INR). Warfarin should be discontinued 5days prior to surgery for a goal INR of less than

Since VKA antagonists must be held for days prior to surgery, patients at high risk of thrombo­sis will require the interval use of short acting anticoagulants such as low molecular weight heparin or unfractionated IV heparin. This prac­tice is call “bridging anticoagulation.” Bridging reduces the amount of time a patient is not anti­coagulated and thereby reduces thrombotic and cardioembolic events. Bridging is primarily used for long-acting anticoagulants such as coumadin. Bridging anticoagulation also increases the risk of surgical bleeding. In patients who are at a high risk for a cardioembolic event (recent dvt/pe, atrial brillation with a high CHADs2Vasc score, and high-risk mechanical heart valves), bridging with an unfractionated heparin drip or LMWH is indicated. Patients with low risk of thrombosis do not require bridging. Bridging is achieved by dosing LMWH (enoxaparin 1mg/kg every 12h or dalteparin 100 units/kg every 12h) or starting an unfractionated heparin drip either 3days prior to surgery (2 days after stopping coumadin) or when INR is no longer in the therapeutic range [55]. Discontinue LMWH 24h prior to the proce­dure. Discontinue an unfractionated heparin drip 4–5 h prior to the procedure. After the last planned procedure, Warfarin may be resumed that day, and LMWH or an unfractionated hepa­rin drip is typically started 24–48h after the pro­cedure assuming adequate hemostasis. The short acting heparinoids and coumadin are overlapped and both continued until the INR is in a therapeu­tic range for at least 24h [55]. At that point the heparin or LMWH can be stopped as the patient is therapeutic on their warfarin.

The direct Xa inhibitors include apixaban and rivaroxaban and the direct thrombin inhibitors include dabigatran. These medications are also known as the DOACs. The timing of discontinuing these medications was studied in the perioperative

DVT/PE is a common postoperative problem and one of the most preventable types of hospital mor­bidity/mortality [60]. Limb salvage surgery is typically a lower risk procedure for major bleed­ing. LMWH can therefore be started 12h prior to surgery and resumed 2–12h after a procedure. The most commonly used agents include enoxaparin 40mg every 24h and dalteparin 5000 units every 24h [61]. An alternative is fondaparinux, which is started 6–8h postoperatively and dosed at 2.5mg every 24h [62]. In patients with advanced kidney disease, subcutaneous unfractionated heparin at 5000 q8 h is recommended. VTE prophylaxis should be continued until the patient becomes ambulatory or until hospital discharge.

Postoperative complications are common in the hospitalized patient and require prompt medical evaluation and treatment. The limb salvage patients are at higher risk of complications due to their underlying age and comorbidities including diabetes, vascular disease, chronic kidney disease. Medical complications increase length of stay, morbidity, and mortality. We will focus on the rec­ognition and treatment of acute kidney injury, delirium, and postoperative gastrointestinal com­plications. Development of complications can affect a patient’s readiness for the operating room and also for safe hospital discharge. The internist must work in careful coordination with the surgi­cal team as delay in surgery may be required.

Delirium is common in the hospitalized patient, affecting up to 50% of hospitalized patients and may be preventable in as much as 30–40% of cases [65]. The development of delirium is asso­ciated with increased length of stay, increased risk of discharge to a nursing facility, and increased risk of death. Risk factors for delirium include dementia or cognitive impairment, func­tional impairment, vision impairment, history of alcohol abuse, age >70, comorbidity burden, polypharmacy, psychoactive medication use, physical restraints, and anormal laboratory val­ues [65].

Simple non-medical interventions such as keeping shades up/lights on during daytime, fre­quent reorientation, therapeutic activities, main­taining hydration and nutrition, and providing vision and hearing aids such as is described in the Hospital Elder Life Program (HELP) and help with prevention [66]. Minimization of psy­choactive medications such as narcotic analge­sics, muscle relaxants, benzodiazepines will help the patient to clear their delirium. The addi­tion of antihistamines, sedative hypnotics, and anti- psychotic medications should be avoided

Common gastrointestinal complications that will be addressed include postoperative nausea and vomiting (PONV), opioid induced constipation (OIC), postoperative ileus (POI), and antibiotic associated diarrhea. The internist should be pre­pared to institute preventive therapies, recognize complications, and implement appropriate treat­ment options.