Combination dihydroergotamine mesylate and heparin sodium with lidocaine HCl. Pharmacokinetics, mechanism of action, clinical efficacy, and adverse effects

Deep Venous Thrombosis and Pulmonary Embolism in Trauma Patients

Trauma patients are at exceedingly high risk for the development of deep venous thrombosis and pulmo nary embolism. The incidence, pathophysiology, diag nosis, prophylaxis, and therapy of deep venous throm bosis and pulmonary embolism in the trauma patient are reviewed. The type of injury, systemic pertubations, and enforced immobility are important factors in pathogenesis. Patients with lower extremity injuries and spine fractures with paraplegia appear to be at highest risk. Orthopedic devices used to treat these injuries of ten preclude the conventional noninvasive diagnostic modalities. Further, hemorrhagic risk often impacts the judgment regarding the use of prophylactic measures as well as the therapy once deep venous thrombosis is diagnosed. Better data regarding the incidence of ve nous thromboembolism and the applicability of existing diagnostic, prophylactic, and treatment approaches in this population are needed.

Accidents are responsible for over 140,000 deaths and approximately 70 million nonfatal injuries an nually in the United States [1]. Most of the fatalities occur within hours of injury as a result of exsangui nation or a lethal head injury, but approximately 20% survive for days or weeks [2], usually in the intensive care unit. The primary causes of late death are sepsis and multiple-organ failure [2]. Increasing evidence, however, suggests that pulmonary embo lism (PE) is now becoming a leading cause of late death, especially in some high-risk groups [3-5]. The increase in the incidence of PE is due in part to improvements in trauma care, which have lowered the early mortality rate [6-8], leaving more patients at risk for late death. In addition, autopsy examina tions, used more frequently to audit trauma care systems [6,9], have documented an increase in clini cally unsuspected deep venous thrombosis (DVT) and PE.

This review was prompted because of the appar ent increase in DVT and PE in the trauma popula tion, and because the trauma patient presents very difficult and unique problems compared with the nontrauma patient with regard to the diagnosis, prophylaxis, and treatment of these disorders. In this review, we address the incidence, pathophys iology, diagnosis, treatment, and prophylaxis of DVT and PE in the trauma patient. We do not con sider the entities of fat embolism or pulmonary microemboli as a cause of late pulmonary failure.

St. Anthony's fire: successful reversal of ergotamine-induced peripheral vasospasm by hydrostatic dilatation

A 60-year-old trauma victim developed severe ischemia of all four extremities following administration of heparin-dihydroergotamine as prophylaxis against deep venous thrombosis. Despite cessation of heparin-dihydroergotamine and infusion of intraarterial papaverine into the right femoral artery, both lower extremities progressed to frank gangrene and amputation (above-knee on the left and below-knee on the right). However, both ischemic upper extremities were salvaged following intraoperative hydrostatic dilatation with balloon catheters. Ergotism is an avoidable and potentially treatable cause of peripheral gangrene in the critically-ill patient.

Two strategies for prophylaxis of fatal postoperative pulmonary embolism. Cost-effectiveness analysis

While subcutaneous heparin is a standard prophylaxis for death from pulmonary embolism following general surgery, it has been suggested that adding the vasoconstricting drug dihydroergotamine would improve survival compared to heparin alone. Dihydroergotamine may be associated with rare but life-threatening side effects; thus, reduced mortality from pulmonary embolism could be offset by increased mortality from other causes. Because a clinical trial to examine this possibility would be impractical, we performed a cost-effectiveness analysis to evaluate the effects of prophylactic dihydroergotamine on mortality. Based on published data, despite its favorable effects on the prevention of deep vein thrombosis, the addition of dihydroergotamine did not appear to save lives when added to heparin as prophylaxis. Probabilistic sensitivity analysis demonstrated that even if published risk estimates are in error, substantial changes would still not support the conclusion that dihydroergotamine is life-saving. In the absence of clear potential for improved survival, the increased costs associated with dihydroergotamine provide reason to question its routine prophylactic use in general surgery.

Silent deep vein thrombosis in immobilized multiple trauma patients

Although few trauma patients sustain fatal pulmonary embolism, a large population is at risk from nonfatal embolism due to unrecognized deep vein thrombosis (DVT). Thirty-eight of 39 immobilized trauma patients at bed rest for 10 days or longer had venographic study of their lower extremities to evaluate for the presence of silent DVT. Sixty percent of patients had silent DVT, with thrombi extending above the knee in half the patients with clot. DVT was documented in 67 percent of patients with major lower extremity fractures and 59 percent of patients without major fractures. DVT increased with increasing age but not with injury severity score.

Detection and prevention of deep venous thrombosis

Deep venous thrombosis (DVT) is a significant problem in the postoperative course of high-risk patients. Risk factors that further predispose patients to DVT include obesity, age over 40 years, smoking, dehydration, and a prior history of thromboembolism. Diagnosis of DVT by physical examination and medical history is difficult; objective diagnostic techniques are often required. Considerable emphasis has been placed on the cost-effectiveness of implementing prophylactic measures in patients who are at high risk for developing DVT. Physical maneuvers attempt to reduce stasis and enhance venous return and pharmacologic approaches alter blood coagulability. The drug therapy used in preventing DVT consists of dextran, low-dose heparin, a combination of low-dose heparin and dihydroergotamine, and warfarin. Effective prophylactic regimens differ according to the type of patients at risk. Prophylactic therapy should be tailored according to the patient's disease and degree of risk.