Acute pulmonary thromboembolism induced by prophylactic heparin use and a heparin-coated catheter: a case of heparin-induced thrombocytopenia and thrombosis syndrome

Access technique and its problems in parenteral nutrition - Guidelines on Parenteral Nutrition, Chapter 9

Catheter type, access technique, and the catheter position should be selected considering to the anticipated duration of PN aiming at the lowest complication risks (infectious and non-infectious). Long-term (>7-10 days) parenteral nutrition (PN) requires central venous access whereas for PN <3 weeks percutaneously inserted catheters and for PN >3 weeks subcutaneous tunnelled catheters or port systems are appropriate. CVC (central venous catheter) should be flushed with isotonic NaCl solution before and after PN application and during CVC occlusions. Strict indications are required for central venous access placement and the catheter should be removed as soon as possible if not required any more. Blood samples should not to be taken from the CVC. If catheter infection is suspected, peripheral blood-culture samples and culture samples from each catheter lumen should be taken simultaneously. Removal of the CVC should be carried out immediately if there are pronounced signs of local infection at the insertion site and/or clinical suspicion of catheter-induced sepsis. In case PN is indicated for a short period (max. 7-10 days), a peripheral venous access can be used if no hyperosmolar solutions (>800 mosm/L) or solutions with a high titration acidity or alkalinity are used. A peripheral venous catheter (PVC) can remain in situ for as long as it is clinically required unless there are signs of inflammation at the insertion site.

Heparin-induced thrombocytopenia in the critical care setting: Diagnosis and management^

BACKGROUND

Thrombocytopenia is a common occurrence in critical illness, reported in up to 41% of patients. Systematic evaluation of thrombocytopenia in critical care is essential to accurate identification and management of the cause. Although sepsis and hemodilution are more common etiologies of thrombocytopenia in critical illness, heparin-induced thrombocytopenia (HIT) is one potential etiology that warrants consideration.

OBJECTIVE

This review will summarize the pathogenesis and clinical consequences of HIT, describe the diagnostic process, and review currently available treatment options.

DATA SOURCE

MEDLINE/PubMed search of all relevant primary and review articles.

DATA SYNTHESIS AND CONCLUSIONS

HIT is a clinicopathologic syndrome characterized by thrombocytopenia (>/=50% from baseline) that typically occurs between days 5 and 14 after initiation of heparin. This temporal profile suggests a possible diagnosis of HIT, which can be supported (or refuted) with a strong positive (or negative) laboratory test for HIT antibodies. When considering the diagnosis of HIT, critical care professionals should monitor platelet counts in patients who are at risk for HIT and carefully evaluate for, a) temporal features of the thrombocytopenia in relation to heparin exposure; b) severity of thrombocytopenia; c) clinical evidence for thrombosis; and d) alternative etiologies of thrombocytopenia. Due to its prothrombotic nature, early recognition of HIT and prompt substitution of heparin with a direct thrombin inhibitor (e.g., argatroban or lepirudin) or the heparinoid danaparoid (where available) reduces the risk of thromboembolic events, some of which may be life-threatening.

Effects of MCI-186 (edaravone), a novel free radical scavenger, upon experimental atherosclerosis in apolipoprotein E-deficient mice

BACKGROUND

Recent evidence suggests that oxidative stress may play a role in the development of atherosclerosis. MCI-186 (3-methyl-1-phenyl-1-phyrazolin-5-one, edaravone) is a novel free radical scavenger, but it remains unclear whether free radical scavengers would be effective for the prevention of the disease.

METHODS AND RESULTS

Experimental atherosclerosis was induced in apolipoprotein E-deficient mice fed a high-fat diet containing 0.3% cholesterol. Mice were treated with an intraperitoneal injection of either MCI-186 1 mg/kg per day or MCI-186 10 mg/kg per day on alternate days over 4 weeks. Fatty streak lesion was suppressed by MCI-186 10 mg/kg per day administration, but not by mg/kg per day. Immunohistochemical analysis showed that macrophage and CD4+ T-cell accumulation and oxidative stress overload in the fatty streak lesion were suppressed in mice that received MCI-186 treatment.

CONCLUSIONS

MCI-186 administration suppressed the development of atherosclerosis, associated with reduced expression of both immune-activated cells and oxidative stress in fatty streak plaques.

Effects of late administration of immunoglobulin on experimental atherosclerosis in apolipoprotein E-deficient mice

BACKGROUND

Although immunoglobulin treatment, beginning simultaneously with the initiation of atherosclerosis, suppresses experimental atherosclerosis in apolipoprotein E-deficient mice, it remains unclear whether the treatment at a subsequent stage of atherosclerosis would be effective.

METHODS AND RESULTS

Experimental atherosclerosis was induced in mice fed a high-fat diet containing 0.3% cholesterol. After confirming the presence of atherosclerotic lesions at 11 weeks, the mice were treated with an intraperitoneal injection of either intact type of immunoglobulin or F(ab')2 fragments of immunoglobulin (both, 1 g.kg-1.day-1) on alternate days over 4 weeks. Fatty streak lesion was suppressed by intact immunoglobulin administration, but not by F(ab')2 fragments of immunoglobulin. Immunohistochemical analysis showed that macrophage and CD4+ T-cell accumulation in the fatty streak lesion was suppressed in mice that received intact immunoglobulin but not in those that received F(ab')2 fragments.

CONCLUSIONS

Immunoglobulin treatment, even at a later stage of atherosclerosis, suppresses the development of lesions associated with the reduced expression of immune-activated cells in fatty streak plaques, demonstrating the benefits of immunoglobulin therapy for prevention of atherosclerosis.

Heparin-induced thrombocytopenia type II: A rare but significant complication of plasma exchange

Type II heparin-induced thrombocytopenia (HIT) is a rare but well-recognised and potentially life-threatening complication of unfractionated heparin therapy, and has been reported in association with heparin locks for central venous lines. We report a case of type II HIT complicated by iliofemoral deep venous thrombosis and pulmonary embolism in a 43-year-old woman in the course of plasma exchange for myasthenia gravis. A Gamcath central venous line had been inserted femorally due to poor peripheral venous access, and this was locked with heparin 5000 U/ml between procedures. Twelve days after initial heparin exposure, she presented with new-onset thrombocytopenia, a painfully swollen right leg, and pleuritic pain. Deep venous thrombosis and pulmonary embolism were confirmed radiologically, and serology for heparin/PF4 antibodies was unequivocally positive. The line was removed, and she was successfully managed with intravenous lepirudin, switching to warfarin on platelet recovery. This case demonstrates that Type II HIT can occur in association with heparin line locks in the course of plasmapheresis, despite previous reports of successful use of plasma exchange to treat Type II HIT.