air embolism

embolism /em·bo·lism/ (em´bŏ-lizm) the sudden blocking of an artery by a clot or foreign material which has been brought to its site of lodgment by the blood current.

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air embolism  that due to air bubbles entering the veins from trauma, surgical procedures, or severe decompression sickness.

cerebral embolism  embolism of a cerebral artery.

coronary embolism  embolism of a coronary artery.

fat embolism  obstruction by a fat embolus, occurring especially after fractures of large bones.

miliary embolism  embolism affecting many small blood vessels.

paradoxical embolism  blockage of a systemic artery by a thrombus originating in a systemic vein that has passed through a defect in the interatrial or interventricular septum.

pulmonary embolism  obstruction of the pulmonary artery or one of its branches by an embolus.

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air embolism

n.

Bubbles of air in the heart or vascular system that create an obstruction and are usually the result of surgery or trauma.

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air embolism,

the abnormal presence of air in the cardiovascular system, resulting in obstruction of blood flow. Air embolism may occur if a large quantity of air is inadvertently introduced by injection (for example, during IV therapy or surgery) or by trauma (for example, with a puncture wound). Also called aeroembolism. See also decompression sickness, embolus. Compare fat embolism, gas embolism.

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embolism (em´blizm),

n the clogging of a blood vessel by matter, such as a clot, air, or oil, that is carried by the bloodstream to some point where the lumen of the blood vessel narrows. This is the opposite of thrombosis, in which the clotting mechanism is organized in situ.

embolism, air,

n See aeroembolism.

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embolism

the sudden blocking of an artery by a clot of foreign material (embolus) that has been brought to its site of lodgment by the blood current. The obstructing material is most often a blood clot, but may be a fat globule, air bubble, piece of tissue, e.g. degenerated intervertebral disk, or clump of bacteria. It may therefore be the site of origin of a shower of microabscesses or a neoplastic metastasis. See also saddle thrombus, iliac artery thrombosis.

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air embolism

air injected accidentally into veins which may cause temporary paralysis or dyspnea, or may be fatal if the embolism occurs in the heart or brain. It has been used as a method of performing euthanasia but is too uncertain and inhumane to be recommended.

cerebral embolism

embolism of a cerebral artery; one of the causes of cerebral vascular accident.

renal embolism

embolism in the kidney causes no observable clinical effect unless it involves a very large area, when toxemia may result and be followed by uremia.

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transfusion reaction

Blood transfusion reaction, incompatibility reaction Transfusion medicine Any untoward response to the transfusion of non-self blood products, in particular RBCs, which evokes febrile reactions that are either minor–occurring in 1:40 transfusions and attributed to nonspecific leukocyte-derived pyrogens, or major–occurring in 1:3000 transfusions and caused by a true immune reaction, which is graded according to the presence of urticaria, itching, chills, fever and, if the reaction is intense, collapse, cyanosis, chest and/or back pain and diffuse hemorrhage Note: If any of above signs appear in a transfusion reaction, or if the temperature rises 1ºC, the transfusion must be stopped; most Pts survive if < 200 ml has been transfused in cases of red cell incompatibility-induced transfusion reaction; over 50% die when 500 ml or more has been transfused; TF mortality is ± 1.13/105 transfusions Clinical Flank pain, fever, chills, bloody urine, rash, hypotension, vertigo, fainting

Transfusion reactions

Immune, non-infectious transfusion reactions  

• Allergic Urticaria with immediate hypersensitivity

• Anaphylaxis Spontaneous anti-IgA antibody formation, occurs in ± 1:30 of Pts with immunoglobulin A deficiency, which affects 1:600 of the general population–total frequency: 1/30 X 1/600 = 1/18,000

• Antibodies to red cell antigens, eg antibodies to ABH, Ii, MNSs, P1, HLA

• Serum sickness Antibodies to donor's immunoglobulins and proteins

Non-immune, non-infectious transfusion reactions  

• Air embolism A problem of historic interest that occurred when air vents were included in transfusion sets

• Anticoagulant Citrate anticoagulant may cause tremors and EKG changes

• Coagulation defects Depletion of factors VIII and V; this 'dilutional' effect requires massive transfusion of 10 + units before becoming significant

• Cold blood In ultra-emergent situations, blood stored at 4º C may be tranfused prior to reaching body temperature at 37º C; warming a unit of blood from 4 to 37º C requires 30 kcal/L of energy, consumed as glucose; cold blood slows metabolism, exacerbates lactic acidosis, ↓ available calcium, ↑ hemoglobin's affinity for O₂ and causes K⁺ leakage, a major concern in cold hemoglobinuria

• Hemolysis A phenomenon due to blood collection trauma, a clinically insignificant problem

• Hyperammonemia and lactic acid Both molecules accumulate during packed red cell storage and when transfused, require hepatorenal clearance, of concern in Pts with hepatic or renal dysfunction, who should receive the freshest units possible

• Hyperkalemia Hemolysis causes an ↑ of 1 mmol/L/day of potassium in a unit of stored blood, of concern in Pts with poor renal function, potentially causing arrhythmia

• Iron overload Each unit of packed RBCs has 250 mg iron, potentially causing hemosiderosis in multi-transfused Pts

Microaggregates Sludged debris in the pulmonary vasculature causing ARDS may be removed with micropore filters

Pseudoreaction Transfusion reaction mimics, eg anxiety, anaphylaxis related to a drug being administered at the same time as the transfusion

Infections transmitted by blood transfusion

• Viruses B19, CMV, EBV, HAV, HBV, HCV, HDV, HEV, Creutzfeldt-Jakob disease, Colorado tick fever, tropical viruses–eg Rift Valley fever, Ebola, Lassa, dengue, HHV 6, HIV-1, HIV-2, HTLV-I, HTLV-II

• Bacteria Transmission of bacterial infections from an infected donor is uncommon and includes brucellosis and syphilis in older reports; more recent reports include Lyme disease and Yersinia enterocolitica  Note: Although virtually any bacteria could in theory be transmitted in blood, the usual cause is contamination during processing rather than transmission from an infected donor

• Parasites Babesiosis, Leishmania donovani, L tropica, malaria, microfilariasis–Brugia malayi, Loa loa, Mansonella perstans, Mansonella ozzardi, Toxoplasma gondii, Trypanosoma cruzi