Hematology

You are administering factor VIII to a patient with hemophilia A. What is the half-life of factor VIII?

12 hours The half-life of factor VIII is about 12 hours, which means that during the perioperative period, infusions of 30 units/kg may have to be repeated every 8-12 hours to keep factor VIII levels at half of normal.

During transfusion therapy for trauma or significant postoperative bleeding, it is recommended that you maintain a platelet count of at least

50,000

How long prior to surgery should aspirin be discontinued?

7-10 days Because of its effect on platelet activity, aspirin should be discontinued 7-10 prior to surgery.

Which of the following coagulation assay findings are consistent with a diagnosis of von Willebrand disease? (select two) A. A prolonged bleeding time B. A decreased PTT C. Increased factor VIII activity D. A prolonged rapid platelet function assay

A prolonged bleeding time A prolonged rapid platelet function assay Patients with von Willebrand disease will display a low von Willebrand factor concentration (the normal is 5-10 mg/dL), a prolonged bleeding time, prolonged PTT, and a decreased factor VIII activity. A decrease in factor IX is associated with hemophilia B, not von Willebrand disease.

Which form of porphyria is considered to exhibit the most serious symptoms and therefore causes the most concern for anesthetic management? A. Variegate porphyria B. Acute intermittent porphyria C. Hereditary coproporphyria D. Porphyria cutanea tarda

Acute intermittent porphyria Acute intermittent porphyria affects the central and peripheral nervous system and results in the most serious and life-threatening symptoms. Variegate porphyria is characterized by neurotoxicity and cutaneous photosensitivity on exposure to sunlight. The attacks associated with hereditary coproporphyria are less common and less severe than either acute intermittent or variegate and involve cutaneous hypersensitivity to sunlight and neurotoxicity as well. Porphyria cutanea tarda involves cutaneous hypersensitivity to the sun, but does not involve neurotoxicity.

What is the most common type of acute porphyria?

Acute intermittent porphyria Acute intermittent porphyria is the most common ACUTE form of porphyria. It produces the most serious symptoms such as hypertension, renal dysfunction, and CNS symptoms and can be precipitated by the administration of certain drugs. Porphyria cutanea tarda is the most common form of porphyria, but is not an acute form. It usually appears as photosensitivity in males over the age of 35 and is not stimulated by the administration of any drugs, nor does it exhibit any forms of neurotoxicity.

Which of the following would be an appropriate intervention for a patient with acute intermittent porphyria? A. Administering ketorolac for postoperative pain B. Administering a barbiturate for preoperative anxiolysis C. Avoiding the use of beta-blockers D. Administering D5NS while the patient is NPO

Administering D5NS while the patient is NPO Fasting has been identified as a precipitating factor for acute intermittent porphyria. As such, prolonged NPO times should be avoided, and the administration of a glucose-saline solution during the NPO time should be considered. Both ketorolac and barbiturates should be avoided. Beta-blockers are safe for use in these patients.

Which of the following would be an appropriate preoperative treatment for the patient with hemophilia A about to undergo surgery?

Administration of factor VIII concentrate Factor VIII concentrate should be administered to the patient with hemophilia A until levels are at or near 100% of normal prior to surgery, which may require a dose of 50-60 units/kilogram. Factor IX preparations are for use in patients with hemophilia B.

Patients with which of the following conditions would be most likely to suffer an allergic reaction to protamine? (select two) A. Porphyria B. Allergy to fish products C. Allergy to aspirin D. History of protamine zinc insulin use

Allergy to fish products History of protamine zinc insulin use Patients with a history of exposure to protamine zinc insulin and men who have undergone vasectomies have an increased risk for allergic reaction to protamine, especially if they have a history of allergic reaction to the insulin. Also, because protamine is derived from salmon milt, patients with a history of allergy to fish products have an increased risk for allergic reaction to protamine.

Which of the following drugs affects coagulation by inhibiting cyclooxygenase? A. Dipyridamole B. Aspirin C. Clopidogrel D. Abciximab

Aspirin Aspirin inhibits cyclooxygenase which prevents the synthesis of thromboxane A2, which normally promotes platelet aggregation and causes vasoconstriction. Dipyridamole is a phosphodiesterase inhibitor, clopidogrel is an ADP receptor antagonist, and abciximab is a glycoprotein IIb/IIIa receptor antagonist.

Which of the following statements regarding cyclooxygenase (COX) inhibitors is false? A. COX-1 receptor inhibition results in inhibition of thromboxane A2 B. COX-2 receptor inhibition results in decreased platelet aggregation C. COX-1 receptors are distributed throughout the body D. COX-2 receptors are concentrated in the kidneys and central nervous system

B. COX-2 receptor inhibition results in decreased platelet aggregation COX-1 receptor inhibition results in inhibition of thromboxane A2. By doing so, it disrupts thromboxane A2's ability to promote platelet aggregation. COX-2 receptor inhibition has been shown to reduce prostacyclin release from the vascular epithelium and can result in increased platelet aggregation. COX-1 receptors are widespread throughout the entire body, (although they are slightly more concentrated in the kidneys, gastric mucosa, platelets, and endothelium). COX-2 receptors are present in the kidneys and central nervous system and can be synthesized in response to inflammatory processes.

Which herbal supplement is used to treat depression and anxiety? A. Ginger B. Licorice C. St. John's wort D. Gingko

C. St. John's wort Common uses for St. John's wort are treatment of depression and anxiety. Ginger is used as an antinausea agent. Licorice is used for the treatment of gastritis, ulcers, cough, and bronchitis. Ginkgo is used as a blood thinner.

Which test is most widely used to assess the intrinsic coagulation pathway?

C. partial thromboplastin time The partial thromboplastin time is a commonly used test that assesses the intrinsic coagulation pathway. The prothrombin time evaluates the extrinsic pathway. The INR is a normalization calculation performed on the prothrombin time.

Which of the following statements regarding COX-2 inhibitors is false? A. COX-2 inhibitors have a lower incidence of gastrointestinal side effects than non-selective NSAIDs B. COX-2 inhibitors inhibit prostaglandin synthesis C. COX-2 inhibitors decrease platelet aggregation D. COX-2 inhibitors are highly protein bound

COX-2 inhibitors decrease platelet aggregation COX-1 receptor inhibition by NSAIDs is responsible for the gastric irritation, decrease in renal blood flow, and platelet inhibition associated with nonselective NSAIDs. COX-2 receptor inhibition is responsible for the decrease in pain and inflammation.

Which of the following agents would be appropriate to administer in the treatment of a patient with von Willebrand disease? (select two)

Cryoprecipitate and Desmopressin The most common treatment is desmopressin 0.3 mcg/kg IV. It may also be administered as a nasal spray. Other treatment options include vWF concentrates such as cryoprecipitate or vWF-Factor VIII concentrate.

Which of the following values may be elevated in patients with disseminated intravascular coagulation?

D-dimer The PT, PTT, thromboplastin time, D-dimer, and fibrin degradation products are all elevated in patients with acute DIC.

Which of the following is an acceptable treatment for uremic platelet dysfunction?

Desmopressin Uremic platelet dysfunction can be relieved by dialysis, which removes the chemicals (succinic acid and hydroxyphenolic acid) responsible for the dysfunction. The administration of desmopressin (DDVAP) increases the release of von Willebrand factor which relieves the disorder. The administration of cryoprecipitate also improves the platelet dysfunction. If the situation is considered life-threatening, however, platelet concentrates should be administered

A patient with acute intermittent porphyria receives ketorolac at the end of a procedure and experiences a tonic-clonic seizure during emergence. An appropriate treatment would be the administration of

Diazepam Ketorolac should be avoided in patients with porphyria as it can precipitate a porphyric crisis. One of the most severe symptoms of a porphyric crisis is seizures. The traditional treatment using barbiturates such as thiopental or thiamylal is contraindicated as they also precipitate porphyric crises. Benzodiazepines should be administered. Propofol is another anesthetic agent that can be administered until other measures can be taken. Etomidate may also precipitate a porphyric crisis.

Which of the following contribute to the development of disseminated intravascular coagulation? A. The absence of tissue factor release B. Thrombocytosis C. A rapid decrease in fibrin degradation products D. Excessive fibrinolysis

Excessive fibrinolysis DIC is characterized by extensive depletion of the coagulation factors and excessive fibrinolysis to compensate for the consumption of coagulation factors during the clotting process.

Which of the following statements regarding hemophilia is false? Factor VIII is known as Christmas factor Patients with hemophilia A are deficient in factor VIII Hemophilia B is also known as Christmas disease Hemophilia A is a sex-linked disorder

Factor VIII is known as Christmas factor Hemophilia A is a sex-linked deficiency of factor VIII that is carried on the X chromosome. Hemophilia B results from a decreased level of factor IX, also known as Christmas factor.

Which clotting factor mechanically stabilizes fibrin to help protect it from fibrinolysis?

Factor XIII Factor XIII mechanically stabilizes fibrin to help protect it from fibrinolysis. A defect in factor XIII results in a severe bleeding disorder. Tissue factor initiates hemostasis when endothelial tissue is disrupted. Von Willebrand Factor helps bind platelets to the damaged tissue. Protein C plays a role in the anticoagulation process.

Select two herbal supplements that may increase bleeding.

Garlic and Ginseng

Which herbal medication lowers blood glucose and has the potential to increase bleeding?

Ginseng

Which herbal supplement may decrease blood glucose? A. Garlic B. Ginger C. Ginkgo D. Ginseng

Ginseng Ginseng may inhibit platelet aggregation and increase bleeding. It may also decrease blood glucose.

Which of the following statements regarding heparin-induced thrombocytopenia (HIT) syndrome are true? A. HIT syndrome occurs in about 5% of patients receiving heparin B. HIT syndrome usually develops within 6 hours of initiating heparin therapy C. HIT syndrome is mediated by IgE antibodies D. Both A and C are true

HIT syndrome occurs in about 5% of patients receiving heparin Heparin-induced thrombocytopenia syndrome is a potentially life-threatening disorder that occurs in about 5% of patients receiving heparin. The patient develops severe thrombocytopenia, becomes resistant to the effects of heparin, and may develop thombosis despite the low platelet count. It usually develops after 6-10 days of heparin therapy. It is due to the development of platelet-associated immunoglobulin (IgG) antibodies.

Porphyria is a disorder affecting the synthesis of which of the following proteins? A. Albumin B. Fibrinogen C. Alpha-1 acid glycoprotein D. Heme

Heme All of the porphyrias result in a defect in the synthesis of the pigment heme. Heme pigments are essential elements in the construction of hemoglobin, myoglobin, and the cytochromes. A complete deficiency of these enzymes is not compatible with life but a partial deficiency can result in the accumulation of intermediate compounds in the synthesis process. It is these compounds that produce the symptoms of porphyria which include psychiatric disturbances, nausea and vomiting, hemiplegia and quadriplegia, electrolyte abnormalities, altered consciousness, and pain. Many pharmacologic agents (especially those that induce the cytochrome p450 system) can precipitate a porphyric crisis such as barbiturates, sulfonylureas, sulfonamides, estrogens, lidocaine, phenytoin, tolbutamide, and ethanol. Agents such as propofol, opioids, and muscle relaxants appear to be safe.

Which form of hemoglobin is most commonly found in the normal, adult bloodstream? A. Hemoglobin A B. Hemoglobin C C. Hemoglobin F D. Hemoglobin S

Hemoglobin A Hemoglobin A comprises about 97% of all the hemoglobin found in the normal, adult bloodstream. Hemoglobin C is implicated in a type of hemolytic anemia, hemoglobin F is found in fetuses, and hemoglobin S is found in patients with sickle cell anemia.

Match the bleeding disorder with the clotting factor that is deficient.

Hemophilia A is a deficiency of Factor VIII. Hemophilia B is a deficiency of factor IX. Hemophilia C is a deficiency of Factor XI. Alexanders disease is a congenital Factor VII deficiency.

Which of the following statements regarding hemophilia is true?

Hemophilia B exhibits a prolonged PTT Both hemophilia A and hemophilia B exhibit a prolonged PTT and a normal PT. The clinical course of the diseases is virtually identical except that they are treated with different clotting factors. They are both X-linked recessive disorders.

Which of the following is a potential side effect of DDAVP administration in the treatment of von Willebrand disease?

Hypotension Too rapid administration of DDAVP IV can cause hypotension. Flood P, Rathmell JP, & Shafer S. Stoeltings Pharmacology and Physiology in Anesthetic Practice. 5th ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2015: 642.

Which of the following is a cause of polycythemia without an increase in total red cell mass?

Hypovolemia Hypovolemia results in an elevated hematocrit because of the decreased volume in which the red cell mass resides without an actual increase in red cell mass. Chronic lung disease and living at high altitudes both result in a compensatory increase in red cell mass and an increased hematocrit as a compensatory mechanism to increase tissue perfusion in the face of decreased blood oxygen levels. Hypoxia is associated with an increased red cell mass.

Prothrombin complex concentrates contain a concentration of factors

II, VII, IX, and X Prothrombin complex concentrates contain a concentration of factors II, VII, IX, and X. It can be used in the treatment of warfarin reversal and hemophilia B, but it is used for many off-label purposes as well. Compared to fresh frozen plasma, PCCs resolve the INR more quickly and do not require crossmatching.

Patients with polycythemia exhibit (select two):

Increased risk for thrombosis Increased blood viscosity Polycythemia places the patient at risk for thrombosis due to the increase in blood viscosity. It also produces a risk for bleeding due to a paradoxical conformational change in the structure of von Willebrand's factor.

What are the effects of COX-2 receptor inhibition? (select two) A. It decreases prostacyclin release from the vascular epithelium B. It inhibits thromboxane A2 C. It inhibits platelet aggregation D. It promotes platelet aggregation

It decreases prostacyclin release from the vascular epithelium It promotes platelet aggregation COX-2 receptor inhibition has been shown to reduce prostacyclin release from the vascular epithelium and can result in increased platelet aggregation. COX-1 receptor inhibition results in inhibition of thromboxane A2. By doing so, it disrupts thromboxane A2's ability to promote platelet aggregation.

Which of the following is true of acute chest syndrome? A. It most commonly affects patients with acromegaly B. Chest x-ray evidence is rarely seen C. It is often precipitated by overhydration D. It typically develops 2-3 days after surgery

It typically develops 2-3 days after surgery Acute chest syndrome is the second most common cause of hospitalization in sickle cell patients and accounts for 25 percent of all sickle cell related deaths. It is diagnosed by the development of new infiltrates on chest film and may be caused by atelectasis, pulmonary microembolic episodes, or pulmonary infection. Acute chest syndrome is a potential complication of sickle cell disease. When it develops, it is typically 2-3 days following surgery and requires aggressive hydration, oxygenation, transfusions to treat anemia, antibiotics to treat pulmonary infection, and occasionally nitric oxide may be used to treat pulmonary hypertension.

Which of the following drugs would not be safe for use in the anesthetic management of a patient with acute porphyria? A. Nitrous oxide B. Neostigmine C. Morphine D. Ketorolac

Ketorolac Nitrous oxide, neostigmine, morphine, fentanyl, succinylcholine, pancuronium, lidocaine, and propofol are considered safe for use in patients with porphyria. Ketorolac, thiopental, thiamylal, etomidate, pentazocine, methohexital, and nifedipine should all be avoided.

Which of the following statements regarding hemophilia A are true?

Patients with hemophilia A have a decrease in Factor VIII The PTT is prolonged in patients with hemophilia A Hemophilia A is sex-linked recessive disorder but affects both males and females (males are just much more likely to have the disease). It is associated with a decrease in Factor VIII levels. Patients with hemophilia A will exhibit a prolonged PTT. Hemophilia B is also known as Christmas disease because Factor IX, which is deficient in patients with hemophilia B, is also known as Christmas factor

Which of the following classes of drugs inhibits platelet function by increasing the level of cyclic AMP?

Phosphodiesterase inhibitors Phosphodiesterase inhibitors increase the level of cyclic AMP which is an inhibitor of platelet aggregation. Cyclooxygenase inhibitors such as aspirin cause irreversible inhibition of platelet cyclooxygenase which prevents synthesis of thromboxane A2. ADP receptor antagonists such as ticlopidine and clopidogrel block the ADP receptor non-competitively and irreversibly inhibit IIb/IIIa platelet aggregation. Glycoprotein IIb/IIIa receptor antagonists such as abciximab reversibly block the IIb/IIIa site by which fibrinogen crosslinks platelets together.

What is the most common cause of bleeding after surgery?

Platelet dysfunction

In the intrinsic pathway, what is the component required to convert factor XII to factor XI? A. Prothrombin activator B. Thrombin C. Prekallikrein D. Calcium

Prekallikrein Factor XII reacts with Prekallikrein and other components like High Molecular Weight Kininogen to activate Factor XI.

Which of the following is a precipitating factor for acute intermittent porphyria? A. Regional anesthesia B. D5W C. Midazolam D. Prolonged NPO times

Prolonged NPO times Fasting has been identified as a precipitating factor for AIP. As such, prolonged NPO times should be avoided and the administration of a glucose-saline solution during the NPO time should be considered

Which test assesses the integrity of the extrinsic hemostasis pathway?

Prothrombin time

Which of the following conditions does not lead to an elevated hematocrit? A. Chronic hypertension B. Polycythemia C. Dehydration D. Sickle cell crisis

Sickle cell crisis Chronic hypertension leads to a contracted fluid volume status, which results in a concentration of the red blood cells in a smaller space, thereby increasing the hematocrit. Polycythemia is a condition resulting in an elevation of the hematocrit due to an overproduction of red blood cells. Dehydration also concentrates the red blood cells in a smaller fluid space, resulting in an increased hematocrit. Sickle cell results in the destruction of red blood cells which lowers the hematocrit

Acute chest syndrome is associated with what disease process?

Sickle cell disease infiltrates on chest film and may be caused by atelectasis, pulmonary microembolic episodes, or pulmonary infection. Acute chest syndrome is a potential complication of sickle cell disease. When it develops, it is typically 2-3 days following surgery and requires aggressive hydration, oxygenation, transfusions to treat anemia, antibiotics to treat pulmonary infection, and occasionally nitric oxide may be used to treat pulmonary hypertension.

Which of the following is false regarding disseminated intravascular coagulation?

The most common cause related to septic shock is gram-positive organisms DIC is associated with a wide range of disorders including septic shock, placenta previa, abruption, amniotic fluid embolism, presence of a dead fetus late in pregnancy, and tumor lysis syndrome. Prolonged surgery and surgery for certain procedures such as prostatectomy for carcinoma, liver transplantation, and coronary bypass surgery are associated with significant bleeding abnormalities. When associated with septic shock, it is most often caused by gram-negative organisms.

Which of the following is true of aspirin toxicity?

There is no direct antidote for aspirin overdose Symptoms of aspirin toxicity include nausea, vomiting, tinnitus and hearing difficulty, abdominal pain, acidosis, CNS derangements, and renal failure. There is no direct antidote for aspirin, but it can be removed from the bloodstream by hemodialysis. The administration of activated charcoal should be considered within an hour of an aspirin overdose. Urine alkalinization will also increase excretion of aspirin through the urine.

Which statement is true of NSAIDs? A. They are more than 90% protein-bound B. They are not metabolized by the liver C. Oral NSAIDs are absorbed in under 2 minutes D. They have a large volume of distribution

They are more than 90% protein-bound NSAIDs are more than 90% protein-bound. Hypoalbuminemia can result in an increase in the free fraction of the drugs. NSAIDs are metabolized by the liver and excreted in the urine or bile. Oral NSAIDs are absorbed in the gastrointestinal tract in 15-30 minutes. NSAIDs have a low volume of distribution (between 0.1 and 0.3 L/kg).

The extrinsic pathway of the hemostatic response is initiated by the release of a group of proteins known as A. Proaccelerins B. Fibrinogen C. Tissue factor D. Collagen

Tissue factor The extrinsic pathway is initiated by the release of a group of proteins known as Tissue Factor when tissues are damaged. Tissue Factor forms a complex with Factor VII, and in an enzymatic reaction requiring calcium, catalyzes the activation of Factor X. Proaccelerin is the other name for factor V, and fibrinogen is another name for factor I. Exposure of the blood to collagen can initiate the intrinsic pathway.

Which of the following causes of platelet dysfunction can be treated with dialysis? A. Uremia B. Thrombocytopenia C. Myeloproliferative disorders D. Disseminated intravascular coagulation

Uremia Platelet dysfunction in common in patients with uremia due to the accumulation of succinic acid and hydrophenolic acid which interfere with the platelet's ability to expose its phospholipid surface. These substances, however, can be removed via dialysis and coagulability improves following treatment. Myeloproliferative disorders can produce defects in both the shape and function of platelets. Thrombocytopenia describes a deficiency of platelets and disseminated intravascular coagulation is a consumptive defect usually due to extensive vasculitis

What is the blood oxygen content in a patient with a hemoglobin of 14.5 g/dL, an oxygen saturation of 97%, and a PaO2 of 102 mmHg? (Calculate answer in mL/dL and to two decimal places)

Using the formula: (1.34 X Hgb X O2 Sat/100) + (0.003 X PaO2), the answer is (18.8471 + 0.306) or (19.15 mL)/dL

Which anticoagulant is a vitamin K antagonist?

Warfarin Warfarin is a vitamin K epoxide reductase inhibitor that alters vitamin K dependent proteins (factors II, VII, IX, and X). Warfarin is an oral medication that takes 36 to 72 hours to reach its peak effect.

Transfusion-related acute lung injury is more likely to occur when the donated blood is from

a female donor TRALI is most commonly due to human leukocyte antigen or human neutrophil antigen from the donor. Because these antigens are more common in females, the risk of TRALI is more common when using donor blood from females.

Which agent irreversibly inactives cyclooxygenase?

acetylsalicylic acid

What are the primary goals for the anesthetic of a patient with sickle cell disease? (select two)

adequate hydration and adequate pain control The anesthetic goals for a patient with sickle cell disease are aimed at preventing a sickle cell crisis. Maintaining adequate hydration, avoiding hypoxia, providing adequate pain control, maintaining normothermia and acid-base status, transfusing blood to maintain a Hgb level of at least 10-11 g/dL, and avoiding tourniquets where possible are all keys to avoiding sickle cell crisis.

Heparin produces its anticoagulant effects by binding to

antithrombin Heparin is a mixture of glycosaminoglycans that produce their anticoagulant effect by binding to antithrombin (formerly known as antithrombin III). This accelerates the rate of thrombin-antithrombin binding by 1,000 to 10,000 times.

Which of the following agents is a low molecular weight heparin? A. warfarin B. ximelagatran C. dalteparin D. rivaroxaban

dalteparin Dalteparin and enoxaparin are low molecular weight heparins that exhibit higher anti-Xa and anti-IIa activity than regular heparin. Warfarin is a vitamin K antagonist. Rivaroxaban and apixaban are direct factor Xa inhibitors. Ximelagatran is a direct thrombin inhibitor.

Patients with von Willebrand disease bleed more readily due to A. inhibition of thromboxane A2 production B. inactivation of platelet cyclooxygenase C. decreased factor VIII activity D. Factor X deficienc

decreased factor VIII activity Von Willebrand factor (vWF) is responsible for carrying factor VIII and serves to help link platelets. Patients with von Willebrand disease have a prolonged bleeding time, low plasma vWF concentration, and decreased factor VIII activity. Aspirin inhibits the production of thromboxane A2. Aspirin and other NSAIDs acetylate and inactivate platelet cyclooxygenase. Aspirin inactivates cyclooxygenase for the life of the platelet but other NSAIDs inactivate them reversibly, and the effect lasts only about 24 hours. Factor X deficiency is Stuart-Prower deficiency and is unrelated to von Willebrand disease.

Compared to COX-1 inhibitors, selective COX-2 inhibitors have a(n) ________ risk of gastrointestinal complications and a(n) ________ risk of cardiovascular complications.

decreased, increased

A major limitation of using the PT and PTT to monitor hemostasis function during a massive transfusion is that they

do not provide information about platelet function The PT and PTT are often used to monitor hemostasis during massive transfusion, but they are limited in their usefulness because they do not provide information about platelet function and may be prolonged due to protein C deficiency. As a result, other techniques such as thromboelastometry and thromboelastography are being used more frequently.

Hemophilia B can be treated with

factor IX concentrate Hemophilia B (also called Christmas disease) is treated with factor IX concentrate. Hemophilia A can be treated with desmopressin, cryoprecipitate, and factor VIII concentrate. Congenital factor VII deficiency is known as Alexander's disease or proconvertin deficiency. Severe liver disease is also associated with an acquired factor VII deficiency.

In the extrinsic coagulation pathway, disruption of the endothelium leads to exposure of tissue factor which binds to

factor VII The extrinsic pathway is initiated by the release of a group of proteins known as Tissue Factor when tissues are damaged. Tissue Factor forms a complex with Factor VII, and in an enzymatic reaction requiring calcium, catalyzes the activation of Factor X.

The activation of plasminogen to plasmin is a major step in

fibrinolysis The activation of plasminogen to plasmin is a major step in fibrinolysis. The substance primarily responsible for activating plasminogen is tissue plasminogen activator (tPA).

Tranexamic acid is used in the treatment of severe bleeding because it

inhibits fibrinolysis Tranexamic acid inhibits fibrinolysis. This is a strategy being used increasingly in the treatment of severe bleeding because it preserves the initial clot formation at bleeding sites.

Clinically, one of the first signs of vitamin B12 deficiency is

megaloblastic anemia Vitamin B12 deficiency can produce symptoms such as peripheral neuropathy, myelopathy, and encephalopathy, but the first clinical presentation is typically megaloblastic anemia (also known as pernicious anemia). Megaloblastic anemia is also the most common presentation of folic acid deficiency.

Hypersensitivity reactions to NSAIDs are more common in patients with A. congestive heart failure B. allergies to kiwi or bananas C. a history of chickenpox D. nasal polyps

nasal polyps Hypersensitivity reactions to NSAIDs are more common in patients with nasal polyps or asthma. The reactions usually appear as urticaria, rhinitis, and bronchospasm.

The underlying cause of organ failure due to disseminated intravascular coagulation is

organ ischemia due to thrombosis The widespread bleeding and thrombosis from DIC can cut off the blood supply to tissues and organs, resulting in ischemia.

Which test is most widely used to assess the intrinsic coagulation pathway?

partial thromboplastin time The partial thromboplastin time is a commonly used test that assesses the intrinsic coagulation pathway. The prothrombin time evaluates the extrinsic pathway. The INR is a normalization calculation performed on the prothrombin time.

NSAIDs fundamentally inhibit the synthesis of

prostaglandins NSAIDS prevent arachidonic acid from binding to the COX enzyme site, resulting in the inhibition of prostaglandin synthesis.

Warfarin therapy is best monitored with the

prothrombin time The prothrombin time is especially sensitive to the vitamin K-dependent clotting factors and is best for monitoring warfarin therapy.

Which of the following agents produces irreversible inhibition of platelet function by preventing the synthesis of thromboxane A2?

salicilates

The primary function of von Willebrand factor is

to promote platelet aggregation and adhesion to collagen Von Willebrand Factor binds platelet receptors to exposed collagen initially by a Ib-vWF and collagen interaction and eventually assists in a stronger binding between platelets and collagen via the IIb-IIIa-vWF and collagen interaction. It also acts as a bridge between the glycoprotein IIb/IIIa receptors to promote platelet aggregation.

Severe heparin-induced thrombocytopenia

typically occurs within 4-5 days of heparin administration Thrombocytopenia can develop within a few hours of heparin administration, but the severe form (resulting in a drop in the platelet count by as much as 50%) is due to heparin-dependent antibodies to platelet factor IV and typically occurs after 4-5 days of treatment.

Tumor lysis syndrome is associated with elevated levels of (select three) A. sodium B. chloride C. uric acid D. phosphate E. potassium F. parathyroid hormone G. calcium H. vasopressin

uric acid, phosphate, potassium Tumor lysis syndrome occurs when tumor cells are destroyed by chemotherapy, resulting in the release of uric acid, potassium, and phosphate. It most commonly is associated with hematologic cancer such as acute lymphoblastic leukemia. The effects are particularly severe when accompanied by renal compromise. The elevated phosphate level can also result in a secondary hypocalcemia

What treatment regimens are effective in ameliorating the symptoms of von Willebrand disease? (select two)

vWF concentrate desmopressin

The circulating levels of what components will be increased by DDAVP administration in a patient with von Willebrand disease? (select two)

von Willebrand factor Factor VIII DDAVP causes vWF to split from Factor VIII and increases the serum levels of both components.

The perioperative use of NSAIDs should be avoided in patients

who are hypovolemic The perioperative use of NSAIDs should be avoided in patients with hypovolemia as it can increase the risk of renal injury.