Which of the following statement(s) is/are correct concerning the cardiovascular response to shock? a. Changes in cardiac contractile function shift the Frank Starling curve up and down b. Venoconstriction from skeletal muscle is a significant contributor to the restoration of blood volume with shock c. Arterial vasoconstriction affects all vascular beds equally d. The total circulating blood volume is equally split between the arterial and venous system

Which of the following statement(s) is/are correct concerning the cardiovascular response to shock? a. Changes in cardiac contractile function shift the Frank Starling curve up and down b. Venoconstriction from skeletal muscle is a significant contributor to the restoration of blood volume with shock c. Arterial vasoconstriction affects all vascular beds equally d. The total circulating blood volume is equally split between the arterial and venous system
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Answer: a  Central in the general cardiovascular response to shock is the action of the heart itself. The principle determinants of cardiac function in the normal heart are the volume of blood available for the heart to pump (preload), the systolic contractile capability, and the diastolic filling of the ventricles. In hypovolemia, the two dynamic variables of cardiac function, ventricular filling and myocardial contractility remain paramount and determine the stroke volume. The product of stroke volume and heart rate in turn determines the cardiac output. Increases in ventricular end-diastolic volume, reflecting venous return, cause ventricular distention. Ventricular distention in turn produces increased volume output with each stroke, the Frank Starling mechanism. Contractile function may vary independent of volume status. Changes in the contractile function shift the Starling curve up and down, producing increases or decreases in stroke volume for any given end-diastolic volume. A fundamental requirement for cardiovascular function is adequate cardiac filling, and cardiac output cannot exceed venous return. The venous system contains nearly two-thirds of the total circulating blood volume, including 20% to 30% within the splanchnic venous system. Most of this volume resides in small veins, which comprise the bulk of venous capacitance. The venous system, especially that of the splanchnic circulation, becomes important in the physiologic compensation to hypoperfusion because it serves as a dynamic reservoir for the autoinfusion of blood volume involving both active and passive mechanisms. The splanchnic circulation makes major contributions to the maintenance of venous return, therefore, it is likely that sympathetic venoconstriction is responsible for a portion of the blood mobilized from the splanchnic venous circulation. Sympathetic mediated venoconstriction in skin and skeletal muscle is probably not as significant as a source of blood volume. Selective vasoconstriction occurs in response to alpha adrenergic receptor stimulation with increased sympathetic activity in shock. Sympathetic stimulation does not cause significant vasoconstriction of either cerebral or coronary vessels, with normal blood flow maintained in these circulations. Blood flow to the skin is sacrificed early, followed by that to the kidneys and splanchnic viscera
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Which of the following statement(s) is/are true concerning the relationship between cardiac function and effective blood volume? a. A pulmonary capillary wedge pressure of 5–10 rules out fluid overload as a cause of pulmonary edema b. A shift to the right in the Frank-Starling curve is associated with compromised cardiac function c. Dilutional anemia may contribute to tachycardia even though blood volume and filling pressures are normal d. The sole purpose of a pulmonary artery catheter is to measure pulmonary artery pressure and cardiac output

Description : Which of the following statement(s) is/are true concerning the relationship between cardiac function and effective blood volume? a. A pulmonary capillary wedge pressure of 5-10 rules out ... sole purpose of a pulmonary artery catheter is to measure pulmonary artery pressure and cardiac output

Last Answer : Answer: b, c Although physical findings are often adequate to establish a diagnosis and institute management of cardiac failure, direct measurement of filling pressures of the right heart ( ... blood volume is normal, filling pressures are normal, and total body extracellular fluid is excessive

Which of the following statement(s) is/are true concerning the neuroendocrine responses to shock? a. Sympathetic nerve endings release epinephrine which is responsible for greater than 80% of systemic vascular resistance b. Endogenous epinephrine is the primary contributor to systemic vascular resistance c. Increased pancreatic secretion of glucagon contributes to glucose intolerance associated with injury and sepsis d. The renin-angiotensin axis further augments the sympathetic-mediated vasoconstriction

Description : Which of the following statement(s) is/are true concerning the neuroendocrine responses to shock? a. Sympathetic nerve endings release epinephrine which is responsible for greater than 80% ... injury and sepsis d. The renin-angiotensin axis further augments the sympathetic-mediated vasoconstriction

Last Answer : Answer: c, d The neuroendocrine response to shock attempts to achieve restoration of effective blood volume, mobilization of metabolic substrates, and maintenance of central ... . Angiotensin II is an extremely effective vasoconstrictor that further augments sympathetic-mediated vasoconstriction

Which of the following statement(s) is/are true concerning septic shock? a. The clinical picture of gram negative septic shock is specifically different than shock associated with other infectious agents b. The circulatory derangements of septic shock precede the development of metabolic abnormalities c. Splanchnic vascular resistance falls in similar fashion to overall systemic vascular resistance d. Despite normal mechanisms of intrinsic expansion of the circulating blood volume, exogenous volume resuscitation is necessary

Description : Which of the following statement(s) is/are true concerning septic shock? a. The clinical picture of gram negative septic shock is specifically different than shock associated with ... mechanisms of intrinsic expansion of the circulating blood volume, exogenous volume resuscitation is necessary

Last Answer : Answer: d The clinical findings in sepsis and septic shock represent the host response to infection. Gram-positive and gram-negative bacteria, viruses, fungi, rickettsiae, and ... intravascular volume, exogenous volume resuscitation must be provided to restore venous return and ventricular filling

Which of the following statement(s) is/are true concerning oxygen delivery? a. The amount of oxygen delivered to peripheral tissues is dependent upon the oxygen content in arterial blood and cardiac output b. Oxygen content is commonly measured in arterial blood c. The normal arterial-venous difference is 4 cc O2/dL d. Normal systemic oxygen delivery for a typical adult is approximately 1000 cc/min

Description : Which of the following statement(s) is/are true concerning oxygen delivery? a. The amount of oxygen delivered to peripheral tissues is dependent upon the oxygen content in arterial blood and cardiac ... O2/dL d. Normal systemic oxygen delivery for a typical adult is approximately 1000 cc/min

Last Answer : Answer: a, c, d The amount of oxygen that is delivered to peripheral tissues is the product of the oxygen content in arterial blood times the cardiac output. Normally, oxygen content of arterial blood is ... of venous blood is 16 cc/dL. Hence, the normal arterial-venous difference is 4 cc O2/dL

Which of the following statements about septic shock are true? A. A circulating myocardial depressant factor may account for the cardiac dysfunction sometimes seen with shock due to sepsis or SIRS. B. A cardiac index (CI) of 6 liters per minute per square meter of body surface, a pulmonary capillary wedge pressure of 15 mm. Hg, and a systemic vascular resistance index (SVRI) of 800 dynes-sec/(cm 5-m 2) is a hemodynamic profile consistent with septic shock. C. An increase in SvO 2 in septic patients may be explained by the finding of anatomic arteriovenous shunts. D. Results of human trials employing antimediator therapy, such as antiendotoxin antibodies, IL-1 receptor antagonist, and tumor necrosis factor (TNF) antibodies, have confirmed animal studies that demonstrate a significant im

Description : Which of the following statements about septic shock are true? A. A circulating myocardial depressant factor may account for the cardiac dysfunction sometimes seen with shock due to sepsis or ... animal studies that demonstrate a significant improvement in survival with the use of such agents.

Last Answer : Answer: AB DISCUSSION: Shock due to sepsis or SIRS frequently manifests as a hyperdynamic cardiovascular response, consisting of an elevated CI and a decreased SVR or SVRI. Occasionally, ... been encouraging thus far in human clinical trials, despite the promising results from many animal studies

A 32-year-old man suffers a spinal cord injury with a resultant paraplegia in a motorcycle accident. He presents to the emergency room with hypotension. Which of the following statement(s) is/are true concerning his diagnosis and management? a. The low blood pressure can be assumed to be due to neurogenic shock b. The sole cause of hypotension is the loss of sympathetic input to the venous system c. Despite significant hypotension, secondary organ injury will be uncommon d. There is no role for pharmacologic intervention to maintain blood pressure

Description : A 32-year-old man suffers a spinal cord injury with a resultant paraplegia in a motorcycle accident. He presents to the emergency room with hypotension. Which of the following statement(s) is/ ... injury will be uncommon d. There is no role for pharmacologic intervention to maintain blood pressure

Last Answer : Answer: c Neurogenic shock results from interruption of sympathetic vasomotor input and develops after spinal cord injury, spinal anesthesia, and severe head injury. Under normal conditions, baseline ... the cause is not neurogenic and search for occult blood loss or cardiogenic causes of shock

Which of the following statement(s) is/are correct concerning the immunoinflammatory response to shock? a. The anaphylactoxins, C3a and C5a, are products of activation of only the classical pathway of the compliment cascade b. Eicosanoids, such as prostaglandins are stored in platelets and endothelial cells and released in response to inflammatory stimuli c. Thromboxane and PGI2 have similar effects d. Platelet-activating factor can be released by both circulating and fixed tissue cells

Description : Which of the following statement(s) is/are correct concerning the immunoinflammatory response to shock? a. The anaphylactoxins, C3a and C5a, are products of activation of only the classical pathway ... effects d. Platelet-activating factor can be released by both circulating and fixed tissue cells

Last Answer : Answer: d Inflammatory mediators have recently been recognized as playing a significant role in the clinical manifestations and progression of shock and the development ... increased pulmonary vascular resistance, bronchoconstriction, peripheral vasodilatation, and increased vascular permeability

Which of the following statement(s) is/are true concerning the pulmonary response to shock? a. The acute pulmonary vascular response to shock differs markedly from that of systemic vasculature b. The pulmonary edema of ARDS occurs in the face of elevated left heart pressures c. The initial physiologic changes of ARDS involve the capillary endothelial cells and the type I pneumocyte d. Mechanisms proposed in the pathogenesis of ARDS include injury from mediators of inflammation elsewhere and from activated cellular elements e. A decrease in lung compliance may result from the loss of type I pneumocytes

Description : Which of the following statement(s) is/are true concerning the pulmonary response to shock? a. The acute pulmonary vascular response to shock differs markedly from that of systemic vasculature b. The ... elements e. A decrease in lung compliance may result from the loss of type I pneumocytes

Last Answer : Answer: c, d, e Contributing pathophysiologic processes to the pulmonary manifestations of shock include the pulmonary component of the cardiovascular response, disruption of the normal ... injury from mediators of inflammation elaborated elsewhere, and from activated cellular blood elements

Which of the following statement(s) is/are true concerning the vascular response to injury? a. Vasoconstriction is an early event in the response to injury b. Vasodilatation is a detrimental response to injury with normal body processes working to avoid this process c. Vascular permeability is maintained to prevent further cellular injury d. Histamine, prostaglandin E2 (PGE2) and prostacyclin (PGI2) are important mediators of local vasoconstriction

Description : Which of the following statement(s) is/are true concerning the vascular response to injury? a. Vasoconstriction is an early event in the response to injury b. Vasodilatation is a ... Histamine, prostaglandin E2 (PGE2) and prostacyclin (PGI2) are important mediators of local vasoconstriction

Last Answer : Answer: a After wounding, there is transient vasoconstriction mediated by catecholamines, thromboxane, and prostaglandin F2 (PGF2a). This period of vasoconstriction lasts for only five to ten minutes. Once ... and mast cells and enhance the egress of cells and substrate into the wound and tissue

Which of the following statement(s) is/are true concerning pharmacologic agents used in the treatment of shock? a. The primary difference between dopamine and dobutamine is the absence of significant a adrenergic activity b. The renal and mesenteric vasoconstrictive effects of norepinephrine complicate and sometimes restrict its use c. The apparent paradoxical use of vasodilators, such as nitroprusside, in shock is indicated as a means to augment cardiac function d. Isoproterenol with its potent b-adrenergic effect, is a particularly useful agent in the treatment of all forms of shock

Description : Which of the following statement(s) is/are true concerning pharmacologic agents used in the treatment of shock? a. The primary difference between dopamine and dobutamine is the absence of significant a ... b-adrenergic effect, is a particularly useful agent in the treatment of all forms of shock

Last Answer : Answer: a, b, c Therapeutic adjustments of intravascular volume (preload) and systemic vascular resistance (afterload) form the basis of the treatment strategies for all ... careful constant monitoring of arterial pressure and repeated hemodynamic measurements with a pulmonary artery catheter

Which of the following statement(s) is/are true concerning tumor necrosis factor (TNF)? a. TNF is a product of activated macrophages secreted in response to contact with endotoxin or lipopolysaccharide, antibody complexes, or inflammatory stimuli b. The liver and gut appear to be a major source of TNF following hypoperfusion c. Circulating levels of TNF correlate well with severity of tissue injury in shock d. Recently completed clinical trials of anti-TNF antibody in septic patients shows a marked improvement in survival

Description : Which of the following statement(s) is/are true concerning tumor necrosis factor (TNF)? a. TNF is a product of activated macrophages secreted in response to contact with endotoxin or ... completed clinical trials of anti-TNF antibody in septic patients shows a marked improvement in survival

Last Answer : Answer: a, b Tumor necrosis factor (TNF), a protein product of activated macrophages, is secreted in response to contact with endotoxin or lipopolysaccharide, antibody complexes, or ... patients utilizing infusion of monoclonal antibodies to the TNF molecule have shown no overall survival benefit

Which of the following statement(s) is/are true concerning O2 venous saturation monitoring? a. The normal saturation of mixed venous blood is 50% b. Mixed venous blood obtained for saturation monitoring can be obtained from any peripheral vein c. If arterial blood is fully saturated, the saturation of mixed venous blood is 80% d. In less than fully saturated blood, the difference between arterial and venous saturation corresponds to oxygen extraction

Description : Which of the following statement(s) is/are true concerning O2 venous saturation monitoring? a. The normal saturation of mixed venous blood is 50% b. Mixed venous blood obtained ... than fully saturated blood, the difference between arterial and venous saturation corresponds to oxygen extraction

Last Answer : Answer: c, d The relationship between oxygen delivery and oxygen consumption is reflected in the amount of oxygen in venous blood. Under normal circumstances, oxygen delivery is 1000 ... and venous saturation corresponds to the oxygen extraction, hence the oxygen delivery/oxygen consumption ratio

Which of the following statement(s) is/are true concerning CO2 transfer in the lung? a. Carbon dioxide excretion is a direct function of alveolar ventilation b. Normally end tidal CO2 should be identical to PaCO2 c. The gradient between end tidal and arterial CO2 can be an indirect measure of nonperfused alveoli d. Positive pressure ventilation under normal airway pressures creates a significant end tidal PaCO2 gradient

Description : Which of the following statement(s) is/are true concerning CO2 transfer in the lung? a. Carbon dioxide excretion is a direct function of alveolar ventilation b. Normally end tidal ... d. Positive pressure ventilation under normal airway pressures creates a significant end tidal PaCO2 gradient

Last Answer : Answer: a, b, c The amount of carbon dioxide excretion is directly related to alveolar ventilation. While oxygenation is a function of matching blood flow to alveoli, carbon dioxide excretion is ... high (over 30 cm H2O) and the compression volume is a significant component of each exhaled breath

Which of the following statement(s) is/are true concerning the microvascular and cellular response to shock? a. Osmodically induced mobilization of intracellular fluid is the initial response to restore intravascular volume b. With larger volume hemorrhagic shock deterioration of normal cellular transmembrane potential occurs resulting in an increase in extracellular sodium and water c. The accumulation of anaerobic metabolites override normal homeostatic vasomotor tone and contribute to the maladaptive vasodilatation d. Abnormal intracellular calcium homeostasis may contribute to the cellular dysfunction of shock

Description : Which of the following statement(s) is/are true concerning the microvascular and cellular response to shock? a. Osmodically induced mobilization of intracellular fluid is the initial ... d. Abnormal intracellular calcium homeostasis may contribute to the cellular dysfunction of shock

Last Answer : Answer: c, d Moderate hypovolemia results in a relatively rapid spontaneous restitution of intravascular volume through expansion of the plasma space. This plasma expansion by ... potassium pump. Cellular dysfunction also appears to be related to abnormal intracellular calcium homeostasis

Which of the following statements regarding cytokines is incorrect? A. Cytokines act directly on target cells and may potentiate the actions of one another. B. Interleukin 1 (IL-1) is a major proinflammatory mediator with multiple effects, including regulation of skeletal muscle proteolysis in patients with sepsis or significant injury. C. Platelet-activating factor (PAF) is a major cytokine that results in platelet aggregation, bronchoconstriction, and increased vascular permeability. D. Tumor necrosis factor alpha (TNF-a), despite its short plasma half-life, appears to be a principal mediator in the evolution of sepsis and the multiple organ dysfunction syndrome because of its multiple actions and the secondary cascades that it stimulates.

Description : Which of the following statements regarding cytokines is incorrect? A. Cytokines act directly on target cells and may potentiate the actions of one another. B. Interleukin 1 (IL-1) ... organ dysfunction syndrome because of its multiple actions and the secondary cascades that it stimulates.

Last Answer : Answer: C DISCUSSION: Cytokines are soluble peptide molecules that are synthesized and secreted by a number of cell types in response to injury, inflammation, and infection. Cytokines, which ... is thought to play a central role in the stress response, particularly in response to endotoxemia

A 68-year-old male who underwent a repair of an abdominal aortic aneurysm 5 days ago, develops tachycardia, tachypnea, hypotension with cool, pale, mottled cyanotic extremities. He is agitated and complains of shortness of breath. Which of the following statement(s) is/ are correct concerning his diagnosis and management? a. Myocardial ischemia secondary to preexisting coronary artery disease is most likely the underlying cause of this problem b. Invasive hemodynamic monitoring with a Swan-Gantz catheter will demonstrate a low cardiac output, a high systemic vascular resistance, and elevated cardiac filling pressures c. The use of morphine sulphate and nitrates should be part of the initial management d. The primary pharmacologic treatment involves the use of moderate doses of inotropic ag

Description : A 68-year-old male who underwent a repair of an abdominal aortic aneurysm 5 days ago, develops tachycardia, tachypnea, hypotension with cool, pale, mottled cyanotic extremities. He ... use of moderate doses of inotropic agents e. Afterload reduction with nitroprusside is absolutely contraindicated

Last Answer : Answer: a, b, d Intrinsic cardiogenic shock results from failure of the heart as an effective pump. Coronary artery disease is the most common cause of myocardial ... hemodynamic monitoring. Infusion of afterload-reducing agents can be administered in conjunction with inotropic support

Which of the following statement(s) is/are true concerning the antibody response to an invading antigen? a. All antibodies are composed of one type of heavy and one type of light protein chain b. The carboxyl terminus of the heavy chain is the antigen binding site c. Antibody of the immunoglobulin G class is the initial antibody produced in response to an antigenic stimulus d. Immunoglobulins A, D, and E play an active role in the circulating humoral response

Description : Which of the following statement(s) is/are true concerning the antibody response to an invading antigen? a. All antibodies are composed of one type of heavy and one type of light protein chain b. ... stimulus d. Immunoglobulins A, D, and E play an active role in the circulating humoral response

Last Answer : Answer: a Humoral defenses consist of antibody (immunoglobulin; Ig) and complement. All Ig classes (IgM, IgG, IgA, IgE, IgD) and IgG subclasses are composed of one type (M, G, A, E, D ... exist in smaller amounts in the circulation and do not appear to play a major role as host defense components

Which of the following statement(s) is/are true concerning the treatment of MOFS? a. Prevention and therapy of MOFS requires control of the infectious or inflammatory source b. Restoration of normal clinical parameters such as blood pressure, pulse rate, and urine output ensures optimal resuscitation in most patients c. Branch chain amino acids play and important role in the nutritional support of the patient d. Because of the nature of gut injury, total parenteral nutrition is preferred for most patients with MOFS

Description : Which of the following statement(s) is/are true concerning the treatment of MOFS? a. Prevention and therapy of MOFS requires control of the infectious or inflammatory source b. Restoration of normal ... of the nature of gut injury, total parenteral nutrition is preferred for most patients with MOFS

Last Answer : Answer: a, c The therapy of MOFS is directed towards interrupting the involving pathophysiologic process and providing an optimal physiologic environment for healing and recovery. ... Enteral absorption and processing of nutrients appears superior to TPN and lessens overall complications

Which of the following statement(s) is/are true concerning the physiology of the microvascular system? a. Filtration of capillary fluid into the interstitial and the subsequent reabsorption is influenced by Starling’s law of ultrafiltration b. The most important variable controlling blood to a capillary bed is the length of the vessel c. Most of the resistance to systemic blood flow occurs at the arteriolar level d. Adrenergic vasoconstriction can arrest blood flow to an entire capillary bed

Description : Which of the following statement(s) is/are true concerning the physiology of the microvascular system? a. Filtration of capillary fluid into the interstitial and the subsequent reabsorption is ... the arteriolar level d. Adrenergic vasoconstriction can arrest blood flow to an entire capillary bed

Last Answer : Answer: a, c, d Exchange of material between the vascular space and the cell of various tissues via the interstitial space is essential for organ viability and occurs at the ... contractions are potent enough that blood flow to entire capillary beds can be arrested by adrenergic vasoconstriction

In contrast to a patient undergoing an elective operation, which of the following statement(s) is/are true concerning a patient who has suffered a multiple trauma? a. Basal metabolic rates are similar b. The patient is highly sensitive to insulin c. Utilization of the amino acids, glutamine and alanine, is similar to their composition in skeletal muscle d. Fat and protein stores are rapidly depleted

Description : In contrast to a patient undergoing an elective operation, which of the following statement(s) is/are true concerning a patient who has suffered a multiple trauma? a. Basal metabolic rates are ... is similar to their composition in skeletal muscle d. Fat and protein stores are rapidly depleted

Last Answer : Answer: b, d The degree of hypermetabolism is generally related to the severity of injury. Patients with long-bone fractures have a 15-25% increase in metabolic rate, whereas metabolic ... in injured subjects, if unfed, severely injured patients rapidly deplete their fat and protein stores

All of the following are true about neurogenic shock except: A. There is a decrease in systemic vascular resistance and an increase in venous capacitance. B. Tachycardia or bradycardia may be observed, along with hypotension. C. The use of an alpha agonist such as phenylephrine is the mainstay of treatment. D. Severe head injury, spinal cord injury, and high spinal anesthesia may all cause neurogenic shock.

Description : All of the following are true about neurogenic shock except: A. There is a decrease in systemic vascular resistance and an increase in venous capacitance. B. Tachycardia or bradycardia may be ... Severe head injury, spinal cord injury, and high spinal anesthesia may all cause neurogenic shock.

Last Answer : Answer: C DISCUSSION: Neurogenic shock occurs when severe head injury, spinal cord injury, or pharmacologic sympathetic blockade leads to sympathetic denervation and loss of vasomotor tone. ... of treatment. The use of alpha-adrenergic agonist is infrequently necessary to treat neurogenic shock

Which of the following statement(s) is/are true concerning metabolic derangements in sepsis and the systemic inflammatory response syndrome which may follow progressive shock? a. Alterations in glucose metabolism lead to the development of efficient substrate utilization b. A progressive rise in serum triglyceride levels result from less efficient clearance and increased hepatic lipogenesis c. A net negative nitrogen balance occurs due to the oxidative metabolism of proteins to meet energy needs d. The serum aromatic amino acids fall rapidly as they are actively used in oxidative metabolism

Description : Which of the following statement(s) is/are true concerning metabolic derangements in sepsis and the systemic inflammatory response syndrome which may follow progressive shock? a. Alterations in glucose ... The serum aromatic amino acids fall rapidly as they are actively used in oxidative metabolism

Last Answer : Answer: b, c A broad spectrum of metabolic abnormalities become apparent in sepsis and the systemic inflammatory response syndrome following shock. Disruption of the normal cycles of carbohydrate, ... acetyl coenzyme A. This results in reduced serum level of leucine, isoleucine and valine

Tests of coagulation are used to monitor anticoagulation treatment and detect intrinsic abnormalities in coagulation. Which of the following statement(s) is/are true concerning coagulation tests? a. Prothrombin time (PT) measures both the intrinsic and extrinsic clotting pathways and fibrinogen b. Activated partial thromboplastin time (aPTT) can be used to monitor both oral anticoagulation with Warfarin and intravenous anticoagulation with heparin c. Thrombin clotting time (TCT) is a measurement of the time it takes for exogenously administered thrombin to turn plasma fibrinogen into fibrin clot d. Whole blood activated clotting time (ACT) is a measurement of the ability of whole blood to clot and is used to monitor heparin levels intraoperatively during cardiovascular and peripheral vascu

Description : Tests of coagulation are used to monitor anticoagulation treatment and detect intrinsic abnormalities in coagulation. Which of the following statement(s) is/are true concerning ... is used to monitor heparin levels intraoperatively during cardiovascular and peripheral vascular operations

Last Answer : Answer: a, c, d Coagulation tests include prothrombin time (PT), which measures the intrinsic and extrinsic pathways of fibrinogen production and is the most common method for ... more while for peripheral vascular applications, values of 250 seconds or greater are considered appropriate

Which of the following statement(s) is/are true concerning carrier proteins? a. Carrier proteins are distinguished by three types of mechanisms: carrier-type, channel-type, and conduction-type b. Conformational changes in the membrane protein occur between the conducting and the nonconducting states c. A channel-type carrier protein has two states—closed and open d. Carrier-type transport proteins are equally accessible from either side of the membrane

Description : Which of the following statement(s) is/are true concerning carrier proteins? a. Carrier proteins are distinguished by three types of mechanisms: carrier-type, channel-type, and conduction-type b. ... and open d. Carrier-type transport proteins are equally accessible from either side of the membrane

Last Answer : Answer: b, c Most transport proteins appear to function as carriers, rather than channels. Important distinctions can be made between types of carrier proteins on the basis of transport kinetics. ... a carrier mechanism, the binding site is available only one side of the membrane at any instant

Which of the following statement(s) is/are true concerning oxygen kinetics in a critically ill, febrile patient? a. Oxygen consumption will likely exceed three times normal b. The high cardiac output and pulse rate are designed to increase oxygen delivery c. The hyperdynamic response may actually increase oxygen delivery to exceed the increase in oxygen consumption d. The patient can maintain adequate compensation as long as the oxygen delivery/oxygen consumption rate is greater than 2:1

Description : Which of the following statement(s) is/are true concerning oxygen kinetics in a critically ill, febrile patient? a. Oxygen consumption will likely exceed three times normal b. The high cardiac ... adequate compensation as long as the oxygen delivery/oxygen consumption rate is greater than 2:1

Last Answer : Answer: b, d In critically ill patients oxygen consumption may be elevated or depressed, but slight to moderate elevations in oxygen consumption is the most common abnormality in critically ill patients. ... however, and the patient will remain stable as long as the ratio is greater than 2:1

Which of the following statement(s) is/are true concerning methods of nutritional support? a. Optimal results for enteral feedings are achieved with approximately half of calories supplied as carbohydrate and half as fat b. Diarrhea is the most common complication of enteral feeds and is due to the high osmolarity of the carbohydrate components c. The hyperosmolar nature of parenteral fat solutions requires central venous administration d. Approximately 25–50% of calories should be provided as fat emulsion in patients receiving total parenteral nutrition

Description : Which of the following statement(s) is/are true concerning methods of nutritional support? a. Optimal results for enteral feedings are achieved with approximately half of calories supplied as ... -50% of calories should be provided as fat emulsion in patients receiving total parenteral nutrition

Last Answer : Answer: a, b, d Most formulas for enteral feeding range from 1.0 to 2 cal/ml and include 3 to 7% protein. Most of the calories are supplied as glucose or sucrose, so that the solutions ... up to 25 to 50% of calories each day as fat emulsion may optimize the delivery of this caloric delivery

Which of the following statement(s) concerning intravenous nutritional support is/are true? a. Concentrations of glucose no higher than 5% should be used to avoid peripheral vein sclerosis b. A major disadvantage of the peripheral technique is limited caloric delivery c. If total parenteral nutrition is required, access to the superior vena cava via the external jugular vein is the most suitable site d. Venous thrombosis is an uncommon complication for long-term central vein catheterization

Description : Which of the following statement(s) concerning intravenous nutritional support is/are true? a. Concentrations of glucose no higher than 5% should be used to avoid peripheral vein sclerosis ... suitable site d. Venous thrombosis is an uncommon complication for long-term central vein catheterization

Last Answer : Answer: b Although peripheral access can be used for intravenous nutrition, the major disadvantage of this technique is limited caloric delivery to meet catabolic demands within tolerated fluid ... studies that use phlebography or radionucleotide venography indicate the incidence is as high as 35%

External pneumatic compression has been advocated for the prevention of deep venous thrombosis during operative procedures. Which of the following statement(s) concerning the use of external pneumatic compression devices is/are true? a. Intermittent pneumatic compression is as effective as low-dose heparin in prevention of venous thrombosis b. These devices function by compressing the lower extremities therefore augmenting venous return c. Pneumatic compression devices may also exhibit their antithrombotic effect through stimulating local and systemic fibrinolysis d. The length of time that intermittent pneumatic compression should be used includes through the operation and for at least several days in the postoperative period

Description : External pneumatic compression has been advocated for the prevention of deep venous thrombosis during operative procedures. Which of the following statement(s) concerning the use of external pneumatic ... includes through the operation and for at least several days in the postoperative period

Last Answer : Answer: b, c, d In many well-controlled studies of venous prophylaxis, intermittent pneumatic compression has been found to be as effective as low-dose heparin therapy. In addition to augmentation ... be used through the operation and for at least five days in the face or prolonged immobilization

Useful steps to optimize systemic oxygen delivery include: a. Maintaining mean arterial blood pressure between 50 and 90 mm Hg b. Optimizing PEEP levels by monitoring mixed venous saturation c. Turning the patient prone d. Sedation or paralysis

Description : Useful steps to optimize systemic oxygen delivery include: a. Maintaining mean arterial blood pressure between 50 and 90 mm Hg b. Optimizing PEEP levels by monitoring mixed venous saturation c. Turning the patient prone d. Sedation or paralysis

Last Answer : Answer: a, b, c, d Optimizing systemic oxygen delivery in relationship to oxygen requirement is the primary goal of management. Improving oxygenation of the blood itself by ... sedation, and establishing muscular paralysis decrease oxygen consumption, and decrease the need for oxygen delivery

Which of the following statement(s) is/are true concerning the pathophysiology of gas exchange? a. Hypoventilation in relation to perfusion can result in an oxygen saturation of less than 100% b. Diffusion block and / mismatch can almost completely be overcome by breathing 100% oxygen c. Transpulmonary shunting does not occur under normal circumstances d. The normal arterial oxygen saturation should be 100%

Description : Which of the following statement(s) is/are true concerning the pathophysiology of gas exchange? a. Hypoventilation in relation to perfusion can result in an oxygen saturation of less than 100% ... does not occur under normal circumstances d. The normal arterial oxygen saturation should be 100%

Last Answer : Answer: a, b Under normal conditions, red blood cells in the pulmonary capillaries become fully saturated and oxygen dissolves in plasma resulting in blood PO2 of 100 and O2 saturation of 100%. This ... the fact that normal arterial PO2 is 90-100 mm Hg and the normal O2 saturation is 98%

Thrombolytic therapy has become a useful adjunct in the management of peripheral arterial occlusion. In this setting, direct intraarterial administration rather than intravenous has been advocated to decrease the risk of systemic bleeding. Which of the following true statement(s) concerning the use of thrombolytic agents for arterial occlusion is/are true? a. A standard technique involves infusing high-dose urokinase, 4000 units per minute for 1–2 hours, directly into the clot by a catheter embedded in the thrombus b. If progress is made, further fibrinolytic therapy is given at 1000 to 2000 units per minute until clot lysis has occurred c. The usual infusion time by the above-stated technique is usually in excess of 24 hours d. Successful clot lysis occurs more frequently in arterial graf

Description : Thrombolytic therapy has become a useful adjunct in the management of peripheral arterial occlusion. In this setting, direct intraarterial administration rather than intravenous has been advocated ... may be indicated for situations where complete clot evacuation cannot be accomplished surgically

Last Answer : Answer: a, b, e The most popular method for intraarterial thrombolytic therapy for arterial occlusion involves passing a guidewire through the thrombus with arteriographic guidance and ... acute arterial occlusion) or when distal vasculative is occluded and precludes appropriate inflow patency

Which of the following statement(s) is/are true concerning protein/amino acid metabolism in man? a. The major source of amino acids is breakdown of circulating proteins b. The recommended daily allowance for protein may triple in critically ill patients c. Urinary nitrogen losses will approach 0 in the face of protein starvation d. Negative nitrogen balance refers to a decrease in nitrogen taken into the body versus the amount of nitrogen lost

Description : Which of the following statement(s) is/are true concerning protein/amino acid metabolism in man? a. The major source of amino acids is breakdown of circulating proteins b. The recommended daily ... balance refers to a decrease in nitrogen taken into the body versus the amount of nitrogen lost

Last Answer : Answer: b, d About 15% of the total body weight is made up of proteins, about half of which are intracellular and half extracellular. In man and other animals, dietary protein is the source of ... is exceeded by the amount of nitrogen lost in the urine, stool, skin, wounds, and fistula drainage

All of the following statements about hemorrhagic shock are true except: A. Following hemorrhagic shock, there is an initial interstitial fluid volume contraction. B. Dopamine, or a similar inotropic agent, should be given immediately for resuscitation from hemorrhagic shock, to increase cardiac output and improve oxygen delivery to hypoperfused tissues. C. The use of colloid solutions or hypertonic saline solutions is contraindicated for treatment of hemorrhagic shock. D. In hemorrhagic shock, a narrowed pulse pressure is commonly seen before a fall in systolic blood pressure.

Description : All of the following statements about hemorrhagic shock are true except: A. Following hemorrhagic shock, there is an initial interstitial fluid volume contraction. B. Dopamine, or a similar inotropic ... shock, a narrowed pulse pressure is commonly seen before a fall in systolic blood pressure.

Last Answer : Answer: BC DISCUSSION: Hemorrhagic shock is associated with a contraction of the interstitial fluid compartment because of precapillary vasoconstriction and reabsorption of interstitial fluid ... definitive evidence that such solutions are better than standard crystalloid solutions is lacking

Which of the following statement(s) is/are true concerning the results of a National Institute of Health Consensus Conference on venous thrombosis and low-dose heparin prophylaxis? a. The odds of developing deep venous thrombosis with low-dose heparin prophylaxis decreases by 67% b. The risk of pulmonary embolism is decreased by almost 50% c. There is no increase in mortality from other causes found in patients treated with low-dose heparin d. There was no difference in the incidence of bleeding complications

Description : Which of the following statement(s) is/are true concerning the results of a National Institute of Health Consensus Conference on venous thrombosis and low-dose heparin prophylaxis? a. The odds of ... treated with low-dose heparin d. There was no difference in the incidence of bleeding complications

Last Answer : Answer: a, b, c In a metaanalysis of 70 randomized trials in 16,000 patients comparing low-dose heparin prophylaxis with standard therapy, the odds of developing deep venous thrombosis ... Similarly, the effectiveness of prophylaxis was not influenced by either two or three times daily dosage

The standard management oral anticoagulant therapy for chronic treatment of venous thromboembolism is with the drug warfarin. Which of the following statement(s) is/are true concerning the administration of warfarin? a. An important complication of warfarin therapy is skin necrosis in patients with protein C deficiency b. Warfarin interferes with vitamin K dependent clotting factors II, VII, IX, X c. For effective anticoagulation the prothrombin time (PT) should be kept at 2 control d. It is recommended that warfarin be continued for at least one year after initial episode of deep venous thrombosis

Description : The standard management oral anticoagulant therapy for chronic treatment of venous thromboembolism is with the drug warfarin. Which of the following statement(s) is/are true concerning the administration ... warfarin be continued for at least one year after initial episode of deep venous thrombosis

Last Answer : Answer: a, b Warfarin interferes with the vitamin K dependent clotting factors II, VII, IX and X, protein C, and protein S. An important complication of warfarin is skin ... the benefit from anticoagulant therapy and thus is the basis for discontinuing warfarin administration at this time

There are a number of hypercoaguable states which can be associated with arterial or venous thrombosis and embolic phenomenon. These include: a. Heparin-associated thrombocytopenia b. Antithrombin III deficiency c. Von Willebrand disease d. Vitamin C deficiency

Description : There are a number of hypercoaguable states which can be associated with arterial or venous thrombosis and embolic phenomenon. These include: a. Heparin-associated thrombocytopenia b. Antithrombin III deficiency c. Von Willebrand disease d. Vitamin C deficiency

Last Answer : Answer: a, b A number of hypercoaguable states are present. These include heparin-associated thrombocytopenia in which a heparin-dependent platelet antibody causes aggregation of ... soft tissue increasing vascular permeability and fragility resulting in the potential for bleeding disorders

A 55-year-old male undergoes a total abdominal colectomy. Which of the following statement(s) is/are true concerning the hormonal response to the surgical procedure? a. Adrenocorticotropic hormone (ACTH) is secreted from the anterior pituitary gland b. ACTH stimulation results in elevation of serum cortisol levels for up to a week after the operation c. An increased secretion of aldosterone and ADH may contribute to postoperative fluid retention d. An increase in serum insulin and a fall in glucagon accelerate hepatic glucose production and maintain gluconeogenesis

Description : A 55-year-old male undergoes a total abdominal colectomy. Which of the following statement(s) is/are true concerning the hormonal response to the surgical procedure? a. Adrenocorticotropic ... in serum insulin and a fall in glucagon accelerate hepatic glucose production and maintain gluconeogenesis

Last Answer : Answer: a, c One of the earliest consequence of a surgical procedure is the rise in levels of circulating cortisol that occur in response to a sudden outpouring of ACTH ... hepatic glucose production, and, with other hormones (epinephrine and glucocorticoids), gluconeogenesis is maintained

The initiation of a humoral immune response involves a complex interaction of the antigen, cells and intercellular messengers. Which of the following statement(s) concerning the initiation of the humoral immune response is/are correct? a. Helper T lymphocytes stimulate B lymphocytes through secretion of cytokines such as interleukin 4 and 6 b. A number of cells can aid in presenting the antigen to the helper T cell including B lymphocytes and macrophages c. All antigens require coordinated efforts of the various cellular components of the immune system d. An antigen must be a living microorganism

Description : The initiation of a humoral immune response involves a complex interaction of the antigen, cells and intercellular messengers. Which of the following statement(s) concerning the initiation of the ... various cellular components of the immune system d. An antigen must be a living microorganism

Last Answer : Answer: a, b Stimulation of the immune system occurs after a variety of antigen-presenting cells (B lymphocytes, macrophages, dendritic cells, and Langerhans cells) act to engulf ... polysaccharides), most antigens require coordinated efforts of the various cellular components of the immune system

The complement system consists of a series of serum proteins that exist in a quiescent or very low-level state of activation in the uninfected host. Which of the following statement(s) is/are true concerning complement activation? a. The alternate (properdin) pathway of complement activation can occur directly through contact with fungal or bacterial cell wall compounds b. Complement component fragments may serve to decrease vascular permeability c. Excessive complement activation can produce deleterious effects d. Fragments of certain complement components serve as chemoattractants to additional cellular components of the host defense mechanism

Description : The complement system consists of a series of serum proteins that exist in a quiescent or very low-level state of activation in the uninfected host. Which of the following ... certain complement components serve as chemoattractants to additional cellular components of the host defense mechanism

Last Answer : Answer: a, c, d Complement activation can occur through either classic or alternate (properdin) pathways, both of which eventuate in deposition of terminal complement pathway components on the ... and release of lysosomal enzymes that can directly damage certain target tissues, such as the lung

Which of the following statement(s) is/are true concerning hypoadrenal shock? a. In the United States, idiopathic adrenal atrophy (Addison’s disease) is the most common cause b. Laboratory abnormalities include hyponatremia, hypochloremia, and hyperkalemia c. Fever may be seen with hypoadrenal shock d. ACTH stimulation test is the diagnostic test of choice to confirm hypoadrenal shock

Description : Which of the following statement(s) is/are true concerning hypoadrenal shock? a. In the United States, idiopathic adrenal atrophy (Addison's disease) is the most common cause b. Laboratory ... hypoadrenal shock d. ACTH stimulation test is the diagnostic test of choice to confirm hypoadrenal shock

Last Answer : Answer: b, c, d Shock of a dramatic nature, poorly responsive to resuscitation, may develop as a consequence of adrenal insufficiency. In this country, adrenal insufficiency most ... of an ACTH stimulation test. A significant major cortisol response should be elicited by ACTH administration

A 22-year-old man sustains a single stab wound to the left chest and presents to the emergency room with hypotension. Which of the following statement(s) is/are true concerning his diagnosis and management? a. The patient likely is suffering from hypovolemic shock and should respond quickly to fluid resuscitation b. Beck’s triad will likely be an obvious indication of compressive cardiogenic shock due to pericardial tamponade c. Echocardiography is the most sensitive noninvasive approach for diagnosis of pericardial tamponade d. The placement of bilateral chest tubes will likely resolve the problem

Description : A 22-year-old man sustains a single stab wound to the left chest and presents to the emergency room with hypotension. Which of the following statement(s) is/are true concerning his ... diagnosis of pericardial tamponade d. The placement of bilateral chest tubes will likely resolve the problem

Last Answer : Answer: c Shock from cardiac compression occurs when external pressure on the heart impairs ventricular filling. Because ventricular filling is a function of venous return and myocardial compliance, ... sternotomy. Chest tube placement would not be appropriate as the sole treatment in this patient

Which of the following statement(s) is/are true concerning the diagnosis and management of hypovolemic shock? a. A fall in hematocrit or hemoglobin always accompanies hemorrhagic shock b. The treatment of shock is generic regardless of the etiology c. Pharmacologic intervention to increase myocardial contractility in hypovolemic shock is an important part the early management d. Complications are less frequent after treatment of hemorrhagic shock than septic or traumatic shock

Description : Which of the following statement(s) is/are true concerning the diagnosis and management of hypovolemic shock? a. A fall in hematocrit or hemoglobin always accompanies hemorrhagic shock b. The ... d. Complications are less frequent after treatment of hemorrhagic shock than septic or traumatic shock

Last Answer : Answer: d Hypovolemic shock is readily diagnosed when there is an obvious source of volume loss and overt signs of hemodynamic instability and increased adrenergic output are present. ... response systems and consequences of their disseminated, indiscriminate cellular injury can be quite profound

Which of the following statement(s) is/are true concerning the various types of shock? a. Traumatic shock is more commonly associated with subsequent organ injury and multiorgan failure syndrome than hemorrhagic shock b. Cardiogenic shock can be of either an intrinsic or compressive nature c. Hypodynamic septic shock is associated with a decreased mortality risk when compared with hyperdynamic septic shock d. Hypoadrenal shock usually responds quickly to resuscitation e. Neurogenic shock occurs with the absence of sympathetic activity

Description : Which of the following statement(s) is/are true concerning the various types of shock? a. Traumatic shock is more commonly associated with subsequent organ injury and multiorgan failure ... responds quickly to resuscitation e. Neurogenic shock occurs with the absence of sympathetic activity

Last Answer : Answer: a, b, d, e Classification schemes of shock based on cause have been developed for the seemingly dissimilar processes leading to circulatory collapse and the shock state. ... and pressor agents. The response to exogenous corticosteroids is usually dramatic and potentially life-saving

Most hormone receptors are localized on the cell membrane and transduce hormone binding into altered levels of intracellular messengers. A limited number of intracellular receptors do exist. Which of the following statement(s) is/are true concerning intracellular receptors? a. The messengers or hormones must by lipophilic b. These intracellular receptors generally regulate protein synthesis c. The intracellular receptors are located entirely in the nucleus of the cell d. A heat-shock protein serves as an inhibitor protein blocking the DNA-binding domain of the steroid receptor

Description : Most hormone receptors are localized on the cell membrane and transduce hormone binding into altered levels of intracellular messengers. A limited number of intracellular receptors do exist. Which of ... protein serves as an inhibitor protein blocking the DNA-binding domain of the steroid receptor

Last Answer : Answer: a, d Although most hormone and other messenger receptors are extracellular, intracellular receptors have been identified. The hormone messengers involved for these receptors are primarily ... DNA-binding domain of the receptor. Activation involves the dissociation of the inhibitor protein

Eicosanoids mediate inflammation in a variety of ways. Of the following statements, which are true with regard to this? a. Eicosanoids are stored in cytoplasmic granules for release after receptor mediated signaling b. Eicosanoids include prostaglandins, thromboxanes, leukotrienes and lipoxins c. Eicosanoids generally have a plasma half-life measured in hours d. Physiologic responses to eicosanoids include vasodilatation, vasoconstriction, increased vascular permeability and both chemotaxis and chemoattractant inhibition

Description : Eicosanoids mediate inflammation in a variety of ways. Of the following statements, which are true with regard to this? a. Eicosanoids are stored in cytoplasmic granules ... include vasodilatation, vasoconstriction, increased vascular permeability and both chemotaxis and chemoattractant inhibition

Last Answer : Answer: b, d The eicosanoids are derived from arachidonic acid (eicosatetraenoic acid) and consist of prostaglandins, thromboxanes, leukotrienes and lipoxins. The eicosanoids are not ... nervous system d. Mononuclear phagocytes release a variety of proinflammatory cytokines and growth factors

True statements concerning hypoadrenal shock include which of the following? A. Adrenocortical insufficiency may manifest itself as severe shock refractory to volume and pressor therapy. B. The presence of hyperglycemia and hypotension may suggest the diagnosis of shock due to adrenocortical insufficiency. C. Hydrocortisone does not interfere with the serum cortisol assay and should be given to hemodynamically unstable patients suspected of having hypoadrenal shock. D. The rapid adrenocorticotropic hormone (ACTH) stimulation test should be performed to help establish the diagnosis of acute adrenocortical insufficiency.

Description : True statements concerning hypoadrenal shock include which of the following? A. Adrenocortical insufficiency may manifest itself as severe shock refractory to volume and pressor therapy. B. ... test should be performed to help establish the diagnosis of acute adrenocortical insufficiency.

Last Answer : Answer: AD DISCUSSION: Shock due to acute adrenocortical insufficiency is relatively uncommon but must be considered when shock refractory to volume replacement and pressor therapy is present. ... and it is the corticosteroid of choice while the ACTH stimulation test is being performed

The most likely mechanism of antihypertensive action of thiazide diuretics in the long-term is: A. Reduction of circulating blood volume B. Reduction in cardiac output C. Decreased sympathetic tone D. Reduction in total peripheral vascular resistance and improved compliance of resistance vessels

Description : The most likely mechanism of antihypertensive action of thiazide diuretics in the long-term is: A. Reduction of circulating blood volume B. Reduction in cardiac output C. Decreased sympathetic tone D. Reduction in total peripheral vascular resistance and improved compliance of resistance vessels

Last Answer : D. Reduction in total peripheral vascular resistance and improved compliance of resistance vessels

Which of the following statement(s) is/are true concerning the autoregulation necessary to maintain oxygen consumption and oxygen delivery? a. A change in oxygen consumption is followed by a proportionate change in oxygen delivery b. A change in oxygen delivery is followed by a change in oxygen consumption c. Increases in oxygen delivery are due solely to an increase in cardiac output d. The normal ratio of oxygen delivery to consumption is 2:1

Description : Which of the following statement(s) is/are true concerning the autoregulation necessary to maintain oxygen consumption and oxygen delivery? a. A change in oxygen consumption is followed by a proportionate ... increase in cardiac output d. The normal ratio of oxygen delivery to consumption is 2:1

Last Answer : Answer: a The relationships between oxygen consumption and oxygen delivery represent one of the most interesting regulation systems in homeostasis. First of all, if one of the three components ... in oxygen consumption. The normal ratio of oxygen delivery to consumption is approximately 5:1

The best understood intracellular messenger is cyclic AMP (cAMP). Which of the following statement(s) concerning this intracellular messenger is/are correct? a. Intracellular cyclic AMP is constantly degraded by a specific enzyme, cAMP phosphodiesterase b. Most of the actions of cAMP are mediated by activation of protein kinase A c. Intracellular levels of cAMP are relatively stable and change solely in response to activation of adenylate cyclase d. cAMP is the only cyclic nucleotide active as an intracellular messenger

Description : The best understood intracellular messenger is cyclic AMP (cAMP). Which of the following statement(s) concerning this intracellular messenger is/are correct? a. Intracellular cyclic AMP is constantly ... of adenylate cyclase d. cAMP is the only cyclic nucleotide active as an intracellular messenger

Last Answer : Answer: a, b The prototypic intracellular messenger is cAMP. To function as a mediator, the concentration of cAMP must change rapidly. In resting cells, cAMP is continuously being degraded by ... produce cGMP. Intracellular calcium ions also serve as second messengers in a large number of cells