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

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
by

1 Answer

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 a direct function of ventilation or hyperventilation of alveoli with some blood flow. Normally the end tidal CO2 represents mixed alveolar gas which is at equilibrium with pulmonary capillary blood, hence with arterial blood. Therefore, the end tidal CO2 and the PaCO2 should be identical. End tidal CO2 measurement is a very useful continuous measurement of PaCO2 which can be used as a monitor when the lung is normal, as in ventilator weaning. Furthermore, the gradient between end tidal and arterial CO2, when it is large, acts as an indirect measure of nonperfused alveoli and/or compression volume. In patients who are ventilated with positive pressure ventilation, a significant end tidal PaCO2 gradient occurs only when peak airway pressures are very high (over 30 cm H2O) and the compression volume is a significant component of each exhaled breath
by
selected

Related questions

Which of the following statement(s) is/are true concerning carbon dioxide kinetics? a. The amount of carbon dioxide produced is equivalent to the amount of oxygen consumed b. Carbon dioxide levels in blood, present mostly as a bicarbonate ion, can quickly change c. Normally the amount of carbon dioxide excreted through the lung is exactly equal to the amount of carbon dioxide produced in peripheral tissues d. The amount of carbon dioxide excreted is a function of ventilation of perfused alveoli

Description : Which of the following statement(s) is/are true concerning carbon dioxide kinetics? a. The amount of carbon dioxide produced is equivalent to the amount of oxygen consumed b. Carbon dioxide levels ... tissues d. The amount of carbon dioxide excreted is a function of ventilation of perfused alveoli

Last Answer : Answer: a, c, d The total amount of carbon dioxide produced by systemic metabolism is roughly equivalent to the amount of oxygen consumed (100-120 cc/m2/min, 200 cc/min in a typical ... carbon dioxide excreted is a function of ventilation of perfused alveoli (i.e. the alveolar ventilation/min).

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 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 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

Description : 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. ... d. The total circulating blood volume is equally split between the arterial and venous system

Last Answer : 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 ... Blood flow to the skin is sacrificed early, followed by that to the kidneys and splanchnic viscera

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 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 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

A striking feature of living cells is a marked difference between the composition of the cytosol and the extracellular milieu. Which of the following statement(s) concerning the mechanisms of maintenance of these differences is/are true? a. The cell membrane is able to maintain a 10,000 fold gradient between the extracellular concentration of ionized calcium and the intracellular concentration b. The key to these differences is the fact that the plasma membrane is normally impermeable to sodium, potassium and calcium c. The selectivity of biologic membranes is highly consistent and seldom changes d. The selectivity of cell membranes relates only to ions and not organic compounds

Description : A striking feature of living cells is a marked difference between the composition of the cytosol and the extracellular milieu. Which of the following statement(s) concerning the mechanisms of maintenance ... d. The selectivity of cell membranes relates only to ions and not organic compounds

Last Answer : Answer: a The survival of the cell requires that cytosolic composition be maintained within narrow limits, despite the constant influx of nutrients and the simultaneous outflow of waste. A ... be altered drastically as a result of regulatory or signaling processes that occur within the cell

Which of the following statements(s) is/are true concerning human energy requirement? a. In normal subjects, less than 5% of basal energy requirement is spent on cardiac output and the work of breathing b. Mechanical ventilation can decrease the energy expenditure for normal respiration c. For a 70 kg male, average resting energy consumption is almost 1500 kcal/day d. Similar increases in energy expenditures are associated with elective surgery and trauma or thermal injury

Description : Which of the following statements(s) is/are true concerning human energy requirement? a. In normal subjects, less than 5% of basal energy requirement is spent on cardiac output and the ... d. Similar increases in energy expenditures are associated with elective surgery and trauma or thermal injury

Last Answer : Answer: a, c Basal energy requirements are measured with the subject at rest when no external work is being done; the energy is used mainly for transport and synthetic work within cells. A ... average-sized adult who sustains a major burn rarely may require more than 3500 kcal/day for maintenance

The figure given below shows a small part of human lung where exchange of gases takes place. Select the option which represents labelled part (A, B, C or D) correctly identified along with its function. (a) C : Arterial capillary - Passes oxygen to tissues (b) A : Alveolar cavity - Main site of exchange of respiratory gases (c) D : Capillary wall - Exchange of O2 and CO2 takes place here (d) B : Red blood cells - Transport of CO2 mainly

Description : The figure given below shows a small part of human lung where exchange of gases takes place. Select the option which represents labelled part (A, B, C or D) correctly identified along with its function. ... Exchange of O2 and CO2 takes place here (d) B : Red blood cells - Transport of CO2 mainly

Last Answer : (b) A : Alveolar cavity - Main site of exchange of respiratory gases

Which of the following statement(s) is/are true concerning oxygen consumption (O2)? a. O2 is normally 100–120 cc2/m2/min b. Resting O2 is controlled by the level of thyroid and catecholamine hormones c. Under steady state conditions the amount of oxygen consumed exceeds the amount of oxygen taken up by the pulmonary capillaries d. O2 is dependent on the status of pulmonary function

Description : Which of the following statement(s) is/are true concerning oxygen consumption (O2)? a. O2 is normally 100-120 cc2/m2/min b. Resting O2 is controlled by the level of thyroid and catecholamine ... of oxygen taken up by the pulmonary capillaries d. O2 is dependent on the status of pulmonary function

Last Answer : Answer: a, b Oxygen consumed in the process of metabolism is expressed as the volume of oxygen per minute (O2). O2 is normally 100-120 cc2/m2/min, or 200 cc/min for a typical adult. ... , so we measure O2 across the lung and assume that it is exactly the amount consumed in the systemic metabolism

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 assessment of protein reserve? a. Conventional serum proteins such as albumin and globulin are early indicators of malnutrition b. The total lymphocyte count reflects immune status and not nutrition c. Antigen skin testing reflects patient immunity and not nutrition d. Measurement of urea excretion in urine can be used as a measurement of protein breakdown

Description : Which of the following statement(s) is/are true concerning the assessment of protein reserve? a. Conventional serum proteins such as albumin and globulin are early indicators of malnutrition b. The ... d. Measurement of urea excretion in urine can be used as a measurement of protein breakdown

Last Answer : Answer: d Since protein is the functional and structural chemical of the body, most nutritional assessment techniques are estimates of protein reserves. The actual nitrogen balance can ... patients convert from reactive to anergic, and reactivity can be restored by nutritional repletion

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

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

The following statement(s) is/are true concerning cellular defense mechanisms. a. Macrophages function solely as antigen processing cells in the initial reaction to exposure to an antigen b. Macrophages may become activated and secrete cytokines c. Macrophages serve as phagocytic cells in the tissues but not within the bloodstream d. Polymorphonucleocytes (PMNS) are normally present in only small numbers within the tissue and enter an area of infection through diapedesis

Description : The following statement(s) is/are true concerning cellular defense mechanisms. a. Macrophages function solely as antigen processing cells in the initial reaction to exposure to an antigen b. Macrophages ... in only small numbers within the tissue and enter an area of infection through diapedesis

Last Answer : Answer: b, d A wide variety of cell types serve to provide host defense at several levels. Macrophages act as the initial antigen processing cell that serves to ... through diapedesis after chemotactic stimuli are excluded by macrophages, bacterial breakdown products, and complement activation

There are two properties of the cell necessary to maintain nonequilibrium cellular composition; the first is selectivity and the second is energy conversion. Which of the following statement(s) is/are true concerning energy converting transport? a. The site of energy conversion and transport in the plasma membrane involves the phospholipid component b. The Na+-K++-ATPase derives energy from hydrolysis of extracellular ATP c. In some systems, energy inherent in the transmembrane ion gradient can be used to drive transport of a second species d. Examples of species transported via secondary active transport include hydrogen ions, calcium, amino acids and glucose

Description : There are two properties of the cell necessary to maintain nonequilibrium cellular composition; the first is selectivity and the second is energy conversion. Which of the following statement(s ... transported via secondary active transport include hydrogen ions, calcium, amino acids and glucose

Last Answer : Answer: c, d The selectivity of the plasma membrane, although impressive, cannot account for the nonequilibrium composition of living cells. A cell can be maintained in a nonequilibrium state only by ... to drive the transport of a second species such as protons, calcium, amino acids, or glucose

Which of the following statement(s) is/are true concerning hemophilia A? a. Hemophilia A is inherited as a sex-linked recessive deficiency of factor VIII b. A positive family history for bleeding disorders present in all patients c. Laboratory tests reveal a prolongation of aPTT, prothrombin time (PT), thrombin clotting time and platelet aggregation d. Spontaneous bleeding is unusual with factor VIII levels greater than 10% of normal

Description : Which of the following statement(s) is/are true concerning hemophilia A? a. Hemophilia A is inherited as a sex-linked recessive deficiency of factor VIII b. A positive family history for ... platelet aggregation d. Spontaneous bleeding is unusual with factor VIII levels greater than 10% of normal

Last Answer : Answer: a, d Hemophilia A is inherited as a sex-linked recessive deficiency of factor VIII although 0% of cases are secondary to spontaneous mutation. The incidence of this abnormality is ... factor levels as low as 1% have been noted and patients are at risk for spontaneous bleeding

Which of the following statements concerning monitoring techniques in the intensive care unit are true? A. Pulmonary artery and pulmonary capillary wedge pressure readings should be made at end inspiration, to minimize ventilatory artifacts. B. Continuous SvO 2 monitoring based on the technique of reflectance spectrophotometry has been shown to be accurate and reliable. C. Direct measurement of gastric intramucosal pH can be provided by gastrointestinal tonometry. D. Hyperlactatemia may be seen in a number of clinical conditions not associated with tissue hypoxia, including liver disease and hypermetabolic states.

Description : Which of the following statements concerning monitoring techniques in the intensive care unit are true? A. Pulmonary artery and pulmonary capillary wedge pressure readings should be made ... clinical conditions not associated with tissue hypoxia, including liver disease and hypermetabolic states.

Last Answer : Answer: BD DISCUSSION: Many different monitoring techniques may be used to assess the adequacy of therapy for shock. The pulmonary artery catheter can provide important hemodynamic and oxygen ... also be seen with liver disease, toxin ingestion, and hypermetabolic states not associated with shock

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

The neurohormonal arm of the stress response is well defined. Less is known about the inflammatory arm mediated primarily by cytokines. Which of the following statement(s) is/are true concerning this arm of the surgical stress response? a. Cytokines primarily work locally via direct cell-to-cell communication b. Cytokines are never detectable in the systemic bloodstream c. Cytokines are produced only by immune cells attracted to the site of injury d. Cytokine release may stimulate the release of other cytokines leading to an important cascade of events

Description : The neurohormonal arm of the stress response is well defined. Less is known about the inflammatory arm mediated primarily by cytokines. Which of the following statement(s) is/are true ... Cytokine release may stimulate the release of other cytokines leading to an important cascade of events

Last Answer : Answer: a, d Cytokines, which are produced at the site of injury by endothelial cells and by diverse immune cells throughout the body, also occupy a pivotal position in the stress response ... act as hormones and spill over into the systemic circulation and become detectable in the bloodstream

The following statement(s) is/are true concerning HIV infection. a. Initial screening with ELISA is highly sensitive but can be associated with a false positive rate of 25% b. Treatment with azidothymidine (AZD) appears to prolong survival when administered early in the disease c. Predisposition to infection in HIV infection is primarily due to reduction in the number of helper T cells d. Common infections in patients with AIDS are Pneumocystis, carinii pneumonia, CMV pneumonitis, Cryptococcus meningitis, and disseminated infection due to atypical mycobacteria

Description : The following statement(s) is/are true concerning HIV infection. a. Initial screening with ELISA is highly sensitive but can be associated with a false positive rate of 25% b. ... , carinii pneumonia, CMV pneumonitis, Cryptococcus meningitis, and disseminated infection due to atypical mycobacteria

Last Answer : Answer: b, c, d Acquired immunodeficiency syndrome (AIDS) is a syndrome caused by the human retrovirus (HIV-1) that infects T lymphocytes and causes severe immunosuppression. Individuals who ... to prolong survival when administered early in the course of disease and is considered routine therapy

Which of the following statement(s) concerning laboratory studies used in monitoring a patient with intravenous heparinization is/are correct? a. The platelet count should be followed because of the risk of heparin-associated thrombocytopenia b. The prothrombin time should be observed if prolonged treatment is necessary c. The activated partial thromboplastin time (aPTT) should be maintained at approximately 1.5 times normal d. The serum creatinine should be measured daily to allow adjustments in dose based on renal function

Description : Which of the following statement(s) concerning laboratory studies used in monitoring a patient with intravenous heparinization is/are correct? a. The platelet count should be followed because of the ... serum creatinine should be measured daily to allow adjustments in dose based on renal function

Last Answer : Answer: a, c In monitoring the effect of heparin, an activated partial thromboplastin time (aPTT) of 1.5 control or a thrombin clotting time (TCT) of 2 times control reflects adequate ... system. Therefore the dose of heparin need not be adjusted in cases of liver or renal dysfunction

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 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

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 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

Bleeding complications are frequently associated with fibrinolytic therapy. Which of the following statement(s) concerning complications of fibrinolytic therapy is/are true? a. Careful monitoring of prothrombin time and aPTT time are necessary to avoid bleeding complications b. A level of serum fibrinogen less than 100 mg/dl is associated with an increased risk of bleeding c. Recent (less than 10 days) major surgery is a contraindication to systemic but not regional fibrinolytic therapy d. A patient with a cerebrovascular event occurring less than two months ago can be treated with fibrinolytic therapy if head CT scan is normal

Description : Bleeding complications are frequently associated with fibrinolytic therapy. Which of the following statement(s) concerning complications of fibrinolytic therapy is/are true? a. Careful monitoring of prothrombin time ... months ago can be treated with fibrinolytic therapy if head CT scan is normal

Last Answer : Answer: b Fibrinolytic therapy induces a hemostatic defect through a combination of factors. Hypofibrinogenemia and fibrin degradation products inhibit fibrin polymerization and, in combination ... is considered a major relative contraindication to either regional or systemic thrombolytic therapy

Von Willebrand’s disease is a common, congenital bleeding disorder. Which of the following statement(s) is/are true concerning Von Willebrand’s disease? a. As in hemophilia, it is much more common in men b. A history of spontaneous bleeding is common c. Screening laboratory tests will include a prolonged aPTT with a normal prothrombin time d. Pre-treatment for elective surgery require administration of cryoprecipitate to achieve levels of 23–50% of normal

Description : Von Willebrand's disease is a common, congenital bleeding disorder. Which of the following statement(s) is/are true concerning Von Willebrand's disease? a. As in hemophilia, it is ... -treatment for elective surgery require administration of cryoprecipitate to achieve levels of 23-50% of normal

Last Answer : Answer: c, d Von Willebrand's factor is an adhesive protein that mediates platelet adhesion to collagen. In addition, it protects and prevents the rapid removal of factor VIII ... platelet aggregation responses to ristocetin. The most reliable source of Von Willebrand's factor is cryoprecipitate

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 the remodeling phase of wound healing? a. Total collagen content increases steadily through this phase b. The normal adult ratio of collagen is approximately 4:1 of type I to type III collagen. c. Eventually a scar will achieve the strength of unwounded skin d. The proteoglycans are responsible for the ground substance of the extracellular matrix

Description : Which of the following statement(s) is/are true concerning the remodeling phase of wound healing? a. Total collagen content increases steadily through this phase b. The normal adult ratio ... unwounded skin d. The proteoglycans are responsible for the ground substance of the extracellular matrix

Last Answer : Answer: b, d The transition from the proliferative phase to the remodeling phase of wound healing is defined by reaching collagen equilibrium. Collagen accumulation within the wound becomes maximal by ... in strength for six months or more, eventually reaching 70% of the strength of unwounded skin

A 45-year-old solicitor had an onset of severe, crushing, substernal chest pain while attending a football match. He collapsed on his way to the car. Bystander Cardiorespiratory Resuscitation was begun immediately and continued until arrival in Casualty where an endotracheal tube was inserted and ventilation was maintained on 100% oxygen. Investigations revealed: pH 7.13 PaO2 560 mmHg PaCO2 18 mmHg Bicarbonate 5.8 SaO2 98% Based on these laboratory values, which of the following statements best describes his current pathophysiology? 1) He is demonstrating a primary respiratory alkalosis 2) He probably developed a large right to left intracardiac shunt 3) His anion gap is probably normal 4) His oxyhemoglobin curve is shifted to the left 5) His pulmonary artery pressure is probably elevated

Description : A 45-year-old solicitor had an onset of severe, crushing, substernal chest pain while attending a football match. He collapsed on his way to the car. Bystander Cardiorespiratory Resuscitation ... His oxyhemoglobin curve is shifted to the left 5) His pulmonary artery pressure is probably elevated

Last Answer : Answers-5 This young patient with severe central chest pain has probably arrested due to myocardial infarction and arrhythmia. His gases reveal high PO2 following 100% O2 but severe acidosis ... no left to right shunting and high pulmonary pressures would be expected after this arrest scenario.

Which of the following statement(s) is/are true concerning the outcome in patients with acute renal failure? a. Mortality for ischemic acute tubular necrosis without other organ failure is approximately 6% b. Multiple organ failure complicated with acute renal failure is associated with mortality ranging from 50% to 90% c. Recovery of renal function after six weeks is unlikely d. There is no difference in survival between oliguric and nonoliguric renal failure

Description : Which of the following statement(s) is/are true concerning the outcome in patients with acute renal failure? a. Mortality for ischemic acute tubular necrosis without other organ failure is ... is unlikely d. There is no difference in survival between oliguric and nonoliguric renal failure

Last Answer : Answer: a, b, c Survival of patients with acute renal failure is a function of the successful treatment of the primary disease from which the renal failure was derived. The mortality ... is unlikely. Nonoliguric renal failure is usually limited in its extent and is almost always reversible

Which of the following statement(s) is/are true concerning the effects of MOFS? a. Pulmonary dysfunction tends to arise early and may resolve within 7 to 10 days b. Unless the precipitating insult has prompted oliguric acute tubular necrosis, renal function tends to be maintained early in the course of MOFS c. Although hepatic dysfunction is common with MOFS, the GI tract plays little role in this process d. Intercurrent nosocomial infection, most commonly pulmonary, is a common complication providing a “second hit” to the patient

Description : Which of the following statement(s) is/are true concerning the effects of MOFS? a. Pulmonary dysfunction tends to arise early and may resolve within 7 to 10 days b. Unless the precipitating ... infection, most commonly pulmonary, is a common complication providing a second hit to the patient

Last Answer : Answer: a, b, d Pulmonary dysfunction typically arises early in the development of systemic inflammation and may represent mild relatively localized acute lung injury or it may be a prelude ... is marked by progressive rise in serum bilirubin levels after a latent period of several days

The first line of host defense is the barrier presented to the external environment. Which of the following statement(s) is/are true concerning host barriers? a. Sebaceous glands secrete chemical compounds that maintain a relatively high pH, providing effective bacterial stasis b. Within the respiratory tract, ciliary function serves to extrude microorganisms trapped within the mucus secretion layer c. The low pH within the stomach markedly decreases bacterial content of the upper gastrointestinal tract d. Gut peristalsis serves to prevent microbial adherence and invasion

Description : The first line of host defense is the barrier presented to the external environment. Which of the following statement(s) is/are true concerning host barriers? a. Sebaceous glands secrete ... of the upper gastrointestinal tract d. Gut peristalsis serves to prevent microbial adherence and invasion

Last Answer : Answer: b, c, d The skin, mucus membranes, and epithelial layers of various organs of the body constitute effective physical barriers against microbial invasion. In certain portions of the ... very low pH within the stomach and gut peristalsis both serve to prevent microbial adherence and invasion

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

Which of the following statement(s) is/are true concerning the cell function of phagocytosis? a. Phagocytosis is a mechanistically distinct process of endocytosis performed by special cells to take up larger particles such as bacteria or erythrocytes b. Lymphocytes are the primary blood cell involved with this process c. The process involves a coating of the cytoplasmic surface known as clathrin d. Phagocytosis is performed only by white blood cells and tissue macrophages

Description : Which of the following statement(s) is/are true concerning the cell function of phagocytosis? a. Phagocytosis is a mechanistically distinct process of endocytosis performed by special cells to take ... known as clathrin d. Phagocytosis is performed only by white blood cells and tissue macrophages

Last Answer : Answer: a Phagocytosis is a specialized form of endocytosis by which large particles are internalized by specialized cells primarily macrophages and neutrophils. To be phagocytosed, particles ... the lumen of the thyroid follicle, thereby releasing the thyroid hormones, thyroxine triiodothyronine

Which of the following statement(s) is/are true concerning water movement across cell membranes? a. Water moves only actively through cell membrane transport proteins b. For most cells of the body, the transmembrane hydrostatic pressure is 0 c. Water distribution is determined entirely by solute distribution d. Specialized cells such as the glomerulus of the kidney actively transport water to maintain hydrostatic pressure

Description : Which of the following statement(s) is/are true concerning water movement across cell membranes? a. Water moves only actively through cell membrane transport proteins b. For most cells of ... cells such as the glomerulus of the kidney actively transport water to maintain hydrostatic pressure

Last Answer : Answer: b, c The energetics of water transport across cell membranes is simplified by the fact that water moves only passively due to gradients of hydrostatic pressure or water ... water is distributed at equilibrium. Water distribution is determined entirely by solute to solute distribution

The following factor delays induction with an inhaled general anaesthetic: A. Alveolar perfusion-ventilation mismatch B. Hyperventilation C. Low blood:gas partition coefficient of the anaesthetic D. Inclusion of 5% carbon dioxide in the inhaled gas mixture

Description : The following factor delays induction with an inhaled general anaesthetic: A. Alveolar perfusion-ventilation mismatch B. Hyperventilation C. Low blood:gas partition coefficient of the anaesthetic D. Inclusion of 5% carbon dioxide in the inhaled gas mixture

Last Answer : A. Alveolar perfusion-ventilation mismatch

Which of the following statement(s) is/are true concerning the treatment of pulmonary interstitial edema? a. Diuresis and blood transfusion is a valuable step b. Salt-poor albumin leaks through the capillaries and worsens the condition c. Mannitol is contraindicated as a diuretic in this clinical situation d. Isoproterenol is a poor choice as an ionotropic agent

Description : Which of the following statement(s) is/are true concerning the treatment of pulmonary interstitial edema? a. Diuresis and blood transfusion is a valuable step b. Salt-poor albumin leaks through the ... a diuretic in this clinical situation d. Isoproterenol is a poor choice as an ionotropic agent

Last Answer : Answer: a Treatment of pulmonary edema has two important goals, the first is to improve oxygenation if it is impaired, and the second is to minimize fibrosis and bacterial infection, which often ... leaks out , the short term effects of expanding blood volume and decrease in edema will appear

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) is/are true concerning the multiorgan failure syndrome (MOFS)? a. Changes in the splanchnic and pulmonary microcirculation are critical to the development of MOFS b. Tissue fixed microphages, including the liver Kupffer cell, have little role in the development of MOFS c. MOFS represents systemic consequences of loss of homeostatic control of local inflammation and microcirculatory hypoperfusion d. The nature of MOFS is highly dependent upon the etiology of the underlying problem

Description : Which of the following statement(s) is/are true concerning the multiorgan failure syndrome (MOFS)? a. Changes in the splanchnic and pulmonary microcirculation are critical to the development of MOFS ... d. The nature of MOFS is highly dependent upon the etiology of the underlying problem

Last Answer : Answer: a, c The nature of multiorgan failure syndrome (MOFS) is that of a diffuse cellular injury, developing systemically as a consequence of losing homeostatic control of local ... of microorganism. In noninfectious cases, the response also appears independent of the specific underlying cause

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

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

Which of the following statement(s) is/are true concerning ischemia reperfusion injury? a. During ischemia, ATP degradation results in increased plasma and intracellular levels of hypoxanthine and xanthene b. Oxygen free radicals such as the superoxide radical are involved in the expression of the proinflammatory phenotype of endothelial cells, macrophages and neutrophils c. The intracellular adhesion molecule-1 (ICAN-1) contributes to injury and disruption of the endothelial lining, with extensive capillary leak and resultant interstitial edema d. Animal models have demonstrated that passive immunization with antibodies to neutrophil adhesive complex lessen the ischemic/reperfusion microvascular injury

Description : Which of the following statement(s) is/are true concerning ischemia reperfusion injury? a. During ischemia, ATP degradation results in increased plasma and intracellular levels of ... immunization with antibodies to neutrophil adhesive complex lessen the ischemic/reperfusion microvascular injury

Last Answer : Answer: a, b, c, d During the ischemia and hypoperfusion phase, degradation of ATP stores essential to maintain cell integrity and significant loss of diffusible ... either the neutrophil adhesive complex or the endothelial selectins dramatically lessens ischemia/reperfusion microvascular injury

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

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 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