Cardiovascular Flashcards
Which of the following mediators has different effects on vascular tone in different vascular beds?
A. Prostacyclin
B. Bradykinin
C. Endothelin
D. Nitric Oxide
E. Oxygen
E. Oxygen
(Lucking Ch. 4)
Which statement is correct regarding the biochemical consequences of tissue hypoxia?
A. Anaerobic metabolism is as equally efficient as aerobic metabolism in producing energy, but produces acid byproducts such as lactate.
B. Elevated lactate levels can be readily buffered by the addition of sodium bicarbonate.
C. Lactate is produced as a byproduct of anaerobic glycolysis during tissue hypoxia, but may also be produced in the absence of tissue hypoxia.
D. Restoring tissue perfusion and oxygenation results in lactate being reconverted into glucose in the liver.
E. The reduction in pH seen during states of tissue hypoxia is primarily due to the accumulation of lactate.
C. Lactate is produced as a byproduct of anaerobic glycolysis during tissue hypoxia, but may also be produced in the absence of tissue hypoxia.
(Lucking Ch. 2)
A 12 year old 50 kg male is admitted after correction of severe scoliosis via a combined anterior and posterior approach. Upon admission, he is mildly tachycardic to 108 bpm, normotensive and well perfused. His oxygen saturation is 99%, PaO2 is 198 mm Hg on 30% FiO2 and his hemoglobin is 10.9 g/dL. You are called to the bedside due to a steady increase in chest tube output. He is now tachycardic to 149 bpm, has a blood pressure of 96/58 mm Hg and is cool distally. His oxygen saturation is 87% and PaO2 is 65 mm Hg on 30% FiO2. Current hemoglobin is 7.6 g/dL. What percent decrease in arterial oxygen content has occurred?
A. 10%
B. 15%
C. 30%
D. 40%
E. 50%
D. 40%
(Lucking Ch. 2)
The above child (12yo 50kg male after scoliosis surgery, oxygen saturation is 87% and PaO2 is 65 mm Hg on 30% FiO2, hemoglobin 7.6 g/dL) is ordered a transfusion of packed red blood cells. While awaiting transfusion, he is placed on 100% FiO 2 resulting in an oxygen saturation of 99% and PaO 2 of 265 mm Hg. Which of the following is true regarding oxygen administration in this patient awaiting transfusion?
A. Administration of oxygen will increase the arterial oxygen content from 9 to 11 mL/dL.
B. Administration of oxygen will increase the arterial oxygen content from 9 to 13 mL/dL.
C. Administration of oxygen will increase the arterial oxygen content from 10 to 12 mL/dL.
D. Administration of oxygen will increase the arterial oxygen content from 10 to 13 mL/dL .
E. Administration of oxygen will increase the arterial oxygen content from 10 to 14 mL/dL.
A. Administration of oxygen will increase the arterial oxygen content from 9 to 11 mL/dL.
(Lucking Ch. 2)
Which of the following is true regarding oxygen-hemoglobin dissociation curve?
A. Fetal hemoglobin increases oxyhemoglobin dissociation in the capillary circulation thereby making more oxygen available at the tissue level.
B. Hypoxemia increases oxyhemoglobin dissociation in the capillary circulation thereby making more oxygen available at the tissue level.
C. Increased temperature decreases oxyhemoblobin dissociation in the capillary circulation thereby making less oxygen available at the tissue level.
D. Severe acidosis decreases oxyhemoblobin dissociation in the capillary circulation thereby making less oxygen available at the tissue level.
E. Severe alkalosis decreases oxyhemoblobin dissociation in the capillary circulation thereby making more oxygen available at the tissue level.
B. Hypoxemia increases oxyhemoglobin dissociation in the capillary circulation thereby making more oxygen available at the tissue level.
(Lucking Ch. 2)
Which is the following is a true statement regarding physiologic determinants of oxygen delivery?
A. Arterial oxygen content can be maximized, yet a state of decreased oxygen delivery may persist.
B. Oxygen delivery is primarily determined by the rate of oxygen extraction.
C. The determinants of cardiac output and the determinants of arterial oxygen are different and have limited interdependence.
D. The fractional inspired oxygen content impacts arterial oxygen content, and therefore, oxygen delivery greater than the hemoglobin concentration.
E. Therapies aimed at improving oxygen delivery are primarily related to maintaining alveolar oxygenation.
A. Arterial oxygen content can be maximized, yet a state of decreased oxygen delivery may persist.
(Lucking Ch. 2)
Which of the following is most correctly matched?
A. Dobutamine 5 mcg/kg/min – decreased myocardial oxygen consumption
B. Low oxygen delivery – increased oxygen extraction
C. Mitochondrial poisoning – increased oxygen extraction
D. Neuromuscular blockade – increased oxygen consumption
E. Seizure – decreased oxygen consumption
B. Low oxygen delivery – increased oxygen extraction
(Lucking Ch. 2)
Which statement best reflects the ability of the body to extract oxygen?
A. Baseline oxygen extraction varies among individual organs, but remains constant during changes in clinical conditions.
B. High oxygen extraction is reflected in a lower venous oxygen content.
C. The normal oxygen extraction ratio (O 2 ER) is approximately 50% of the oxygen being delivered to the tissues. The excess in delivered oxygen allows for an increase during stress states, thereby, minimizing the need for anaerobic metabolism.
D. Organs with lower metabolic demand will consume less oxygen and consequently, will have a lower venous oxygen content.
E. The oxygen extraction ratio (O 2 ER) is determined by dividing the difference of the arterial and venous oxygen content by the cardiac output.
B. High oxygen extraction is reflected in a lower venous oxygen content.
(Lucking Ch. 2)
A 5 year old presents with pallor, a murmur, and a heart rate of 140 bpm. He is afebrile and his oxygen saturation via pulse oximetry is 97%. There is no history of acute blood loss and his mom explains that his symptoms have evolved over several weeks. Laboratory analysis reveals a white blood cell count of 12, 300 cells/mL, hemoglobin of 4.5 g/dL, and a platelet count of 210,000/mL. His red blood cell indices are microcytic and hypochromic. His electrolytes are unremarkable except for a bicarbonate of 18 mmol/l. His arterial blood gas reveals pH 7.32, PaCO 2 33 mm Hg, PaO 2 65 mm Hg, base deficit (−) 9, and an oxygen saturation of 97%. The most appropriate next course of action is which of the following?
A. Transfuse 15 mL/kg of packed red blood cells over 2 h.
B. Transfuse 5 mL/kg packed red blood cells over 4 h and administer a dose of sodium bicarbonate.
C. Transfuse 5 mL/kg packed red blood cells over 4 h and begin iron supplementation and erythropoietin.
D. Transfuse 5 mL/kg of packed red blood cells over 4 h and begin supplemental oxygen.
E. Transfuse 15 mL/kg of packed red blood cells over 4 h and monitor for signs of pulmonary edema utilizing furosemide if necessary.
D. Transfuse 5 mL/kg of packed red blood cells over 4 h and begin supplemental oxygen.
(Lucking Ch. 2)
A 14 year old multiple trauma victim with adult respiratory distress syndrome is admitted to the PICU. To optimize his care, you have placed an intravenous oximetric catheter with its tip in the superior vena cava to monitor venous oxygen saturation continuously. The patient is intubated, mechanically ventilated, and heavily sedated. His superior vena cava saturation has consistently been in the low 80 range, but has suddenly begun to decrease into the low 70s. His pulse oximeter is unchanged and continues to read 99%. His vital signs are stable except for a fever spike up to 39.8° Celsius and a 5– 10 beat increase in his heart rate. He remains heavily sedated on a midazolam infusion. The most likely explanation for his sudden decrease in superior vena cava saturation is which of the following?
A. Acute occult blood loss
B. Decreased cardiac output
C. Fever
D. Migration of the catheter into the right atrium
E. Subclinical seizure
C. Fever
(Lucking Ch. 2)
Hypoxemia is detected by special nerve chemical receptors located in the carotid and aortic bodies. When these chemoreceptors are triggered by hypoxemia (PaO 2 < 60 mm Hg, corresponding to SaO 2 < 93%), which of the following physiologic responses ensue?
A. Stimulation of the respiratory area of the medulla resulting in a decrease in minute ventilation, respiratory pauses, and potentially apnea.
B. Stimulation of the respiratory area of the medulla resulting in an increase in minute ventilation, a higher alveolar oxygen concentration (PAO 2 ), and ultimately, an increase in the arterial oxygen content.
C. Stimulation of the vasomotor center of the brainstem leading to decreased sympathetic tone and bradycardia.
D. Stimulation of the vasomotor center of the brainstem resulting in decreased sympathetic tone, decreased metabolic rate, and decreased oxygen consumption.
E. Stimulation of the vasomotor center of the brainstem resulting in increased sympathetic tone, increased systemic vascular resistance, and decreased cardiac output.
B. Stimulation of the respiratory area of the medulla resulting in an increase in minute ventilation, a higher alveolar oxygen concentration (PAO 2 ), and ultimately, an increase in the arterial oxygen content.
(Lucking Ch. 2)
While evaluating an 11 month old, 10 kg infant with tachycardia (180 beats per minute) and poor perfusion; the critical care physician notes that the heart rate decreases momentarily to 170 beats per minute and the pulses became stronger after compressing the liver of the infant. Which of the following physiological changes most likely explains the response?
A. The compression on the liver produced a sudden increase in the systemic vascular resistance and the increased afterload resulted in the stronger pulses and decreased heart rate.
B. The compression on the liver produced a sudden vagal response clinically manifested by the decreased heart rate.
C. The compression on the liver produced a temporary increase in contractility with a resultant increase in cardiac output (stroke volume) and a slowing of the heart rate.
D. The compression on the liver reduced venous return to the heart thereby decreasing preload resulting in clinical deterioration manifested by the decreased heart rate.
E. The compression on the liver transiently increased preload with a resultant increase in cardiac output (stroke volume) and a slowing of the heart rate.
E. The compression on the liver transiently increased preload with a resultant increase in cardiac output (stroke volume) and a slowing of the heart rate.
(Lucking Ch. 3)
A 2 month old infant presents with renal failure secondary to an obstructive uropathy. The infant is tachypneic and noted to have a metabolic acidosis with a blood pH of 7.20. Sodium bicarbonate (1 mEq/kg) is administered intravenously in an attempt to improve the blood pH. Shortly thereafter, the perfusion of the infant is clinically noted to decline. Which of the following is the best potential explanation for the change in hemodynamics?
A. Despite bicarbonate therapy, the blood pH remained sufficiently low to negatively affect the myocardium.
B. The increase in the blood pH further reduced the low serum ionized calcium levels, negatively effecting myocardial contractility.
C. The increase in the blood pH led to direct systemic vasodilatation resulting in hemodynamic compromise.
D. The rapid rise in sodium concentration resulted in a negative inotropic effect on the heart.
E. The respiratory rate increased further after the bicarbonate therapy resulting in further energy expenditure and cardiovascular compromise.
B. The increase in the blood pH further reduced the low serum ionized calcium levels, negatively effecting myocardial contractility.
(Lucking Ch. 3)
A previously healthy 10 year old child develops ARDS after sustaining abdominal and lower extremity trauma in a motor vehicle collision. She received crystalloid fluid resuscitation and multiple blood product transfusions to achieve hemodynamic stability. She requires a positive end expiratory pressure (PEEP) of 15 cm H 2 O to maintain acceptable arterial oxygenation, but develops poor cardiac output with this ventilator strategy. Which of the following is the primary cause of her decreasing cardiac output?
A. A decrease in left ventricular contractility due to myocardial depressant factors.
B. A decrease in left ventricular filling due to intraventricular septal shift into the left ventricle.
C. A decrease in systemic venous return secondary to increased mean airway pressure.
D. An increase in left ventricular afterload due to increased transmural wall pressure.
E. An increase in right ventricular afterload secondary to lung overdistension.
C. A decrease in systemic venous return secondary to increased mean airway pressure.
(Lucking Ch. 3)
Which of the following is a contributing factor in the clinical presentation of pulsus paradoxus?
A. A decrease in left ventricular afterload
B. A decrease in pulmonary vascular resistance
C. A decrease in systemic venous return
D. An increase in right ventricular volume
E. A rightward shift of the intraventricular septum
D. An increase in right ventricular volume
(Lucking Ch. 3)
A 3 year old male with a known cardiomyopathy and decreased left ventricular function is admitted to the pediatric intensive care unit with a presumed viral laryngotracheobronchitis. In addition to reducing the work of breathing, tracheal intubation and the use of positive pressure ventilation will benefit cardiac function in this child in which of the following ways?
A. A decrease in left ventricular afterload
B. A decrease in right ventricular afterload
C. A decrease in systemic venous return
D. An increase in cardiac contractility
E. An increase in systemic venous return
A. A decrease in left ventricular afterload
(Lucking Ch. 3)
A 12 year old male with a severe asthmatic exacerbation has worsening respiratory distress that is now accompanied by poor perfusion, worsening tachycardia (190 beats per minute), and hypotension (86/45 mm Hg). The physiologic explanations for the hypotension include relative hypovolemia secondary to increased insensible water losses and decreased intake, hypoxemia-induced myocardial dysfunction and:
A. decreased right ventricular afterload.
B. decreased systemic vascular resistance.
C. increased left ventricular afterload.
D. increased partial pressure of carbon dioxide.
E. untoward effect of steroid therapy.
C. increased left ventricular afterload.
(Lucking Ch. 3)
A 12 year old male with a severe asthmatic exacerbation has now developed compromised perfusion with significant tachycardia (185 beats per minute), and hypotension (82/42 mm Hg). An appropriate initial hemodynamic intervention in this child would be to:
A. administer a crystalloid fluid bolus (10 mL/kg) to augment preload.
B. initiate a low dose epinephrine infusion (0.05 mcg/kg/min) to augment contractility.
C. initiate an infusion of milrinone (0.5 mcg/kg/min) to augment contractility and foster ventricular relaxation.
D. initiate an infusion of sodium nitroprusside (1 mcg/kg/min) to decrease systemic afterload.
E. initiate inhaled nitric oxide (20 ppm) to decrease pulmonary vascular resistance.
A. administer a crystalloid fluid bolus (10 mL/kg) to augment preload.
(Lucking Ch. 3)
Which of the following statements regarding cardiovascularpulmonary interactions is false?
A. An increase in systemic venous return or in right ventricular afterload during respiration will displace the intraventricular septum into the left ventricle and decrease left ventricular compliance and preload.
B. Extremes in lung volumes (both low and high) can result in elevations in pulmonary vascular resistance.
C. Adequate intravascular volume is important for both RV and LV output when initiating positive pressure ventilation.
D. Negative intrathoracic pressure generated during spontaneous breathing increases the pressure gradient from the systemic veins to the right atrium.
E. Negative intrathoracic pressure generated during spontaneous breathing has no effect on extra thoracic large veins.
E. Negative intrathoracic pressure generated during spontaneous breathing has no effect on extra thoracic large veins.
(Lucking Ch. 3)
The right and the left coronary arteries receive most of their blood flow during which phase of the cardiac cycle?
A. Both during diastole
B. Both during systole
C. Left during diastole and Right during systole
D. Left during diastole and Right continuously E. Left during systole and Right during diastole
C. Left during diastole and Right during systole
(Lucking Ch. 4)
In which of the following conditions is the vasodilatory effect of elevated PaCO 2 in the cerebral circulation lost or blunted?
A. core body temperature of 32 Celsius
B. mean arterial pressure of 90 mm Hg with an intracranial pressure of 18 mm Hg
C. mean arterial pressure of 90 mm Hg with an intracranial pressure of 28 mm Hg
D. severe hypertension
E. all of the above
A. core body temperature of 32 Celsius
(Lucking Ch. 4)
What is the mechanism of hypoxic pulmonary vasoconstriction?
A. a direct action on vascular smooth muscle.
B. local release of vasoconstrictor
C. local suppression of a vasodilator
D. all of the above.
E. none of the above.
D. all of the above.
(Lucking Ch. 4)
Medullary blood flow of the kidneys appears to be refractory to increases in circulating catecholamines within the physiological range. Medullary blood flow will decrease only with extremely high concentrations of norepinephrine. Which of the following mechanisms is responsible for this unique property?
A. counter regulatory role of nitric oxide
B. endothelin induced vasodilation.
C. paradoxical vasodilation as a response to the effect of angiotensin II.
D. vasopressin induced vasodilation.
E. A and C
E. A and C
(Lucking Ch. 4)
In order to abolish human cutaneous vasoconstriction what pharmacological blockage is necessary?
A. peripheral alpha and beta blockade
B. peripheral alpha blockade
C. peripheral beta blockade
D. peripheral alpha, beta and neuropeptide Y blockade
E. peripheral neuropeptide Y blockade
D. peripheral alpha, beta and neuropeptide Y blockade
(Lucking Ch. 4)
Pulmonary vascular tone is regulated by a complex interplay of local mediators and neural regulation. Which mediator primarily cause pulmonary vascular vasoconstriction?
A. acetylcholine
B. angiotensin II
C. bradykinin
D. natriuretic peptides
E. nitric oxide
B. angiotensin II
(Lucking Ch. 4)
Which is the most correct statement regarding regulation of splanchnic circulation?
A. blood flow increase after a meal is dependent of the hollow organ stretch
B. hydrolytic products of food, especially glucose and fatty acids with bile salts, are triggers responsible for the greatest increase in blood flow in the prandial and post prandial states
C. larger arteries of the splanchnic bed have tone regulated by β-adrenergic and α-adrenergic effects more than the α-adrenergic effects resulting in a baseline vasodilated state
D. sympathetic and parasympathetic innervation is primarily responsible for postprandial hyperemia
E. vasoactive hormones and peptides have a significant role in postprandial hyperemia
B. hydrolytic products of food, especially glucose and fatty acids with bile salts, are triggers responsible for the greatest increase in blood flow in the prandial and post prandial states
(Lucking Ch. 4)
Which statement accurately reflects the utility of the physical assessment of the cardiovascular status of a child?
A. Capillary refill time is independent of ambient temperature.
B. Pulse pressure will be decreased in conditions characterized by low systemic vascular resistance.
C. Tachycardia, in and of itself, is a sensitive and specific sign of hemodynamic instability.
D. The peripheral skin to ambient temperature gradient (dTp-a) decreases during states of high systemic vascular resistance.
E. Urine output is influenced by many factors and therefore should not serve as a proxy for distal tissue perfusion.
D. The peripheral skin to ambient temperature gradient (dTp-a) decreases during states of high systemic vascular resistance.
(Lucking Ch. 5)
In the following illustration of an arterial waveform, which number identifies the incisura or dicrotic notch?
A. 1
B. 2
C. 3
D. 4
E. 5
D. 4
(Lucking Ch. 5)
Which statement best describes wave frequency and resonance?
A. A system with high resonance may falsely increase the diastolic pressure by as much as 30%.
B. An accurate monitoring system at heart rates of 180 beats per minute (bpm) should have its natural frequency be equal to 6 Hz.
C. If the frequency of the system is in the same range as the frequency of the arterial waveform, the amplitudes of the waves become additive and can overestimate the systolic pressure.
D. Resonant augmentation of the arterial pressure wave causes an artifactual increase in both systolic and diastolic recorded pressures.
E. The effect of resonance becomes less problematic when the monitoring system has a low natural frequency and the heart rate is high.
C. If the frequency of the system is in the same range as the frequency of the arterial waveform, the amplitudes of the waves become additive and can overestimate the systolic pressure.
(Lucking Ch. 5)
Which statement is correct regarding arterial monitoring systems?
A. Damping describes the interaction between the oscillatory energy of a wave and the electrical properties of the monitoring system.
B. Due to the turbulent flow and the high oxygen tension found in arteries, infections associated with arterial catheters are extremely uncommon.
C. Pressure monitoring devices must be leveled to the point at which the catheter enters the artery.
D. The delivery of a small “fast flush” to the arterial catheter allows for quantification of excessive resonance within the system.
E. The phlebostatic axis is the determined by locating the junction of the vertical line drawn down from the clavicle and the horizontal mid-axillary line.
D. The delivery of a small “fast flush” to the arterial catheter allows for quantification of excessive resonance within the system.
(Lucking Ch. 5)
In assessing a normal central venous pressure (CVP) waveform (Figure), the a wave represents which of the following?
A. The decline in atrial pressure that occurs during atrial relaxation and ventricular systole.
B. The displacement of the tricuspid valve toward the atrium during isovolumic ventricular contraction.
C. The fall in atrial pressure that occurs as the tricuspid valve opens and the atrium is drained.
D. The increase in intra-atrial pressure observed during atrial contraction that occurs at the end of ventricular diastole.
E. The rise in atrial pressure during the end of ventricular systole as the atrium fills with venous blood from the inferior and superior venous cava.
Pediatric Critical Care Study Guide : Text and Review, edited by Steven E. Lucking, et al., Springer London, Limited, 2012. ProQuest Ebook Central, http://ebookcentral.proquest.com/lib/harvard-ebooks/detail.action?docID=973340.
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D. The increase in intra-atrial pressure observed during atrial contraction that occurs at the end of ventricular diastole.
(Lucking Ch. 5)
In assessing a normal central venous pressure (CVP) waveform (Figure), the c wave represents which of the following?
A. The decline in atrial pressure that occurs during atrial relaxation and ventricular systole.
B. The displacement of the tricuspid valve toward the atrium during isovolumic ventricular contraction.
C. The fall in atrial pressure that occurs as the tricuspid valve opens and the atrium is drained.
D. The increase in intra-atrial pressure observed during atrial contraction that occurs at the end of ventricular diastole.
E. The rise in atrial pressure during the end of ventricular systole as the atrium fills with venous blood from the inferior and superior venous cava.
B. The displacement of the tricuspid valve toward the atrium during isovolumic ventricular contraction.
(Lucking Ch. 5)
In assessing a normal central venous pressure (CVP) waveform (Figure), the x descent represents which of the following?
A. The decline in atrial pressure that occurs during atrial relaxation and ventricular systole.
B. The displacement of the tricuspid valve toward the atrium during isovolumic ventricular contraction.
C. The fall in atrial pressure that occurs as the tricuspid valve opens and the atrium is drained.
D. The increase in intra-atrial pressure observed during atrial contraction that occurs at the end of ventricular diastole.
E. The rise in atrial pressure during the end of ventricular systole as the atrium fills with venous blood from the inferior and superior venous cava.
A. The decline in atrial pressure that occurs during atrial relaxation and ventricular systole.
(Lucking Ch. 5)
In assessing a normal central venous pressure (CVP) waveform (Figure), the v wave represents which of the following?
A. The decline in atrial pressure that occurs during atrial relaxation and ventricular systole.
B. The displacement of the tricuspid valve toward the atrium during isovolumic ventricular contraction.
C. The fall in atrial pressure that occurs as the tricuspid valve opens and the atrium is drained.
D. The increase in intra-atrial pressure observed during atrial contraction that occurs at the end of ventricular diastole.
E. The rise in atrial pressure during the end of ventricular systole as the atrium fills with venous blood from the inferior and superior venous cava.
E. The rise in atrial pressure during the end of ventricular systole as the atrium fills with venous blood from the inferior and superior venous cava.
(Lucking Ch. 5)
In assessing a normal central venous pressure (CVP) waveform (Figure), the y descent represents which of the following?
A. The decline in atrial pressure that occurs during atrial relaxation and ventricular systole.
B. The displacement of the tricuspid valve toward the atrium during isovolumic ventricular contraction.
C. The fall in atrial pressure that occurs as the tricuspid valve opens and the atrium is drained.
D. The increase in intra-atrial pressure observed during atrial contraction that occurs at the end of ventricular diastole.
E. The rise in atrial pressure during the end of ventricular systole as the atrium fills with venous blood from the inferior and superior venous cava.
C. The fall in atrial pressure that occurs as the tricuspid valve opens and the atrium is drained.
(Lucking Ch. 5)
Which of the following Fick derived equations is correct?
E. Flow = Consumption / (Aortic Content - Venous Content)
(Lucking Ch. 5)
In the following illustration of an arterial waveform, which number identifies peak left ventricular ejection?
A. 1
B. 2
C. 3
D. 4
E. 5
B. 2
(Lucking Ch. 5)
In the following illustration of an arterial waveform, which number identifies the anacrotic limb?
A. 1
B. 2
C. 3
D. 4
E. 5
A. 1
(Lucking Ch. 5)
In the following illustration of an arterial waveform, which number identifies diastolic runoff?
A. 1
B. 2
C. 3
D. 4
E. 5
E. 5
(Lucking Ch. 5)
Common QTc prolonging medications in PICU
Duke criteria for infective endocarditis
