Question 1

A measure of the resistance or force against which the heart must pump defines which of the following terms?

Accepted Answer

Afterload is a measure of the resistance or force against which the heart must pump.

Question 2

Assessment of an infant suspected of having shock reveals skin that is warm,pink,and well perfused.How should the therapist interpret these findings?

Accepted Answer

Evaluation of skin color and temperature is easily performed.The skin of children in shock may be pale,cyanotic,or mottled because of poor perfusion.Traditionally,practitioners have described two phases of septic shock.In early septic shock the skin appears well perfused,warm,and pink.These signs are caused by vasodilation and increased cardiac output.Later in the course of shock,the cardiac output begins to fall.Skin examined during this period is likely to be cool,cyanotic,or mottled,representing a decrease in the amount of substrate reaching the skin.

Question 3

In which of the following clinical situations may the administration of packed red blood cells be indicated?

Accepted Answer

If there is evidence of anemia or suspected losses of blood,repletion of the intravascular volume with packed red blood cells should be performed.

Question 4

A 7-year-old patient with insulin-dependent diabetes is evaluated in the emergency department due to ketoacidosis.What type of shock is most commonly associated with diabetic ketoacidosis?

Accepted Answer

In hypovolemic shock,rapid restoration of the vascular volume is paramount.For hemorrhagic shock,a subtype of hypovolemic shock,blood loss causes shock and thus treatment requires replacement of the lost blood volume.Other potential causes of hypovolemic shock include osmolar diuresis such as from diabetic ketoacidosis or from infectious enteritis.

Question 5

A respiratory therapist has intubated a child with septic shock who has also received intravenous fluids and vasopressors.What condition could explain a lack of response to therapy?

Accepted Answer

When septic shock is refractory to fluid and/or catecholamines,consideration must also be given to adrenal insufficiency as a component of the shock state,particularly in patients who are at risk for impairment in their hypothalamic-pituitary-adrenal axis or who have had a history of steroid exposure.In such patients,the clinical status may not improve unless the patient receives "stress-dose" steroids with hydrocortisone.

Question 6

During the treatment of sepsis,what intervention may be needed if hypotension persists despite the maximal application of inotropic and vasomotor support?

Accepted Answer

Patients remaining in shock despite the supportive therapies may benefit from mechanical cardiac support,such as extracorporeal membranous oxygenation (ECMO).ECMO is highly effective for cardiogenic shock because it helps support the ailing heart,but it is less successful in septic shock,except possibly in treating refractory low-cardiac output septic shock.

Question 7

How should the therapist interpret a capillary refill time of approximately 1 second in a pediatric patient?

Accepted Answer

Capillary refill (the process of blanching the skin for several seconds and timing the return of blood flow to the blanched skin)is a quick,useful,and noninvasive test that provides important information regarding perfusion in the acute setting.The normal capillary refill time should be less than 2 seconds and correlates with a cardiac index of > 2.0 L/min/m².

Question 8

A therapist is calculating oxygen delivery for a patient admitted with a diagnosis of shock.Which of the following parameters should the therapist measure?
I.Hemoglobin
II.Oxygen bound to hemoglobin
III.Dissolved oxygen
IV.Cardiac output

Accepted Answer

Oxygen delivery depends on oxygen-carrying capacity (% hemoglobin),oxygen provided (oxygen bound to hemoglobin plus dissolved oxygen),and cardiac output.

Question 9

When cardioversion is indicated,at what point during the cardiac cycle must it be applied?

Accepted Answer

An unstable tachycardia manifested with hypotension or signs of shock should be treated with electrical therapy in the form of synchronized cardioversion or defibrillation.Cardioversion synchronizes the delivery of the shock with the QRS complex to prevent deterioration to a more lethal arrhythmia and should be used in patients who have a palpable pulse.

Question 10

Which of the following hemodynamic assessments can be obtained from a pulmonary capillary wedge pressure measurement?

Accepted Answer

The use of PA catheters in children is supported by the American College of Critical Care Medicine for circumstances in which irreversible shock manifesting as poor perfusion,acidosis,and hypotension persists despite the use of therapies directed at the arterial blood pressure,CVP pressure,and oxygen saturation indices.In addition to the measurements obtained directly from the catheter,a number of derived values provide information regarding the homeostatic function of the child,including systemic vascular resistance as a measure of afterload and oxygen consumption and oxygen extraction.

Question 11

Which of the following can be obtained from a central venous pressure measurement?

Accepted Answer

The placement of a catheter in the central venous system allows for an assessment of the volume status of the child with shock.The catheter,when attached to a continuous column of fluid and a pressure transducer,measures the downstream intravascular pressure,or CVP,in the right atrium.This intravascular pressure represents preload,one of the contributors to the stroke volume,which contributes to the cardiac output.

Question 12

A child admitted to the emergency department with a diagnosis of shock has a cardiac index is 3.5 L/min/m².How should the therapist interpret this value?

Accepted Answer

In children,normal values for the cardiac index are in the range of 3.3 to 6.0 L/min/m².A cardiac index of < 2.0 L/min/m² has been associated with an increase in mortality.

Question 13

A child has been treated for shock with 60 mL/kg of normal saline.What should be considered at this time?

Accepted Answer

Large fluid deficits typically exist and initial volume resuscitation usually requires 40 to 60 mL/kg but can require as much as 200 mL/kg in some cases of septic shock.Continued fluid losses and persistent hypovolemia due to capillary leak can persist despite fluid resuscitation.Ongoing fluid replacement is necessary to maintain adequate tissue perfusion,and large volumes may be required as vascular permeability results in peripheral and third space losses.When total administered volumes of 60 mL/kg are reached,intravascular monitoring and initiation of vasoactive support should be considered.

Question 14

What is the mainstay of therapy for patients with anaphylactic shock?

Accepted Answer

Providing oxygen will help ensure adequate oxygenation,and the wheezing often abates with the administration of epinephrine for circulatory support.Epinephrine is the mainstay of therapy.Circulatory dysfunction and shock are the next most pressing issues.For circulatory collapse,large volume infusions,as in other types of shock,help to restore the circulating blood volume.Hypotension can be severe and resistant to therapy.Circulatory support with repeated doses of epinephrine and a continuous epinephrine infusion help support the patient until the directed therapy can begin.

Question 15

Which of the following signs is one of the first to indicate decreased peripheral perfusion in children?

Accepted Answer

Infants and children have a limited ability to increase stroke volume.As a result,they will attempt to compensate for a reduction in cardiac output by increasing their heart rate.Tachycardia is one of the first signs of decreased peripheral perfusion in children.Hypotension is an unreliable and late finding of shock in children occurring when the child's compensatory mechanisms have already failed.

Question 16

Which of the following types of shock is the most common among children?

Accepted Answer

Typically,shock can be classified in four general states: hypovolemic,cardiogenic,obstructive,and distributive.The first,hypovolemic shock,is most common worldwide among children,most often resulting from severe dehydration.

Question 17

Which vascular site would provide the most reliable measurement of the beat-to-beat monitoring of the blood pressure in an infant who is suspected of having shock?

Accepted Answer

The placement of a catheter in a peripheral or central artery can be performed for the monitoring of blood pressure on a continuous basis in the intensive care unit.Arterial catheterization can provide beat-to-beat monitoring of the blood pressure.

Question 18

Which of the following microorganisms are likely responsible for neonatal meningitis?
I.Klebsiella species
II.Neisseria meningitidis
III.Escherichia coli
IV.Listeria monocytogenes

Accepted Answer

The common causative agents for meningitis are age specific.For neonates,the primary bacterial agents include Streptococcus agalactiae,Klebsiella species,Escherichia coli,and uniquely Listeria monocytogenes.

Question 19

A respiratory therapist is gathering equipment to intubate a patient with anaphylactic shock who has severe bronchospasm.What is one of the most prominent inflammatory mediators responsible for the increase in airway resistance and fall in the PaO₂?

Accepted Answer

Histamine is one of the most prominent mediators and is believed to be responsible for the increase in airway resistance and the fall in partial pressure of oxygen due to its contractile action on the smooth muscle of the lung.

Question 20

A child is receiving aggressive therapy for shock.Cardiac failure has developed.Which of the following inotropes is the most frequently used under these circumstances?

Accepted Answer

Inotropic agents are used to increase contractility and cardiac output.Dobutamine is a beta-1 adrenergic agonist with chronotropic and inotropic actions,as well as afterload reduction.Dopamine,the most frequently used inotrope,increases renal blood flow but also has vasoconstrictive properties at high doses due to release of norepinephrine.Epinephrine is a naturally circulating neurohormone that increases contractility during stress and shock.At low dose it provides inotropy but at higher doses increases peripheral vascular tone and acts as a vasopressor.Patients with heart failure and increased systemic vascular resistance may be harmed by these higher doses unless epinephrine is combined with an inodilator or vasodilator.

Quiz 30: Shock, Sepsis and Anaphylaxis