6.Shock Flashcards
anaphylactic shock is classified by what type of shock?
a. Hypovolemic
b. Cardiogenic
c. Distributive
d. Hypoxic
c. Distributive - correct
Septic shock is classified by what type of shock?
a. Hypovolemic
b. Cardiogenic
c. Distributive
d. Hypoxic
c. Distributive - correct
CO x arterial oxygen content =?
Global oxygen delivery (DO2) which reflects the total vol of oxygen delivered to the tissues per minute, irrespective of how blood flow is distributed in the regional circulation.
1) What is true regarding defects in oxygen uptake?
a) Diffusional resistance is caused by slow blood velocity
b) Diffusional shunting results from poor diffusion of oxygen to reach the cells
c) Perfusion/metabolism mismatch occurs during a PTE
d) Cytopathic hypoxia is classically associated with sepsis
D is correct = mitochondrial dysfunction
slow blood –> diffusional shunting
Edema and increased distance –> more diffusional resistance
PTE/thrombi–>arteriovenous shunting
sustained tachycardia –>perfusion mismatch (not enough coronary perfusion and increased O2 demand)
How much oxygen is carried by 1 gram of fully saturated hemoglobin? a)0.34 b)0.15 c)1.34 d)0.003
c) 1.34
What is the oxygen solubility coefficient at 37 degrees Celsius? a)0.003 b)0.05 c)0.15 d)0.08
a)0.003
What causes a left shift in the oxygen-hemoglobin dissociation curve? a)Decreased temperature b)Decreased pH c)Increased DPG d)Increased PaCO2
a)Decreased temperature
Which of the following is not a mechanism of providing adequate oxygen delivery in
shock?
a.Maintaining mean circulatory pressure
b.Maximizing cardiac performance
c.Redistributing perfusion
d.Optimizing oxygen perfusion at the lungs
D optimizing oxygen unloading
Do
circulating volume and pressure
max cardiac performance
Which of the following is true?
a.Baroreceptors in the thoracic arteries (carotid sinus and aortic arch) stimulate
parasympathetic reflexes
b.Chemoreceptors within the carotid and aortic bodies are activated in response
mainly to increase in H+ or CO2
c.Chemoreceptors aide in activation of respiration leading to enhanced
oxygenation and CO2 elimination
d.Reduced circulating volume leads to stimulation of baroreceptors which leads to
constriction of arterioles and relaxation of venules and veins
C is correct
Sympathetic reflexes stimulated by baroreceptors
Chemoreceptors sense reduction in o2 and lesser extent them; H+ and CO2 more sensitive in brain stem)
activated baroreceptors–> constriction of
both arterioles and veins
Which is true?
a.The absence of a palpable pulse in a peripheral artery is considered a sign of
hypotension with a systolic arterial pressure less than 60 mm Hg.
b.Loss of a palpable femoral pulse is considered a sign of profound hypotension
with a systolic arterial pressure less than 40 mm Hg.
c.There is no clinical data to support determining BP from pulse palpation.
d.In dogs, the shock organ is the lungs, whereas in cats the shock organ is the GI
tract.
C is correct
(80 mm Hg) peripheral
(60 mm Hg) femoral
cats = lung, dogs = GI
MAP ranges that keep the following organs at a constant perfusion?
a. Renal circulation →
b. Myocardial circulation →
c. Cerebral circulation →
a. Renal circulation → 70 to 130 mm Hg
b. Myocardial circulation → 60 to 140 mm Hg
c. Cerebral circulation → 50 to 180 mm Hg
What is the equation to estimate mean arterial pressure?
a.MAP = DAP +1/3 × (SAP −DAP)
Which is false?
a.To limit possible errors, the BP cuff width should be 40% of the limb circumference
b.Central venous pressure (CVP) is the hydrostatic pressure measured through a
catheter, in which the tip is placed in the cranial or caudal vena cava or in the
right atrium
c. Physiologic CVP for the dog and cat is between 0 and 5 cm H2O
d.The gold standard for cardiac output measurement involves thermodilution
and requires the placement of a Carl-tanner pulmonary artery catheter.
D
d.The gold standard for cardiac output measurement involves thermodilution
and requires the placement of a – pulmonary artery catheter.
(Swan-Ganz art cath)
When should oxygen therapy be continued after initial stabilization of a patient in shock?
a. SpO2 < 94% or PaO2 < 80 mm Hg
b. SpO2< 80% or PaO2 < 60 mm Hg
c. When PaO2:FiO2 ratio > 500
d. When gums are still cyanotic indicating >3 to 5 g/dL of deoxygenated hemoglobin
A is correct
(Normal PaO2 > 90 mm Hg)
(Normal PaO2/FiO2 ratio should be approximately 500)
d.When gums are still cyanotic indicating >3 to 5 g/dL of deoxygenated hemoglobin in circ (This is subjective but true, so not the best answer when thinking about goal directed endpoints)
At what point does oxygen toxicity occur?
a. Exposure to 40% Fi O2 for 48 hours
b. Exposure to 60% FiO2 for > 24 hours
c. O2 flow > 100 ml/kg/min in a nasal canula
d. 2-3 L/min of flow by
B is correct
c.O2 flow > 100 ml/kg/min in a nasal canula (reported to cause patient discomfort)
d.2-3 L/min of flow by (this is a normal supportive care to provide about 25-40%
FiO2)
What is a documented reason to avoid colloids in critical canine patients?
a.Renal lesions and renal dysfunction after administration
b.Coagulopathy from reduction in circulating fVIII and vWB factor, nonspecific
platelet coating, and interference with fibrin polymerization
c.All of the above
C. Both
a.Renal (conflicting evidence,
AKI known in people)
b.Coagulopathy(unknown clinical
significance in veterinary patients)
What is NOT a benefits of hypertonic saline?
a. Reduction of endothelial swelling
b. Increased intracranial pressure
c. Immunomodulation
d. Improved myocardial function
B
(Decreased) intracranial pressure
T/F: Glucocorticoids should be considered in septic patients?
TRUE at LOW doses– when vasopressor-refractory hypotension is noted.
T/F: recombinant Human Activated Protein C (rhaPC) has been shown to block the
pro-inflammatory cascade?
TRUE – but no other therapies have been shown to help.
Super expensive and lack of efficacy related to species specificity and high clearance rates
Which of the following is false?
a. Ampicillin and ceftazidime provides broad spectrum coverage
b. Empiric IV bactericidal antibiotic therapy should be instituted as soon as suspicion for sepsis arises
c. In one study, 80% of septic dogs who were on the incorrect antibiotic died
d. The escalation strategy starts with a broad antibiotic spectrum and covers all
pathogens likely involved and is then changed once the culture results are available?
D
De-escalation
Which of the following is true?
a. Limited fluid volume resuscitation is only for cardiogrenic shock
b. Dyspneic patients may use up to 30% of oxygen consumption in respiratory effort
c. Active rewarm and then fluid resuscitate
d. Stratification by sepsis category is better than the PIRO scheme
B is correct
a. Limited fluids good for hemorrhagic shack and those in which fluid extravasation should be avoided (pulmonary contusion, TBI)
c. Once volume resus. active warming may be required
d. PIRO (predisposition, infection, response, organ dysfunction) is better predictor
Which is true regarding pathophys of Shock?
a. Coagulant systems (activated protein C, antithrombin pathway) are altered –> hypocoagulable state
b. Neutrophil receptors CD14 and TLR play a role in inflammatory response
c. Damage to endothelial glycocalyx contributes to increased microvascular permeability, loss of vascular tone
d. Cytopathic hypoxia is not a part of sepsis
C is correct
a. ANti-coagulant systems: apC and antithrombin –> initial hypercoagulable
b. Macrophage receptros
d. Cytopathic hypoxia inhibition of mitochondial function
Which of the following is not a compensatory mechanism of shock? Bradycardia Tachypnea Peripheral vasoconstriction Dull mentation
Bradycardia–> tachycardia to increase oxygen delivery
Which type of shock is…Impairment of mechanisms regulating vascular tone
distributive shock
Which type of shock is…Inability of the heart to propel the blood through circulation
cardiogenic shock
Which type of shock is…Decreased circulating vascular volume
hypovolemic shock
Which type of shock is…Adequate tissue perfusion but decreased arterial oxygen content or cellular oxygen usage
Hypoxic shock
Which is false?
A Cardiac output is the main determinant of tissue perfusion
B Stroke volume is influenced by preload, afterload, and contractility. The classic example of a reduction in preload is hemorrhagic shock
C A “tension pneumothorax” increases intrathoracic pressure and results in collapse of the great vessels and left ventricle.
D Pericardial effusion can lead to cardiac tamponade and collapse of the chambers of the right heart.
C (right)
What toxin can lead to impaired ability of hemoglobin to carry O2?
carbon monoxide
What other factors cause a decreased hemoglobin affinity for O2? (3)
Hyperthermia
Hypercarbia
Increased 2-3 DPG
Name the 5 defects of O2 uptake?
Diffusional shunting (slow blood velocity)
Diffusional resistance
AV shunt
Perfusion/metabolism mismatch
Cytopathic hypoxia (i.e. occurs in sepsis)
Which of the following is true?
A Early decompensatory shock is characterized by mildly increased heart rate, decreased pulse pressure, absent capillary refill time, decreased glucose
B The shock organ in dogs is the lungs and in cats is the GI tract
C Perfusion is constant in the myocardial circulation as long as MAP 70-130 mm Hg
D The gold standard for cardiac output measurement involves thermodilution and requires placement of a Swan-Ganz catheter
D true
A Early decompensatory shock is characterized by TACHYCARDIA, NORMAL to decreased pulse pressure, PROLONGED capillary refill time, INCREASED glucose
B The shock organ in CATS is the lungs and in DOG is the GI tract
C Perfusion is constant @
myocardial MAP 60-140 mm Hg
Renal MAP 70-130 mm Hg
Cerebral MAP 50-180 mmHg
Central venous pressure can be seen as a surrogate for preload and index of the ability of the heart to cope with venous return?
True
Why is CVP approximate preload?
Catheter placed at the cranial or caudal vena cava, or the jxn between the VC and the right atrium. CVP in absence of vascular obstruction, closely correlated with right atrial pressure which is related to end diastolic volume which determines cardiac preload
What causes increase in CVP? What value?
What causes decrease in CVP? Value?
INCREASE: Cardiogenic shock (often > 10 cm H2O); right sided heart failure, volume overload, pericardial effusion, pleural space disease, increased intrathoracic pressure (Positive pressure ventilation, tension pneumothorax)
DECREASE: Shock patients with hypovolemia or vasodilation ( decreased < 0 cm H2O)
Which of the following is true? A Hyperlactatemia with normal oxygen delivery is not possible. B Cyanosis indicates >3-5 g/dL of deoxygenated hemoglobin in circulation C SpO2 is a good indicator of oxygen exchange especially during oxygen therapy D ScvO2 (central venous oxygen saturation) values underestimate SvO2 (mixed venous oxygen saturation)
A Hyperlactatemia with normal oxygen delivery is called type B lactic acidosis (mitchondrial impairment with sepsis, DM, neoplasia, drugs/toxins) B TRUE C SpO2 is a POOR indicator of oxygen exchange especially during oxygen therapy; LATE marker of respiratory failure D ScvO2 (central venous oxygen saturation) values OVERESTIMATES SvO2 (mixed venous oxygen saturation)
Which of the following is true regarding oxygen supplementation to patients in shock
A After initial stabilization oxygen supplementation is indicated if SpO2 is <94% and PaO2 < 70 mmHg
B The FiO2 of room air is normally 32%
C Unilateral and bilateral nasal catheters at a flow rate of 100ml/kg/min provides an FiO2 of 40% and 60%
D Oxygen toxicity can occur in patients exposed to FiO2 greater than 60% for longer than 48 hours
A < 80 mm Hg
B 21%
C TRUE
D 24 hrs
What the three most common sites for intraosseous catheterization?
Femoral trochanteric fossa
Proximal humerus
Tibial crest
Which of the following is false regarding synthetic colloids
A Redistribution to the interstitium is slower than crystalloids due to the higher molecular weight
B Plasma, blood, albumin solutions and dextran solutions are classified as natural colloids
C Result in coagulopathy due to reduction in circulating factor VIII and vWF
D No definitive evidence associates colloids with AKI and increased mortality in canine septic patients
B False
The principle of hypotensive resuscitation aims for what mean arterial blood pressure? 40 mmHg 50 mmHg 60 mmHg 70 mmHg
60
Which of the following is not a diagnostic criteria for ARDS?
A Acute onset (<72 hours) of tachypnea, labored breathing at rest
B Presence of unknown risk factor
C Evidence of pulmonary capillary leak without increased pulmonary capillary pressure
D History of chronic bronchitis or pneumonia
E Evidence of diffuse pulmonary inflammation
D Evidence of inefficient gas exchange (History of chronic bronchitis or pneumonia is not a thing)
Which of the following is not a compensatory clinical sign of septic shock? Tachycardia Tachypnea Pale mucous membranes Depressed mentation Normal to hyperthermic temperature Hyperglycemia
Hyperemic mucous membranes (not pale)
Which of the following is not typically a sign of decompensated septic shock Tachycardia/bradycardia Tachypnea Weak or absent pulse Hyperthermic Hypotension
HYPOthermic
SIRS criteria for cats (TPR, WBC)
100-103.5 N
140-225 N
> 40 abnormal
5,000-19,500
SIRS criteria for dogs (TPR, WBC)
99-102.6 N
>140 abnormal
>30 abnormal
6,000-19,000
