Therapeutics - Shock Part 1 Flashcards
shock is a syndrome of….
impaired tissue perfusion
if shock is left untreated/undertreated, ____ eventually wanes and ____ can occur
compensation eventually wanes and decompensation can occur
3 main types of shock and their general cause
hypovolemic (vol reduction)
cardiogenic (heart pump failure)
distributive (increased vascular compliance)
septic shock falls under which of the 3 types
distributive
true or false
determining the type of shock is not important to manage it
FALSE - it is important
what is the hallmark of septic shock?
explain what it is
SIRS (systemic inflammatory response syndrome)
-profound vasodilation
-increased capillary permeability
increased capillary permeability seen in septic shock causes what
edema - fluid leaves the intravascular compartment and goes into the interstitial compartmner
septic shock most commonly occurs from what
infection (typically bacterial)
explain when a patient meets SIRS criteria
have to meet 2 or more of these abnormalities:
-temperature
-high heart rate
-high respiration rate
-WBC high or low
explain the criteria for someone to have sepsis
have to meet 2 or more of the SIRS criteria (temp, white count, respiration rate, heart rate), AND a suspected source of infection has to exist
what is the main determinant of tissue perfusion and how is it calculated
MAP (mean arterial pressure) – average pressure that drives the blood throughout the organs
ABP + DBP + DBP
all divided by 3
MAP is a function of….
cardiac output * systemic vascular resistance (SVR)
cardiac output is a function of….
heart rate * stroke volume
name some clinical presentation features of a shock patient
tachycardia (over 90)
tachypnea (over 20 breaths/min)
mental confusion
oliguria (less than 20mL/hour)
mental confusion
skin vasoconstriciton (cold and pale)
acidosis
systolic BP less than 90 or a DROP over 60 from baseline
why do shock patients tend to have tachycardia (over 90 bpm) and tachypnea (over 20 breaths/min)
because the body is trying to compensate for the lack of blood flow and oxygen to the tissues
3 signs of organ damage from shock
oliguria
mental confusion
metabolic acidosis
when would we do invasive vs noninvasive hemodynamic monitoring in shock patients
invasive is only necessary in critically ill patients
noninvasive typically used - provides limited info but valuble info
true or false
an echocardiogram is considered a NONINVASE hemodynamic monitoring strategy
true
3 methods of invasive monitoring to watch hemodynamic control
arterial line
central venouos catheter
pulmonary artery catheter
true or false
arterial lines used to monitor hemodynamics in shock patients can be used to administer meds
FALSE - only central venous catheter can
which invasive hemodynamic monitoring method allows the measurement of CO (cardiac output) and PCWP (pulmonary capillary wedge pressure)
pulmonary artery catheter
which value is the best indicator for preload? represents total body volume
PCWP (pulmonary capillary wedge pressure)
name what is FIRST AFFECTED In each shock:
hypovolemic
cardiogenic
distributive
hypovolemic - decreased cardiac output and preload 9PCWP) is first
cardiogenic - decreased cardiac output is first
distributive - decreased SVR (systemic vascular resistance) is first
true or false
all of the 3 types of shock cause an increased HR
true
when EDV (end diastolic volume )is affected, what kind of shock is this?
what about when ESY (end systolic volume) is affected
EDV affected - hypovolemic shock
ESV affected - cardiogenic shock
as mentioned, when a patient loses volume, compensation will occur and the SVR and heart rate will increase.
what happens when these compensatory mechanisms are overcome
blood pressure will decrease, along with perfusion to orfans
true or false
in cardiogenic shock, cardiac output decreases, but this is NOT due to a loss in volume
true
general treatment goals for shock patients
regain hemodynamic control
reverse the cause!
stop organ dysfunction
goal for treatment in hypovolemic shock
correct inadequate tissue perfusion and oxygenation by INCREASING THE INTRAVASCULAR VOLUME
as mentioned, in hypovolemic shock, we hope to fix inadequate tissue perfusion by increasing the intravacular volume
what is an important consideration about this
DO NOT FLUID OVERLOAD! (Can cause something like pulmonary edema)
3 potential options for fluid replacement in hypovolemic shock patient
crystalloids
colloids
blood
what is the primary intervention in hypovolemic shock
infusion of IV fluids
which fluid is considered 1st line in hypovolemic shock
crystalloids ( ie - dextrose, NS, LR, hypertonic saline
differentiate between the general volumes of crystalloids vs colloids in hypovolemic shock patients
crystalloids - need a larger volume. this is bc colloids stay in the intravascular space more
crystalloids shift more to the extravascular space
general approach to the volume of crystalloids to be given in shock patients
1-2L (only 25% stays in intravascular space) of isotonic fluid as fast as possible, and then additional fluid as necessary
4 examples of crystalloids
NS, hypertonic saline, lactated ringer’s, dextrose
*important crystalloid to AVOID when replacing fluid and why
D5W
it is an ineffective osmole. water will not stay in the vein like normal saline and other things
name some colloids
which is preferred
albumin 5% (isotonic) or 25% (hypertonic), dextrans, hydroxyethyl starch(es)
all are considered equally effective
true or false
compared to crystalloids, colloids need to be given for a longer duration and a LOWER volume
true
potential concerns with albumin
-hypersensitivity reactions
-potential increased mortality in burn/trauma patients – but this is still inconclusive
true or false
effective osmoles stay in the extracellular space
TRUE - therefore, water also stays in the extracellular space (blood vessels)
ineffective osmoles cross freely into the INTRACELLULAR space
true or false
in a hypovolemic shock patient, the decision to give blood transfusions is solely based on the hemoglobin and hematocrit
FALSE - not solely based on this
based on clinical evidence - if pt is hypovolemic and has severe blood loss for instance
some AE of giving blood transfusions for hypovolemic shock
electrolyte abnormalities
hemolysis
infectious disease
immunosuppression, etc
general goals when giving a blood transfusion in a hypovolemic shock patient
1 unit of packed red blood cells (~200mL) should increase the hemoglobin by 1g/dL and the hematocrit by 3%
goal in treating CARDIOGENIC shock
correct inadequate perfusion and oxygenation by IMPROVING CARDIAC FUNCTION
3 intervention choices for cardiogenic shock
can they all be used together?
fluid challenge
inotropic support
vasodilators
yes can use combo
explain the fluid challenge and its effect for cardiogenic shock
purpose of the fluid challenge is to see if the patient is hypovolemic. if they are – we have to correct that first or there will be AE
will increase the PCWP
the fluid challenge is done by giving a small amount of fluid like 100mL of normal saline, and then the cardiac output is reevaluated.
if the cardiac output didnt improve from that volume added. it is UNLIKELY to benefit from more fluid and hypovolemia can be ruled out
true or false
if a patient’s cardiac output increased with the fluid challenge, but cardiac output is still at goal, we can switch to an inotrope or vasodilator
false - can ADD inotropes or vasodilators
as long as the patient’s cardiac output did in fact respond to the fluid challenge
explain what inotropic support does in patients with cardiogenic shock
increases MAP by increasing cardiac performance
disadvantage of inotropic support for cardiogenic shock
while it does increase cardiac performance and thus MAP, it also increase heart oxygen consumption — leading to potential increased mortality in heart failure patients
true or false
inotropes increase cardiac output by increasing heart rate, contractility, and ventricular wall tension
true
explain the genera; approach and dosing to inotropic agents for cardiogenic shock
it can only be given via what route?
give AFTER the volume has been repleted.
titrate by 1-2mcg/kg/min every 10 mins to get to the LOWEST EFFECTIVE DOSE that achieves the goal but AVOID tachycardia
only given through central line
true or false
if a cardiogenic shock patient’s blood pressure is very low, we can give a vasodilator but do NOT give inotropic agents
FALSE
DO NOT GIVE A VASODILATOR!
inotropic agents are better option to not further decrease the BP
goal MAP range for cardiogenic shock patients
75-80mmHg
goal HR in cardiogenic shock patient
less than 110 bpm
true or false
inotropic agents can be given through central line ONLY
true
name 3 potential inotropic agents for cardiogenic shock
dopamine
dobutamine
epinephrine
dobutamine is ______ tachycardic than dopamine
LESS
explain what happens as the dose of dopamine increases
2-5mcg/kg/min — primarily only B1 stimulation that b blockers can inhibit
5-10mcg/kg/min - B1 AND alpha stimulation which usually increases the MAP and PCWP
15mcg-20mcg/kg/min and higher - primarily a1 stimulation that can cause cardiac irritability
true or false
dobutamine is less tachycardic than dopamine. It generally decreases the SVR and PCWP as the dose increases
true
true or false
the effects of dobutamine are impaired by beta blockers
true
dose of dobutamine and its effect
2.5-15mcg/kg/min
b1 and b2 stimulation that exceeds a1 constriction
net vasodilation! but this is impaired by b blockers
true or false
as the dose of epinephrine increases, the SVR tends to decrease
false - as dose of epi increases SVR also tends to increase
varying doses of epi and its effects
0.01-0.1 mcg/kg/min - B1 stimulation
over 0.1mcg/kg/min - alpha 1 stimulation
