Chapter 5 - Shock Flashcards
What is shock?
A syndrome of inadequate tissue perfusion which results from insufficient oxygen delivery, uptake and utilisation to met metabolic demands of cells and organs
What does shock result in?
cellular and tissue hypoxia
How does shock start?
when cells are hypoperfused and set off a series of responses to preserve homeostasis and producing far-reaching effects on all systems and organs
How does shock start?
if this condition goes unrecognised and untreated, the hypoperfused cells shift from aerobic to anaerobic metaloblism. - causing acidosis, tissue ischemia and cellular death when coupled with the incomplete removal of metabolic waste producet
What happens if shock is unrecognised?
if this condition goes unrecognised and untreated, the hypoperfused cells shift from aerobic to anaerobic metaloblism. - causing acidosis, tissue ischemia and cellular death when coupled with the incomplete removal of metabolic waste producet
Pathophysiology of shock
- cellular level = For cells to perform metabolic function they require the production of ATP.
- IN the presence of oxygen, aerobic metabolism produces ATP by breaking down carbohydrates and proteins. When this is efficient it has a high ATP yield that supports energy production and the patience of the electrical gradient known as the “sodium-potassium pump”
*Hypoperfusion depreives the cells of oxygen and in an effort to maintain homoestsics, compensation occurs in which the body shifts to anaerboci merabolusm. ATP
Pathophysiology of shock
- cellular level = For cells to perform metabolic function they require the production of ATP.
- IN the presence of oxygen, aerobic metabolism produces ATP by breaking down carbohydrates and proteins. When this is efficient it has a high ATP yield that supports energy production and the patience of the electrical gradient known as the “sodium-potassium pump”
*Hypoperfusion deprives the cells of oxygen and in an effort to maintain homeostasis, compensation occurs in which the body shifts to anaerobic metabolism. ATP production occurs at a less efficient rate which results in lactic acid formation and metabolic acidosis.
- If shock is prolonged it doesn’t met the body’s energy depends and the cellular membrane loses the aboloty to maintain its integrity.
- Adiitionally, the normal
CARDIAC OUTPUT
HR X Stroke volume (ml/beat) = cardiac output (l/min)
Pathophysiology of shock
- cellular level = For cells to perform metabolic function they require the production of ATP.
- IN the presence of oxygen, aerobic metabolism produces ATP by breaking down carbohydrates and proteins. When this is efficient it has a high ATP yield that supports energy production and the patience of the electrical gradient known as the “sodium-potassium pump”
*Hypoperfusion deprives the cells of oxygen and in an effort to maintain homeostasis, compensation occurs in which the body shifts to anaerobic metabolism. ATP production occurs at a less efficient rate which results in lactic acid formation and metabolic acidosis.
- If shock is prolonged it doesn’t met the body’s energy depends and the cellular membrane loses the aboloty to maintain its integrity.
- Additionally, the normal electrical gradient of the sodium potential pump is lost, causing sodium to remain within the cell and potassium outside of the cell. This results in cellular swelling and ultamily cellular death and destruction
1st type of shock
Compensated
- increase in sympathetic discharge
- fluid conserved by the kidney
* To maintain BP and Cardiac output
The sympathetic nervous system response and vasoconstriction are selective, blood goes away from small organs (gastric, small bowel, pancreatic and splen) to the bigger organs
SYMPTOMS
*Anxiety
*Systolic BP is normal
* rising diastolic BP resulting in a narrow pulse pressure is a reflection of perfinal vascontritcio
* bounding or tachycardia pulse as a result of catecholamine release
* >RR
*< Urine, kidenye are trying to remain fluid within the circ. system
3rd type of shock
Irreversible shock
- cellular hypoxia
- severe metabolic acidosis
- multisystem organ failure
*tissues and cells become ischemic and necrotic and multi-organ dysfunction.
SIGNS
- hypotension
- brady
- shallow RR
- organ failure
- severe acidosis
2nd type of shock
Decompensated shock
- widespread tissue hypoxia
- anaerobic glycolysis leads to lactic acid
- peripheral pooling of blood
- stages of impaired tissue perfusion
*occurs when compensatory mechanism begin to fail
* reduced blood flow impairs oxygen and C02 transport. Increased lactate levels (>2)= metabolic acidosis
SIGNS
* Unconcious (lactate and anerobic response)
* narrow pulse pressure
*tachy
*weak and threay puslse
* rapid and shallow pulse
* cool, clammy
* base excess outside normal range (-2 mEg/L to +2 mEq/L)
What dose hypoperfusion lead to?
systemic inflammatory response syndrome (SIRS) causing the release of cell mediators or cytokines and releasing in wholesale vasodilation increased cap permeability and coagulopathy.
MODS
Multi-organ dysfunction syndrome
The body’s compensatory response to shock
The vascular response can be activated in two different pathways;
- barrorectopter activation
Baroreceptors are found in the carotid sinus and along the aortic arch. They are sensitive to the degree of stretch within the arterial wall. when they sense a decrease in stretch they stimulate the sympathetic nervous system to release epinephrine and norepirnphone causing constriction of blood vessels, this triggers a rise in HR and diastolic BP - chemoreceptor activation
Peripheral chemoreceptors consist of carotid and aortic bodies, whereas central chemoreceptors are located in the medulla of the brain stem. Perfineral receptors detect changes in blood oxygen levels, whereas central chemoreceptors respond to changes in C02 and Ph.
*c02 rises or 02 or PH falls = then these recptors increase RR and depth and BP.
Adrenal gland response
“fight or flight response”
Causes the release of two catecholamines - epinephrine and norepinephrine.
EPI
High levels of epinephrine produce smooth muscle relaxation in the airways and cause arteriole smooth muscle contractibility. Epinrophoe also increases the HR
* peripheral vasoconstriction; manifests as narrow pulse pressure. ( can be the first concern that a pt. cir. system if compromised).
NorEPI
Increases HR and Vascular tone through alpha-adrenergic receptor activation, and blood flow to skeletal muscle. it also triggers the release of glucose from energy stores.
Pulmonary response to shock
During shock the pulmonary system responses to both hypoperfusion and acidosis. The resp rate increases in an attempt to improve oxygen delivery.
Renal response to shock
- renal ischemic causes the kdiney to secret renin
- renin accelerates the production of angiotensin 1.
- Angiotension 1 is turned in angiotensin 2 in the lungs by a converting enzyme.
ANGIOTENSIN 2
_ Potent vasoconstriction which increases vascular resistance and arterial pressure
_ release of aldosterone which increases reabsorption of sodium and water
_ stimulates arginine vasopressin which increases the retention of water
TRAUMA TRIAD OF DEATH
Hypothermia; impairs platelet and thrombin function and when protein C is activated it inhibits factors V and V111.
Acidosis; impairs thrombin production and other coag factors due to reduced PH, elevated lactate and increasing base deficit.
*metabolic acidosis also contributes to prolonged clotting times and reduced clotting strength
Coagulopathy; whole blood loss = clotting factors are depleted
What falls under - hypovolemic shock
hemorrhage and burns
*** VOLUME ISSUE
What falls under - cardiogenic
MI
Dysrhythmias
Blunt cardiac trauma
** PUMP PROBLEM
What falls under - obstructive
cardiac tamponade ; accumlaion of blood
tension pneumo ; increases throatic pressure
tension heamo
Air embolism
** MECHANICAL PROBLEM
What falls under - distributive
Neurogenic (SC Injury)
anaphylactic
septic
** PIPE PROBLEM
What do you have to be careful of in an MTP
Hypocalcemia is a concern with MTP as calcium citrate is used as a preservative in banked blood to prevent clotting.
SIGNS OF HYPOCALCEMIA = cardiac dysthymias and muscle tremors and seizures
MTP
UNMATCHED CROSS TYPED 0 NEG blood, thawed FFP and plasma
If no blood; warmed isotonic crystalloid solution and recess status after each 500 ml
Vasopressions?
contraindicated in early shock as they can worsen tissue perfusion
