Hemorrhage & Sock

Question 1

What is the result if chronic hemorrhage?

Answer 1

Leading to anemia and may be hypotension, but it may reflect a serious disease.

Question 2

Describe the body responsed to loss of different blood percentages.

Answer 2

Less than 10%, no significant effect on COP or ABP, as blood donation.
10-20%, variable degrees of compenated hemorrahgic shock occurs
>20%, the shock becomes uncompensated
>30%, the shock becomes irreversible

Question 3

What is the aim of body compensatory mechanisms in shock?

Answer 3

Correct drop in ABP and blood volume.

Question 4

Mention Immediate compensatory reactions that correct ABP

Answer 4

1. Diminished rate of discharge of impulses from arterial & atrial baroreceptors
2. Chemoreceptors stimulation
3. CNS ischemic response
4. Increased production of Ang II & ADH

Question 5

Mention effect of Diminished rate of discharge of impulses from arterial & atrial baroreceptors

Answer 5

1. VC of arterioles ex brain & heart, leading to pale and cold skin, dec GFR & diminished urine volume.
2. Venoconstriction to inc VR & COP
3. INC symp discharge to heart inc rate & contractility, a rapid weak pulse.
4. Inc symp discharge to adrenal medulla & inc CA which stimulate reticular formation causing restlessness & inc VR due to inc muscle tone.

Question 6

Describe mechanisms if stimulation of chemoreceptors

Answer 6

1. Diminished blood flow to aortic & carotid bodies (less than 80 mmHg)
2. Hypoxia produces lactic acid & H+
3. PO2 less than 60 mmHg

Question 7

Describe results of chemoreceptor stimulation

Answer 7

Inc sympathetic discharge to heart & vessels & dec vagal tone
Stimulation of rapid breathing & rapid shallow breathing

Question 8

GR: CNS ischemic reflex is active below ABP 60 mmHg

Answer 8

Because that us the lower limit if the range of cerebral autoregulation

Question 9

Describe effect of Ang II

Answer 9

Arteriolo p4 & venoconstriction, thirst sensation, inc aldosterone (thus inc Na+ reabsorption)

Question 10

Describe effect if ADH in shock

Answer 10

VC & inc blood volume by dec urine output

Question 11

Mention mechanisms to correct blood volume in shock (short-term)

Answer 11

Capilary fluid shift phenomenon
Plasma protiens are restored by movement of labile tissue and liver proteins to plasma
RBCs are restored by contraction of splenic capsule

Question 12

Mention mechanisms to correct blood volume in shock (long-term)

Answer 12

1. Plasma volume is restired within 12-72 hrs by thirst & hormonal conservation
2. Plasma proteins are replaced by hepatic synthesis 3-4 days
3. RBCs are 4-8 weeks due to inc release of erythropoietin hormone leading to inc in erythropoiesis

Question 13

Define circulatory shock

Answer 13

It is acute decrease in tissue perfusion so that the amount of O2 & nutients reaching the the cells is not sufficient to maintain life processes particularly in vital organs like brain & heart.

Question 14

GR: ABP is not a good measure for progression of shock

Answer 14

Because ABP is strongly defended by several regulatory mechanisms, as decrease in ABP would be compensated by more VC which dec tissue oerfusion and priduce more shock.

Question 15

Write a short note on hypovolemic shock

Answer 15

It is due to dec in volume of circulating blood, due to blood loss as in hemorrhage, plasma loss in burns, nody fluid loss in vomiting & diarrhea.
The heart is normal but VR and thus COP is reduced, compensation is through VC of splanchnic & skeletal muscle BVs.

Question 16

Write a short note on cardiogenic shock

Answer 16

There is severe reduction in the pump function of the heart as in massive MI, the VR and heart filling are normal but CO is dec because of HF, compensation is mainly by VC leading to cold pale skin.

Question 17

Define low resistance shock

Answer 17

The CO and blood volume are normal but they are relatively inadequate due to sudden inc in vascukar capacitance as a result of marked VD. Hypotension is due to reduced MCP & peripheral resistance. The type of shock is also “warm shock” because skin is not cold as hypovolumic or cardiac shock.

Question 18

What are causes of low resistance shock?

Answer 18

Neurogenic shock:
Deep general anaesthesia 
Spinal shock
Brain damage
Generalized VD in severe pain & strong emotions
……….
Anaphylactic shock

Question 19

In anaphylactic shock, …..cells release…..

An example is ……

Answer 19

Mast, histamine

Incomoatible blood transfusion

Question 20

Mention elements of septic shock

Answer 20

Low resistance, cardiogenic & hypovolemic shock

Question 21

Mention cause of septic shock

Answer 21

1. Generalized VD, inc blood flow to infected areas further deprives healthy tissues from blood flow.
2. Increase capillary permeability with resultant loss of plasma in tissues
3. Cardiac depression

Question 22

Mention elements of traumatic/surgical shock

Answer 22

Neurogenic shock (low resistance due to severe pain)
Extenal hemorrhage as well as bleeding into tissues (hypovolemic shock)

Question 23

Define compensated shock

Answer 23

In which normal compensatory circulatory mechaisms can cause full recovery without help from outside. These compensatory mechanisms are immediate acting on ABP & CO and delayed, restoring blood volume.

Question 24

Define decompensated shock

Answer 24

In which without therapy, the shock becomes steadily worse until death

Question 25

Define refractory shock

Answer 25

In which shock has progressed to such an extent that all forms of known therapy are inadequate to save the oerson’s life, although for the moment they are alive.

Question 26

GR: Compensatory mechanisms fail to prevent deterioration, in decomensated shock

Answer 26

They are replaced by decompensatory mechanisms (+ve feedback) mechanisms, giving rise to viscous cycle which leads to rapid death to the patient.

Question 27

Explian the decompensatory mechanisms

Answer 27

1. Severe cerebral ischemia with VMC failure. 2. Metabolic acidosis (cardiac depresssion & arteriolar VD, inc capillary filtration & further dec in blood volume) 3. HF due to myocardial ischemia, lactic acid, myocardial toxic factor from pancreas & release of toxins from dead gram -ve barcteria in intestine 4. Hypercoagulability of blood

Question 28

GR: Coronary blood vessels are blocked in decomp shock

Answer 28

Due to blood hypercoagulability

Question 29

GR: Release of MTF

Answer 29

From pancreas due to anoxia

Question 30

GR: Hypercoagulability of blood in decompensated shock

Answer 30

Due to sluggish blood flow and toxins from ischemic tissues which may block blood flow.

Question 31

Describe sequence of events in refractory shock

Answer 31

1. Strong VC of precapillary sphincters causes hypoxic tissue damage with release of deleterious substances. 2. After sometime precapillary sphincter opens while postcapillary resistance remains high 3. This leads to stagnantion of blood in capillaries, escape of plasma, more hypovolemia 4. Blood cells start forming rouleux formation and small clot fragments. 5. After some time venules relax and allow abnormal contents to reach circulation leading to PE & lung comp

Question 32

First organ damaged by refractory shock is ….., leading to …..

Answer 32

Liver | Decreased metabolism & detoxification + coagulopathy

Question 33

GR: Shock lung occurrence

Answer 33

1. Decreased blood flow, damaging endothelium & epithelium 2. PE by products of capillary imbalance between pre and post capillary resistances 3. Failure of synthesis of pulmonary surfactant leading ti edema and collapse.

Question 34

Describe effect if refractory edema on: 1. Intestine 2. RES

Answer 34

1. Breakdown intestinal mucosa with easy access of intestinak bacteria and endotoxins to circukation 2. Lack of opsonization and dec phagocytosis & Ab formation.