circulatory shock and its treatment

Question 1

cause of anaphylactic shock

Answer 1

• basophils + mast cells release histamine/histamine like substance
• causes great reduction in venous return

Question 2

effects of histamine

Answer 2

• venous dilation -> increased venous return
• arteriolar dilation -> decrease venous return
• increased capillary permeability -> rapid loss of fluid and protein
• NET effect: great reduction in venous return -> shock

Question 3

what is septic shock?

Answer 3

bacterial infection widely disseminated throughout the body, with the infection being carried from one tissue to another and causing extensive damage

Question 4

what are the special features of septic shock?

Answer 4

• high fever
• vasodilation throughout body
• high cardiac output in half of pts
• sludging of blood caused by RBC agglutination in resp to degenerating tissue
• micro blood clots in widespread areas of body (disseminated intravascular coagulation) - > uses up clotting factors -> haemorrhaging

Question 5

physiological basis of neurogenic shock

Answer 5

• sudden loss of vasomotor tone
• increased vascular capacity
• reduced mean systemic filling pressure
• reduced venous return to heart

Question 6

causes of neurogenic shock

Answer 6

• deep general anaesthesia -> vasomotor paralysis
• spinal anaesthesia -> blocks sympathetic nervous outflow
• brain damage; concussion or contusion. prolonged ischemia can cause total inactivation of vasomotor neurons in brain

Question 7

what is the best therapy for haemorrhagic shock

Answer 7

transfusion of whole blood

Question 8

best therapy for shock caused by plasma loss

Answer 8

plasma administration

Question 9

best therapy for shock caused by dehydration

Answer 9

electrolyte solution

Question 10

shock treatment when whole blood is not available

Answer 10

• plasma; increases blood volume, restores normal haemodynamics
• if plasma is unavailable, dextran solution used

Question 11

what drug is used in treatment of neurogenic shock

Answer 11

sympathomimetic drug takes place of diminished sympathetic functions, can restore circulatory function

Question 12

drug used in treatment of anaphylactic shock

Answer 12

sympathomimetic drugs have vasoconstrictor effect -> oppose vasodilating effects of histamine

Question 13

examples of sympathomimetic drugs

Answer 13

• epinephrine
  -norepinephrine

Question 14

why are sympathomimetic drugs not effective for haemorrhagic shocks?

Answer 14

• sympathetic nervous system is already maximally activated
• no additional benefit

Question 15

what is the head down treatment

Answer 15

• head placed at least 12 inches below feet
• promotes venous return
• increases cardiac output
• 1st essential treatment

Question 16

How is oxygen therapy used to treat shock

Answer 16

• major deleterious effect of most shocks is too little delivery of oxygen to tissues
• not as beneficial as expected as problem is in transport of o2 not insufficiency

Question 17

what are glucocorticoids

Answer 17

adrenal cortex hormones that control glucose metabolism

Question 18

how are glucocorticoids used to treat shock

Answer 18

• they increase the strength of the heart in late stages of shock
• stabilise lysosomes in tissue cells -> prevent release of lysosomal enzymes into cytoplasm - prevents deterioration from this source
• aids in glucose metabolism by severely damaged cells