CVS 12 Shock, Review and Hypertension

Question 1

What can cause poor regional perfusion?

Answer 1

arterial occlusion- peripheral artery disease, coronary artery disease
venous congestion- varicose veins, DVT

Question 2

In which direction do veins drain?

Answer 2

Superficial to deep

Question 3

What constitutes a positive exercise stress test for ischaemic heart disease?

Answer 3

If there is chest discomfort or ECG changes

Question 4

What ECG abnormality is seen in angina?

Answer 4

ST segment depression

Question 5

What is stable angina treated with?

Answer 5

Nitrates
Beta- blockers
Calcium channel antagonists

Question 6

What is the principle action of nitrates in angina relief?

Answer 6

Venodilation causing decreased preload to heart to reduce workload

Question 7

What abnormalities are see in an ECG with unstable angina?

Answer 7

ST depression and/or T wave inversion

Question 8

What ECG changes are seen with a STEMI?

Answer 8

ST elevation
T wave inversion
Pathological Q waves

Question 9

What feature of a STEMI ECG persists even weeks after recovery?

Answer 9

Pathological Q waves

Question 10

What is troponin and which isoforms are used to detect MI?

Answer 10

Regulatory protein that is bound on tropomysosin, involved in muscle contraction
Troponin I and Troponin T

Question 11

What is cardiac arrest?

Answer 11

Unresponsiveness associated with lack of pulse

Heart has either stopped or ceased to pump effectively

Question 12

What is asystole?

Answer 12

Loss of electrical and mechanical activity

Question 13

What is the most common form of cardiac arrest and when does it occur?

Answer 13

Ventricular fibrillation

May occur following MI or electrolyte imbalance or some arrhythmias (e.g long QT and Torsades de Pointes)

Question 14

What is pulseless electrical activity?

Answer 14

Form of cardiac arrest where ECG looks normal but there is no pulse

Question 15

What basic life support is used to treat cardiac arrest?

Answer 15

Chest compression and external ventillation

Question 16

How does defibrillation work?

Answer 16

Electrical current delivered to heart
Depolarises all cells and puts them in the refractory period
Allows coordinated electrical activity to restart

Question 17

Why is adrenaline used in cardiac arrest?

Answer 17

Enhances myocardial function and increases peripheral resistance

Question 18

What is shock?

Answer 18

Acute condition of inadequate blood flow throughout body

Question 19

What causes circulatory shock?

Answer 19

Catastrophic fall in arterial blood pressure due to a fall in CO or TPR

Question 20

How is mean arterial BP calculated from cardiac output and TPR?

Answer 20

Mean arterial BP=COxTPR

Question 21

In what ways can CO fall to cause shock?

Answer 21

Mechanical- pump can’t fill
Pump failure
Loss of blood volume

Question 22

What causes a fall in peripheral resistance?

Answer 22

Excessive vasodilation

Question 23

What is cardiogenic shock?

Answer 23

Acute pump failure causing a drop in CO
Following MI, serious arrythmias or ACUTE WORSENING of heart failure (standard heart failure is not cadiogenic shock, it is chronic)

Question 24

What is oliguria?

Answer 24

Reduced urine production

Occurs when poor kidney perfusion

Question 25

What kind of shock can cardiac tamponade cause?

Answer 25

Mechanical

Question 26

How does cardiac tamponade cause shock?

Answer 26

Blood or fluid fills the pericardial space Restricts filling of the heart- limits end diastolic volume and so STROKE VOLUME Affects both sides of heart High CVP Low arterial BP Heart still attempts to beat so continued electrical activity

Question 27

What kind of shock does a pulmonary embolism cause?

Answer 27

Mechanical

Question 28

How does a pulmonary embolism cause shock?

Answer 28

``` Embolus occludes a large pulmonary artery PA pressure HIGH right ventricle can't empty CVP high Reduced return of blood to left heart limiting filling LA pressure low Arterial blood pressure low CO lowered due to reduced SV ```

Question 29

What other symptoms are felt with pulmonary embolism?

Answer 29

Chest pain, dyspnoea (SOB)

Question 30

How many litres of blood are in a normal man?

Answer 30

5l

Question 31

What is the most common cause of hypovolaemic shock?

Answer 31

Haemorrhage

Question 32

How much blood loss causes a shock response?

Answer 32

20-30% some signs of shock response | 30-40% serious shock response

Question 33

What happens to pressures during Haemhorrage?

Answer 33

Venous pressure falls Cardiac output falls (starling's law) Arterial pressure falls Detected by baroceptors

Question 34

What happens in the compensatory response to haemorrhage?

Answer 34

``` Increased sympathetic stimulation Tachycardia Inc force of contraction Peripheral vasoconstrcition VENOCONSTRICTION- inc VP and so venous return ```

Question 35

How does the patient present when in hypovolaemic shock?

Answer 35

Tachycardia, weak pulse, pale skin, cold, clammy extremeties

Question 36

What other causes of hypovolaemic shock are there?

Answer 36

Severe burns | Severe diarrhoea or vomiting and loss of Na+

Question 37

What is decompensation?

Answer 37

Failure of a system to adapt and compensate for stressors

Question 38

What happens in decompensation in hypovolaemic shock?

Answer 38

Peripheral vasoconstriction causes tissue damage due to hypoxia Chemical mediators released in response causing vasodilation TPR falls Blood pressure falls dramatically Vital organs no longer perfused Multi system failure

Question 39

What is distributive shock?

Answer 39

Low resistance (normovolaemic) shocl where profound peripheral vasodilation causes a decrease in TPR and BP

Question 40

What are two types of distributive shock?

Answer 40

Toxic shock | Anaphylactic shock

Question 41

What happens in toxic (septic) shock?

Answer 41

Septicaemia Endotoxins released by circulationg bacteria Cause profound vasodilation Dramatic fall in TPR Fall in arterial pressure Inpaired perfusion of vital organs Capillaries become leaky and reduce blood volume

Question 42

What happens to compensate in toxic shock?

Answer 42

Low arterial pressure detected by baroceptors Increased sympathetic output Vasoconstrictor affect overriden by mediators of vasodilation HR and SV increase

Question 43

How will a person in toxic shock present?

Answer 43

Tachycardia, warm, red extremities (initial vasodilation)

Question 44

What happens in anaphylactic shock?

Answer 44

Histamine released from mast cells due to allergen (other mediators too) Powerful vasodilator- fall in TPR Dramatic drop in arterial pressure Impaired perfusion of vital organs Mediators cause bronchoconstricition and laryngeal oedema

Question 45

What is the compensatory response in anaphylactic shock?

Answer 45

Increased sympathetic drive increases CO but this cant overcome the vasodilation

Question 46

How will a patient with anaphylactic shock present?

Answer 46

Difficulty breathing Collapsed Tachycardia Red warm extremities

Question 47

How is anaphylactic shock treated?

Answer 47

Adrenaline injection | High adrenaline conc above physiological levels activates a1 receptors causing vasoconstriction

Question 48

What BP classes as hypertensive?

Answer 48

140/90mmHg

Question 49

At what three sites is blood pressure regulated?

Answer 49

Kidneys- regulates blood vol which alters SV Heart- rate and force of contraction Vasculature- TPR

Question 50

What does long standing hypertension cause in the heart?

Answer 50

LV hypertrophy and risk of heart failure

Question 51

What does long standing hypertension cause in the arteries?

Answer 51

``` Arterial disease: Coronary arteries- MI, angina Cerebrovascular system- stroke Renal vasculature- kidney failure Retina Aorta ```

Question 52

In what non-pharmological ways can hypertension be treated?

Answer 52

Weight loss, exercise, reduced salt intake

Question 53

In what pharmological ways can hypertension be treated?

Answer 53

Duiretics Vasodilators ACE inhibitors Beta blockers