10. Drugs used in radiology I: emergency drugs

Question 1

what are medical emergencies

Answer 1

any clinical situation that requires immediate medical attention to prevent harm or loss of life

Question 2

what are sympathomimetics

Answer 2

mimic sympathetic nervous system

Question 3

what are antiarrhytmics in terms of what they do

Answer 3

restore cardiac rhythm

Question 4

what is the goal in prescribing emergency drugs

Answer 4

restore normal physiology

Question 5

what is normal physiology

Answer 5

any physiology that allows you to maintain homeostasis and allows perfusion of vital organs and respiration

Question 6

what is DRABC

Answer 6

D = remove from danger 
R = check for response 
A = check airways are open 
B = if patient is attempting to breathe
C = circulatory refill, check blood pressure and pulse and see if capillary refill is normal

Question 7

what are the determinants to blood pressure

Answer 7

cardiac output and total peripheral resistance

Question 8

what is CO determined by

Answer 8

stroke volume and heart rate

Question 9

what is SV determined by

Answer 9

venous return/preload

Question 10

what is the determinants of systemic resistance

Answer 10

arteriolar constriction

Question 11

what 3 aspects of blood pressure does SNS affect

Answer 11

Heart rate, arteriolar constriction and veno-constriction,

Question 12

what does IV fluids affect in terms of blood pressure

Answer 12

blood volume -> preload -> stroke volume

Question 13

what does the autonomic nervous system allow the body to do

Answer 13

maintain homeostasis by determining individual end organ homeostasis

Question 14

what response is determined by the SNS and PSNS

Answer 14

SNS = fight or flight
PSNS = rest and digest

Question 15

what are the SNS and PSNS in relation to each other in homeostasis

Answer 15

SNS and PSNS are in balance

Question 16

what does SNS do to the heart rate and contraction

Answer 16

increases both

Question 17

how does the SNS impact contraction of the heart

Answer 17

arteries constrict as want to move blood from periphery to central compartments for heart to pump more and get better contraction

Question 18

when SNS is activated, veins constricting do what to the TPR and BP

Answer 18

increase total peripheral resistance and BP

Question 19

what effect does BP and TPR increase due to venous constriction have on perfusion (when SNS is activated)

how is the bronchus involved

Answer 19

improves perfusion to end organs and dilation of bronchus to get more air into the lung so more air transfers

Question 20

what happens to the gut and liver when the SNS is activated

Answer 20

Decrease gut and liver and constrict to get blood out of reservoir and vasoconstrict in lungs to get more blood circulating

Question 21

how is the SNS used to manipulate blood pressure and what receptors are involved

Answer 21

using drugs that act on adrenoreceptors that are receptors associated with SNS to mimic flight or fight situation

Question 22

in hypotension what does heart rate needed to do

Answer 22

Heart rate want to increase and want to increase contractility and reduction of conduction velocity as want heart to repolarise quicker

Question 23

what does veins constriction do to SV

Answer 23

increase preload so increases SV

Question 24

what are the 2 types of adrenoreceptors

Answer 24

alpha and beta

Question 25

what does alpha 1 adrenoreceptors work on

Answer 25

vascular smooth muscle to increase vasoconstriction

Question 26

what does beta adrenoreceptors work on

Answer 26

acts on heart for positive ionotropic to increase force of contraction and chronotropic to increase heart rate

Question 27

how do direct catecholamines act

Answer 27

direct interact with A and B receptors

Question 28

how do naturally indirect catecholamines act

Answer 28

indirect = affect presynaptic preterminal to release adrenaline and noradrenaline to produce effect

Question 29

what are 2 naturally occuring catecholamines

Answer 29

adrenaline noradrenaline

Question 30

what are 2 synthetic catecholamines

Answer 30

alpha 1 and B2 antagonists

Question 31

what is metaraminol and how does it work

Answer 31

synthetic indirect mixed a and b receptor antagonist, release adrenaline and noradrenaline across synaptic terminal to cross synapse and interact with alpha and beta

Question 32

why do you need to raise the legs or give fluid bolus for someone who has collapsed to the ground

Answer 32

Raise legs for someone collapsed to shift blood from legs to central compartment to increase blood volume to increase SV and preload give fluid bolus rapidly to make heart think its got a lot of blood transfused and act as pump Increases SV

Question 33

what is the bronchospasm mechanism

Answer 33

Only affect one organ with anaphylaxis Narrowing and constriction of airways

Question 34

what are symptoms of a bronchospasm

Answer 34

Cant get air in or out (easier to get air in than out) Cough wheeze, shortness of breath, severe can have silent chest (no air in or out) and in this case need to help them expel air by pushing on chest mechanically or by using drugs

Question 35

what are the anatomic mechanisms of bronchospasm

Answer 35

Airway inflammation and mucous secretion, smooth muscle constriction, swelling of membrane in acute phase

Question 36

what is salbutamol similar to and how do they work

Answer 36

Salbutamol is similar to adrenaline structurally and act mainly on Beta 2 receptors so don’t get cardiac effects, works more on smooth muscles of lungs

Question 37

What do anticholinergics do and how do they work

Answer 37

Anticholinergic as PSNS relies on acetylcholine as a neurotransmitter and by giving anticholan blocks acetylcholine from work so don’t have PSNS working against us to relax the smooth muscle

Question 38

how do nebulizers work and what do they do

Answer 38

Nebulizers deliver drug to site of action - bronchial smooth muscle - relaxes smooth muscle by B2 effect and anticholinergic effect

Question 39

what are the 2 types of medications to treat acute bronchospasm

Answer 39

sympathomimetics and anticholanergic

Question 40

For someone who goes through a anaphylatic shock reaction what happens to their blood pressure and why

Answer 40

low blood pressure as the trigger goes systemically and all blood vessels don’t know what it is so it has peripheral relaxation, not going to get venous return and SV low so increase HR to compensate - and systemic vascular resistance is going to be low so BP is low as well

Question 41

how does adrenaline treat anaphylatic shocks

Answer 41

Give adrenaline as it treats/stabilises mast cell degranulation makes vessels bronchi leaky and peripheral vasodilation Stops mast cells from producing histamine

Question 42

how is adrenaline administered to treat anaphylactic shocks

Answer 42

Bolus of adrenaline into muscle via epipen or injection Muscles are vascular rich and can repeat administration every 5 min Can also give intravenous bolus

Question 43

what is a con of using adrenaline to treat anaphylactic shock

Answer 43

Problem with adrenaline is that it pushes patient into fight flight, muscles in body get charged metabolically and release hydrogen ions and get acidotic and potassium release so hyperbulemic (not good in long term)

Question 44

what are the 2 types of shockable rhythms

Answer 44

ventricular tachycardia and ventricular fibrillation

Question 45

how does amiodarone treat anaphylactic shock

Answer 45

antiarrythmic blocks potassium channels in the heart and slows rate of repolarisation

Question 46

how does amiodarone block potassium channels in the heart and slows rate of repolarisation - 2 ways

Answer 46

increases duration of action potential increases refractory period

Question 47

what is predisone

Answer 47

corticosteroid that acts as anti-inflammatory and stabilize mast cells and inflammation that leads to anaphylaxis

Question 48

what is loratidine

Answer 48

antihistamine, histamine acts of histamine receptor and loratadine drug blocks receptor so reduces chance of having allergy reaction