Anaesthesia IV Week 1-6 Flashcards
(160 cards)
1
Q
What is a hypotonic solution?
A
The ECF has less solute and less osmotic pressure than what’s in the cells therefore water moves into the cell to attempt to balance solute concentrations.
The cell gets lysed (burst)
2
Q
What is a hypertonic solution?
A
The solution has more solute and higher osmotic pressure than what’s in the cell therefore water moves out of the cell to dilute the solute.
The cell shrivels and crenates
3
Q
What is an isotonic solution?
A
The fluid has the same concentration of solute and osmotic pressure as within the cell
4
Q
What are the sodium and water requirements per day?
A
100-150 mmol Na
2-3 L water
(Usually 2500ml in and 2500ml out)
5
Q
What is a crystalloid?
A
An aqueous solution of mineral salt or other water soluble molecules
A solution which mimics plasma
Contains electrolytes and small particles
6
Q
What is a colloid solution?
A
Large insoluble molecules which cannot cross the membrane - exerts osmotic pressure causing fluid to remain in this space
Suspended in a solution
Increase the circulating volume
Longer effect than crystalloids - slower to break down
7
Q
What is a problem with dextrose 5% solution?
A
The dextrose gets metabolised quickly leaving water (solution) in the ECF which is hypotonic. Therefore water moves into the cells and dilutes electrolytes (hyponatraemia)
8
Q
What is the fluid replacement scheme?
A
40ml/kg/24hr
For replacement fluids
This can be increased by 15% for every 1 degree Celsius over normal temperature
9
Q
What is the paediatric fluid replacement guideline?
A
The 4-2-1 regime
4ml/kg/Hr for each of the first 10kg
2ml/kg/Hr for each of the second 10kg
1ml/kg/Hr for each subsequent 1kg
Fluid: 0.45% NaCl/5% dextrose
10
Q
Why are lactated ringers contraindicated when infusing blood?
A
Contains calcium.
Blood has an additive in it which prevents the RBCs from clotting by binding to the calcium. By adding calcium from the Hartmans solution, clots are able to form.
11
Q
Why is it ok to give calcium during MTP?
A
Because most of the calcium in the blood is bound and the levels in the body are becoming low. By giving calcium, the heart becomes more efficient at contracting.
12
Q
What fluids are contraindicated with blood products?
A
5% dextrose may induce haemolysis
Lactated ringers and gelofusine may induce clotting
13
Q
Define haemolysis.
A
The destruction of RBCs
14
Q
What is the fluid to blood ratio of the fluid groups?
A
Crystalloid: 3:1
It travels throughout the ECF whereas colloids have large insoluble molecules which encourages them to stay in the plasma compartment
Colloid: 1:1
15
Q
What are the fluid compartments?
A
Total 60% (45L) fluid in body (75% child)
Intracelluar: 2/3 (28L) of the water (40%)
Extracellular: 1/3 (14L) of the water (20%)
- interstitial: 11L (3/4) of ECF
- plasma: 3L (1/4) of ECF
16
Q
+/- colloids
A
Replace blood 1:1 Expands circulating volume High cost Can affect coagulation Large molecules don't cross membrane At high volumes the affects may reverse Anaphylaxis risk
17
Q
+/- crystalloids
A
Replace blood 3:1 No allergy risk Water soluble molecules Electrolytes Mimics the plasma Low cost
18
Q
What are the hazards of rapid infusion?
A
Air embolism Drug error Accidental bolus from fluid refluxing Tissue toxicity (incorrect IV) Phlebitis Anaphylaxis Temperature high or low Fluid overload Fluid contaminations Mechanical faults in lines Arterial injection
19
Q
Describe the components of blood.
A
RBC: 45%
Plasma: 55%
Buffy coat (WBC, platelet) 1%
20
Q
What is plasma?
A
The liquid part of the blood which contains antibodies and proteins
21
Q
What are red blood cells?
A
Enucleated cells which contain haemoglobin capable of transporting oxygen throughout the body.
Last for 120 days
Also called erythrocytes
22
Q
What is third spacing?
A
When too much fluid moves from the intravascular space to a transcellular space (a space somewhere in the body it shouldn’t be eg bowel lumen) where it cannot participate in fluid movement
23
Q
What are normal blood volumes?
A
Normal blood volume is 70ml/kg (5L adult) and 80ml/kg child
24
Q
What is the total body water?
A
60% men
50% women
75% child
TBW= 0.6 X weight (for a man)
Therefore 45L of water for a 70Kg man
25
What is extra cellular fluid?
All fluid outside the cells
26
What is interstitial fluid?
The fluid which surrounds the cells
27
What is transcellular fluid?
A part of the ECF and is contained in epithelial lined spaces
28
What is osmosis?
Diffusion of water across a semi permeable membrane from an area of low solute concentration to an area of high solute concentration
29
What is a fluid challenge?
100-200ml bolus of fluid
A sustained rise is CVP >3mmhg suggests the patient is well filled.
If not sustained rise, keep bolusing
30
What is hypernatraemia and the treatment?
High serum sodium
Treat with 5% dextrose (hypotonic)
31
What happens in untreated hypovalaemia?
```
Low perfusion
Low oxygenation
Organ damage
Organ failure
Death
```
32
What are colloids made of?
Albumin - protein
Dextran - polysaccharide (can affect cross match and clotting)
Gelatines - collagen
Starches - maize
33
What is a syringe pump?
```
Programmable
Set infusion rate and bolus
Maintain a constant infusion
Mechanism: pulsatile continuous delivery
2.5% accurate
Battery and mains
Need Anti syphon valves prevent free flow
Correctly engage syringe
Shouldn't be >100cm above patient
```
34
What's a burette?
A accurate fluid delivery device placed between bag and giving set
1ml divisions
High accuracy for volume infused
Ball valve prevents air entry
35
What are the protocol around blood infusing equipment?
```
Approved devices only
Sterile sets
170-200 micron pore filter
Prime with normal saline or product
Change set every 4 units or 10 units in MTP or 8 hourly
Need new set for platelets
Don't add drugs to this line
Warm if large/rapid volumes
Keep below 41 degrees
```
36
Name 4 isotonic solutions.
Normal saline
Hartmans
Gelofusine
Volulyte
(Also plasmalyte, dextrose 5%)
37
Name 3 hypertonic solutions.
Saline 3%
Dextrose 10%
Mannitol
38
Name 3 hypotonic solutions.
0. 45% saline
2. 5% dextrose
0. 18% saline
39
What is an acute haemolytic reaction?
Incompatible red cells react with patients antibodies
Can cause DIC and renal failure
Fever, rash, hypotension or sudden spike, oozing wounds, Hb in plasma or urine, difficult breathing, agitation
40
What is a bacterial contamination reaction?
Can be from IV site, skin plug, donor, processing contamination.
Signs of infection and sepsis
More likely in warmer products eg platelets
To reduce: check product bag and expiry, donor testing, disinfect donor skin, discard initial 10ml sample, monitor platelets with detection system
41
What is a DHTR?
Delayed haemolytic transfusion reaction
A haemolytic reaction >24hours after infusion
Secondary immune response
Commonly Jk or Rh
42
What is a NHFTR?
Non-haemolytic febrile transfusion reaction
Fever or rigors during transfusion
Slow/stop rate; give antipyretic
Can be mild to moderate
Washed cellular products may be better for these patients
43
What is a TRALI?
Transfusion related acute lung injury
When donor plasma has antibodies against patients leukocytes
Respiratory distress, hypoxaemia, pulmonary oedema, cyanosis, tachy, fever
Female donor with multiple children commonly have the antibodies (HLA, HNA)
44
What is a TACO?
Transfusion associated circulatory overload
Infusion too rapid or too much volume
Respiratory distress, tachy, high BP, distended neck veins
Treat with diuretic, O2, compress lower limbs, sit up
45
What reactions can occur with a blood transfusion?
```
Acute haemolytic
Bacterial contamination
DHTR
NHFTR
Allergy/anaphylaxis
TRALI
TACO
Graft-vs-host disease (donor lymphocytes attack)
Immunosuppression
Post transfusion purpura (low platelets cause haemorrhage)
```
46
What biochemical reactions may occur from blood transfusions?
Hypocalcaemia from citrate binding to Ca
Hyperkalaemia (high potassium during storage)
Acid-base disturbances
47
Describe ABO blood typing.
A, B, AB, O
Determined by antigens on cell surface (agglulinogens)
Plasma contains antibodies to any antigens not present on cells
(Agglutinins)
48
What are the blood universals?
Donor: O- because it has no surface antigens to attack
Recipient: AB because these people have no antibodies to attack other blood groups
49
Why is recipient blood most important when blood matching?
Consider a patient who is AB blood group therefore have no antibodies. So we could give them a unit of A (which in theory would have B antibodies) because it is just RBC ie there isn't plasma (which carries antibodies). A bag of RBC has a small amount of plasma that passes through but not enough to harm the patient.
CONSIDER DONOR ANTIGEN BUT RECIPIENT ANYIBODY
50
Describe the Rhesus factor.
Present +
Carries on RBC surface
Not spontaneously formed antibodies: Rh + never forms, Rh - may form antibodies from exposure
First exposure sensitises and second exposure causes reaction
51
Why is Rh a problem on pregnancy?
When there is a Rh- mother with a Rh+ child
First pregnancy is ok but mother gets sensitised at birth and produces Rh antibodies
During second pregnancy the mothers antibodies will attack the child
Mothers antiD crosses placenta and agglutinates babies RBC - death or brain damage
52
How is Rh problems treated?
Inject mother with anti D agglutinins to agglutinate Rh factor so mother can't become sensitised
Inject at 28 weeks and after birth
53
What is the compatibility of the products?
RBC: must match
Platelet or cryoprecipitate: ideally the same but can differ
FFP: must match but remember it's inverse to normal chart
54
What should be considered when giving O-?
Can use to start an emergency
Take G+H as soon as possible
Preferred no more than 4 units
Remember it's precious and does contain some A and B antibodies!!!
55
What are the conditions of donation?
```
At an approved centre
16-60 y/o
In good health
>50Kg
Complete paperwork
Informed consent
Test for ABO, antibodies and disease
Leukodeplete (filter out WBC to reduce infection and affects)
Labelled correctly
```
56
What is apheresis?
Process where a particular substance is removed and the rest is returned to the donor eg plasma
57
How must a sample be collected?
Check patient ID
Informed consent
Hand write blood tube
Collect and complete entire process in presence of patient with no interruption
58
How long are samples valid for?
Pt transfused/pregnant/Hx antibodies: 72 hours
None of above, in hospital: 7 days
None of above, pre admit clinic: 21 days
59
What is autologous donation?
Patient donates own blood prior to surgery
Includes:
pre operative collection - weeks before
Peril prestige acute haemodilution - immediately prior
Cell salvage
High cost, stringent planning, risk getting it wrong, weakens the patient, high waste, no haemolytic risk, bacterial risk remains
60
Describe pre operative autologous collection.
Patient donates a unit per week in the month before surgery.
Reduced transfusion risk
Bacterial risk remain
May need Fe supplement
Circulatory overload possible with whole blood
61
Describe perioperative acute haemodilution donation.
Patient donates whole blood immediately before surgery - replace volume with fluids - then return blood at the end providing clotting factors etc
Unstable patient
Less cost and less error risk
Storage correct in theatre
62
Describe cell salvage.
Hooked up to surgical suction; or from drains
Can replace close to what is lost
Endless
Debra risk - DIC
Need skilled staff
Cell destruction occurs
Can't use with OBS - reinfuse fetal contaminants, not for bacterial contaminated sites, malignant disease
63
What is a directed donation?
A certain person is sought after and donates for a specific person
Doesn't use bank supply, available quickly
Transfusion risks remain, increased GVHD of family, donor may not disclose, high cost, major planning
64
What are surgical techniques to reduce blood loss?
```
Radiology help
Diathermy
Laparoscopic
LA with adrenaline
Pre- surgical optimise eg iron
Tourniquet
```
65
What are anaesthetic techniques to reduce blood loss?
```
Keep a lower BP
Keep patient warm
Position eg head up
Drugs - maintain clotting
Haemodilution - reduce RBC loss
```
66
What is a volumetric pump?
```
(Alaris)
Programmable
Specific giving set
Ideal for accuracy of total volume NOT precise flow
5-10% accuracy
Various mechanisms
Battery/mains
```
67
Define massive transfusion.
One blood volume in 24 hrs
50% in 3 hrs
>150ml/min
68
What is TURP syndrome?
Hyponatraemia
Watch height, volume and time of glycerine solution given. This is absorbed out of the blood leaving hypotonic water therefore sodium is diluted and some leaves the cell to balance.
Confusion, N+V, fitting, ^RR, headache
High HR and high BP
69
What is the make up of the nervous system?
Central nervous system communicates with the peripheral nervous system which can be split into two: sensory which gathers information from sensory organs and motor which sends out signals to organs. Motor can be divided into somatic (voluntary) control of skeletal muscle and autonomic which controls glands, cardiac and smooth muscle. Autonomic can further divide to sympathetic and parasympathetic
70
Describe a somatic fibre
One ganglion
| Acetylcholine at the junction
71
Describe the sympathetic fibre
Thoracolumbar
Pre ganglion: T1 - L2, short, acetylcholine
Post ganglion: long, nor adrenaline
72
Describe the parasympathetic fibre.
Craniosacral
Pre ganglion: cranial nerves (3, 7, 9,10) and S2-S4, long, acetylcholine nicotinic
Post ganglion: short, acetylcholine muscarinic
73
Define agonist
A chemical that binds to a receptor and triggers a biological response
Full: produce full efficacy
Partial: produce mild efficacy
Inverse: produce negative efficacy (bind to receptor but induce opposite response to agonist)
74
Define antagonist
A chemical that binds to a receptor and blocks it preventing other chemicals from binding
Competitive: (reversible) will compete with agonists for the site eg naloxone
Non-competitive: (irreversible) binds to different site than agonist and prevents activation eg ketamine
75
Define bioavailability.
A subcategory of absorption and is the amount (%) of an administered drug that reaches the systemic circulation unchanged. IV is 100%.
Affected by first pass metabolism, solubility and chemical stability
76
Define clearance
A pharmacokinetic measurement of the volume of plasma from which a substance is completely removed per unit of time (ml/min). Excreted via urine, sweat, saliva, expiration.
77
Define context sensitive half time
The time taken for the blood plasma concentration of drug to decline by one half after an infusion designed to maintain steady state has been stopped
78
Define half life
The time required for the concentration of a drug in the plasma to be reduced by one-half. This depends on how quickly the drug is eliminated
79
Define pharmacodynamics
The physiological and biochemical effects a drug had on the body and its mechanism of action
80
Define pharmacokinetics
The movement of drugs within the body including the processes of absorption (entering circulation), distribution (dispersing through fluid and tissue), metabolism (becoming metabolite) and excretion (removal).
81
Define receptor
A protein molecule on a cell surface or inside a cell which has a high affinity for a specific chemical group or molecule which can bind and trigger a response. Can be ion channels, G-proteins (activate second messenger) or enzyme linked.
82
Define tachyphylaxis
A rapid decrease in the response to a repeated dose over a short period of time
83
Define tolerance
A persons diminished response to a drug when it is continually used and the body adapts to its presence.
84
Define volume of distribution
The theoretical volume (L) needed to contain the total amount of a drug at the same concentration that is observed in the plasma. This represents the spread within the body. A large number (42) indicates good spread into the tissues. Vd= dose/plasma conc.
85
Define drug
A chemical that affects physiological function in a specific way
86
Define metabolism
Mainly liver - process of chemically changing drug to metabolite
Phase 1: chemical reaction changes to metabolites (oxidation, reduction, hydrolysis)
Phase 2: conjugation to inactive compounds by attaching ionised groups. Changes drug/metabolite into soluble compound for excretion by increasing its polarity (glucuronidation, suphonidation)
87
Define first pass metabolism
Drug absorbed from agai tract and passes through the liver via the hepatic portal before entering the systemic circulation. Results in a very small amount reaching circulation
88
Describe the nicotinic receptor
```
Acetylcholine
Found in all pathways
Ion channel which is opened by acetylcholine binding
Brief and fast response
All excitatory
```
89
Describe the muscarinic receptor.
```
Acetylcholine
Parasympathetic pathway only
G protein coupled - when Ach binds it changes its shape and activates a secondary messenger
Slow and prolonged
Can be both excitatory and inhibitory
```
90
Describe adrenergic receptor
```
Noradrenaline
Sympathetic pathway only
G protein coupled
A1: vasoC smooth muscle
A2: inhibit NA
B1: cardiac contractility and HR
B2: lung bronchodilator
```
91
Describe propofol
```
10mg/ml
2-3mg/kg induction
0.5mg/kg bolus sedation
Soya bean oil and egg protein
Short acting; quick onset
Sedative/hypnotic
GABA agonist
Injection pain, myoclonic spasm (caution epilepsy), hypotension, reduced PONV
```
92
Describe thiopentone
```
3-5mg/kg
Fast onset, short acting
Doesn't cross placenta
Barbiturate/hypnotic
Accumulation with repeat doses
Anticonvulsant, cerebral protection, hypotension, high PONV, injection pain
```
93
Describe midazolam
```
0.5-5mg titration
Sedative/amnesiac/anxiolytic/anticonvulsant
20-60min duration
Reversal by flumezanil
GABA agonist
PO, IV, IM
```
94
Describe ketamine
```
Dissociative anaesthetic/analgesic
NMDAR antagonist; opioid agonist
Good for shock and trauma
Bronchodilator, ^ICP, ^BP, ^salivation, respiratory depression, delirium
IV, IM
```
95
Describe etomidate
```
0.3mg/kg
Hypnotic
CVs stability
Fast onset, short acting
Pain on injection, PONV, myoclonic movements, adrenocorticol suppression
```
96
What are the competitive (non-depolarising) relaxants?
Short- mivacurium
Medium- rocuronium, atracurium, vecuronium
Long- pancuronium
97
Describe rocuronium
```
0.6-1mg/kg intubation
Non-depol/comp
2-40min action
Ach Nic antagonist
antagonised by acetylcholinesterase
Tachycardia
```
98
Describe atracurium
```
Benzylisoquinolinium, non-depol/comp
90s - 35min
Ach Nic antagonist
Low anaphylaxis risk, histamine release
Hoffman elimination: temp and pH dependant so spares renal and hepatic
```
99
Describe mivacurium
```
Short acting
Non-depol/comp
16min duration
Metabolised by plasma cholinesterase so risk of long block
Antagonised by neostigmine
```
100
Describe suxamethonium
50mg/ml
1-1.5mg/kg (1-2paeds)
Non competitive/depolarising
Rapid onset and short acting
Similar to 2x Ach molecules
Bind to Ach Nic first opening then blocking
Fasiculations from first activating the receptor = repetitive firing
Metabolised by plasma cholinesterase risk of long block
Can cause low calcium, MH, high IOP, ICP, bradycardia with second dose, muscle pain, high potassium
Don't use in burns, head injury, eye injury, spine injury, MH, crush injury, cholinesterase deficiency
101
Put the common analgesics in order of increasing potency
```
Pethidine
Morphine
Alfentanyl
Fentanyl
Remifentanyl
```
102
Describe opioid receptors
Inhibitory G-protein coupled receptors with opioids acting as agonists. These slow the transmission of pain signals and also encourage release of chemicals such as dopamine
```
Delta
Kappa
Mu
Nociceptin
Zetta
```
103
Describe morphine
Mu and kappa agonist
PO, IV, PCA, IM, SC, epidural, spinal
104
Why is ITM an advantage?
Close to effect site, less respiratory depression, small dose and dose times, less side effects, stays at the site, long duration
105
Describe fentanyl
30-60min duration
CVS stable
IV: 1-5mcg/kg
Epidural: 50-100mcg
Spinal: 5-10mcg
106
Describe remifentanyl
Short acting 5-10min
| Supplement anaesthetic
107
Describe alfentanyl
10min duration
5-10mcg/kg
108
Describe tramadol
Drug of threes: opiate receptor agonist, increase serotonin, reduce reputable or noradrenaline
Caution in epilepsy
50-100mg 4 hourly
109
Describe parecoxib
NSAID, cox-2 inhibitor
Inhibits enzyme causing pain and inflammation
40mg then 20-40mg 6-12hourly
110
Describe paracetamol
Analgesic,antipyretic
Caution in neonate, liver damage - toxic metabolite can build up and cause failure. This is treatable with N-acetylcysteine which is a precursor to glutathione, the antioxidant of the liver that the paracetamol metabolite damages.
Load dose 30mg/kg then 15mg/kg max60mg/kg/day
111
What are common adverse effects of opioids?
```
Respiratory depression
Reduced GI mobility
N+V
Constipation
Addiction
Sedation
Pruritis
Tolerance
Hallucinations
Dry mouth
```
112
What are common adverse effects of NSAIDS?
```
GI upset
Ulceration
Asthma trigger
Reduced platelet aggregation
Renal impairment
^MI risk
```
113
Describe clonidine
Selective A2 agonist
Sympathetic pathway: A2 receptor is prejunctional and prevents release of NA
Reduced opioid requirement, sedative, reduce blood pressure
Acts centrally at brain stem and reduces sympathetic outflow
150-300mcg
114
Describe ondansetron
Serotonin (5HT3) antagonist - preventing it binding and triggering the N+V centre
Antiemetic
4mg Qds
115
Describe dexamethasone
Corticosteroid, antiemetic, reduce oedema
2-8mg
116
What are considered high PONV risks?
```
Female
Motion sickness
Non-smoker
Opioids
GI, gynae, craniotomy, strabismus, otolaryngology
```
117
What is step up opioid therapy?
1: non-opioid
2: mild opioid
3: strong opioid
4: RA
Remember a multimodal approach is best
118
What is the antiemetic combination therapy?
Mild risk: 1 drug
Moderate: droperidol OR Dexamethasone with a serotonin antagonist
High risk: combination therapy
119
Describe neostigmine
```
Anti cholinesterase
Reversal of non-depol relaxants
Acts at the Ach junction by inhibiting acetylcholinesterase from breaking down Ach therefore more available to compete. Some receptors must be available in order to work. Also increase flow along parasympathetic causing bradycardia.
50-70mcg/kg with atropine or glyco
Glycopyrolate matches timing better
```
120
Describe atropine
Anti muscarinic/anticholinergic
Ach muscarinic receptor antagonist
Increase HR, reduce secretions, confusion
10mcg/kg IV
121
Describe adrenaline
A+B adrenergic agonist
Can prolong LA
Causes vasoC, contractility and ^HR
High BP, high HR, anxiety, arrhythmia, reduced uterine blood flow
122
Describe ephedrine
A+B adrenergic receptor agonist
Increase contractility, vasoC and HR
Safe in pregnancy, tachyphylaxis
123
Describe phenylephrine
Alpha adrenergic agonist
| Peripheral vasoconstriction
124
Describe metoprolol
Beta adrenergic antagonist
| Reduce contractility and HR
125
Describe labetalol
A+B adrenergic antagonist
| Reduce vasoC, contractility and HR
126
Describe esmolol
Beta adrenergic antagonist
| Reduce contractility and HR
127
Describe salbutamol
Beta2 agonist
Bronchodilator
High doses also bind to B1 causing high HR/tremor
128
Describe sevoflurane
Halogenated ether
Potentiate GABA, glycine and two-pore domain K channels
Reduce TV, increase RR, reduces MAP, prolong QT, increase PONV
Removed by lungs
Risk MH, compound A, carbon monoxide
129
What is special about the adrenal medulla?
In the adrenal gland
Contains chromaffin cells which excrete adrenaline, NA and dopamine.
Considered post ganglion neutron of SNS and received info via pre ganglion neuron directly from CNS
Quick signal!
Chemicals excreted directly into blood stream
130
What is the second gas effect?
Increase in the pp of other gases in the alveolar due to rapid uptake of N2O
Induction and emergence
N2O is highly soluble so taken up quickly - the reduction of volume of N2O in alveolar (due to rapid uptake to blood) then increases concentration of agent available to go into the blood
131
Describe amiodarone
anti-arrhythmic
Treats SVT and V arrhythmia
Acts on nodes to increase the gap via sodium and potassium channels
300mg slow IV bolus for adult defib
132
Describe carboprost
Prostaglandin
Treat PPH after ergometrine and oxytocin fail
Never give IV - deep IM or direct myometrium
133
Describe dantrolene
Direct acting skeletal muscle relaxant
Treatment of MH
Reconstitute in 60ml water and put through giving set
Crosses placenta, muscle weakness, phlebitis
134
Describe ergometrine
Control uterine bleeding
| Don't give IV - IM with oxytocin
135
Describe oxytocin
Hormone
Stimulates uterine contraction and increases tone, milk release
Induce labour and treat PPH
Slow IV 5U or 40U 125ml/Hr
136
How to calculate the number of Mg in a drug?
%conc X volume X 10
137
Describe bupivicaine
With glucose
Slower than lignocaine
200-400 minutes
High cardio toxicity so not for IVRA
Max 2mg/kg/4hr
138
Describe lignocaine
Rapid onset
30-90 minutes
Also treats V arrhythmia and reduces pressor effect from intubation
Max 3mg/kg/4hr (6mg with adrenaline)
139
Describe ropivicaine
200-400min
Less cardio toxic
Max 3-4mg/kg/4hr
140
Describe prilocaine
Lowest toxicity; toxicity reduced with methylene blue
Good for IVRA
Rapid onset
30-90 min
Max 6mg/kg/4hr (8mg with adrenaline)
141
How do the local anaesthetics work?
Sodium channel blockers
| Prevent sodium channels opening therefore sodium cannot enter and depolarise the cell
142
What is EMLA?
Eutectic mixture of local anaesthetic
2.5% lig and 2.5% pri cream
143
Describe sodium citrate
Alkaline solution
| Neutralises stomach acid immediately
144
Describe ranitidine
H2 receptor antagonist
| Stops stomach acid production
145
Describe tranexamic acid
Inhibit plasminogen activation (plasminogen dissolves fibrin)
Not for pregnant or renal impaired
146
Describe intralipid
20% emulsion
Soya oil (fatty acids)
Draws local out of plasma where it binds to it or the lipid counteracts the LA inhibition of myocardial fatty acid metabolism therefore preserving ATP in the heart
147
What needs to be considered in renal and hepatic impairment?
Reduced metabolism and clearance
Prolonged duration and build up of metabolites
Initial dose may be the same but subsequent dose intervals will be longer and dose sizes reduced to maintain peak concentration and avoid toxicity
Avoid some - NSAIDs
Swap some - sux for atracurium
148
Describe sugammedex
Selective relaxant binding agent
Binds to rocuronium and vecuronium
16mg/kg
149
Describe excretion
Mainly in the kidney (also sweat, saliva, milk, lung, intestine)
Glomerular filtration
Active tubular secretion and some passive reabsorption
Secretion from peri tubular capillaries to the nephron and reabsorption from nephron back to capillaries.
Water and electrolytes
Polar compounds cannot reabsorb
Secretion important for drugs
150
What are some sources of ECF?
```
CSF
Lymph
Synovial fluid
Pleural fluid
Aqueous humour
```
151
Describe GABA
Gamma aminobutyric acid
Inhibitory NT
Reduced excitability of cells
Both ion and G-protein function
152
What is Hoffman elimination?
Spontaneous degradation of a drug at normal body temperature and pH
153
What is DIC?
Disseminated intravascular coagulation
Widespread activation of the clotting cascade causes clots to form in small vessels leading to multiple organ damage. Consumption of coagulation factors then leads to severe bleeding.
Diagnosed via lab tests
Some causes: MTP, PPH, sepsis, blood cancer, transfusion reaction
154
What is the volume, storage, time requirements and use of Cryoprecipitate?
```
100ml
-25 degrees
2 years
Must be thawed for use (2-6 degrees)
4 hours after thawed
Use in 4 hours
Return In 30 minutes
Fibrinogen, von Willebrand, factor VIII and factor XIII
```
155
What is the volume, storage, time requirements and use of FFP?
```
280ml
-25 degrees
2 years
Must be thawed for use (2-6 degrees)
24 hours after thawing
Use within 4 hour
Return within 30 minutes
Coagulation factors and proteins
>4 RBC
```
156
What is the volume, storage, time requirements and use of platelet?
```
300ml
20-24 degrees, agitated
7 days
Use within 1 hour
Return within 1 hour
Clotting
>4 RBC
```
157
What is the volume, storage, time requirements and use of RBC?
```
300ml
2-6 degrees
35 days
Use within 4 hours
Return within 30 minutes
Increase tissue oxygenation
Hb less than 70
```
158
What is aminophylline for?
Treats lower airway obstruction in paediatric anaphylaxis
Bronchodilator
Improves diaphragm contraction
159
What is irradiation and leukodepletion?
Leukodepletion removes leukocytes to reduce immune mediated response
Irradiation removes lymphocytes to reduce GVHD (lymphocytes attack the recipient)
160
Why thiopentone for obstetrics?
Because it is historically safer and better known than other agents
