Anaesthetics Flashcards
What are the normal ranges for sodium and potassium in the blood and why is there such a difference?
Sodium: 135-145mmol/L
Potassium: 3.5-5.0mmol/L
Sodium mostly exists in the extracellular compartment (ECF and blood), potassium mostly exists in the intracellular compartment
What are the daily requirements of water, glucose, sodium and potassium?
Important things to remember when prescribing maintenance fluids?
DAILY REQUIREMENTS 24 HOURS
WATER 25-30 ml/kg/day
K+/Na+/Cl- 1 mmol/kg/day
Glucose 50-100 g/day of glucose to limit starvation ketosis
- will not address the patient’s nutritional needs
- reduce flow rate to 20-25 ml/kg/day if renal impairment/heart failure/ frail/elderly/malnourished (re-feeding syndrome)
- reduce maintenance if also eating and drinking
What kinds of things cause FLUID LOSS?
Poor oral intake (elderly, dysphagia, unconsciousness, fasting NBM) Increased requirements (Trauma, burns, post-operative) Increased loss (fever, sweating, bleeding, D+V, renal loss, drugs, NG tube or stoma loss or billary drainage loss)
How do we classify fluid loss?
As mild, moderate or severe
MILD
- 4% body weight, loss of skin turgor and dry mucus membranes
MODERATE
- 5-8% body weight, oliguria, tachycardia and hypotension
SEVERE
- >8% body weight, profound oliguria and CVS collapse
What are some crystalloids and what are some examples?
They are water soluble substances dissolved in solution. They can be rapidly administered but can cause pulmonary oedema
NaCl 0.9%
Dextrose
Haartmans
What is in NaCl and what are some risks?
(0.9% mean 9g in 100ml) - contains 154mmol/L Na and 154mmol/L Cl
So about the right amount of sodium but there is a risk of hyperchloraemic acidosis
What is in dextrose and when should it be used?
5% = 50g per L water
Good if people have glucose requirements
What is in Haartman’s and what are some benefits of using it?
Na - 131 Cl - 111 K - 5 Ca 2 Lactate 29
-reduses risk of hypokalaemia and hyperchloreamia
What are some examples of colloids? Where are they sometimes used?
Gelfusin Voluven Volulyte Albumin Sometimes used in trauma but rarely elsewhere
What is a fluid challenge?
Getting IV access with a wide bore cannula and administering 250-500mL of fluid as quickly as possible (usually 10-15mins) and monitoring for a response (BP, HR, UOP, JVP)
If an unwell patient hasn’t improved after 3 fluid challenges then need senior support
What is maintenance fluid?
What is an example of a good maintenance fluid regimen in a 70kg man?
MAINTAINANCE FLUID
-total amount of fluid in a day, presuming everything else is normal (e.g. no dehydration, no drugs that will effect)
0.9% NaCl + 40mmol K over 8 hours
5% dextrose + 20mmol K over 8 hours
5% dextrose + 20mmol K over 8 hours
Why will people need more than just maintenance fluid after surgery?
People loose fluids during surgery (on average 600-900mL) so they will need some extra fluids before they’re placed on a maintenance regime
How do you manage fluid therapy in fever?
Add 10% extra fluids for every degree of fever
What should you ask in the history section of a pre-operative assessment?
- what is your understanding of the op?
- who do you live with at home? well supported?
- can you normally independently care for yourself?
- Current illness (health in the past 2 weeks, any new problems or infections)
-Vision and hearing
-Dental care
-Neuro (epilepy and stroke)
-Neck and jaw (trauma, movements, RA/OA)
Cardiac
-how far are you able to walk? (should be 4+ METS)
-how do you sleep at night?
-chest pain?
-MI/HF/diabetes/HTN/valve problems/arrythmias
Resp
-SOB
-cough?
chest infections?
COPD/asthma/infections/sleep apnoea
GI
-reflux/indigestion/heartburn/liver/kidney problems
Anaesthetic history (personal and family-MH/suxapnoea) Drug hx and allergies Social history (smoking, alcohol, drugs, pregnancy, blood products)
ICE
What ongoing medical conditions in particular should you ask about during anaesthetic history?
Any drugs you should avoid with certain conditions?
epilepsy/stroke/ heart attacks/diabetes/HTN/asthma/COPD/liver or kidney disease. Always ask how well controlled these are
Diabetes-done give Dexamethasone
Renal failure-dont give Rocuronium/NSAIDS/morphine
What should you examine in a pre-operative assessment? (4)
Examination pre-op
- Neck movement, jaw opening and dental health (dentures, caps, crowns or loose teeth)
- Mallampati score
- ASA score
- General examination (listen to heart and chest, feel abdomen, feel peripheries, feel calves for swelling or tenderness)
- Pregnancy test
What is the mallampati score?
I - complete visualisation of soft palate
II - Complete visualisation of uvula
III - Can only see base of uvula
IV - Cannot see soft palate
What is the ASA-GRADING for surgery?
How does emergency surgery change ASA grade?
1 - Healthy patient, no ongoing disease. Non smoker and no/minimal alcohol
2 - Mild/mod chronic disease with no functional impairment (e.g. well controlled diabetes, HTN, smoker or social drinker)
3 - Severe chronic disease with functional impairment e.g. angina or COPD
4- Severe chronic disease with constant threat to life e.g angina, ESRD or liver disease
5 - Moribund patient who is unlikely to survive with or without operation
6 - Brainstem dead patient for organ donor transplant
EMERGENCY BUMPS YOU UP BY ONE
What are the surgical grades for the operation?
Minor - skin excision/ toenail removal/ absess drainage/cystoscopy
Intermediate - hernia repair/tonsillectomy/ knee arthroscopy/varicose veins
Major/complex - emergency laparotomy/ hysterectomy/ thyroidectomy/joint replacement/thoracic operational/ radical neck dissection
In MAJOR surgery, what investigations would everyone get?
-FBC for all ASAs
For ASA 2+
-Kidney function (or ASA1 at risk AKI) and ECG (or ASA 65+)
group and save would be useful if expected blood loss
What are some extra investigations for specific things in pre-operative assessment?
LFTs for liver or billiard op
Sickle cell screen for Afro-Caribbean patients
TFTs if they’re on thyroxine
CXR if ICU care might be required
Echo if they’ve got valve problem or murmur
Spirometry if lung disease
What must you correct before the operation if found to be abnormal?
INR (with vit K or prothrombin complex)
Anaemia
What is the general rule for stopping medications before an operation?
In general omit on the day of operation and resume the day after
What more specific medications must be stopped before operation?
COCP - stop 4 weeks before
Aspirin/clopidogrel - stop 7 days before
Warfarin-stop 5 days before (give therapeutic dose LMWH in interim)
LMWH - stop 48h before (hep infusion if at risk)
DOACs - stop 24h before
Insulin - don’t have morning dose
Metformin-can continue on day (dont cause hypo)
Oral hypoglycaemic - avoid on day of op
Diuretics/ACE-is - avoid on day of op
Long-term steroids - consider switch to hydrocortisone higher dose
What are the fasting guidelines before an operation?
- No food for 6 hours before (have dinner nil else)
- No breastmilk for 4 hours before
- Only clear fluids (black tea, purples juice) until 2 hours before (30ml only for tablets)
- Children allowed water 1 hour before
- No alcohol 24 hours before
How much oxygen can be given through nasal cannulas?
1-6L (most commonly 2L)
24-40% O2
How much oxygen can be given through a simple face mask (hudson)?comment on flow and FiO2
Flow 5-10L (CO2 can accumulate if the flow is less than 5L)
FiO2 35-60%
Not very reliable
Can humidify to help with comfort
What demonisations are there of venturi devices? In whom are they commonly used?
BLUE 24% WHITE 28% YELLOW 35% RED 40% GREEN 60%
Non rebreather mask (80-95%)
Good in CO2 retainers (COPD, long term rep condition) to control concentration of O2
How much oxygen can be given through a non rebreathe mask? comment on flow and FiO2
Non re breath mask
-15L and probably gives up to around 80-95% - this is about as good as we can get unless we artificially ventilate someone
What options do we have if the patient need assistance with ventilation?
Ventilation options
- BAG-VALVE MASK
- NIV
- ET tube or airway adjunct or igel
How do you measure a Gedell airway?
SOFT TO SOFT
-tragus to corner of mouth
What are the average sizes of NP tubes? When should they not be used
NASOPHARYNGEAL TUBES (little finger of patient)
6-7mm for women
7-8mm for men
Do not use if any suspicion of basal skull fracture
What are some examples of supraglottic airways?
Laryngeal mask airway (LMA) and iGEL
When are LMAs preferably used and how do you insert an LMA?
-Used in shorter surgeries when an ET tube is not required -or if you cannot intubate someone (easier to put in)
NOT A DEFINITIVE AIRWAY
-Reflexes should be suppressed e.g. with propofol then insert with the curve of the airway (no need to rotate)
What kind if airway is an ET tube? How are the sized
ET tube
- Definitive (no aspiration risk)
- Sized by internal diameter of tube - 7/8mm for women, 8/9mm for men
What is the process of inserting an ET tube?
- preoxygenate the patient
- Wait for the neuromuscular blockage (90-120s)
- Place the patient in the sniffing the morning air position
- Hold laryngoscope in L hand
- Insert the laryngoscope in the R hand corner of the mouth and slide it down between the tongue and the epiglottis
- then lift with your whole arm up and to the left
- Aim to visualise the vocal cord
- Insert the tube to just beyond the vocal cords
- should be 23 cm for men and 21 cm for women, measured at the central incisors
- Inflate the cuff of the tube, attach to the bag valve mask and look for signs that it is in the right place
What signs are there that the ET tube is in the right place?
ET tube
- see it go in right place (through vocal cords)
- misting tube
- EtCO2 properly traced (5 clear traces)
- symmetrical rise and fall of chest
- ausciltation reveals air in chest, not in abdomen
What are some possible complications of ET tubing?
- Breaking teeth with the laryngoscope
- Incorrectly positioned tube (into oesophagus) if in doubt take it out
- Right lung intubation if put too far down
- Laryngospasm - especially if someone has asthma or COPD
What are the three types of anaesthetic?
Local, Regional, General
When putting someone under a general anaesthesia what three things do you need to achieve?
AMNESIA - unconscious and won’t remember
AKINESIA - cannot move
ANALGESIA - won’t be in pain or have a pain response
How do we achieve amnesia in general anaesthesia?
AMNESIA
- INDUCTION AGENTS INITIALLY (propofol, thiopentone, etomiidate and ketamine) these last 4-10 mins
- Then maintained with VOLATILE AGENTS or TIVA
benefits and unwanted effects of Propofol?
Propofol 1.5-2.5mg/kg
Benefits
-Excellent suppression of airway reflexes
-Good at preventing PONV
Unwanted effects
- Causes a marked drop in HR and BP (give vast active)
- Also can be painful to inject because it is lipid based
- Unwanted movements
What type of drug is thiopentone?
when would you be more likely to use thiopnetone?
unwanted effects thiopentone (inc effects on BP and HR)
when would you not use thiopentone?
Thiopentone 4-5mg/kg
-This is a BARBITUATE
Uses
- It works much faster than propofol and thus is often used in RSI (emergency surgery/risk of aspiration)
- It also has anti-epileptic properties and is quite neuroprotective
Unwanted effects
- Drops BP but INCREASES HR
- rash and bronchospasm
- requires intra-arterial injection (lead to gangrene and thrombus)
Avoid
-Avoid in porphyria
What effects does ketamine have?
what are some unwanted effects? (inc effects on BP and HR)
Ketamine 1-1.5mg/kg
- It is a DISSOCIATIVE ANAESTHETIC (anterograde anaethsesia) and is also profoundly analgesic
- it is quite slow to act (90s)
Unwanted effects
- INCREASES HR and BP
- bronchodilation
- can causes PONV and EMERGENCE PHENOMENON (vivid dreams and hallucinations)
Benefits of Etomidate?
WHos it good for?
Unwanted effects of Etomidate?
Etomidate 0.3mg/kg
- rapid onset
- good haemodynamic stability (good for pens with cardiovascular conditions)
- lowest incidence of hypersensitivity
Unwanted effects
- pain on injection
- spontaneous movements
- post op NV
- ADRENOCORTICAL SUPPRESION (cortisol is suppressed for up to 72 hours suggesting it should not be used in very unwell who need the stress response)
What agents are used to maintain anaesthesia?
Volatile agents (desflurane, isoflurane, enflurane, sevoflurane and NO)
What is minimum alveolar concentration?
MAC - this is the minimum concentration of gas required to eliminate a reaction to a standard stimulus
What are the MACs of nitrous oxide, sevoflurane, isoflurane, desflurane and enflurane?
Nitrous oxide 104% Sevoflurane 2% Isoflurane 1.15% Desoflurane 6% Enflurane 1.6%
How does pain affect people under anaesthesia?
They don’t FEEL pain because this is a conscious interpretation. However, they do have nociceptors stimulated which can cause the physiological response of increased HR and BP. That’s why it’s important to give someone analgesics
What are some examples of short acting analgesics used to suppress response to laryngoscope?
Fentanyl, ramifentanil, alfentanyl
What are some examples of long acting analgesics used for post op pain?
Morphine and oxycodone
Where do the anti-kinetic agents act?
At the neuromuscular junction - NICOTINIC FIBRES lead to muscular contraction
Explain the two types of akinesis agents and give examples
DEPOLARISING
- these act in a similar way to acetyl choline on nicotine receptors (agonists)
- broken down slower than Ach so block the receptors
- contraction at first, then fatigue
- E.g. Suxamethonium (rapid onset and offset)
NON-DEPOLARISING
- these block the nicotinic receptor without activating them (competitive antagonists)
e. g. rocuronium
What is an example of a depolarising akinesis agent?
what are some adverse effects?
SUXAMETHONIUM - OFTEN USED IN RSI Side effects: -muscle pains -fasciculations -hyperkalameia, -malignant hyperthermia, -rise in ICP, IOP and gastric pressures
What are some examples of short-acting non-depolarising agents?
Atracurium and mivacurium
What are some examples of intermediate acting akinesis agents?
vecuronium and rocuronium
What is an example of a long acting akinesis agent?
pancuironium
What is the main advantage of non-depolarising agents and the main reason they are used?
THEY ARE REVERSIBLE
How do we reverse non-depolarising agents? How does it work?
With neostigmine
- an anti-cholinesterase that prevents breakdown of ACh
- increasing its conc so that it can outcompete akinesis agent
-Can also give suggammadex (however really expensive)
What is the problem with neostigmine and how can we prevent this?
It is NON-SELECTIVE for nicotinic and also works on muscarinic receptors leading to bradycardia and dry mouth etc.
We can give GLYCOPYRROLATE (anti-muscanaric) to prevent this. (may cause N+V)
What other drugs are often prescribed peri-operatively?
Anti-emetics and vaso-active drugs
Name the most commonly used post op antiemetics.
- Odansetron 30 min before end (5HT3 blocker)
- Dexamethasone (steroid)
- Cyclizine (antihistamine) (in recovery)
Others
- metaclopramide (anti dopamine)
- prochlorperazine (phenothiazine
What vaso-active drug should you consider if someone’s HR and BP are low?
Ephedrine (rise in rate and contractility of heart) (alpha and beta receptors )
What vaso-active drug should you consider if someones BP is low but their HR is high?
Phenylephrine - is more alpha selective and just causes vasoconstriction OR Metaraminol (another vasoconstrictor, longer acting)
If someones hypotension is severe and non-responsive what drugs should you consider?
Adrenaline, Noradrenaline or dobutamine
What is the sequence of events when putting someone under a GA?
- Oxygenate
- Opioid- airway managment is painful and opioids take a little while to work (fentanyl/afentanil)
- INDUCTION AGENT (e.g. propofol to send them to sleep)
- MUSCEL RELAXANT if ET tube (not if LMA) (rocuronium)
- Turn on volatile agent - keep them asleep
- Bag valve mask ventilate them to maintain oxygenation (sevofurane/isoflurane)
- Insert the airway and ventilate them
READY FOR SURGERY
What things should you consider prescribing for post-operative patient?
Analgesics - most patients will need some analgesic cover
Fluids - most patients will lose fluids during surgery so will need some element of replacement and then maintenance
Antibiotics - internal surgeries sometimes require prophylactic abx
How do we manage pain post-operatively?
Following guidelines from essential pain management (EPM) RAT system of pain management - Recognise - Assess - Treat
How do we recognise pain?
If the patient is conscious they will tell you - pain is what the patient says it is
Pain response might be dulled in trauma when sympathetic surges of adrenaline dull the response
How do we assess the pain?
Need to get an idea of WHERE it is
Need to get an idea of what the CHARACTER of the pain is like?
Get an idea of associated symptoms
Scale of 1-10: this gives idea of baseline
What are the three classification strategies for pain?
Is it acute or chronic?
Is it cancerous or non-cancerous?
Is it neuropathic or nociceptive?
What is nociceptive pain?
Sometimes called inflammatory or physiological pain this is pain that is in response to illness or injury
It has a protective function - is usually well localised
What is neuropathic pain?
Nerve damage e.g. sciatica or CES
Does not have a protective function
Might be burning, shocking or feel hot/cold
What is the nociceptive pathway?
- Peripheral tissue injury
- nociceptors are activated by histamine, bradykinin
- prostaglandins created (lower pain threshold)
- THEN EITHER TRAVELS in A-delta (fast response) or C pathway (later throbbing pain) to spinal cord DORSAL HORN - Spinal cord dorsal horn (1st relay station)
- signal passed to 2nd order neutron and cross to the contralateral spinothalamic tract
- travel up spinal cord - Thalamus (2nd relay station)
- thalamus receives signal and sends to cortex, limbic, brainstem - Modulation
- Moderated by sending inhibitory signals via descending pathway
How does pain impact the surgical recovery process?
Physical immobility - e.g. chest pain limits breathing leading to infections
If someone has had lots of pain from one procedure might be less willing to have another
Longer stay in hospital and more time off work
How does the body respond to pain?
Tachycardia and hypertension
GI N&V
RESP reduced VC and FRC
DVT and PE
What is the WHO analgesic ladder?
step 1 mild pain -paracetamol
step 2 moderate pain- weak opioid (dihydrocodine, codeine, tramadol)
step 3 severe pain- strong opioid (morphine, fentanyl, oxycodone)
How does paracetamol work?
Inhibits PG production
Selective inhibitor of COX-3
Good anti-pyretic
Poor anti-inflammatory
How do NSAIDs work?
COX-inhibitors
Block production of PGs and thromboxane which potentiate the action of cytokines on nociceptors
What is the difference between COX-1 and COX-2?
COX-1 is a constitutive isoenzyme responsible for lots of homeostatic measures thus is the reason for lots of the side effects (bronchospasm, GI effects, renal, platelets)
COX-2 is a INDUCIBLE enzyme - responsible for inflammation
Which NSAIDs are most COX-2 specific?
PARECOXIB and Celocoxib
In whom are NSAIDs contraindicated?
Those prone to bleeding
Those with peptic ulcers
Caution with asthma
CI’d in renal failure - really excreted
What are some examples of weak opioids and how do they work? Common doses?
Codeine and tramadol Work by unregulated the signal from the descending pathway moderating pain (activate mu receptors) Codeine: 30-60mg Tramadol: 50-100mg Dihydrocodeine: 30-60mg
What are some examples of strong opioids, how do they work and what kind of pain are they useful in?
Morphine, oxycodone and diamorphine
Strong OP3 receptor agonists
Work well on longer term C fibre pain and less for A-delta pain
What are some examples of short acting opioids?
Fentanyl
Ramifentanil
Alfentanyl
What are some side effects of opioids?
Drowsy, constipated, N&V, tolerance and dependence, hypotension
Respiratory depression - infrequent gulping breaths
What methods of administration are there for post-operative morphine?
What must you remember when patient is on morphine?
oromorph PRN - works very quickly and is very effective
IV morphine (3 times stronger than oral) - common. Give 10mg increase by 1mg/mL until 20mg
PCAS - patient gives themselves 1mg every 5mins. ALL PATIENTS MUST HAVE nasal cannular oxygen
NO OTHER OPIATES WITH MORPHINE (except tramadol)
How do you dose paracetamol and ibuprofen?
Paracetamol you can have 1g (2 tablets) every 4 hours no more than 4 times a day (max 8 tablet per day)
Ibuprofen can take 400mg every 6-8 hours up to 3 times a day.
What doses are appropriate for codeine, tramadol and morphine?
Codeine - 30-60mg every 4 hours up to 240mg every 24h
Tramadol - 50-100mg every 4 hours up to 400mg every 24h
Morphine - give them a 10mg dose titrated in over 10mins (they might not need all 10mg)
What can you give for a patient who has had an overdose of opioids?
Naloxone
Other than oral analgesics what other options do we have for managing pain post-operatively?
- Local anaesthetic injections
- Very often after surgery local anaesthetics are injected around the surgical site to numb it and block the pain
- BUPIVACAINE IS OFTEN GIVEN (longer acting)
What drugs are more often given for chronic pain and why?
Amitriptyline, Pregablin and gabapentin, Clonidine, corticosteroids, capsaicin
Different types of drugs are needed because chronic pain is more likely to be neuropathic in nature
How do you wake someone from surgery?
WAKING UP
- turn off anaesthetic vapour
- oxygenate
- suction
- reverse muscle relaxant (neostig and glycopyrollate)
- prescribe rescue (fluids, analegesia antiemetics, their medication)
Which NSAIDS can be given IV?
Parecoxib and ketorolac can be given IV
Describe sevoflurane?
When would you use it?
Sevoflurane 2% MAC
- sweet smelling gas
- often used for induction
Describe desflurane?
When would you use it?
Desflurane 6% MAC
- low lipid solubility
- rapid onset and offset
- use for long operations
Describe isoflurane?
When would you use it?
Isoflurane 1.15% MAC
- least effect on organ blood flow
- use for organ donor retrieval
How do local anaesthetics work?
Local anaesthetics inhibit Na channels in the axon, blocking transmition of nerve impulse
2 main categories of local anaesthetics?
ESTERS (coo-)
-hydrophobic aromatic group
AMIDES (nh-)
-hydrophilic amide group
examples of esters?
ESTERS
- TETRACAINE/AMETHOCAINE is used as topical gel
- procaine, coccaine, benzocaine
examples of amides?
AMIDES-we like these more
- lidocaine/lignocaine
- bupivicaine and levobupivicaine
- prilocaine
- mepicaine
- ropivicaine
EMLA 50:50 mix is prilocaine and lidocaine
Give the doses of lidocaine/lignocaine with and without adrenaline.
What are the features of lidocaine?
lidocaine/lignocaine is quick acting and short duration
- 3mg/kg alone
- 7mg/kg with adrenaline
Give the doses of levobupivicaine/bupivicaine with and without adrenaline.
What are the features of bupivicaine?
levobupivicaine/bupivicaine is longer acting so is not affected by adrenaline
- 2mg/kg alone
- 2mg/kg with adrenaline
Give the doses of prilocaine with and without adrenaline.
Prilocaine
- 6mg/kg alone
- 9mg/kg with adrenaline
When ca you not give local anaesthetic with adrenaline?
Cant give adrenaline with LA when risk of ischema (e.g. ring block risks ischemia to hand)
What are symptoms of LA overdose?
LA overdose
- neuro problems first (ringing ears, tingling mouth, confusion, convulsions)
- followed by cardio (HTN, tachycardia, then hypotensive and bradycardia, heart block and VF)
Management of LA overdose?
LA overdose
- ABCDEG approach
- call for help (crash trolley) and stop surgeon
- 100% oxygen, IV fluids
- ONLY THEN CAN YOU GIVE intra lipid 1.5ml/kg
Name the ASA grades
• Normal fit healthy patient
• 70 year old patient on ICU with non-survivable brain injury for insertion of ICP monitor
• Well controlled asthma or hypertension
• Moderately obese diabetic patient on insulin
20 year old patient with severe head injury from
• Normal fit healthy patient - ASA 1
• 70 year old patient on ICU with non-survivable brain injury for insertion of ICP monitor - ASA 5
• Well controlled asthma or hypertension - ASA 2
• Moderately obese diabetic patient on insulin - ASA 3
20 year old patient with severe head injury from RTA - ASA 4
For intermediate surgery, when would you check kidney function and ECG?
Intermediate
- check ECG and kidney function in ASA 3/4
- also check in ASA 2 if risk of AKI or CVD/diabetes
Reasons for delayed gastric emptying?
What would you do for these surgical patients?
Delayed gastric emptying Anatomical (pyloric stenosis) Obstructive (pregnancy, obesity) Metabolic (diabetes, end stage renal failure) Trauma (RTA, head injury) Anxiety High fat content
- could do RSI to reduce risk of aspiration
- could prolong fasting (e.g.if had high fat content foods)
What do you do for resuscitation fluids?
- Initial bolus of 500ml NaCl 0.9% up to 2000ml - then seek expert advice
- (weight based potassium prescriptions should be rounded to the nearest common fluid available - do not directly manually add potassium to fluids as this can be dangerous)
How do you draw brachial plexus
Brachiel plexus is from C5-T1 'rugby teams drink cold beer' roots trunks divisions cords branches 1. draw 3 Ys (middle one opposite) 2. draw 2 Es 3. draw X between C6 and C7 4. label nerves (most alcoholics must really urinate) musculocutaneous, axially, median, radial, ulna
Which nerve effects flexion of elbow?
musculocutaneous
which nerve effects abduction of arm from 15-90 degrees?
axillary
When using USS, explain and give examples of
a) hyperechoic
b) anechoic
c) isoechoic
Hyperechoic-substance that reflect anything (white)-BONE
Anechoic-doesn’t absorb USS (black) VESSELS
Isoechoic- muscel/tendons
Explain how to work USS machine?
- Turn on
- Select transduction
○ Deeper structure(abdo/obsetric)=low frequency (less sharp, less resolution)
○ Superficial structure (e.g. blood vessels/muscles)=high frequency - Adjust the depth (knob or slider)
○ 3/4 screen depth (1/4 below the anatomy of interest) - Adjust gain
○ (make things more white, less black) - Optional dopler
Towards=red
Away=blue
Explain a fast scan (Focussed Assessment with Sonography for Trauma)
• Subcostal (pericardial) • RUQ (liver, morrisons pouch, pleural, diaphragm) • LUQ (spleen, kidney, pleural, diaphragm) • Pelvic Is there any free fluid/air in: -Pericardial cavity -Peritoneal cavity -Pleural cavity
When would you use rapid sequence induction?
Risk of slowed gastric emptying/aspiration
- Emergency surgery/inadequate fasting (status epilepticus)
- Metabolic: diabetes, end stage renal failure
- Mechanical: obesity, pregnancy/GORD/ ludwigs angina (need to secure airway ASAP)
- Trauma: RTA, head injury
- Others: high fat content, anxiety
describe rapid sequence induction
RAPID SEQUENCE INDUCTION
- Pre-oxygenation (3 mins of 5 full vital capacity breaths)
- this will replace functional residual capacity with oxygen
- reducing apnoeas when knocked out - DRUGS (1 induction agent+1 muscle relaxant
- induction: propofol or thiopentone
- muscle relaxant: suxamethonium or rocuronium
Technique:
- cricoid pressure (Sellick manœuvre)
- no ventilation (risk of aspirate)
- remove cricoid after confirmation of tube position (EtCO2) and other signs (equal expansion/misting/chest auscultation)
How many ‘pops’ is a spinal?
Where does a spinal go?
What do they have to penetrate?
- Spinal has 2 pops
- Spinals go in the subarachoid space (deeper)
- Skin -> SC fat -> supraspinous ligament -> infraspinous ligament -> ligamentum flavum (1st pop) -> epidural space -> dura mater (2nd pop) -> arachnoid mater -> subarachnoid space
Where does a epidural go? What do they have to penetrate?
- Epidurals have 1 pop
- Epidurals go the the epidural space
- Skin -> SC fat -> supraspinous ligament -> infraspinous ligament -> ligamentum flavum -> epidural space
difference between epidural and spinal?
Spinal-nothing left in
Epidural-catheter left in
Spinal more profound block (effects sensation and proprioception more) and more drop in BP (dont do if cant compensate)
Epidural-bigger needle (headache if go too far)
- can often move there legs (less motor effect)
- opiod and LA (spinal just LA)
Where does the spinal cord end? where should you put the spinal?
spinal cord ends L1
put spinal in L3/L4 to be safe. No lower than
In terms of a V/Q missmatch, what is a shunt? Example?
Shunt is good perfusion but no ventilation (e.g. pnuemonia, COPD, foreign body obstruction, anaphylaxis)
In terms of a V/Q missmatch, what is deadspace? Examples?
Deadspace is good ventilation but no perfusion (e.g. PE, shock, heart failure)
Name some common side effects of GA?
Name some more uncommon side effects of GA?
Common side effects
- sore throat
- drowsiness/confusion/memory problems
- damage to lips or tounge
- PONV
- itching
- aching
- pain and bruising
Rarer side effects
- chest infection
- damage to teeth
- existing medical condition worsening (pressure on body)
What are the 4 CEPOD classification
- Immediate/emergency
E.g. Repair of ruptured AAA, Fasciotomy
2.Urgent (6 hours)
-potentially life or limb threatening conditions
E.g. Debridement plus fixation of fracture,abdo perforation
3.Expeded (24-48 hours)
-Early treatment, not an immediate threat to life or limb
E.g. Repair of tendon or nerve injuriesor Excision of tumour with potential to bleed or obstruct
- Elective
- elective cholesustectomy, elective AAA repair
