Anaesthetics/peri-operative care Flashcards
Define anaesthesia
An-aesthesis- loss of sensation
What is the anaesthetics triad?
Analgesia (comfortable)
Hypnosis (asleep)
Muscle relaxation (immobile)
What is the purpose of GA?
Reversible loss of consciousness
What is the purpose of regional anaesthesia and types?
Numbs an area of the body
- local infiltration
-nerve/plexus blocks
- central neuraxial blocks
Explain triad - asleep
Propofol - IV induction agents causing sleep in arm-brain circulating time
Sevoflurane - volatile agents are dispensed using vapourisers
Explain triad - immobile
Atracurium
Rocuronium
Suxamethonium
…muscle relaxants
Explain triad - comfortable
Opiates, local anaesthesia
What are the phases of GA?
Induction
Maintenance
Emergence
Recovery
What are the minimum monitoring standards?
Capnography
Pulse oximetry
ECG
BP
Agent analyser
Temperature
What are the types of induction agents?
IV Propofol
Thipentone sodium
Ketamine
Volatile agents - sevoflurane
What are two types of muscle relaxants?
Depolarising muscle relaxants - succinylcholine
Non depolarising muscle relaxants - atracurium, rocuronium
What are the two types of intubation?
Endotracheal intubation - emergencies, with ‘full stomach’, long duration surgery
Larngeal mask airways/i gel - elective, well fasted, short duration surgery
Describe maintenance
IV and inhalation
Fluid management
Other essential drugs - abx, insulin
Drugs ro prevent post op n+v
Describe waking up
Wears off - suxamethonium, mivacurium
Withdraw - TIVA, volatiles
Reverse - antagonising non depolarising muscle relaxants - neostigmine + glycopyrrolate
Antagonise - opiates, BZDs (Naloxone)
Stimulate - not often used, doxapram speeds awakening
Describe recovery
Monitoring - EWS, fluid balance
Airway
Side effects of GA - sedation, PONV, shivering
Side effects of regional anaesthesia - monitoring sensory snd motor block levels and hypotension
Observing for complications - bleeding, vascular supply
Post op pain management
Fit for ward tests
Describe follow up
In clinic
Define sepsis
Life threatening organ dysfunction due to dysregulated host response to infection
How is sepsis screened?
qSOFA:
RR>22
Altered mental status
Systolic BP < 100 mmHg
OR
SOFA
What are the red flags for sepsis?
Responds only to voice/pain
Acute confusional state
Systolic BP less than 90 (or drop more than 40 from normal)
Heart rate more than 130
Resp rate more than 25
Needs oxygen for Sp02 more than 90%
Non blanching rash, motttled, ashen, cryanotic
Not passed urine in last 18 hours or output less than 0.5ml/kg/hr
Lactate more than 2mmol/l
Recent chemo
Define septic shock
Sepsis + persistent hypotension or lactate more than 2 after appropriate fluid resuscitation
What is sepsis 6?
Give 02 (so more fhan 94%)
Blood culture
Give iv antibiotics
Give fluid
Measure lactate
Measure urine output
How do you manage sepsis?
Sepsis 6
Identify source
Vasopressors - adrenaline
Organ support
How are deteriorating patients identified?
NEWS
Why is nutrition of surgical candidates important and how is it measured?
Surgery causes physiological stress - hyper metabolic state and catabolic state
Underlying disease reduces their nutritional reserves
Malnourished patients increased risk of post op complications - reduced wound healing, increased infection and skin breakdown
…MUST tool and then expert input from registered dietitian (BMI)
What is the hierarchy of feeding?
If unable to eat sufficient calories - oral nutritional supplements
If unable to take sufficient calories orally or dysfunctional swallow - NGT
If oesophagus blocked/dysfunctions - Gastrostomy feeding
If stomach inaccessible or outflow obstruction - jejunal feeding
If jerjunum inaccesinle or intestinal failure - parenteral nutrition
What are some things to consider in terms of the timing of parenteral nutrition?
SNAP
Sepsis - must be corrected first
Nutrition - after infection corrected give nutritional support
Anatomy - of patients GI tract ro plan surgery
Procedure - once ready
What does a low serum albumen reflect?
Chronic inflammation, protein losing enteropathy, Proteinuria, hepatic dysfunction…not reflect malnutrition
How is intra operative nutrition managed?
Reduction in ‘Nil By Mouth’ times (clear fluids up to 2 hours pre-surgery)
Pre-operative carbohydrate loading
Minimally invasive surgery
Minimising the use of drains and nasogastric tubes
Rapid reintroduction of feeding post-operatively
Early mobilisation
When do you begin enteral diet post surgery?
Within 24 hours
How do you manage nutrition in special circumstances?
Entero-cutaneous fistula - The modern nutritional management of ECF is dependent upon the level of the fistula*. High fistula (jejunal) may need support with enteral or parenteral nutrition, whilst low fistulae (ileum/colon) can be treated with low fibre diet. Thus imaging is often critical to deciding how the fistula should be managed effectively.
High output stoma - depends on length of bowel to stoma
How do you take a history of pre operative assessment?
Why and what procedure, which side
Any abnormal anatomy
CVS disease - hypertension and exercise tolerance, any syncopal episodes or Orthopnea, chest pain
Respiratory disease - oxygenation and ventilation - cough and any obstructive sleep apnoea
Renal disease - baseline function
Endocrine disease - DM and thyroid function
GORD - possible aspiration of gastric contents
Pregnancy
Sickle cell
Past surgical history - any problems
Past anaesthetic history - what, type, any post op N+V
Drug history and drug and non drug allergies
Family hsuorry - malignant hyperthermia
Social history - smoking, alcohol, recreational drug use, language spoken, living situation
Which examinations are required for a pre op assessment?
General - CV, resp and abdo
Airway - mallampati score
…given an ASA grade (1-5) -> morality risk increases
Which blood test are require for pre op assessment?
FBC - anaemia, thrombocytopenia
U and E - renal function for fluid management and analgesia (morphine not in CKD)
LFT - mediation choice
Conditions specific - HbA1C or thyroid function
Clotting screen - iatrogenic, inherited or liver impairment
Group and save - blood group +/- cross match - mixes patients and donors blood - if blood loss expected
Which investigations are required for pre operative assessment?
ECG
Echo
…any ischaemia
Spirometry
Plain chest x day
Urinalysis - UTI
MRSA swab
Cardiopulmonary exercise testing - whether need higher level care
why are fluids prescribed?
resuscitation
maintenance
replacement
how is fluid divided in the body?
around 2/3 of body weight is water…2/3 of this distributes into intracellular fluid and 1/3 extracellular.
1/5 of the extra is intravascular and 4/5 interstitium
how does fluid management differ in a septic patient?
vascular permeability increases…increased hydrostatic pressure and reduced oncotic…fluid enters interstitium…so more fluid required to maintain intravascular volume
how much fluid is balanced from equal input and output?
2.5L (1.5L from urine…others from respiration, sweating and faeces)
how does a patient return clinically imrpove in terms of fluid balance?
vascular permeability returns to baseline state … urinate excess fluid required to maintain intravascular volume
what clinical features indicate a fluid depleted patient?
dry mucous membranes and reduced skin turgor
decreased urine output
orthostatic hypotension
increased CRT
tachycardic
hypotensive
U AND E
what clinical features indicate a fluid overloaded patient?
raised JVP, peripheral or sacral oedema, pulmonary oedema. U AND E
what clinical features indicate a fluid overloaded patient?
raised JVP, peripheral or sacral oedema, pulmonary oedema. U AND E
which electrolytes need balanced?
water, glucose, sodium and potassium
what are the two types of IV fluids?
cystalloids - more widely used, in acute settings and theatres (saline, dextrose, hartmanns)
colloids - high colloid osmotic pressure (but don’t seem to raise intravascular volume faster..) (volplex or gelofusine)
how are fluids mantained?
70kg male:
over 24 hours, 70kg x 25ml/kg/day = 1750 ml of water
70kg x 1mmol/kg/day = 70mmol of K
70 x 1 = 70mmol of Na
50g a day of glucose
1st bag:
500mL of 0.9% saline with 20mmol/L K+ to be run over 8 hours….all Na, around 1/3 of K+ and quarter of water
2nd bag:
1L of 5% dextrose with 20mmol/L K+ over 8 hours…now have 2/3 of K, another half water and glucose
3rd bag:
500mL of 5% dextrose with 20mmol/L k over 8 hours…last 1/3 of K and last 1/4 of water and last 1/4 of glucose
how do you correct a fluid deficit?
if mildly dehydrated…based on clinical estimate and not calculated
if urine output less than 0.5ml/kg/hr…give fluid challenge (250 or 500ml over 15-30 minutes (if 120 kg man may need more than 500ml, but if frail and elderly may need 250)
what other things do you need to consider in regard to fluid loss?
vomit
diarrhoea
fluid losses…bowel lumen in bowel obstruction or retroperitoneum in pancreatitis
what does rhesus D mean?
the presence of absence of rhesus D antigens on red blood cells…mostly rhesus postitve
a rhesus negative patient will make a rhesus D antibody if they are given rhesus positive blood…does not matter as can not attack own red blood cells if not have Rh on them
in pregnancy - if baby is rh pos, she develops anitbodies
and has second child who is rh pos, the anti D antibodies will cross the placenta during pregnancy and bind to foetus RhD antigens …destroys its own red blood cells…haemolytic disease of the newborn
which blood group is the universal donor, and which is the universal acceptor?
donor = 0 neg, can be give to anyone even rh
acceptor = AB pos, give this recipient any time of donor blood
give 2 examples of groups requiring irradiated blood groups
patients with hodgkin’s lymphoma
those recieving blood from first or second degree family members
give 2 examples of when packed red blood cells are required
acute blood loss
chronic anaemia
give 3 examples of when platelets may be required
haemorrhagic shock in trauma patient
profound thrombocytopenia
pre op level low
give 2 examples of when fresh frozen plasma may be required
DIC
any haemorrhage secondary to liver disease
massive haemorrhage
give 3 examples of when cryoprecipitate may be required
DIC with low fibrinogen
vwe disease
massive haemorrhage
what should all operative patients be informed of in advance?
stop eating 6 hours before
stop dairy products 6 hours before
stop clear fluids 2 hours before
drugs to stop - CHOW - clopidogre(7 days), hypoglycaemic agents (subcut to IV insulin), COCP/HRT (4 weeks), warfarin (5 days, INR <1.5, if high given PO vit K). steroids become IV due to risk of addisonian crisis
which drugs need to be started for surgery?
LMWH (UP TO 28 DAYS AFTER)
TED stocking excepet in peripheral vascular disease
antibiotic prophylaxis
explain dextrose
5% dextrose solution
across all body compartments
only 7% of fluid stays in intravascular space…has no role in fluid resuscitation
but maintains hydration and can be given alongside K
explain normal saline
0.9% NaCl solution
into intravascular(25%) and intersitial space …fluid resuscitiation and maintenance
can resulting hypercholraemic acidosis can not be used alone…can also add K
explain hartmann’s
contains Na, K, Cl,HCO3 as lactate, Ca and water
into intra vascular and intersititial spaces
most similar to plasma
wht are some complications of blood transfusions?
clotting abnormalities
electrolyte abnormalities -
hypocalcaemia-chelation of calcium by calcium binding agent, hyperkalaemia- partial haemolysis of rbc’s
hypothermia - blood products are thawed from frozen
acute haemolytic reactions
transfusion associated circulatory overload
transfusion related acute lung injury
mild allergic reactions
non haemolytic febrile reactions
anaphylaxis
infective shcok
what are the clinical features of an acute haemolytic reaction?
urticaria, hypotension, fever,
positive direct antiglobulin test
what are some delayed tranfusion complications?
infection - hepatitis, HIV, syphilis, malaria
graft v host disease
iron overload
what are the 7 most likely sources of infecgtion for spesis?
chest infection
cut
catheter - uti
collections - abdomen
calves - DVT
cannula
central line
define sespsi shock
sepsis with hypotension, despite adequate fluid resuscitation or requiring use of inotropic agents to maintain normal systolic pressure
what are the three types of post op haemorrahge?
primary bleeding - within intra op
reactive - within 24 hours of operation (from a ligature that slips or a missed vessel)
secondary - 7-10 days post op (due to erosion of vessel from a spreading infection)
what are the clinical features of post op haemorrhage and how is it assessed?
tachycardic, dizzy, agitation, visible bleeding, decreased urine output, raised resp rate, airway obstruction (as pre tracheal fascia will only extend so far)
class 1 - 4
how is intra op haemorrhage managed?
urgent fluid rescusitiation
what are the three main types of delirium?
hypoactive delirium - lethargy, reduced motor activity
hyperactive - agitation, increased motor activity
mixed agitation - flutuations
what is the difference between delirium and dementia?
acute, fluctuating, poor attention, common delusions - delirium
insidious, constant, good attention, less common delusions - dementia
what are the risk factors for delirium?
over 65
multiple co morbidities
underlying dementia
renal impairment
male
sensory impairment
what are the common causes of delirium?
hypoxia
infection
drug induced - benzodiazepines, diuretics, opiods, steroids
drug withdrawal - alcohol
dehydration
pain
constipation or urinary retention
electrolyte imbalance
how can you assess delirium?
an abbreviated mental state
mini mental state exam
confusional assessment method
what is the 1st line sedative that can be used in delirium?
haloperidol
what are two medical complications of post op n+v?
aspirational pneumonia and metabolic alkalosis
which patient factors increases the risk of post op n+v?
female
young
previous PONV
opiod analgesia
non smoker
which surgical factors increases the risk of post op n+v?
intra abdominal laproscopic surgery
IC or middle ear surgery
squint surgery
gynaecological surgery
prolonged op time
poor pain control
which anaesthetic factors increases the risk of post op n+v?
opiate or spinal analgesia
inhalation agents
prolonged anaesthetic time
intraop dehydration or bleeding
overuse of bag and mask ventilation
how does vomit and nausea work?
the vomiting centre recieves input from the chemoreceptor trigger zone, GI tract, vestibular ystsem and higher cortical structures (sight, smell, pain)
if the stimuli are sufficient, it acts on the diaphragm, stomach and abdominal musculature..vomiting
which neurotransmitters are involved in nausea and therefore targeted in anti emetic medication?
chemoreceptor trigger zone - dopamine and 5HT3 receptors
vestibular apparatus - Ach and histamine receptors
GI tract - dopamine receptors
vomiting centre - histamine and 5HT3 receptors
what are some causes of post op nausea but not due to operation?
infection
post op ileus
bowel obstruction
hyperuricaemia
DKA
antibiotics
opioids
raised ICP
anxiety
how do you manage postnop nausea?
prophylactic - less opiate use and volatile gases, avoiding spinal anaethetics, antiemetic therapy, dexamethasone with anaesthetic
conservative - fluid hydration, analgesia, NG tube insertion
pharmaceutical - impaired gastric empyting - metoclopramide, domperidone, hyoscine. - imbalances - metocloperamide, opiod induced - odanestron or cyclizine
what are the most common sources of infection and antibiotics given?
day 1-2- resp (- co amoxiclav)
3-5 - resp or urinary - (urinary - co amoxiclav or nitrofurantoin)
5-7 - surgical site or abscess
any day - iv or central lines (flucloxacillin and replace line)
what are the clinical features of pain?
tachycardia, tachypnoea,hypertension, sweating, flushing
describe the WHO analgesia ladder
non opiods such as paracetamol or nsaids
opiates - codeine
strong opaite - morphine, fentanyl
how do nsaids work?
inhibiting the synthesis of prostaglandins so reducing inflammatory response causeing pain
what are the side effects of nsaids?
I-GRAB
interact with warfarin
gastric ulceration - PPI
renal impairment
asthma sensitivity
bleeding risk
what are the side effects of opiates?
constipation
nausea
sedation
confusion
resp depression
pruritus
tolerance and dependence
what is patient controlled analgesia?
more intense or immediate analgesia…use of IV pumps that provide a bolus dose of an analgesia when patient presses button
what are the possible cardiorespiratory complications?
post op atelectasis
post op pneumonia
acute resp distress syndrome
fat embolism
venous thromboembolism
what are the possible GI complications?
incisional hernia, bowel adhesions, post op ileus, post op constipation, anastomotic leak
what are the possible urinary complications?
UTI, urinary retention, AKI
what are the possible endocrine complications?
hyperkalaemia, hyponatraemia, hypoglycaemia, hypernatremia, hypokalaemia
what are the possible skin complications?
keloids, surgical site infection, wound dehiscence
describe airway anatomy
nasopharynx - base of skull to upper border of soft palate
oropharynx - soft palate to epiglottis
laryngopharynx - oropharynx (epiglottis) to oesophagus (cricoid cartilage)
larynx
laryngeal inlet - aryepiglottic fold forms free upper border of quadrangular membrane
thyroid cartilage
false vocal cords forms lower border of quadrangular membrane
cricothyroid membrane (true vocal cords are free upper border of this
cricoid cartilage
cricotracheal membrane
laryngeal division:
supraglottis - epiglottis and false vc
glottis - below false, includes true
infraglottis - below true
what route does intubation take?
oral cavity
posterior 1/3 of tongue
oropharynx
supraglottis
epiglottis and aryepiglottic folds
false vocal cords
true vocal cords (glottis)
infraglottis
trachea
which part of the airway is important in intubation?
The vallecula is an important reference landmark used during intubation of the trachea. The procedure requires the blade-tip of a Macintosh-style laryngoscope to be placed as far as possible into the vallecula in order to facilitate directly visualizing the glottis.
which position should a patient assume to allow a patent airway and how is this achieved?
‘sniffing the morning air’
- head tilt and chin rise
what is the main difference between nasopharngeal/i gel and endotracheal tube is?
in igel and ng - not airay protected but patent..stomach contents can enter trachea
in endo - paralysed vocal cords and airway is protected
which two ways can anaesthetic be administered?
volatile gases via lung
IV - propofol (gaba), ketamine(NMDA)
what are guedel’s signs?
stage 1 - analgesia and conscious
stage 2 - unconscious, breathing erratic
stage 3 - surgical anaesthesia, with four levels
stage 4 - resp paralysis and death
how are volatile gases potency described?
volatile anaesthetic potency - minimum alveolar conc…at which 50% of patients fail to move to surgical stimulus
- affected by…
- age (high in infants)
- hyperthermia (increased)
- pregnancy (increased)
- alcoholism (increased)
- sedatives (decreased)
- opioids (decreased)
describe the mechanism of action of anaesthetics - except ketamine, Xe and N2o?
bind to GABA receptors, ligand gated ion channels open and increased cl- conductance…inhibitory transmitter
results in hyperpolarisation, no AP
how are IV anaesthetic potencies described?
the plasma concentration to achieve a specific end point - eg: loss of eyelash reflex
what is used in wound analgesia?
bupivacane - blocks small myelinated afferent nerves
look at lung volumes
what are the different ways 02 can be administered?
humified air - low flow, variable 02 delivery:
- face mask
- nasal prongs
high airflow/fixed o2 entrainment
- venturi mask
- high flow nasal o2
- non rebreathing bag w/ resevoir bag
how do you size guedal airway?
tip of earlobe to tip of nose
how can the difficulty of intubation be predicted?
thyromental distance - want it to be big
see notes on oxygen extraction!
what is preoxygenation and what is its purpose?
apnoea hypoxia time is 1.4 minutes
to 9 mins
how does preoxygenation vary?
obesity and children - may be only a few seconds - see graph
where is the laryngeal mask airway inserted?(i gel)
- tube towards patient
- above glottis, in layngopharynx
- posterior surface is where exchnage occurs
- inflate cuff and attach to 02
whaere is the endotracheal inserted?
- with laryngoscope
- lift epiglottis to see vocal cords, put tip velacula to help
- insert past vocal cords, between two black lines on tube
- blow up balloon and add 02
which order do you give medications?
propofol then paralytic
how is ventilation confirmed?
chest regular
regular end title co2 waves
when does the epidural space continue until?
filum terminale
where is spinal anaesthesia usually inserted and which order of ligaments does it pass through?
L4/5 - upper border of iliac crests
skin - subcutaneous - supraspinous - interspinous - lig flavum - epiderum space - supdural space - subarachnoid space
how can you tell you have reached correct space for the spinal anaesthesia?
csf comes out - subarachnoid space and then insert single shot
how far does spinal anaesthesia travel?
T4
where can epidural be inserted, to what space and what is its purpose?
any level - cervical to sacral-coccygeal membrane
insert catheter to give drugs
into epidural space
how do you know you have inserted needle into epidural space?
after lig flavum - gives way
‘loss of resistance’ technique
what are two other differences of epidural versus spinal?
epidural - slower onset and wider needle in comparison to spinal
define the indications of neuroaxial blocks (spinal and epidural)
surgery below level of the umbilicus
give 3 benefits of neuroaxial blocks
avoids complications of GA
decreases risk of thrombosis and bleeding
decreased cog decline
what are the absolute and relative contraindications of neuroaxial blocks?
absolute - patient refusal, infection at site, uncorrected hypovolaemia, allergy, increased ICP
relative - coagulopathy, sepsis, fixed CO, indeterminate neurological disease
what are the minor complications of neuroaxial blocks?
n + v
hypotension, hearing issues
shivery, itches
urinary retention
what are the moderate complications of neuroaxial blocks?
failure
postdural puncture headache (risk increases if bigger needle)
transient nerve injury
where is spinal anaesthesia usually inserted and which order of ligaments does it pass through?
L4/5 - upper border of iliac crests
skin - subcutaneous - supraspinous - interspinous - lig flavum - epidural space - subdural space - subarachnoid space
what are the major complications of neuroaxial blocks?
infection, meningitis
cauda equina syndrome
haematoma
total spinal anaesthesia (into wrong space)
permanent nerve injury/paralysis
death
what are the indications of an ABG?
- if sick
- ventilated
- hypercapnaeic resp failure
- septic -> LACTATE
- high FiO2
what are the normal values of an ABG?
pH - 7.35-7.45
pO2 - more than 10Kpa
pCO2 - 4.5-6Kpa
sats >94%
base excess +2->-2
HCO3 22-28
lactate <2mmol
electrolyes/hb
glucose
what are the causes for acidosis found on ABG?
CO2 high from resp failure
lactate
other acids - from DKA, methanol poisoning, salicylate poisioning, sepsis
loss of HCO3-
what are the causes for alkalosis found on ABG?
hyperventilation
where is ABG taken from?
radial or femoral artery
what is mixed respiratory and metabolic alkalemic?
high hco3 with respiratory alkalosis
low co2 and not high hco3 in alkalaemia
what is mixed respiratory and metabolic acidosis?
low hco3 with respiratory acidosis
not high co2 and not low hco3 acidaemia
what are some common causes of type 1 resp failure?
pneumonia, PE, pulmonary oedema, acute asthma, ARDS, COPD
how is type 1 resp failure treated
supplementary o2 and correction of underlying cause
what are some common causes of type 2 respiratory failure?
COPD, kyphoscoliosis, opiate, neuromuscular disorder, inhaled foreign body
how is type 2 resp failure treated?
measures aimed to improve ventilation
what is the anion gap?
cations - anions
helps establish cause of metaboliv acidosis
if raised - indicates presence of unmeasured anions - lactate, salicylate
what are some causes of metabolic acidosis?
with raised anion gap:
lactic acidosis
keto acidosis
renal failure
poisoning (aspirin, methanol, ethylene glycol)
with normal anion gap:
renal tubular acidosis, diarrhoea
what are some causes of metabolic alkalosis?
vomiting
diuretic use
conns syndrome
cushings syndrome
milk alkali syndrome
laxative abuse
massive blood transfusion
what are some causes of respiratory acidosis?
drugs
trauma
hypoventilation
polio
tetanus
cardiac arrest
guillian barre syndrome
myasthenia gravis
COPD
asthma
pneumothorax
pulmonary oedema
upper airway obstruction
laryngospasm
bronchopsasm
what are some causes of respiratory alkalosis?
pain
anxiety
fever
psychogenic hyperventilation
hypoxaemic
chronic liver disease
what are some causes of a mixed disorder?
salicylate poisoning
fluid balance
see lecture notes
which order do you give drugs?
- opioid
- propofol
- muscle relaxant
- volatile agents
what is rsi?
rapid sequence induction-
Generally the patient will be manually ventilated for a short period of time before a neuromuscular blocking agent is administered and the patient is intubated. During rapid sequence induction, the person still receives an IV opioid.
what is TIVA?
Total intravenous anesthesia (TIVA) is the use of intravenous agents for induction and maintenance of anesthesia. The most frequently used agent is propofol. Propofol effect is usually augmented with an opioid (e.g., remifentanil
- no difference than when given in canula but have to monitor brain activity as there is no MAC
succinylcholine
temporary paralysis
brief depolatisation at nACHr will activate adjacent sodiu channels due to local spread of charge causes muscle AP…but as maintained depolarisation does not activate channels
atropine
selective muscarinic antagonist that blocks vagal activity to increase HR and speed AV conduction
used for vagal bradycardia to increase HR as anaethetic can cause decreased HR
fentanyl
strong agonist to u receptor(GPCR) ..analgesia and anaesthetic
ondanestron
anti emetic
5HT3 receptor antagonist
peripherally reduces GI secretions and motility
centrally acts to inhibit CTZ
midazolam
buccal or intranasal
benzodiazepine for sedation
increased CL- conudction by binding to gabaa
how do you know you have inserted endotracheal tube to correct place?
vocal cords in between two black lines
how do you check you have correctly ventilated the patient?
chest rises
end tital co2
what does pre oxygenation do to the percentage of gases?
denitrogenation
oxygenation to 100%
when can you not drink and eat before an op?
eat - 6 hours
drink - 2 hours
which two drugs are used for GORD?
H2 antagonist - ranitidine
PPI - omeprazole
how do you operate on someone with alcohol withdrawal?
benzodiazepan
how do you operate on someone with alcohol withdrawal?
benzodiazepine
if platelets are low, which method of anaesthesia is contraindicated?
spinal - as causes haematoma which can compress spinal cord
what is nasopharngeal airway contraindicated in?
neck fracture - tube would enter cranial cavity through cribiform plate
how do you measure sizing for guedel airway?
angle of jaw to corner of mouth
what is ASA?
The ASA (American Society of Anesthesiology) score is a metric to determine if someone is healthy enough to tolerate surgery and anesthesia
1-6
what is mallampti in terms of airway examination?
the ability to see the uvula when opening mouth
what must you do before managing airway in A->E?
call for help
pain
see lecture slides
give 3 examples of spinal anaesthetics
- levobupivacaine
- bupivacaine
- ropivacaine
why are colloids less used?
allergy
ibruprofen
decreased PGE2 synthesis, so decreased neurotransmitter release and decreased pain neuron excitability
- cox1/2 selectivity
opiods
morphine and fentanyl - strong opiod receptor agonist
codeine, buprenorphine and tramadol - moderate opiod receptor agonist
…binds to opioid receptor and reduces transmission of nociceptive impulses
lidocaine, bupivacaine, ropivacaine
blocks sodium channels, less depolarisation and less AP’s
antidepressant
tricyclics
propofol
potentiate GABAa at the GABA receptor
what do you give if blood pressure drops
vasopression - synthetic ADH
what are some of the complications of an epidural?
post dural headache
bleeding
infection
subdural abscess
haematoma
where can you give an epidural vs spinal?
epidural - L2 and below
spinal - any level
what are some key differences of epidural vs spinal?
spine - single injection, works for around 2 hours, can only give bupivaracaine, 1.5-2.0 mls, hypotension and bradycardia immediately
epidural - insert catheter, works for longer, 15-20 mls, hypotension and tachycardia later, sx less profound
what occurs when regional anaesthetic is introduced physiologically?
vasodilation -> hypovolaemic -> decreased venous return -> decreased stroke volume -> decreased BP -> tachycardia
what can bupivicaine be given wtih?
fentanyl, adrenaline and bicarbonate
what are some contraindications of regional anaesthesia?
spinal - cardiac issues such as valve stenosed
both - warfarin, clopidogrel
how do you calculate fluid balance?
adult requires 30mls/kg/day
work out if there are any deficits
add the litres required with the deficit
calculate deficit in electrolytes - especially potassium (can add 0.40 or 0.20 mmol
calculate how much of each electrolyte is needed per day = Na, K, and Cl = 1mmol/kg/day (with how many litres of fluid)
say 2L - 2 x 1L bags changed every 12 hours = 24 hours
which fluids can be used for resuscitation?
NaCl
hartmann’s
plasmolite
How do you take a pre op assessment?
Intended procedure
Past medical history
Past social history and previous anaesthesia
Regular medications
Allergies
Airway assessment
Functional status/exercise tolerance
Reflux/aspiration/POVN risk
Smoking, alcohol, illicit drugs
Weight/height
Fasting status
Vitals/ews
Recent labs
ECG/echo
What does the Guedel airway do?
Provides a patent airway channel between tongue and posterior pharyngeal wall
Inverted for insertion in adults
When is a nasopharyngeal airway useful?
Obstructive sleep apnoea
How does a laryngoscope work?
Lifts epiglottis forced when tip of blade is inserted into mucousal pocket anterior ro epiglottis - called vallecula
A-E assessment
Stridor
Laryngospasm
Oedema
Haematoma
Foreign body
Secretions
What are the pros and cons of crystalloids v colloids?
Crystalloids - cheap, non allergic, no transmission of infection or interference with coagulation. But higher volume needed, short amount of time remaining intravascularly
Colloids - expansions plasma vol better and may be salt sparing, but expensive, risk fo coagulopathy, itch and may exacerbate tissue oedema
What are balanced crystalloids?
Are solutions in which chloride anions are replaced with bicarbonate or buffers to reduce the perturbations in acid-base balance resulting from fluid administration
Raised bicarbonate why?
eg. A raised bicarbonate is seen in chronic type 2 respiratory failure → pH remains normal despite a raised CO2
How does respiratory compensation work?
Metabolic acidosis is sensed by central chemoreceptors (medulla oblongata) and peripheral
chemoreceptors (carotid bodies) o Body responds by increasing depth and rate of respiration → increased excretion of CO2 to
maintain constant pH.
Eg. ‘Kussmaul breathing’ (deep sighing pattern of respiration seen in severe acidosis including DKA) → low pH and a low pCO2 - metabolic acidosis with partial respiratory compensation
How does metabolic compensation work?
In respiratory acidosis eg. CO2 retention in COPD – over period of days, the kidneys retain more
HCO3 in order to correct the pH → low normal pH with a high CO2 and HCO3
