Anaesthetics Flashcards
What factors make a patient high-risk for surgery
Age Severity of surgical disease Severity of proposed procedure Medical co-morbidities Exercise tolerance
Why is exercise tolerance important
Inflammatory stress response after surgery leads to an increased oxygen demand and therefore an increased cardiac output
What is a good way to assess physiological reserve
Can you climb a flight of stairs without getting breathless (consider alternate questions in those with joint pathology)
Hypertension target for surgery
> 180/100
When to do an ECG before surgery
> 55yrs - risk of silent MI
Anyone with cardiac signs/symptoms
Hypertension
Diabetes
Blood pressure medicines advice pre-operative
Continue all and take on day of surgery - especially beta blockers
ACE inhibitors/ARB should NOT be taken on day of surgery
What type of surgery should respiratory investigations be carried out
Upper abdominal
When is CXR require pre-operatively
Clinical indication or having thoracic surgery
How should hiatus hernia patients be managed for anaesthesia
PPI/H2 receptor antagonist and metoclopramide
Important LFTs pre-operatively
Clotting screen!
How should diabetic patients be managed pre-operatively
2-hourly blood glucose, ECG and U&Es. Scheduled at start of list (to minimize fasting)
How long prior to surgery can solids be taken
6 hours
How long prior to surgery can fluids be taken
2 hours
How long prior to surgery can breast milk be taken
4 hours
List medications that should be stopped prior to surgery
Aspirin Warfarin Clopidogrel ACEi/ARB OCP HRT MAOIs Sulfonylureas
Which drugs should be stopped 4 weeks prior to surgery
OCP
HRT
Which drugs should be stopped 1 week before surgery
Aspirin
Clopidogrel
Which drugs should be stopped 5 days before surgery
Warfarin
may required LMWH as replacement
Which drugs should be omitted on the day of surgery
ACEi
ARB
Sulfonylureas
How should airway be managed in suspected c-spine injury
Head in neutral position
Jaw thrust ONLY
Main causes of hypotension post-operatively
Residual anaesthesia
Hypovolaemia
Sepsis
What is the first line management of hypotension
Oxygen therapy and IV fluid challenge
Main causes of hypertension post-operatively
Pain Anxiety CO2 retention Pre-existing hypertension Withdrawal from anti-hypertensives (omission for surgery)
What obs are measured post-operatively
Resp rate Pulse Oxygen sats Blood pressure Urine output Temperature Mental sate Pain
Causes of hypoxaemia post-operatively
Airway obstruction Respiratory depression Respiratory faialure Hypostatic pneumonia Pulmonary atelectasis Aspiration pneumonia Pulmonary embolism
Causes of oliguria post-operatively
Dehydration/hypovolaemia
AKI/acute renal failure
Urinary retention/obstruction
Causes of confusion post-operatively
Hypoxaemia
Alcohol withdrawal
Opiods/sedative drugs
Sepsis/infection
What might cause pain after surgery
Pressure sores
Risk factors for post-operative nausea and vomiting
Pain/anxiety Young Female Breast/bowel/uterus/middle ear surgery Use of opiods drugs History of pprevious post-op N&V History of motion sickness Dehydration
Name some groups of drugs used to treat post-operative nausea and vomiting
Antihistamines
5-hydroxytryptamine antagonists
Dopamine antagonist
Steroids
Antihistamines used to treat nausea
Cyclizine
5-hydroxytryptamine antagonists used to treat nausea (serotonin antagonist)
Ondansetron
Dopamine antagonists used to treat nausea
Metoclopramide, prochlorperazine
Steroids used to treat nausea
Dexamethasone (single dose only)
Guideline for treating post-operative nausea
- Cyclizine
- If no response in 30 mins give 5-HT antagonist
- Dopamine antagonist if no response in 30 minutes
Systemic analgesic ladder
Simple analgesia
NSAID
Weak opiod
Strong opiod
How is post operative pain manaed
Reversed analgesic ladder as pain usually starts worse and gets better
Give some examples of simple analgesia
Paracetamol
Give examples of NSAIDs
ibuprofen
diclofenac
keterolac
Give examples of weak opiods
dihydrocodeine
tramadol
Give examples of strong opiods
Morphine
Diamorphine
Fentanyl
Oxycodone
How does codeine work
Metabolised to morphine in the liver.
25% of people don’t have the enzyme to metabolise codeine and it is ineffective in this population
What are colloids
Fluids containing large suspended molecules such as gelatin which do not leak out of the intravascular compartment and hence act as plasma expanders. Maintain oncotic pressure before blood can be given
Name some crystalloids
Hartmanns, saline, glucose and dextrose saline
Which blood can be given in extreme emergencies
O negative blood
How much to give in resuscitation fluids
Bolus of 500ml crystalloid containing sodium over less than 15 minutes
Routine maintenance fluids
25-30 ml/kg/day water
1 mmol/kg/day sodium, potassium,chloride
50-100g/day glucose
When to consider nasogastric or enteral feeding when giving fluids
If maintenance fluids needed for more than 3 days
What is the average fluid intake of the 70kg male
2-2.5 litres a day
What signs may appear if too much fluid is given
Right heart failure - tachycardia, peripheral oedema, raised JVP
Left heart failure - tachycardia, breathlessness, wheeze, pulmonary oedema
Electrolyte imbalance
What are the changes to the airway in an unconscious patient
Reduced/no protective reflexes
Increased airway obstruction
Absent cough reflex
What are the changes to breathing in an unconscious patient
Respiratory depression
What are the changes to circulation in an unconscious patient
Reduced peripheral vascular tone (BP=COxSVR)
What are the changes to disability in an unconscious patient
Reduced oesophageal sphincter tone & gastric motility
Inability to swallow
Reduced pain response
Reduced corneal reflexes
Decreased ability to regulate body temperature
What are the signs of airway obstruction
Increased respiratory effort tracheal tug intercostal recession cyanosis (later) stridor tachycardia initially leading to a terminal bradycardia cardiac arrest
Signs of apnoea
Absent chest movements
no breath sounds
no evidence of airflow
Signs of respiratory distress
Increased respiratory rate
increased heart rate
signs of CO2 retention (sweating, tremor, increased BP)
abnormal respiratory pattern
What are the basic airway manoeuvres
Head tilt
Chin lift
Jaw thrust
How to manage the airway in a trauma patient
Risk of c-spine injury so ONLY perform jaw thrust! Keep the head and neck isolated
What level of oxygen do patients receive during anaesthesia
Minimum of 30%
Which patients may need several days of oxygen therapy post-operatively
Prolonged abdo/thoracic surgery obese patients sepsis or hypovolaemic shock pre-existing respiratory compromise receiving IV opiods
