Peri-operative Medicine/Anaesthesia Flashcards
(191 cards)
What is Virchows triad
Abnormal blood flow- stasis
Abnormal blood components- hypercoagubility
Abnormal vessel wall- endothelial injury
What are risk factors for VTE?
older age previous VTE smoker malignancy pregnancy recent prolonged immobility
How may a DVT present?
Unilateral calf swelling Tender Painful Low grade pyrexia Pitting oedema 65% are asymptomatic
How do you investigate a possible DVT?
Ultrasound
D-dimer
Wells score
d-dimer is not specific to DVT
Explain the wells score
Each is worth one point Clinical signs of DVT Heart rate > 100bpm Recent surgery or immobilisation Previous PE or DVT Haemoptysis Malignancy Alternative diagnoses less likely than PE
Less than or equal to one- DVT is unlikely and need a D-dimer to exclude
Greater than 1- DVT needs to be confirmed using ultrasound
How would you treat a patient with a confirmed DVT
DOACs, however in some cases vitamin K antagonist. Patients with a provoked DVT will need it for 3 months .
Unprovoked DVT or recurrent DVT may need lifelong anticoagulation
Which drugs need to be stopped pre-op?
CHOW:
Clopidogrel- stop 7 days pre-op
Hypoglycaemics- most sto pped 24 hours before. Metformin stopped the morning of . Sub cut insulin, stopped, reduce dose by 1/3 and omit morning insulin
Oral Contraceptive pill or HRT- stop 4 weeks before
Long term steroids- may be switched to IV to reduce risk of Addisonian crisis
What drugs do you start pre-op
LMWH
TED stockings
Abx prophylaxis
What is the ASA score?
Determine if a patient is healthy enough to tolerate anaesthesia
ASA1: normal, healthy patient
ASA2: A patient with mild systemic disease e.g. obesity, well controlled DM/HTN, smoker
ASA3: A patient with severe systemic disease e.g. poorly controlled DM,HTN, COPD morbid obesity,
ASA4: A patient with a severe systemic disease that is a constant threat to life e.g. recent MI, TIA, sepsis, ESRD not undergoing regular dialysis
ASA5: Moribund patient, not expected to survive without the op e.g.ruptured AAA, massive trauma
ASA5: A declared braindead patient who’s organs are being donated
What investigations would you do pre-op?
Bloods- FBC/ U+Es/LFTs/ condition specific e.g.TFTs, HbA1c, clotting
ECG- if hx of cardiac disease or major surgery
Spirometry e.g. COPD and asthma patients
Urinanalysis- identify a UTI
MRSA swab
Briefly outline the WHO pain ladder
Simple analgesics: paracetamol–> NSAIDS
Weak Opiates: codeine and tramadol
Strong opiates: fentanyl and morphine
What are the two types of fluids available?
Crystalloid, colloid.
For each patient, what should you consider when prescribing fluids?
Age, weight, cardiac function, co-morbidities. Reason for admission. Electrolytes recently given?
What is the aim of maintenance fluids?
To hydrate - all distribute into all compartments.
What is the aim of resuscitation fluids?
To improve tissue perfusion - will stay in intravascular space.
What are the 5R’s of fluid prescribing?
Resuscitation, Routine maintencence, Replacement, Redistribution, Reassess.
A patient is depleted of fluids. What signs should you look for when assessing fluid status?
Dry mucous membranes, reduced skin turgor, decreased urine output, orthostatic hypotension, increased cap refill time, tachycardia, hypotension.
A patient is overloaded with fluids. What signs should you look for when assessing fluid status?
Raised JVP, sacral odema, peripheral oedema, pulmonary oedema.
In what circumstances may you replace ongoing losses?
Third space losses (i.e. fluid losses into spaces that are not visible e.g. bowel lumen in bowel obstruction). In diuresis. When pt is tachypnoeic or febrile. When pt is losing electrolyte-rich fluid.
In what conditions are electrolyte imbalances common?
Dehydration - high urea:creatine ratio.
Vomiting - low K+, low Cl-, alkalosis,
Diarrhoea - low K+ and acidosis.
What fluids would you prescribe for patient with sepsis?
Fluids that get into intravascular space
What is the 4, 2, 1 rule regarding paediatric fluid maintenance?
First 10kg = 4ml/kg/hr. Next 10kg = 2ml/kg/hr. Thereafter = 1ml/kg/hr.
Why is hyponatremia so important to correct?
Can lead to transient or permanent brain damage due to cerebral oedema.
How do you manage a patient on long term oral steroids in the peri-operative period?
Switch oral steroids to 50-100mg IV hydrocortisone
If any associated hypotension, fludrocortisone can be added
Minor ops- oral prednisolone can be restarted immediately post op. If surgery is major than they may require IV hydrocortisone for up to 72 hours post op