Pre-Operative Assessment and Planning Flashcards
What things should you routinely check for Pre-OP?
OP CHECS
- Operative fitness (e.g. cardiorespiratory co-morbidities)
- Pills (look at any medications they are taking)
- Consent - check patient’s understanding of surgery and associated risks
- History: (MI, asthma, HTN; surgical Hx)
- Eeas of intubation: nek arthritis, dentures, loose teeth
- Clexane (DVT prophylaxis)
- Site: correctly marked?
How should you handle the OCP before surgery?
The COCP should be stopped 4 weeks before major surgery or any surgery to legs, pelvis or surgery that involves long periods of immobilisation.
Can be continued 2 weeks post surgery.
When discontinuation is not possibel (e.g. trauma, forgot), then thromboprophylaxis is mandatory.
How should anti-coagulants be handled peri-operatively?
Risk needs to be balanced between bleeding and thormbosis risk.
Some general advice:
- Warfarin should be stopped 5 days before (except minor surgery), continued 1 day post-OP.
- DOACs should be stopped 2-7 days before depending on renal clearance (except minor surgery)
- Consider bridging therapy with LMWH from -3 to -1 day before surgery
- Anti-platelets (Aspirin/clopidogrel etc) can usually be continued unless risk of bleeding is high.
How should steroid dependent patients be treated pre/peri-operatively?
Patients that are steroid dependent taking prednisolone should have hydrocortisone. Rule of thumb:
- Minor procedure under local: no supplementation required
- Moderate procedure: 50mg hydrocortisone before induction and 25mg every 8h for 24h
- Major surgery: 100mg hydrocortisone before induction and 50mg every 8h for 24h, thereafter halving dose every 24h until maintenance dose reached.
What type of anaesthesia should be avoided in patients that have received anti-coagulatns/anti-platelets?
Avoid epidural, spinal and regional blocks.
This is due to risk of spinal haematoma.
What are common pre-operative blood tests?
Routine:
- FBC: check Hb + WCC
- U&E
- Clotting, GS&Xmatch (in case needs blood products)
- Xmatch 4 units in gastrectomy and 6 units for AAA surgery.
- Glucose
LFTs: if there is Hx of liver disease, EtOH abuse, jaundice.
TFTs (if thyroid disease)
What investigations are used pre-operatively to assess cardiopulmonary function, and when would they be used?
- CXR: Cardiorespiratory disease/symptoms
- Echo: if there is poor LV function, undiagnosed murmurs.
- ECG: HTN, Hx of cardiac disease
- Pulmonary function test: known pulmonary disease
What microbiological investigation is now commonly used before elective surgery?
Nose swab for MRSA.
How long should a patient be NBM prior to surgery?
≥2 hours for clear fluids.
≥6 hours for solids.
What are the pros and cons of bowel prep before surgery?
Pros:
- Bowel prep odten done in left-sided OPs as it makes it easier to operate without faecal contents
Cons:
- Liquid bowel contents more likely to spill
- Electrolyte disturbance/dehydration
- Increased risk of anastomotic leak
What are the commonly used prophylactic ABx regimens before surgery?
Most commonly used in GI surgery and Joint replacement. Other surgeries decide on case by case basis.
Common regimens include:
- GI Surgery: ceftriaxone and metranidazole
- Vascular: Co-amoxiclav
- MRSA +ve: add vancomycin
What do the ASA grades indicate?
- Normal and healthy, minmal EtOH use
- Mild systemic disease without substantial functional limitations
- Severe systemic disease that limits activity
- Systemic disease which is a constant threat to life
- Moribund: not expected to survive 24 hours even with OP
What are the diabetic complications related to surgery?
The diabetes-associated risks are:
- patients are NBM -> insulin/carb mismatch
- Hormonal balance during surgery complicates glucose control
- Association with ischaemic heart disease -> added risk factor
- Increased risk of Post-op infections
Summarise the managment of insulin dependant diabetes in surgery?
Insulin
- Consider stopping the long-acting insulin the night before
- Omit morning insulin dose (unless surgery very late in evening)
- Start sliding scale:
- 5% dextrose + 20mmol K+ at 125mL/hour
- Infusion pump with ActRapid
- Regularly check capillary blood glucose and make adjustments, aiming for 7-11 mM
- Post-OP: continue sliding scale until eating normally
Other practical points:
- Put patient early on the list, make sure anaesthetist knows about
- Minor OPs often don’t require sliding scale
Summarise the managment of non-insulin dependant diabetes throughout surgery?
If glucose control poor treat as IDDM.
Omit oral hypoglycaemics on morning of surgery. Resume once eating
What are the surgery related risks in COPD patients and heavy smokers?
- Basal atalectasis
- Aspiration
- Chest infection
What are the aims of anaesthesia?
- Hypnosis (i.e. not being aware/awake)
- Analgeisa
- Muscle relaxation
What is the difference between depolarising and non-depolarising muscle relaxing agents?
Depolarising muscle relaxants:
- Binds to nAChR thus inhibiting the ability of acetylcholine to bind
- Causes persistent depolarisation and thus generalised muscle contraction prior to paralysis. Can cause fasculculations.
- Fast onset, short duration -> agent of choice for rapid sequenze induction for intubation
- Adverse effects:
- Malignant hypothermia
- Hyperkalaemia
Non-depolarising agents:
- Competitive antagonists of nAChR, thus preventing ACh from bindin
- Can be reversed: Acetylcholinesterase inhibitors (e.g. neostigmine)
What is malignant hyperthermia?
What agent is used to treat it with depolarising muscle relaxants?
Malignant hyperthermia is a rare complication during anaesthesia to suxamethonium or halothane. It is autosomal dominant inheritance pattern, and leads to rise in temperature and masseter spasm.
Treat with Dantrolene IV.
What are commonly used anaesthetic maintenance agents?
Maintenance can be intravenous or ihaled.
Intravenous:
- Target control anaesthesia (TCI): drugs are delivered to achieve specific blood concentrations
- Allows maintenance e.g. with propofol or thiopental
Inhalational: (bad for environment, hence less used now)
- Nitrous Oxide
- Sevoflurane/Desflurane
What medications are often given pre-anaesthesia?
the 7 As:
- Anxiolytics and Amnesia: temezepam
- Analgesics: opioids, paracetamol
- Anti-emetics: metoclopramide 10 mg, ondansetron 4mg
- Antacids: lansoprazole
- Anti-sialogue (reduce saliva production): glycopyrolate
- Antibiotics
What is regional anaesthesia?
When can this be used?
Regional anaesthesia means only part of the body is anaesthetised. Drugs are more localised and side effects therefore usually lower.
This can be used in minor procedures or if unsuitable for general anaesthetic.
Examples include nerve blocks and spinal blocks (spinal or epidural anaesthesia).
What is the difference between spinal and epidural anaesthesia?
Spinal is a one-time shot whereas epidural allows for continuous drug delivery.
Spinal has faster onset, less drug delivery volume and leads to torough anaesthesia. However, it only lasts 2-3 hours,
Epidural takes 20-30 min onset, larger drug delivery volume and may be inadequate in some dermatomes. However, it lasts longer.
Describe the WHO pain ladder.
- Non-opioid:
- Paracetamol
- NSAIDs:
- Ibuprofen (400 mg/6h PO max)
- Diclofenac 50mg PO or 75mg IM
- Weak opidoid + non-opidoid
- Codeine
- Dihydrocodeine
- Tramadol
- Strong opioid + non-opioid
- Morphine: 5-20mg/2h max
- Oxycodon
- Fentanyl
