Surgery - L2 Pre-existing Conditions

Question 1

Elective vs Emergency

Answer 1

Elective: Planned procedure
e.g. Joint replacement, Surgery for cancers e.g.: Hysterectomy, bowel resection
Emergency: A&E or GP
e.g. Abdominal pain/ acute abdomen, Trauma

Question 2

Elective surgery pathway - 8

Answer 2

1. Patient sees GP
2. Referred to specialist
3. Diagnosis
4. Adjunct treatment (e.g. chemotherapy)
5. Decision made for surgery
6. Seen in pre-operative assessment clinic a few weeks pre-op
7. Patient sent surgery date
8. Patient arrives at 7:30am in admission suite for surgery

Question 3

Pre-operative assessment - 8

Answer 3

1. Patient ‘clerked’
2. Physical examination
3. Procedure (& risks) explained – consent forms signed
4. Opportunity for questions
5. Discuss post-operative care & needs on discharge
6. Ensures patient ready for surgery e.g.
   - Pre-existing conditions optimized
   - If concerns / high risk - seen by anaesthetist
7. Medicines reconciliation
8. Peri-operative medicines management

Question 4

Day of surgery - 8

Answer 4

1. Patient arrives
2. Surgeon finalises operation detail & consents patients
3. Anaesthetist ensures fit to proceed
4. Nurse gives pre-meds, TED stockings, takes observations
5. Re-check of medicines reconciliation
6. Operation takes place in theatre (intra-operative period)
7. Recovery – woken up, orientated, pain relief, PONV prophylaxis
8. Patient sent to ward (post-operative period)

Question 5

Medicines reconciliation pre-operatively - 4

Answer 5

1. If not preformed, no accurate source of medication to inform prescribing
2. Potential for critical missed doses
3. Pre-op patient is alert, with family / carer, medication is available
4. Post-op patient is drowsy, family not available, medication may have been sent home

Question 6

Pre-op Pharmacist involvement - 5

Answer 6

1. In pre-op assessment clinics
2. Medication experts – can ensure appropriate advice given on management of long terms conditions
3. Minimise post-op complications
4. Prepare patient for discharge
5. Stable workforce compared to rotating junior doctors

Question 7

What determines duration of stay – 5

Answer 7

1. Surgical procedure
2. Previous co-morbidities
3. Need for IV medication (pain relief, antibiotics)
4. Post op complications
5. Enhanced recovery pathway – put on after surgery to discharge patient ASAP

Question 8

Nil by mouth Pre-operatively - 4

Answer 8

1. Pre-operative fast – 6 hours for food, up to 170mL/hr non-milky fluids
2. Risk of aspiration of stomach contents during general anaesthetic
3. Implications for regular medicines dependent on surgeon or anaesthetist input, length of time to be nil by mouth, individual medicine considerations & risks from stopping vs not stopping
4. General rule - Most regular medication should be given on day of surgery with small sips of water

Question 9

Anticoagulant & surgery: the challenge - 4

Answer 9

1. Increasing number of patients on anticoagulants who require either elective or emergency surgery.
2. Anticoagulants + surgery = increased risk of bleeding
3. Interruption of therapeutic anticoagulation may increase risk of thrombosis
4. Need to balance risk of bleeding vs. risk of thrombosis.

Question 10

Approaching anticoagulation on patients requiring invasive procedure - 4

Answer 10

1. Estimate risk of peri-procedural thrombosis (bleeding in operation)
2. Estimate risk of peri-procedural haemorrhage
3. Determine timing of anticoagulant interruption
4. Whether bridging anticoagulation should be used

Question 11

Warfarin - 5

Answer 11

1. Long half life - Stop 5 days pre-op
2. INR <1.5 for surgery to proceed – higher needs review
3. Pre/post op management depends on indication for anticoagulation & post-op bleed risk
4. “Bridging therapy”
5. Possible use of LWMH or Dalterpain as prophylaxis

Question 12

Indications for anticoagulant therapy - 5

Answer 12

1. Prosthetic valves only on warfarin as its easily monitored
2. VTE or PE needs anticoagulation
3. AF or stents need anticoagulation
4. Other vascular indications e.g. stents
5. Other cardiac indications e.g. mural thrombus

Question 13

Reasons for Anticoagulation – 3

Answer 13

1. Mechanical heart valves: Generally considered high risk of thrombosis if anticoagulation held. “Bridging” usually needed.
2. VTE or PE: High risk in 1st 3months post thrombosis. If >3 months generally just prophylactic dose LMWH post procedure. “Bridging” may be needed if recurrent DVTs/PEs or in last 3 months.
3. Atrial fibrillation: Depends on thrombosis risk: previous TIAs & CHADS2 score

Question 14

Warfarin RUH bridging guidelines – Low, Moderate & High

Answer 14

Low (CHADS2 0-2 & no prior stroke/TIA. 1 VTE >12 months ago & no risk factors): Pre-op requires no LWMH, unless admitted day before surgery.

Moderate (CHADS2 3-4, recurrent VTE or past 3-12 months, active cancer). Pre-op requires no LMWH unless admitted day before surgery.

High (CHADS2 5-6 or recent stroke/TIE (in 3months) Mitral valve/Starr Edwards disc valve, VTE in 3 months): Pre-op start LMWH 2 days after warfarin or give unfractionated heparin infusion.

Question 15

CHA2DS score

Answer 15

C=CHF 1points
H=Hypertension 1points
A=75 2points
D=Diabetes 1point
S=Stroke/TIA 2point

Question 16

Warfarin: Post-op Management – 8

Answer 16

1. Usually restart warfarin ASAP post-op, depending on bleeding risk
2. Consider bleeding from wound site
3. Internal bleeding around operation
4. If patient has an epidural continuing post-op
5. Role for pharmacist intervention to ensure discharge is not delayed due to restarting anticoagulant
6. Epidural & anticoagulant increases risk of haemotama, only continue anticoagulant when catheter removed
7. If patient at low or moderate risk: Cover with prophylactic dose LMWH until INR therapeutic
8. If patient is at high risk: Cover with treatment dose LMWH (or IV heparin infusion) until INR therapeutic for 2 days

Question 17

Warfarin - Emergency Surgery - 3

Answer 17

1. Warfarin MOA: Vit K epoxide reductase inhibitor, prevents vitamin K activating reducing activity of clotting factors
2. If need to reverse warfarin quickly, give Human prothrombin complex.
3. Human prothrombin complex, containing several clotting factors: reversal within 1 hour

Question 18

Elective surgery - discontinuation of DOACs (Direct oral anticoagulants e.g. Rivaroxaban) before invasive or surgical procedure – 5

Answer 18

1. DOACs are short acting - anticoagulant effect wears off more quickly
2. Bridging not usually required as DOACs can usually be stopped prior to surgery

Question 19

Antiplatelets - 7

Answer 19

1. Consider risk of bleeding vs risk of ischemic events
2. Different considerations for cardiac surgery or dual antiplatelet therapy
   Aspirin:
3. Low dose: Continue unless very high bleed risk, then stop 7 days prior
4. High dose: Consider reducing to 150mg 7 days prior
   Clopidogrel:
5. Stop 7 days pre-operatively
6. Substitute with aspirin if possible
7. If high risk of coronary/cerebral thrombosis, consider stopping 5 days pre-op

Question 20

Restarting DOACs & antiplatelets - 3

Answer 20

1. Usually restart ASAP post-op, depending on bleeding risk e.g. bleeding from wound site, epidurals post-op
2. DOACs: 24-72 hours post op, cover with LMWH until starting again
3. Antiplatelets: Continue from morning after surgery

Question 21

Cardiac medication - 3

Answer 21

1. Surgery can increase heart rate & BP so continue most cardiac medication
2. ACEi / ARB & diuretics may be omitted due to risk of hypotension
3. Always continue beta blockers, digoxin, anti-arrhythmic as risk of rebound tachycardia, arrhythmia

Question 22

Long-term steroid therapy - 4

Answer 22

1. Patients on oral steroids & steroids via other routes may have pituitary-adrenal suppression & natural stress response impaired which leads to circulatory collapse
2. Stress of surgery causes plasma adrenocorticotrophic (ACTH) hormone & cortisol levels to rise
3. All oral steroids considered, see BNF for equivalent dosing to prednisolone
4. Consider steroids via other routes on case-by-case basis

Question 23

Steroids & surgery – 6

Answer 23

1. Keep steroid use to a minimum; can affect wound healing, increase infection risk & delay recovery
2. Minor Surgery: Recommence usual oral dose after surgery
3. Moderate surgery 24 hours post-op
4. Major surgery 48 to 72 hours post op
5. Recommence usual dose when IV stops
6. Different for Addison’s disease patients

Question 24

Insulin requirements may change during surgery

Answer 24

Management depends on:
- Type 1 / Type 2 / diet-controlled
- Minor / major procedure
- Number of meals to be missed

Minimise starvation time by placing 1st on list

Question 25

Surgery: Non-insulin agents - 5

Answer 25

1. Continue metformin, pioglitazone, DDP4 inhibitors, GLP-1 analogues 2. Omit SGLT2 inhibitors (e.g. dapagliflozin) 24-72 h pre-op & until patient stable post-op 3. Omit sulphonyl urea on morning of surgery & afternoon for PM procedure 4. Metformin prescribed with other agents; omit if combined with SGLT2i 5. Restart post-op once eating & drinking normally & Variable Rate Insulin Inhibitor stopped

Question 26

Mixed insulins - 3

Answer 26

1. Contain long- & short-acting components 2. Halve usual morning dose 3. Restart evening of surgery if oral intake adequate, halve dose if poor, omit if VRII

Question 27

Short acting insulins - 4

Answer 27

1. Typically taken with meals, dependent on carbohydrate content 2. Omit doses if not eating for that meal 3. Can have morning dose if having afternoon surgery & eating breakfast 4. Restart when VRII stopped & eating and drinking post-op

Question 28

Long/intermediate-acting insulins -

Answer 28

1. Continue at 80-100% of normal dose throughout surgery 2. UKCPA: 80% in some cases e.g. if taking in evening pre-op or if on VRII post-op

Question 29

Variable rate IV Insulin infusion - 3

Answer 29

1. VRII contains short acting insulin, so giving another short acting insulin puts patient at risk of hypoglycaemia 2. Given if patient missed meal due to major surgery 3. Uncontrollable hyperglycaemia in patient missing meal

Question 30

Estrogen-containing contraceptives - 5

Answer 30

1. Increases VTE risk when given orally 2. Oral: first pass metabolism – affects clotting cascade by increasing protein S + C anticoagulant activity & fibrinogen activity 3. Progesterone only pills pose do not increase risk, only estrogens containing pills 4. Recommend to stop 4-6 weeks before major elective surgery, lower-limb surgery or surgery causing prolonged immobility 5. Emergency surgery - give thromboprophylaxis

Question 31

Tamoxifen - 6

Answer 31

1. Always discuss decision with oncologist 2. If used for non-oncology indication, it is normally stopped 3. Used in treatment of/preventing recurrence of breast cancer 4. Consider stopping up to 4 weeks before & after major surgery 5. Increased risk of VTE with use 6. Consider if risk of VTE outweighs risk of stopping the treatment

Question 32

MAOIs (monoamine oxidase inhibitors) - 7

Answer 32

1. Potentially fatal drug interactions 2. Analgesics – tramadol increases serotonergic activity leading to CNS toxicity or increase convulsion risk 3. Sympathomimetics – risk of hypertensive crisis 4. Consult with prescriber of MAOI before deciding to stop 5. Reduce down to stop 2 weeks before surgery 6. Switch to reversible MAOI e.g. moclobemide – short t1/2, omit on morning of surgery 7. Caution with anaesthetic choice, if continued – ‘MAOI-safe anaesthesia

Question 33

Lithium Emergency surgery – 8

Answer 33

1. Ensure adequate hydration & monitor renal function closely. 2. Narrow therapeutic range 3. Renally excreted 4. Fluid imbalance can precipitate toxicity 5. Preferably stop 1-2 days before major study If to continue: 6. Monitor lithium levels (target 0.4 – 1 mmol L-1 )‏ 7. Monitor fluids balance 8. Avoid NSAIDs

Question 34

Anticonvulsants & Parkinson's Medications - 7

Answer 34

1. Continuation of treatment essential – ensure taken on morning of surgery 2. Consider alternative routes of administration if NBM or not absorbing post-operatively e.g.: 3. Phenytoin IV – 1:1 conversion 4. Sodium valproate IV – 1:1 conversion 5. Carbamazepine suppository – dosing not equivalent 6. Lamotrigine tablets given rectally 7. Parkinson’s Disorder meds convert to rotigotine patch or tweak timings