Pre-op Mx

Question 1

Pre-op Checks: OP CHECS

Answer 1

Operative fitness: cardiorespiratory comorbidities
Pills
Consent
History
 MI, asthma, HTN, jaundice
 Complications of anaesthesia: DVT, anaphylaxis
Ease of intubation: neck arthritis, dentures, loose teeth
Clexane: DVT prophylaxis
Site: correct and marked

Question 2

Pre-op drugs

Answer 2

Anti coagulant - balance haemorrhage v thrombosis
- avoid epidural, spinal and regional blocks

Antiepileptic drugs - give as usual - post op give IV or NGT

OCP/HRT - stop 4 weeks before major/leg surgery
- restart 2 weeks postop

Beta blockers - continue as usual

Question 3

Pre-op Ix

Answer 3

Bloods
Routine: FBC, U+E, G+S, clotting, glucose
Specific
 LFTs: liver disease, EtOH, jaundice
 TFT: thyroid disease
 Se electrophoresis: Africa, West Indies, Med
Cross-match
 Gastrectomy: 4u
 AAA: 6u

Cardiopulmonary Function
 CXR: cardiorespiratory disease/symptoms, >65yrs
 Echo: poor LV function, Ix murmurs
 ECG: HTN, Hx of cardiac disease, >55yrs
 Cardiopulmonary Exercise Testing
 PFT: known pulmonary disease or obesit

Other
 Lat C-spine flexion and extension views: RA, AS
 MRSA swabs

Question 4

Pre-op Preparation

Nill by mouth

Answer 4

2+h clear fluids, 6+h solids

Question 5

Bowel Prep pre-op

Answer 5

May be needed in left-sided ops
 Picolax: picosulfate and Mg citrate
 Klean-Prep: macrogol

Not usually needed in right-sided procedures

Necessity is controversial as benefit of minimising postop infection might not outweigh risks
 Liquid bowel contents spilled during surgery
 Electrolyte disturbance
 Dehydration
 ↑ rate of post-op anastomotic leak

Question 6

Pre-op prophylactic Abx

Answer 6

GI surgery (20% post-op infection if elective)
Joint replacement 
15-60mins before surgery 

Regiments (local guidelines)
Biliary: Cef 1.5g + Met 500mg IV
CR or appendicetomy: Cef+Met TDS
Vascular: co-amoxiclav 1.2g IV TDS
MRSA+ve: vancomycin

Question 7

DVT Prophylaxis pre-op

Answer 7

Stratify pts according to patient factors and type of
surgery.

 Low risk: early mobilisation
 Med: early mobilisation + TEDS + 20mg enoxaparin
 High: early mobilisation + TEDS + 40mg enoxaparin +
intermittent compression boots perioperatively.

 Prophylaxis started @ 1800 post-op
 May continue medical prophylaxis at home (up to 1mo)

Question 8

ASA Grades (anaesthetist for physical health)

Answer 8

1. Normally healthy
2. Mild systemic disease
3. Severe systemic disease that limits activity
4. Systemic disease which is a constant threat to life
5. Moribund: not expected to survive 24h even c¯ op

Question 9

Diabetic Pre-op Complications

Answer 9

↑ Risk of post-operative complications
 Surgery → stress hormones → antagonise insulin
 Pts. are NBM
 ↑ risk of infection
 IHD and PVD

Pre-op
 Dipstick: proteinuria
 Venous glucose
 U+E: K+

Question 10

Insulin Dependent DM Pre-op

Answer 10

Put pt first on list, inform surgeon and anaesthetist
Sliding scales may not be necessary for minor ops
- if in doubt diabetic nurse

Insulin
± stop long-acting insulin the night before
Omit AM insulin if surgery is in the morning
Start sliding scale
 5% Dex c¯ 20mmol KCl 125ml/hr
 Infusion pump c¯ 50u actrapid
 Check CPG hrly and adjust insulin rate
Check glucose hrly: aim for 7-11mM
Post-op
 Continue sliding-scale until tolerating food
 Switch to SC regimen around a meal

Question 11

Non Insulin Dependent DM Pre-op

Answer 11

If glucose control poor (fasting >10mM): treat as IDDM
Omit oral hypoglycaemics on the AM of surgery
Eating post-op: resume oral hypoglycaemics c¯ meal
No eating post-op
 Check fasting glucose on AM of surgery
 Start insulin sliding scale
 Consult specialist team ore. restarting PO Rx

Diet Controlled - Usually no problem
Pt. may be briefly insulin-dependent post-op
 Monitor CPG

Question 12

Steroids Pre-op

Answer 12

Risks
- poor wound healing, infection, adrenal criss

Mx
 Need to ↑ steroid to cope c¯ stress
 Consider cover if high-dose steroids w/i last yr
 Major surgery: hydrocortisone 50-100mg IV c¯ pre-med
then 6-8hrly for 3d.
 Minor: as for major but hydrocortisone only for 24h

Question 13

Jaundice Pre-op

Answer 13

Avoid operating on jaundiced pt, use ERCP instead

Risks

• pts with obstructive jaundice may have ^risk of post-op renal failure (need to maintain good UO
• coagulopathy
• ^infection risk may > cholangitis

Pre-op
 Avoid morphine in pre-med
 Check clotting and consider pre-op vitamin K
 Give 1L NS pre-op (unless CCF) → moderate diuresis
 Urinary catheter to monitor UPO
 Abx prophylaxis: e.g. cef+met

Intraop - hourly UO monitor, Normale Saline titrated to output

Post-op

• intense monitoring of fluid status
• consider CVP, frusemide if poor output despite NS

Question 14

Patients on anticoagulation pre-op

Answer 14

Consult surgeon, anaesthetist and haematologist
 Very minor surgery may be undertaken w/o stopping
warfarin if INR <3.5.
 Avoid epidural, spinal and regional blocks if
anticoagulated,
 In general, continue aspirin/clopidogrel unless risk of
bleeding is high – then stop 7d before surgery

Question 15

Patients on anticoagulation pre-op

Low thromboembolic risk
High thromboembolic risk
Emergency Surgery

Answer 15

Low thromboembolic risk: e.g. AF
 Stop warfarin 5d pre-op: need INR <1.5
 Restart next day

High thromboembolic risk: valves, recurrent VTE
-Need bridging c¯ LMWH
 Stop warfarin 5d pre-op and start LMWH
 Stop LMWH 12-18h pre-op
 Restart LMWH 6h post-op
 Restart warfarin next day
 Stop LMWH when INR >2

Emergency Surgery
 Discontinue warfarin
 Vit K .5mg slow IV
 Request FFP or PCC to cover surgery

Question 16

COPD and smoking risks pre-op

Answer 16

Risks
 Basal atelectasis
 Aspiration
 Chest infection

Pre-op
 CXR
 PFTs
 Physio for breathing exercises
 Quit smoking (at least 4wks prior to surgery)

Question 17

Immediate Surgical Complications

Answer 17

(<24h)
 Intubation → oropharyngeal trauma
 Surgical trauma to local structures
 Primary or reactive haemorrhage

Question 18

Early Surgical Complications

Answer 18

(1d-1mo)
 Secondary haemorrhage
 VTE
 Urinary retention
 Atelectasis and pneumonia
 Wound infection and dehiscence
 Antibiotic association colitis (AAC)

Question 19

Late Surgical Complications

Answer 19

(>1mo)
 Scarring
 Neuropathy
 Failure or recurrence

Question 20

DVT

Answer 20

25-50% of surgical pt

Sign’s
 Peak incidence @ 5-10d post-op
 65% of below knee DVTs are asymptomatic
 Calf warmth, tenderness, erythema, swelling
 Mild pyrexia
 Pitting oedema

Question 21

Virchow’s Triad

Answer 21

Blood Contents
 Surgery → ↑ plats and ↑ fibrinogen
 Dehydration
 Malignancy
 Age: ↑

Blood Flow
 Surgery
 Immobility
 Obesity

Vessel Wall
 Damage to veins: esp. pelvic veins
 Previous VTE

Question 22

DVT Ix

Answer 22

D-Dimers: sensitive but not specific
Compression US (clot will be incompressible)

Thrombophilia screen if:
 No precipitating factors
 Recurrent DVT
 Family Hx

Question 23

DVT Dx

Answer 23

1. Assess probability using Wells’ Score
2. Low-probability → perform D-dimers
    Negative → excludes DVT
    Positive → Compression US
3. Med / High probability → Compression US

Question 24

DVT Rx

Answer 24

Anticoagulate
Therapeutic LMWH: enoxaparin 1.5mg/kg/24h SC
Start warfarin using Tait model: 5mg OD for first 4d
Stop LMWH when INR 2.5

Duration
 Below knee: 6-12wks
 Above knee: 3-6mo
 On-going cause: indefinite

Graduated Compression Stockings
 Consider for prevention of post-phlebitic syndrome

Question 25

Preventing DVT

Answer 25

Pre-op 
VTE risk assessment 
TED Stockings 
Aggressive optimisation (esp hydration)
Stop OCP 4 weeks pre-op

Intraop
minimise length of surgery
use minimal access surgery if poss
intermittent pneumatic compression boots

post-op 
LWMH
early mobilisation
good analgesia
physio
adequate hydration