Pre-operative care

Question 1

ASA grading: what is it?

Answer 1

The American Society of Anesthesiologists (ASA) grading system classifies the physical status of the patient for anaesthesia. Patients are given a grade to describe their current fitness prior to undergoing anaesthesia/surgery

ASA I – normal healthy patient
ASA II – mild systemic disease
ASA III – severe systemic disease
ASA IV – severe systemic disease that constantly threatens life
ASA V – “moribund” and expected to die without the operation
ASA VI – declared brain-dead and undergoing an organ donation operation
E – this is used for emergency operations

Question 2

ASA grade 1

Answer 2

ASA I – normal healthy patient

Question 3

Define the acronym RAPRIOP

Answer 3

Reassure
Advice
Prescription
Referral
Investigations
Observations
Patient understanding

Don’t forget follow-up

Question 4

Reassurance

Answer 4

Check patient understanding of procedure
ICE
Address concerns

Question 5

Advice (when to fast)

Answer 5

Clear fluids - 2 hours before surgery
Foods and dairy - 6 hours before surgery

Question 6

Why do you advise patients to fast?

Answer 6

Fasting ensures that the stomach is empty of contents. This reduces the risk of reflux during intubation and extubation, which could lead to pulmonary aspiration.

(Complications covered in another card)

Question 7

Potential complications related to con-compliance with fasting?

Answer 7

1. Aspiration pneumonitis (inflammation caused by very acidic gastric contents, leading to desquamation)
2. Aspiration pneumonia (due to secondary infection following pneumonitis or direct aspiration of infected material).

Question 8

Prescriptions to stop

Answer 8

CHOW

Clopidogrel - 7 days prior to surgery due to bleeding risk (aspirin and other anti-platelets can be continued)

Hypoglycaemics (covered in more detail in another card)

Oral contraceptives and HRT - 4 weeks prior to surgery (DVT risk) –> use barrier contraception during this time

Warfarin - 5 days prior to surgery (bleeding risk). Started on LMWH instead
- If on warfarin and INR>1.5 the night before surgery –> PO vitamin K (1–5 mg, IV preparation to be used PO, dose to be given the day before surgery if INR ≥1.5.

If emergency surgery –> 5mg PO +/- dried prothrombin complex

Question 9

Prescriptions to alter

Answer 9

1. Subcutaneous insulin (discussed in another card)
2. Long-term steroids (>5mg oral prednisolone)

If the patient cannot take these orally, switch to IV (a simple conversion rate is 5mg PO prednisolone = 20mg IV hydrocortisone)

Question 10

Pre-operative long-term steroids management
1. What to prescribe?
2. Why is it prescribed?

Answer 10

1. Additional IV hydrocortisone at induction and for the immediate postoperative period (e.g., first 24 hours)

Doubling of their normal dose once they are eating and drinking for 24 – 72 hours depending on the operation

2. Surgery elicits a stress response which activates the HPA axis –> increase in the release of endogenous corticosteroids. In patients on long-term steroids, there is adrenal suppression that prevents them from creating the extra steroids required to deal with this stress.

Patients on steroid therapy (more than physiological replacement) for over two weeks may experience HPA axis suppression. Patients with confirmed (or suspected) HPA axis suppression (through Short Synacthen testing) are therefore at risk of acute adrenal insufficiency (Addisonian crisis) peri-operatively due to their attenuated ability to mount a sufficient endogenous steroid response.

Question 11

Prescriptions to start

Answer 11

1. LMWH e.g. enoxaparin (clexane) –> VTE assessment must be carried out.
   Except –> neck or endocrine surgery
2. TED stockings
   Check contraindications e.g. severe peripheral vascular disease, peripheral neuropathy, recent skin graft, severe eczema.
3. Antibiotic prophylaxis

Question 12

Peri-operative management of Diabetes Mellitus: T1DM
1. Night before surgery
2. While NBM
3. When swapping back from sliding scale to basal insulin

Answer 12

• Night before surgery:
  1. reduce their subcutaneous basal insulin dose by 1/3rd. \
  2. Omit their morning insulin and commence sliding scale (49.5mL of normal saline with 50 units of Actrapid)
• While NBM:
  1. Prescribe 5% dextrose at a rate of 125mL/hr
  2. 2-hourly CBG check (ask nurse)
• When swapping back from sliding scale to basal insulin: give SC insulin 20min before a meal and stop IV infusion 30-60min afterwards

Question 13

Peri-operative management of Diabetes Mellitus: T2DM

Answer 13

If diet-controlled, then no perioperative management required
If controlled by oral hypoglycaemics: STOP
1. Stop metformin in the morning of surgery; other hypoglycaemics app 24hrs before surgery
2. These patients will then be put on IV variable rate insulin infusion along with 5% dextrose as Type I diabetic

Question 14

What is understood by bowel preparation?

Answer 14

Enemas or laxatives

Question 15

Why are bowel preparations used less frequently?

Answer 15

Can lead to fluid shifts in cardiac/renal/elderly patients, leading to lengthened stay

Question 16

What surgeries require bowel preparation?

Answer 16

1. Left hemi-colectomy, sigmoid colectomy, or abdominal-perineal resection: Phosphate enema on the morning of surgery
2. Anterior resection: 2 sachets of picolax the day before or phosphate enema on the morning of surgery

Question 17

Blood products in surgery: what needs to be done pre-operatively?

Answer 17

Group Save + Crossmatch (X-match)

Question 18

Referral?

Answer 18

Potential HDU/ITU bed

Question 19

Patient understanding and follow up

Answer 19

Ensure that the patient is fully informed and understands the plan for their care and discharge.

Book follow-up clinic

Patients undergoing day-case surgery will receive telephone follow-up from a nurse specialist only or may not require follow-up.

Question 20

The preoperative assessment: aims and timing

Answer 20

Aim: identify co-morbidities that may lead to patient complications during the anaesthetic, surgical, or post-operative period

Timing: 2-4 weeks before surgery

Question 21

The preoperative assessment: Pre-operative history - points to focus on

Answer 21

Follow standard framework for hx, but focus on these points too

PMH
- Cardio: exercise tolerance, exertional chest pain, syncopal episodes, or orthopnoea
- Respiratory: able to lie flat for a prolonged period or has a chronic cough? –> may preclude spinal anaesthesia; OSA risk factors?
- Endocrine: Diabetes/thyroid?
- GORD: can lead to aspiration pneumonia; is it controlled?
- Pregnancy: urinary pregnancy test in reproductive age females
- Sickle cell disease:

Past anaesthetic hx
- Administered anaesthesia before? If so, for what operation and what type of anaesthesia? Were there any problems? Did the patient experience any post-operative nausea and vomiting?

DH - see other cards for what to stop/alter/start

FH: rare, but malignant hyperthermia

Question 22

The preoperative assessment: examination

Answer 22

General (cardio, abdo, resp, neuro) + anaesthetic examination (airway)

Question 23

The preoperative assessment: Investigations - Blood tests

Answer 23

• FBC: anaemia or thrombocytopenia can be corrected pre-operatively to reduce the risk of cardiovascular events or allow for preparation of blood products
• U&Es: baseline renal function, which help inform fluid management and drug decisions, both for anaesthesia and post-operative analgesia (e.g. morphine is generally avoided in those with CKD)
• LFTs: liver metabolism and synthesising function, useful for peri-operative management; If impairment –> LFTs may help direct medication choice and dosing
• Condition-specific blood tests e.g. HbA1C or thyroid function tests (TFTs)
• Clotting Screen
• Group and Save (G&S) +/- cross-matching

Question 24

What is the difference between group & save and crossmatch?

Answer 24

1. G&S: determines the patient’s blood group (ABO and RhD) and screens the blood for any atypical antibodies; takes 40 minutes and no blood is issued
   - recommended if blood loss is not anticipated,
2. Cross-match: mixing the patient’s blood with the donor’s blood. If no immune reaction takes place: the donor blood is issued and can be transfused in to the patient, otherwise alternative blood is trialled

• Takes ~40 minutes (in addition to the 40 minutes required to G&S the blood, which must be done first),
• Should be done pre-emptively if blood loss is anticipated

Question 25

The preoperative assessment: Investigations - Cardiac tests

Answer 25

• ECG if hx of CV disease or routine if major surgery
• ECHO if (1) a heart murmur (2) ECG changes (3) signs or symptoms of heart failure
• myocardial perfusion scans: if untreated ischaemia or angina symptoms (checks for inducible ischaemia)

Question 26

The preoperative assessment: Investigations - Respiratory tests

Answer 26

• Spirometry: if chronic lung disease e.g. COPD (sets pre-operative baseline) or if signs of undiagnosed pulmonary disease
• CXR uncommon as routine pre-operative Invx

Question 27

The preoperative assessment: Investigations - Other tests

Answer 27

• MRSA: nostril and perineum; if isolated –> decontamination hair and body wash+ topical ointment to nostrils
• Urinalysis: urological procedures or suspicion of UTI
• Cardiopulmonary Exercise Testing: stationary bike whilst wearing a mask + ECG monitoring –> VO2max and anaerobic threshold, which can be used to risk-stratify patients for post-operative complications and need for higher level care environments

Question 28

ASA grade II

Answer 28

ASA II – mild systemic disease

Question 29

ASA grade III

Answer 29

ASA III – severe systemic disease

Question 30

ASA grade IV

Answer 30

ASA IV – severe systemic disease that constantly threatens life

Question 31

ASA grade V

Answer 31

ASA V – “moribund” and expected to die without the operation

Question 32

ASA grade VI

Answer 32

ASA VI – declared brain-dead and undergoing an organ donation operation

Question 33

ASA grade E

Answer 33

E – this is used for emergency operations