Anaesthetic Assessment & Prep for Surgery

Question 1

Stage 3 px at the preoperative assessment clinic are those who…

Answer 1

1. Have disease that impairs ADL.
2. Are known to have previous anaesthetic difficulties - difficult intubation, allergies to drugs.
3. Are predicted to have difficulties after - morbid obesity, prolonged apnoea.
4. Require ICU post-operatively.

Question 2

What is the aim of the preoperative assessment clinic?

Answer 2

To ensure once patients are admitted for surgery the procedures are not cancelled as a result of them being ‘unfit’ or not adequately optimised for surgery.

Question 3

What does the anaesthetic assessment consist of?

Answer 3

1. History - CVS, respiratory, assessment of exercise tolerance, previous anaesthesia, FHx of problems with anaesthesia, SHx
2. Examination - CVS, resp, nervous, MSK, airway (Mallampati criteria)
3. Appropriate investigations - U+E, LFT, CBG, ECG, CXR, PEFR, coagulation screen, sickledex, cardiopulmonary exercise testing (px ability to increase O2 delivery to tissues), echocardiogram, potentially referred back to GP for optimisation.

Question 4

Why is exercise tolerance measured?

Answer 4

Good predictor of postoperative morbidity and mortality - surgery provokes similar physiological response (increased tissue O2 demand necessitating an increase in cardiac output + O2 delivery).

Question 5

What grades of the Mallampati criteria are considered ‘difficult intubations’?

Answer 5

Grade III and IV

Question 6

Describe the classes of the ASA physical status scale…

1. What class would a fit and well, 80 year old px be in?

Answer 6

I - healthy px with no disease.

II - px with mild to moderate systemic disease, but this does not limit px ADL (e.g. HTN, diabetes) + >80.

III - px with severe systemic disease that imposes functional limitation on activity (e.g. Ischaemic heart disease, COPD).

IV - px with severe systemic disease that is a constant threat to life (e.g. unstable angina).

V - moribund px unlikely to survive 24 hours with/without surgery.

VI - brain dead px who’s organs are to be harvested.

1. Class II (automatically)

Question 7

Define the NCEPOD categories for operations:

1. Immediate
2. Urgent
3. Expedited
4. Elective

Answer 7

National Confidential Enquiry into Perioperative Outcome and Death.

1. To save life, limb or organ. Resuscitation is simultaneous with surgery (e.g. major trauma to abdomen with uncontrolled haemorrhage, ruptured AA).
2. Acute onset or deterioration of condition that threats life, limb or organ (e.g. Compound fracture, cauda equina syndrome).
3. Stable px requiring early intervention - condition not life threatening (e.g. Closed fracture, tendon injury).
4. Planned and booked in advance (e.g. Joint replacement, cholecystectomy, hernia repair).

Question 8

Which px have an increased risk of VTE?

Answer 8

Venous thromboembolism

• anaesthetic + surgical time >90 mins
• surgery to pelvis or LL + >60 mins
• acute admission with inflammatory or intra-abdominal condition
• reduced mobility

Question 9

Can a relative sign the consent form for an unconscious patient to undergo surgery?

Answer 9

No. Doctor must act in ‘patient’s best interest’.

Question 10

Describe 3 methods of assessing a px exercise capacity preoperatively.

Answer 10

1. Assess ADL
2. Estimate how many METs px is capable of (symptoms when dressing = <2, gardening + walk on flat = 5-7, jogs + plays sport = >7).
3. Cardiopulmonary exercise test - measure anaerobic threshold. (>14 ml/kg/min = no risk, <11 ml/kg/min = will need ITU postoperative key).

Question 11

What ASA grade would you assign to a 67 year old woman with DM2, HTN, BMI 38 and an exercise tolerance of 100m on the flat?

Answer 11

ASA III - systemic illness, imposes a restriction on functional activity, but not a constant threat to her life at present.

Question 12

What preoperative investigations are required for a 68 year old px, with controlled HTN and COPD, undergoing major surgery (e.g. Total hip replacement)?

Is a CXR required in this scenario?

Answer 12

1. FBC = identify anaemia (low Hb), cause of anaemia (MCV), occult infection (WCC), clotting problems (low platelet count).
2. Renal function tests (U&Es) = identify electrolyte disturbances, impaired renal function (age related OR consequence of Rx for HTN - diuretics, ACEi).
3. ECG = identify any cardiac ischaemia, conduction disturbance or arrhythmia, LV hypertrophy.
4. Pulmonary function test = severity of COPD
5. If dyspnoeic at rest = ABG
6. Echocardiography = if unable to perform exercise tolerance test due to painful hips.

CXR IS NOT REQUIRED = no signs or symptoms of pulmonary disease + not having thoracic surgery.

Question 13

What are the risks of having general anaesthesia?

Answer 13

Common (1/10-100) = bruising + soreness from cannula, sore throat, headache, dizziness, PONV, urinary retention.

Uncommon (1/1000) = dental damage, chest infection, worsening of existing condition, awareness during GA.

Rare (<1/10,000) = allergic reaction, nerve damage, hypoxic brain injury, death.

Question 14

49 year old lady, BMI = 39, DM2, HTN. Currently on metformin, ramipril, aspirin, simvastatin. Seen in the preoperative clinic prior to a laparoscopic cholecystectomy. She will require T/F:

1. 12-lead ECG
2. CXR
3. FBC, U&E
4. Coagulation screen

Answer 14

1. T = diabetic + hypertensive + obese - increased risk of IHD!
2. F = doesn’t meet criteria
3. T = diabetes may impair renal function
4. F = no hx of coagulopathy, not on warfarin - low dose aspirin does NOT require.

Question 15

Difficulty with tracheal intubation is suggested by finding T/F:

1. Thyromental distance of >7cm
2. Inability to see posterior wall of pharynx
3. Ability to protrude lower incisors beyond upper
4. BMI >35

Answer 15

1. F = <7 cm suggests difficulty
2. T = Mallampati grade III
3. F = no reduced view at laryngoscopy
4. T

Question 16

The following are COMMON risks (1/10-100) of anaesthesia:

1. PONV
2. Urinary retention
3. Dental damage
4. Allergic reaction

Answer 16

1. T = stratified using Apfel score.
2. T = common SE of opioids, anticholinergics + neuraxial blockade.
3. F = 1/1000 (uncommon)
4. F = 1/10,000 (rare)

Question 17

The following factors increase the risk of VTE:

1. Age >50 years
2. BMI >30
3. Taking HRT
4. LL surgery lasting >60 mins

Answer 17

1. F = >60 years increases risk
2. T = obesity increases risk
3. T
4. T = risk is significantly higher until 30 days after surgery!

Question 18

In the assessment of the CVS:

1. Px with preoperative BP 184/116 should have elective surgery delayed until BP is under control.
2. Echo can quantity the severity of heart valve dysfunction.
3. Echo can be used to assess ventricular function during pharmacologically simulated exercise.
4. Cardiopulmonary exercise (CPX) testing assesses px ability to increase CO2 clearance during exercise.

Answer 18

1. T
2. T = echo is used to assess heart valve anatomy, function + pressure gradients across valves.
3. T = dobutamine can be given to raise HR and contractility, simulating exercise while echo is performed to assess ventricular muscle response.
4. F = CPX assesses the body’s ability to increase O2 delivery to tissues to meet demand.