Fundamentals of anaesthetics

Question 1

What are pre-operative investigations dependent on?

Answer 1

• Patient co-morbidities & medication - Type of surgery : minor/intermediate/ complex (including haemorrhage risk) - Setting: elective OR emergency

Question 2

What is the ASA scoring system?

Answer 2

American Society of Anaesthesiologists Classification - List the basics of the ASA Classification - Scoring system pertaining to individual comorbidities - angina, hypertension, diabetes, COPD, asthma.* - Understand that this accurately predicts morbidity and mortality or more broadly the fitness of patients prior to surgery

Question 3

What are the levels of ASA?

Answer 3

ASA 1: Healthy patient ASA 2: Mild systemic disease. No functional limitation ASA 3: Moderate systemic disease. Have functional limitation ASA 4: Severe systemic disease that is a constant threat to life ASA 5: Moribund patient. Unlikely to survive 24 hours, with or without treatment Postscript E indicates emergency surgery

Question 4

What is POSSUM?

Answer 4

Enter patient physiological and operative variables Mortality & morbidity risk Pre-operative: risk discussion Peri-operative: Need for Invasive monitoring? Postoperative: Over 5% mortality risk should -> HDU/ITU post operative

Question 5

What are the parts of POSSUM?

Answer 5

Age, Cardiac, Respiratory, ECG, SBP, Pulse, Hb, WBC, Urea, Sodium, Potassium, GCS

Question 6

How do we optimise operative risk in patients with co morbidities? (Diabetes, HTN, IHD, Asthma, COPD, Anti coag, Sickle cell)

Answer 6

Diabetes Measure: Glycosylated Hb Control: When to use Insulin Sliding scales? Hypertension Measure: When to treat? (BP>160/80) Control: Maintain 20% of normal BP IHD Measure: Symptomatic (or major procedure) /ECG anomaly Control: BP & HR control. Consider post operative HDU Asthma Measure: Symptomatic? Signs? Control: Medication – BTS Guidelines COPD Measure: Symptomatic? Signs? Control: Medication – BTS Guidelines Anti-coagulants Measure: Why? Stop or not? Control: INR/APTR <1.5 Anti-platelets/LMWH resumption? Sickle cell Measure: Haematology review Control: Good care : warm, hydrated, analgesia, infection free

Question 7

Who is suitable for day surgery?

Answer 7

Social - Patient consent, carer, home set up Medical - Fitness, stable chronic, obesity not preclude Surgical - Complication risks, controllable post op symptoms, mobile

Question 8

When should I consider further abnormalities?

Answer 8

Bloods test anomalies : anaemia, renal dysfunction ABG- COPD will change figures need pre and post Lung function tests : Baseline ABG’s, FEV1<40% (predictor for postoperative ventilation) Cardiac: ECG – ischaemia, arrhythmias, baseline Echo – LV function & valves Stress echo – low/int/high risk of ischaemia

Question 9

How does an anaesthetic Hx differ from a normal history?

Answer 9

Past surgery/GA’s – FH of problems? PMH – co-morbidities, Ex tolerance? Medication/ allergies? Smoking/Etoh/ recreational? Teeth (dental work)? Airway – Mallampati, Neck movement NBM?

Question 10

What is the mallampati score?

Answer 10

Classes I- Complete visualisation of soft palate II- Complete visualisation of the uvula III- Visualisation of the base of uvula only IV- No visualisation of the soft palate

Question 11

Why do we ask patients to do NBM?

Answer 11

Reduce risk of aspiration

Question 12

What is the usual NBM guidance?

Answer 12

Food : 6 hours Water: 2 hours (caveat: reflux, obesity, slow gastric transit e.g. trauma)

Question 13

How do you prescribe opioids?

Answer 13

The dose The formulation (tablet, IV, liquid) The strength (where appropriate) The total quantity or dosage units of the preparation in both words and figures For instalment prescriptions, specify the instalment amount AND instalment interval

Question 14

Write out an example of a opioid prescription

Answer 14

Handwritten Name, form and strength: Morphine sulphate SR tablets 10 mg bd 50 (fifity) tablets Your signature and date (inc. bleep)

Question 15

What is an adjunct?

Answer 15

Airway adjuncts and devices for use in surgery e.g. oropharyngeal aurway (name/ when use/ size) Bag mask valve (name/ parts/ when use/ Fi02) Can’t use if spontaneous ventilating

Question 16

What is the Guedel sizing?

Answer 16

Guedel sizing- angle of mandible to mouth edge size: green-2 /orange-3/red-4

Question 17

What are the adjuncts?

Answer 17

Oropharyngeal airway Bag mask valve Endotracheal tube Supraglottic device

Question 18

What is a definitive airway

Answer 18

A cuffed tube in the trachea I.e. endotracheal tube, supraglottic device

Question 19

What is the WHO checklist?

Answer 19

The WHO Surgical Safety Checklist was developed after extensive consultation aiming to decrease errors and adverse events, and increase teamwork and communication in surgery. The 19-item checklist has gone on to show significant reduction in both morbidity and mortality and is now used by a majority of surgical providers around the world.

Question 20

What is the five steps for safer surgery?

Answer 20

1. Brief 2. Sign in 3. Time out 4. Sign out 5. Debrief

Question 21

What do I need to consider for VTE prophylaxis?

Answer 21

Mobility Risk factors Bleeding risk

Question 22

How do I prescribe LMWH prophylaxis?

Answer 22

NICE guidelines plus compression stockings

Question 23

What is the WHO ladder of pain?

Answer 23

Step 1: Non-opioid (paracetamol, NSAIDs and adjuvants) Step 2: Weak Opioid (codeine etc. and adjuvants) Step 3: Strong opioid (morphine etc. and adjuvant)

Question 24

What anti emetics do you prescribe with opioids?

Answer 24

Question 25

How do you control temperature?

Answer 25

Keep temp>36 C Procedure>30mins-> Bair hugger Longer procedures-> consider fluid warming

Question 26

How do you treat acute asthma?

Answer 26

Question 27

How do you acutely treat a pneumothorax?

Answer 27

Needle decompression using a large bore cannula, 2nd ICS in MCL (Chest drain if >30)

Question 28

What can you be anaphylactic to?

Answer 28

Question 29

What might you see in someone with anaphylaxis? (Hint: ABCDE)

Answer 29

Airway problems: - Airway swelling, e.g., throat and tongue swelling (pharyngeal/laryngeal oedema). - The patient has difficulty in breathing and swallowing and feels that the throat is closing up. - Hoarse voice. - Stridor – this is a high-pitched inspiratory noise caused by upper airway obstruction. Breathing problems: • Shortness of breath – increased respiratory rate. • Wheeze • Patient becoming tired. • Confusion caused by hypoxia. • Cyanosis (appears blue) – this is usually a late sign. • Respiratory arrest. Circulation problems: • Signs of shock – pale, clammy. • Increased pulse rate (tachycardia). • Low blood pressure (hypotension) – feeling faint (dizziness), collapse. • Decreased conscious level or loss of consciousness. • Anaphylaxis can cause myocardial ischaemia and ECG changes even in individuals with normal coronary arteries. • Cardiac arrest.

Question 30

How do you diagnose and treat anaphylaxis?

Answer 30

Question 31

When should you transfuse a patient?

Answer 31

See notes (this is the paeds version)

Question 32

How does NEWS work?

Answer 32

NEWS: like many existing EWS systems, based on simple scoring system in which a score is allocated to physiological measurements already undertaken when patients present to, or are being monitored in hospital.

Question 33

What are the parameters for NEWS?

Answer 33

1 respiratory rate 2 oxygen saturations 3 temperature 4 systolic blood pressure 5 pulse rate 6 level of consciousness.

Question 34

What would you do if someone had lower NEWS scores?

Answer 34

Question 35

What is SEPSIS?

Answer 35

INFECTION PLUS SIRS (systemic inflammatory response syndrome) 2+ of: - Temperature above 38 or below 36 - Heart rate over 90 - Resp rate over 20 or PaCO2 less than 32 mmHg (4.3 kPa) - WBC > 12 000 or <4000 /mm^3 or >10% immature band

Question 36

What is the management of SEPSIS? (within 3 hrs)

Answer 36

Sepsis 6: 1) URINE: Measure urine output 2) BLOOD CULTURES: Obtain blood cultures prior to administration of antibiotics 3) LACTATE: Measure lactate level 4) OXYGEN: Give oxygen 5) ANTIBIOTICS: Administer broad spectrum antibiotics 6) FLUIDS: Administer 30 ml/kg crystalloid for hypotension or lactate ≥4mmol/L “Time of presentation” is defined as the time of triage in the emergency department

Question 37

What do you have to do within 6 hours to manage sepsis?

Answer 37

5) Apply vasopressors (for hypotension that does not respond to initial fluid resuscitation) ; maintain a mean arterial pressure (MAP) ≥65 mm Hg 6) In the event of persistent hypotension after initial fluid administration (MAP < 65 mm Hg) or if initial lactate was ≥4 mmol/L, re-assess volume status and tissue perfusion. 7. Re-measure lactate if initial lactate elevated.

Question 38

What is the indications for ABG?

Answer 38

To obtain & interpret oxygenation levels To assess for potential respiratory derangements To assess for potential metabolic derangements To monitor acid-base status To assess carboxyhaemoglobin in CO poisoning To assess lactate To gain preliminary results for electrolytes and Haemoglobin Can be conducted as a one off sample or repeated sampling to determine response to interventions

Question 39

What are the contraindications of ABG?

Answer 39

Local infection Distorted anatomy Presence of arterio-venous fistulas Peripheral vascular disease of the limb to be sampled Severe coagulopathy or recent thrombolysis

Question 40

What are the possible sampling errors?

Answer 40

Presence of air in the sample collection of venous rather than arterial blood an improper quantity of heparin in the syringe, or improper mixing after blood is drawn delay in specimen transportation

Question 41

What are complications of an ABG?

Answer 41

Haematoma Nerve damage Arteriospasm or involuntary contraction of the artery Aneurysm of artery Fainting or a vasovagal response

Question 42

Summarise what you have to do for anaesthetics

Answer 42

Pre-operative – Pre-op Ix/scoring systems, co-morbidities, day surgery criteria, anaesthetic Hx Intra-operative – Safety, airway devices, WHO checklist, VTE prophylaxis, WHO pain ladder, anaesthetic emergencies, Post-operative – NEWS & sepsis, ABG’s

Question 43

What is oxygen therapy and what are the goals?

Answer 43

• Relieve hypoxaemia, maintain tissue oxygenation -Assessed by SpO2 / Sa O2 monitor clinical signs - Prevent CO2 accumulation (flow rate and delivery) - Reduce the work of breathing(e.g. CPAP) - Ensure adequate clearance of secretions and use optimal humidification (dependent on mode)

Question 44

What are the types of oxygen delivery modes?

Answer 44

1. Nasal Canulae (24-30% oxygen, FR- 1-4L/ min) 2. Facemask (Hudson [30-40%, 5-10L/min] and venturi [24-60%, FL dependent on colour]) 3. ACUTE: Non rebreather mask [60-90%, 15 L/min to stop rebreathing of expired air] 4. CPAP Continous positive airway pressure (Type 1 resp failure) High pressure ox with fitted mask 5. BiPAP (Type 2 resp failure) Bilevel positive airway pressure High pressure on insp. low positive ob exp. Type 2 Resp failure (e.g. COPD, need to expel CO2)