Anaesthetic Viva

Front 1

Hypertension Causes

Back 1

1. Inaccurate Measurement

• too small cuff
• inaccurate zero transducer
• transducer height

2. Patient factors

• Essential, pre-existing HT
• renovascular disease
• raised ICP
• full bladder
• phaeo
• thyroid storm
• autonomic dysreflexia
• fluid overload
• per-eclampsia

3. Anaesthetic Factors

• intubation / emergency
• inadequate depth/ analgesia - awareness
• drugs - vasoactive meds
• hypoxia
• hypercarbia
• MH

4. Surgical Factors

• aortic cross-clamp
• torniquet application
• baroreceptor stimulation
• pain/stimulation from surgery

Front 2

Hypotension Causes

(Fall > 20% Baseline, Systolic < 90, MAP <60)

Back 2

1. Reduced Pre-load

• Hypovolaemia - blood loss, dehydration, sepsis
• Reduced Venous Return
• Increased Intrathoracic pressure
• Tamponade
• PE
• Pneumothorax
• Embolus - gas, air, thrombus, cement, fat, amniotic fluid

2. Reduced Contractility

• Drugs - volatiles
• Primary Pump Failure - AMI, cardiomyopathy, arrhythmia
• Sudden increase in afterload

3. Reduced SVR

• drugs - volatile, opioids, vasodilators
• spinal/epidural block
• anaphylaxis
• sepsis
• thyroid disease
• addisonian crisis
• MH

4. Equipment error

• too large cuff
• inaccurate zero transducer
• transducer height

Front 3

Intraoperative Hypoxia Causes

(Fall in SpO2 > 5%, SpO2 <90%, or paO2<60mmHg)

Back 3

1. Reduced O2 Delivery

• decreased FiO2
• Apnoea
• Hypoventilation
• Endobronchial intubation
• Laryngospasm/bronchospasm
• circuit malfunction

2. Reduced blood flow to the lungs

• cardiac arrest/failure
• anaphylaxis
• PE
• shunt

3. Impaired gas exchange / VQ mismatch

• APO
• Aspiration
• atelectasis
• pneumothorax
• ARDS
• bronchospasm

4. Artifact

• hypothermia
• poor peripheral circulation
• probe displacement
• methylene blue / idocyanine green administration

5. Anaemia

6. Increased Oxygen Demand

• MH
• Sepsis

Front 4

Postoperative Hypoxia causes

Back 4

1. Hypoventilation / Inadequate MV

• CNS depression secondary to anaesthetic agents / opiates
• Muscle weakness - inadequate reversal, preexisting myopathy, electrolyte abnormalities

2. Airway obstruction

• Laryngospasm
• airway oedema
• secretions / mucous plug
• Haemorrhage
• Trauma to airway
• Vocal cord paralysis/dysfunction
• trachaeomalacia

3. V/Q Mismatch

• APO
• Aspiration
• Atelectasis
• Pneumothorax
• ARDS

4. Shunt

5. Decreased cardiac output following primary cardiac event

6. Others

• Artifact
• Shivering

Front 5

ST Changes

Back 5

• AMI, reduced coronary perfusion
• Myocardial contusion
• Pericarditis
• Electrolytes - K , Ca
• Raised ICP, head injury
• Decreased Temp
• Artifact
• Abnormal cardiac conduction
• LVH
• PPM

Front 6

Reduced EtCO2

Back 6

1. Reduced production

• decreased temp
• hypothyroid

2. Increased elimination

• Hyperventilation

3. Equipment error

• disconnection
• air entrainment
• increased fresh gas flow

4. Reduced CO2 excretion

• ETT obstruction
• Laryngospasm/bronchospasm
• endobronchial intubation
• increased dead space

Front 7

Increased CO2

Back 7

1. Increased endogenous production

• Sepsis
• MH
• Thyroid storm
• shivering
• neuroleptic malignant syndrome
• reperfusion

2. Increased Exogenous Source

• Bicarbonate
• Insufflation
• TPN
• Inhaled CO2
• Exhausted Soda Lime

3. Reduced Elimination

• Circuit: obstruction, reduced FGF, Valve dysfunction
• Lungs: Hypoventilation, bronchospasm, COPD

Front 8

Raised Airway Pressure

Back 8

1. Circuit

• Valve closed
• kinked/misconnected hose
• Filter blocked / obstructed / wet

2. ETT

• kinked
• biting
• endobronchial
• obstructed: foreign body, mucous, secretions

3. Reduced Pulmonary Compliance

• Increased intra-abdominal pressure
• bronchospasm / anaphylaxis
• atelectasis
• PE
• pneumothorax
• reduced chest wall / diaphragm compliance
• Alveolar pathology - aspiration, oedema, contusion, ARDS

4. Drugs

• Chest wall rigidity
• inadequate neuromuscular blockade
• MH

Front 9

Pulmonary Oedema

Back 9

1. Increased pulmonary hydrostatic pressure

• LV failure
• Volume overload
• Renal failure
• AMI
• acute valvular dysfunction

2. Increased capillary permeability

• ARDS
• airway burns / smoke inhlation

3. Low pulmonary oncotic pressure

• malnutrition
• liver disease

4. Inadequate lymphatic clearance

5. Reduced pulmonary alveolar pressure (negative pressure pulmonary oedema)

6. Neurogenic

Front 10

Intra-operative Cardiac Arrest

Back 10

1. Pre-existing disease states

• Cardiac
• Respiratory
• Renal

2. Surgical manoeuvres

• CO2 insufflation
• Autonomic stimulation
• Femoral prosthesis
• Air Embolism

3. Error in anaesthetic technique

• Inadequate ventilation / hypoxia
• Inadequate monitoring

4. Drug issues

• Overdose of anaesthetic agent / opiate
• Anaphylaxis

Front 11

Bradycardia

Back 11

1. Cardiac Causes

• Ischaemia
• Cardiomyopathy
• Sick sinus syndrome
• Degeneration of conduction pathway
• Myocarditis/pericarditis
• valvular heart disease
• physiological fitness

2. Secondary causes

• electrolyte abnormalities
• raised ICP
• hypothermia
• hypothyroid
• vasovagal / vagal stimulation
• anti-arrhythmic drugs
• oculocardiac reflex

3. Anaesthetic causes

• drugs: narcotics, anticholinesterase
• high spinal / epidural
• vasopressor reflex
• hypoxia

4. Anxiety

Front 12

Tachycardia

Back 12

1. Cardiopulmonary causes

• Ischaemic heart disease
• Cardiomyopathy
• Sick sinus syndrome
• accessory conduction pathway
• myocarditis / pericarditis
• valvular heart disease
• congenital heart disease
• tamponade
• pnuemothorax
• APO

2. Secondary Causes

• Hypovolaemia - blood loss, dehydration, duretics, sepsis
• Hypotension
• Anaphylaxis
• Electrolyte abnormalities
• Sepsis
• Thyrotoxicosis
• Phaeo
• MH
• Anaemia

3. Anaesthetic Causes

• Drugs
• Inadequate depth of anaesthesia / analgesia
• intubation / emergency
• hypoxia / hypoventilation
• pain

4. Anxiety

Front 13

Maternal Collapse

Back 13

1. General causes of collapse

• Vasovagal
• PE
• Cardiac arrest
• Acquired or congenital heart disease
• Anaphylaxis
• Sepsis

2. Anaesthetic

• High Block
• LA Toxicity

3. Obstetric

• Haemorrhage
• Eclampsia
• Uterine Rupture
• AFE
• Aortocaval compression
• Peripartum cardiomyopathy

Front 14

Failure to Wake

Back 14

1. Pharmacological

• Benzos
• Opioids
• Neuromuscular block - inadequate reversal, sux aponea, central anticholinergic syndrome
• IV or volatile anaesthetic agents

2. Metabolic

• Hypo/Hyper glycaemia
• Hypo/Hyper natraemia
• Uraemia
• Hypothermia
• Hypothyroid
• Addisonian crisis

3. Respiratory failure

• Hypoxia
• Hypercarbia

4. Neurological

• Infarction
• Haemorrhage
• Thrombosis
• Air embolism
• Central anticholinergic
• Dissociative coma
• Seizures

Front 15

Regional Anaesthesia Checklist

Back 15

Consent / Contraindications

IV Access

Monitoring, assistance, equipment

Positioning

Landmarks / US anatomy

Endpoints - nerve stimulation or testing block

Front 16

Preparation for any anaesthetic

Back 16

MAADE

Monitoring

Access

Assistance

Drugs

Equipment

Front 17

General crisis management

Back 17

• Declare a crisis, call for help and notify surgeon
  
• Human resource management and role allocation (obtain arrest trolley/defib)
• Simultaneously assess and treat
• FiO2 100% and assess ABC
• Identify causes and consider differentials

Front 18

Management of Errors

Back 18

• Initial management and stabilisation / harm prevention
• Seek advice from senior college / head of department
• Full disclosure and offer apology to patient and/or family
• Documentation in notes, IMMS, M & M meeting
• Notify MDO

Front 19

Lees Revised Cardiac Risk Index Outcomes

Back 19

0 RF - 0.4 % risk of major CV event

1 RF - 0.9%

2 RF - 6.6 %

> 3RF - >11%

Front 20

Lees RCRI measures

Back 20

High Risk Surgery (Intraperitoneal, IntraThoracic, Supringuinal Vascular)

Creatinine > 176.8mcgmol/L

Insulin dependant diabetic

Prior TIA or Stroke

IHD

CCF

Front 21

Child Pugh's Score

Back 21

Predictor of mortality in Liver Disease. Initially during hepatobiliary surgery but now more widely used

Score 5-6 = Class A = 100% one year, 85% 2 year survival

Score 7-9 = Class B = 81% 1 year, 57% 2 year survival

Score 10-15 = Class C = 45% 1 year survival, 35% 2 year survival

Front 22

Meld Score

Back 22

Initially used to predict mortality post TIPS, now used to prioritise for Liver Transplant

Bilirubin, INR, Serum Creatinine combined in a formula to get a score indicating 3 month mortality

• > 40 = 71% mortality
• 30-39 = 52% mortality
• 20 - 29 = 19.6% mortality
• 10 - 19 = 6% mortality
• < 9 = 1.9% mortality

Front 23

Aortic Stenosis Grading

Back 23

• Severe AS: area < 1cm2, Mean gradient >40mmHg
  
• Moderate AS: area 1-1.5cm2, Mean gradient 25-40mmHg
  
• Mild AS: area > 1.5cm2, Meand gradient < 25mmHg

Front 24

Indications for AVR

Back 24

1. Severe AS with symptoms
2. Severe AS with EF < 50%
3. Mod-Severe AS and undergoing other cardiac surgery
4. Severe AS, asymptomatic with abnormal response to exercise

Front 25

Haemodynamic goals in Aortic Stenosis

Back 25

1. Maintain preload
2. maintain afterload
3. sinus rhythm
4. low-normal HR

Front 26

Causes of Aortic Stenosis

Back 26

• Calcific degenerative
  
• Bicuspid Valve
• Rheumatic

Front 27

Prognosis of Aortic Stenosis after Symptoms

Back 27

Congestive Cardiac Failure: 2 years

Syncope : 3 years

Angina: 5 years

Front 28

Mitral Stenosis Causes

Back 28

Rheumatic Disease

Front 29

Mitral stenosis grading

Back 29

1. Normal valve surface area = 4-6cm2
   
2. Symptom-free until 1.6-2.5cm2
3. Moderate Stenosis 1- 1.5cm2
4. Severe stenosis < 1cm2

Front 30

Haemodynamic goals for mitral stenosis

Back 30

• Low normal heart rate 50-70bpm. Treat tachycardia aggressively with beta blockers
  
• Maintain sinus rhythm
• Adequate preload
• High normal SVR
• Avoid hypercarbia, acidosis, hypoxia which may exacerbate pulmonary hypertension

Front 31

Aortic Regurgitation Causes

Back 31

• Acute: Infective endocarditis, dissection
• Aortic root: Marfan's, AS, RA, Syphilis
• Valve: Rheumatic, Bicuspid valve

Front 32

Echo findings in Chronic AR

Back 32

• Vena contracta (narrowest segment of colour jet) > 6mm or >65% outflow tract
• Holodiastolic flow reversal in descending thoracic aorta

Front 33

Echo findings in Severe Acute AR

Back 33

• end diastolic velocity approaches 0 indicating that aortic diastolic pressure = LVEDP
• premature closure of mitral valve

Front 34

Mitral Regurgitation Causes

Back 34

• Mitral valve prolapse
• Dilated cardiomyopathies
• Rheumatic heart disease
• Ischaemic papillary muscle dysfunction
• Endocarditis

Front 35

Echo grading of MR

Back 35

Based on regurgitant fraction

Severe: RF > 50%

Moderate: RF 30-50%

Mild : RF < 30%

Front 36

Haemodynamic goals in MR

Back 36

• Maintain preload
• High HR
• lower afterload
• lower PVR

Front 37

Pulmonary Hypertension Grading

Back 37

Mean Pulmonary Artery Pressure

Mild: 25-50mmHg

Mod: 40-55mmHg

Severe: >55 mmHg

Front 38

Pulmonary Hypertension Classification

Back 38

• Group 1 – PAH (idopathic, heritable, drugs/toxins, connective tissue disorders, congenital heart disease, HIV, Shistosomiasis)
  
• Group 2 – PH due to left heart disease
  
• Group 3 – PH due to chronic lung disease and/or hypoxemia
  
• Group 4 – Chronic thromboembolic pulmonary hypertension (CTEPH)
  
• Group 5 – PH due to unclear multifactorial mechanisms
  

Front 39

Anaesthetic aims in pulmonary hypertension

Back 39

• optimise pre-op
• minimise increase in pulmonary pressures

1. avoid N2O / Ketamine / desflurane
2. avoid decreased paO2, increased paCO2, acidosis
3. avoid increased airway pressures

• Consider dilators, inotropes, vasopressors

Front 40

PPM Codes

Back 40

NASPE Coding

I -> Paced (O,A,V,D)

II -> Sensed (O,A,V,D)

III -> Response (I, T, D, O)

IV -> rate modulation

V -> antitachy functions

Front 41

AICD coding

Back 41

I -> Shock chamber

II -> paced chamber

III -> detection (E, H)

IV -> PPM function as per ppm codes

Front 42

Indications for PPM

Back 42

1. Complete heart block
2. Mobitz type II 2 degree HB
3. Symptomatic bradycardia
4. drug resistant tachyarrhythmias
5. Biventrical for heart failure

Front 43

Indication for AICD

Back 43

1. Previous VT/VF
2. Heart failure with EF < 35%

Front 44

Peripheral Vascular Disease

ABI vs Symptoms

Back 44

ABI 0.6 - 0.9 : Claudication

ABI 0.3 - 0.6 : Rest Pain

ABI <0.3 : Ulcers and gangrene

Front 45

Issues in heart transplant patient

Back 45

Denervation:

- increased resting HR

- resistant to anticholinergics

- poor response to hypovolaemia; stress; valsalva

Complications:

- immune mediated coronary disease

- rejection

- PPM dependance

Immunosuppression:

- Infection, malignancy

- Drug SES (renal & Liver)

- need to continue in periop period

Front 46

Issues in Lung transplant

Back 46

Denervation:

- decreased mucosal sensitivity

- decreased cough

- decreased mucociliary function

- decreased lymphatic drainage

- prone to sputum and oedema

Immunosuppressents:

- infection, malignancy

- steroid dependance

- drug SES (liver, renal)

Intubation/Ventilation

- Protective lung strategies

- ETT just past vocal cords and carefully inflated to minimise damage to tracheal/bronchial anastamosis

Front 47

Marfan's Disease

Back 47

Autosomal dominant connective tissue disorder, FBN1 (fibrillin-1)

Manifestations:

• MSK: tall, long limbs, scoliosis, pectus excavatum, high-arched palate
• CVS: AR, MV prolapse, aortic root dilatation +dissection
• Resp: Spontaneous PTx, fibrosis/emphysema
• Eyes: lens subluxation, astimatism
• Neuro: dural ectasia

Front 48

CHADSVASC Score

Back 48

• CCF
  
• Hypertension
• Age >75 (2 points)
• Diabetes
• Stroke/ TIA (2 points)
• Vascular disease
• Age > 65 but < 75
• Sex (female)

Score out of 90 - no therapy1 - aspirin2 - warfarin / dabigatran / rivaroxaban

Front 49

Cervical Spine X-ray in RA

Back 49

AADI: the distance from the posterior border of the anterior tubercle of the atlas to the dens should be <3mm

PADI: the distance from the posterior border of the dens to the anterior aspect of the posterior arch of C-1. Should be > 14mm

Front 50

Extraarticular Features of RA

Back 50

Skin: nodules, vasculitdes

Eyes: scleritis, sjogrens

Heart: IHF, pericarditis, valvulitis

Lungs: Effusions, Fibrosis

Kidney: Renal amyloidosis

Haematological: anaemia

Neuro: neuropathies

Front 51

Dystrophia myotonica: perioperative management

Back 51

Pre-op:

• assess bulbar weakness
• respiratory function
• CVS function (dysrythmias, MV prolapse, cardiomyopathy)
• Endocrine dysfunction (diabetes, hypothyroid, adrenal insuff, gonadal atrophy)
• Gastric emptying (premed with antacid or prokinetic)

Peri-op

• Avoid sux : prolonged contraction and K release
• non-depolarises are safe but don't always work if myotonia
• Twitch monitoring can trigger tetany
• Neostigmine may provoke contraction
• Invasive arterial monitoring if resp/CVS issues
• Treat spasms with LA directly into muscle or quinine, or phenytoin
• Avoid shivering

Post-op

• HDU care
• Regional analgesia is best

Front 52

Predictors of post-op ventilation in Myasthenia Gravis

Back 52

Leventhal criteria

• Major surgery
• Pyridostigmine dose > 750mg/day
• Disease > 6 years
• Respiratory or bulbar disease
• Vc < 2.9L

Remeber: Myasthenia Patients Deserve Respiratory Ventilation

Front 53

Safe Antiemetics in Parkinsons

Back 53

• Dexamethasone
• 5-HT3 antagonists
• Anticholinergics / Antihistamines
• Domperidone

Avoid Phentiazines / Butyrophenones / Metoclopramide

Front 54

Guillain-Barre : Conduct of anaesthesia

Back 54

• Respiratory support is likely to be necessary
• Autonomic dysfunction leads to severe hypotenstion on induction, PPV and postural change - vasopressors at the ready and pre-hydrate
• Tachycardia to surgical stimulus may be extreme
• Avoid Sux -> hyperkalaemia
• Avoid non-depolarising - use cautiously
• Epidural may be useful

Front 55

CREST

Back 55

• Calcinosis
• Raynaud's
• Esophageal dysmotlity
• Sclerodactyly
• Telangectasia

Localised Scleroderma

Front 56

Scleroderma Anaesthetic issues

Back 56

• Airway : mouth opening
• Oesophogeal dysmotlity
• Heart / Lungs / Kidneys
• Meds