8. Cardiothoracic

Question 1

Regarding the measurement of blood pressure in an adult with a sphygmomanometer, the systolic and diastolic pressures respectively are best indicated by which Korotkov sounds?

A. I and II

B. I and IV

C. I and V

D. II and IV

E. II and V

Answer 1

C. I and V

Question 2

.

Answer 2

Phase I is the first appearance of sound which indicates the systolic.

Phase IV is the abrupt muffling of sounds that was previously used for estimation of the diastolic.

More recently there has been a
move towards using phase V (silence) instead to indicate the diastolic as this is more reproducible
and less amenable to interobserver variation

Question 3

A 62- year- old man is managed in cardiac intensive care with cardiogenic shock following acute myocardial infarction. He has oliguria, raised
lactate, and altered mental status. Which of the following is an absolute contraindication to the use of an intra- aortic balloon pump?

A. Aortic regurgitation
B. Uncontrolled sepsis
C. Tachyarrhythmia
D. Peripheral vascular disease
E. Abdominal aortic aneurysm

Answer 3

A. Aortic regurgitation

Question 4

C/I to IABP

Answer 4

Aortic regurgitation is the only absolute contraindication as the presence of the IABP worsens the
magnitude of regurgitation, particularly undesirable when the left ventricle is failing

Question 5

The most accurate means of measuring cardiac output
is

A. Pulse contour analysis LiDCO
B. Echocardiography
C. Thoracic bio-
impedance
D. Oesophageal Doppler
E. Pulmonary artery catheter

Answer 5

E. Pulmonary artery catheter

Question 6

Gold standard for CO

Answer 6

A pulmonary artery catheter (PAC) with
thermodilution is the gold standard monitor
to measure cardiac output.

It is currently out of favour outside
specialist centres due to the skill required for
correct positioning and the increased risk of major complications.

Question 7

Other ways measure CO issues

Answer 7

A search for less or non- invasive
cardiac output monitoring has led to the advent of many new devices.

However they are subject to varied areas of error/
estimation leading to potential problems with accuracy.

A PAC remains the standard against which other less invasive monitors are measured

Question 8

Regarding paravertebral block, the most common complication is:
A. Pneumothorax
B. Hypotension
C. Vascular puncture
D. Dural puncture
E. Block failure

Answer 8

E. Block failure

Question 9

Complications PVB

Answer 9

The failure rate of paravertebral block in
experienced hands is
quoted between 6.8% and 10%

which his broadly similar to epidural failure rates.

Specifically reported complications include
hypotension 4.6%,
vascular puncture 3.8%,
pleural puncture 1.1%,
and pneumothorax 5.5%.

The risk of complications resulting in long-
term morbidity are exceedingly low

Question 10

A 68- year-old lady presents for an emergency laparotomy for a suspected viscus perforation.

She has chronic moderate mitral
regurgitation.

What is the most important haemodynamic goal in her
perioperative management?
A. Keep pulmonary vascular resistance as low as possible
B. Maintain forward flow through the
heart
C. Aim to reduce preload to the
heart
D. Aim for a slow normal heart
rate
E. Use vasoconstrictors to increase systemic vascular resistance

Answer 10

B. Maintain forward flow through the
heart

Question 11

Goal for regurgitant lesion

Answer 11

For regurgitant lesions the haemodynamic goals are ‘full, fast, and forward’.

Keeping pulmonary vascular resistance as low as possible will help this but can only be achieved by
avoiding hypoxia, hypercarbia, and acidosis

Question 12

How to Rx problems for regurg lesion

HR Goals

Answer 12

Decreased arterial pressure should be treated with fluids and elevating the heart rate.

A high normal heart rate of 80–100 reduces filling time of left ventricle reducing ventricular overload and
encouraging forward flow.

Keeping the patient well filled also promotes forward
flow.

Vasoconstrictors can be used with
care.

Question 13

You anaesthetize a 61 year- old lady for a coronary artery bypass graft.

She is on aspirin and clopidogrel following a myocardial infarction three months ago.

You intend to monitor her coagulation status using
thromboelastography.

Which of these statements most accurately
describes the use of a viscoelastic point-
of care device?

A.
It will reflect the effects of hypothermia
B.
It will demonstrate the effects of aspirin
C.
It will demonstrate the effects of clopidogrel
D.
It can guide the administration of specific blood products
E.
It is more cost effective than conventional laboratory
tests

Answer 13

D.
It can guide the administration of specific blood products

Question 14

TEG and ROTEM are

Answer 14

Thromboelastography (TEG) and
rotational thromboelastometry (ROTEM)

are visco-elastic point-of-care devices
providing rapid bedside assessment
of the overall coagulation status of the patient.

Derived parameters can guide the administration of specific blood products.

Question 15

TEG and ROTEM insensitive to

Answer 15

Their tracings are insensitive to
aspirin and clopidogrel

and are poor at detecting conditions

affecting platelet adhesion
such as Von Willebrand’s disease.

It will not reflect the effects of hypothermia as the measurement is undertaken at 37°C.

It is currently more expensive that conventional testing

Question 16

A 28- year- old man is in the Emergency Department resuscitation room.

He was the driver of a car involved in a head on collision at 40 mph.
He has no significant past medical history.
You carry out the primary survey.

Which potential injury on primary survey is the most
immediately life threatening?

A. Myocardial contusion
B. Pulmonary contusion
C. Massive haemothorax
D. Diaphragmatic rupture
E. Traumatic aortic
injury

Answer 16

C. Massive haemothorax

All of these injuries are severe and in keeping with major thoracic blunt force trauma.

The most immediate life- threatening injury is massive haemothorax requiring chest drain insertion and
thoracotomy if persistent

Question 17

Management of high impact injuries principles

Answer 17

The brief description indicates a high energy impact which raises suspicion of significant injury.

Principles of management are in keeping with the advanced trauma life support doctrine of primary
and secondary surveys with definitive management.

The primary survey focuses on the airway,
breathing, circulation, disability, and exposure (ABCDE) principle.

This is conducted simultaneously with resuscitation of vital functions as set out in the Advanced Trauma Life Support Manual.

The immediately life- threatening injuries identified and treated on primary survey are indicated by the acronym ATOM- FC

Question 18

Immediate life- threatening injuries

Answer 18

ATOM- FC

Airway obstruction
Tension pneumothorax
Open pneumothorax
Massive haemothorax
Flail
chest
Cardiac tamponade

Question 19

Potentially life-threatening injuries

Answer 19

Traumatic aortic injury
Pulmonary contusion
Myocardial contusion
Diaphragmatic rupture
Oesophageal rupture
Tracheobronchial rupture

Question 20

A 59- year- old man is in Intensive Care with severe cardiogenic shock following a massive myocardial infarction.

He has not responded to initial treatment with inotropes so an intra- aortic balloon pump (IABP)
is inserted. What is the most common side effect of IABP insertion?

A. Aortic dissection
B. Iliac dissection
C. Infective endocarditis
D. Aortic perforation
E. Limb ischaemia

Answer 20

E. Limb ischaemia

All of the above are possible complications but limb ischaemia is the most common. Limb ischaemia
can usually be resolved by repositioning or removal of the balloon

Question 21

15. A 72- year- old man presents for a coronary artery bypass graft. You use the EURO Score II to determine his operative risk during your pre- assessment. Which of these factors conveys the highest risk?

A. Emergency surgery
B. Ejection fraction <20%
C. Age >60
D. Chronic lung disease
E. A myocardial infarction 70 days
ago

Answer 21

B. Ejection fraction <20%

Question 22

Blood flow balance in shunt

Answer 22

Blood flow to the lungs and body is a balance between systemic vascular resistance (SVR) and
pulmonary vascular resistance (PVR).

Examples of children with balanced circulation physiology who may present to local hospitals are infants with a large unrepaired atrioventricular septal defect or VSD.

Question 23

ASD - VSD flow physiology

Answer 23

These infants have predominantly left- to- right shunt flow.

High concentrations of oxygen will
increase pulmonary blood flow (PBF) and reduce systemic perfusion;

conversely, large doses of induction agent
may reduce SVR so much that
shunt flow is reversed causing
reduced PBF, worsened shunt, and desaturation

Question 24

Propofol affect on shunt dynamics in septal defects

Answer 24

Propofol profoundly decreases SVR and MAP,
which alters shunt dynamics to
favour right to left flow and cyanosis.

Hyperventilation reduces PVR by removing CO2
and phenylephrine increases SVR,

favouring a left to right shunt,
improving pulmonary blood flow
and reducing cyanosis.

PEEP increases PVR

Question 25

20. You are comparing pressure– volume curves in asthmatic patients during an acute asthma attack and comparing it with healthy subjects.

Which of the following observed differences is the best indicator of the increased work of breathing in the patients with asthma?

A. Larger hysteresis loop
B. Longer expiratory time
C. Pressure– volume curve starts at a higher end-
expiratory pressure
D. Slope of the inspiratory limb is initially less
steep
E. Tidal volume is smalle

Answer 25

A. Larger hysteresis loop

Question 26

DCM affect

Answer 26

Dilated cardiomyopathy results in impaired ventricular function secondary to progressive dilatation.

Patients present with symptoms of chronic heart failure, embolic events, or arrhythmias.

Question 27

DCM anaesthetic management

Answer 27

The important anaesthetic management aims
are to maintain sinus rhythm,
avoid tachycardia,
and reduce or avoid increases in afterload.

Cautious fluid management is
important and should be goal directed.

Preload should be maintained especially in the presence of elevated left ventricular end
diastolic pressure,
but fluid overload should be avoided

Question 28

Pacemaker coding system

Answer 28

Pacemakers are coded as per a standard international system.

1. The first letter denotes chamber paced
   (V, ventricle; A, atrium; D, dual).
2. The second is chamber sensed (V, A, D)
3. The third is the mode of response
   (T, triggered; I, inhibited; D, dual).
4. The fourth letter denotes
   any programmable functions.
5. The fifth letter refers to
   special antitachycardia factors.

Question 29

A 70- year- old man has been diagnosed with bronchial cancer in his left lower lobe.

He is being investigated and pre-
assessed for a lobectomy.
Which result from his investigations would indicate he is potentially
unsuitable for surgery?

A. An FEV 1 of 1.1 L
B. VO2max of 25 mL/kg/min
C. Predicted postoperative FEV1 of 50%
D. Arterial PaCO 2 of 6.5 kPA
E. Oxygen saturation on room air of 91%

Answer 29

A. An FEV 1 of 1.1 L

Question 30

Suitable for lobectomy PFT FEV1

Answer 30

A preoperative FEV1 of
>1.5 L generally indicates
suitability for lobectomy.

Less than this would require further investigation
and may preclude surgery.

If qualitative lung function tests
confirm a predicted postoperative FEV1
≥40% and a predicted postoperative TLCO ≥40%,
it would be safe to proceed to surgery

Question 31

Pao2 and O2 sat in lobectomy

Answer 31

Arterial PaCO2 ≥6 kPa does not appear to be an independent predictor of poor outcome.

Oxygen saturation ≤90% has been associated with an increased risk of complications.

Question 32

Transplanted heart differs how

Answer 32

The transplanted heart has
no autonomic innervation and the resting heart rate will sit around 100 bpm due to loss of vagal tone.

This denervation also alters the pharmacological response to some commonly used anaesthetic
drugs.

Vagolytics such as atropine and glycopyrrolate have no effect on a denervated
heart.

Metaraminol would not treat the bradycardia

Question 33

Drugs to increase HR in denervated heart

Answer 33

Ephedrine, adrenaline (epinephrine), and isoprenaline could all be used to give positive chronotropy
but they should be used cautiously as there may be an exaggerated response.

Adenosine also
demonstrates denervation hypersensitivity and should be used in smaller doses.

Question 34

Thoracotomy principles

Answer 34

Wherever possible, use should be made of synergistic, balanced, multimodal analgesia.

Thoracotomy is notoriously painful postoperatively and creates a challenging acute postoperative
pain management issue.

Additionally, good acute pain management in thoracotomy may reduce the incidence of chronic neuropathic pain.

The decision as to which technique to use for a particular patient is usually a matter of the anaesthetist’s preference and local unit practices.

Question 35

Regional in thoracotomy issues

Answer 35

Regional and neuraxial methods have obvious advantages but are associated with patchy coverage and a significant failure rate.

Some afferent routes will not be blocked by the techniques described above
(for example diaphragmatic irritation via the phrenic nerve) and many patients will also have chest drains inserted.

Question 36

Overall principle thoracotomy

Answer 36

If additional systemic analgesics can be administered, global analgesia will be improved.

Regular paracetamol, NSAIDs where appropriate, parenteral or oral opioids are good choices in addition to a regional technique, embracing the doctrine of balanced multimodal analgesia

Question 37

<2cm PTX with no symptoms management

Answer 37

The patient can be assumed to have a secondary spontaneous pneumothorax due to his age
>50 years and significant smoking history.

However, the pneumothorax is small based on the chest X-ray measurement and there are no obvious signs of current respiratory compromise.

Therefore, an initial attempt can be made at aspirating air with a 16–18G cannula.

The volume should be less than 2.5 L and the attempt at aspiration should abruptly cease indicating an expanded lung with no ongoing air leaks.

A follow- up chest X- ray should demonstrate an improvement in pneumothorax size (<1 cm), otherwise a chest drain will subsequently be required

Question 38

> 2cm PTX / symptoms

Answer 38

If a secondary pneumothorax is larger (>2 cm) or the patient is breathless, then chest drain
insertion is the correct initial action.

All patients with a secondary pneumothorax should be
admitted, commenced on oxygen therapy, and observed for 24 hours.

Question 39

intervention when a patient has been repositioned with DLT

Answer 39

Changes in airway pressures occur commonly during thoracic procedures.

The clue as to their cause is often related to the most recent intervention.

This should be considered as well as general
differential diagnoses.

In this case the patient has just been turned onto their side and even slight movement of the endotracheal tube can change airway pressures significantly if, for example, the tube moves further into a main bronchus or occludes a lobar bronchus.

Positioning of the tube should be reconfirmed each time the patient position is changed.

Question 40

Other interventions

Answer 40

Auscultation of the chest may reveal areas without air entry or reduced air entry but this is less reliable due to transmitted sounds and ambient noise in theatre.

If the patient is thought to be coughing, then suctioning of mucous and ensuring adequate muscle relaxation would be relevant.

The capnography trace may confirm an obstructive pattern of air flow but may also be normal. It
does not help to identify the cause of the problem.

Question 41

What is WOB

What is required to overcome during inspiration and expiration

Answer 41

The work of breathing is the work required to move the lungs both in inspiration and in expiration.

During inspiration the work is to overcome airway resistance and during expiration it is to overcome compliance.

On a pressure–volume curve the work of breathing is best indicated by the area within the hysteresis loop.

Hysteresis means that the curves in inspiration and expiration are different

Question 42

Obstructive vent disorder

Answer 42

In obstructive ventilation disorders such as asthma, more work is needed to overcome the flow
resistance, particularly if positive intrapleural pressures are generated in expiration and this will be
reflected in a larger hysteresis loop on the curve