Basic Sciences Viva

Here are some Basic sciences questions from AnaesthesiaUK but arranged in one document.

Define osmosis.

Explain the difference between osmolality and osmolarity.
- What is the importance clinically?

What are Starling’s forces?
- Give the equations and draw a diagram to illustrate.

Describe the anatomy of the pleura, including:
- The innervation.
- The blood supply
- Clinical application: how would you carry out an intrapleural block?

Regarding catecholamines:
- Describe the biochemical pathways and sites of formation.
- Describe the actions of noradrenaline, adrenaline and dopamine.
- Describe the signs, symptoms, and management of phaeochromocytoma.

Describe the physiology of aortic cross-clamping.
- What are side-effects?
- Describe the attenuation techniques.
- Describe spinal, cardiac and renal protection techniques and evidence for their efficacy.

Define Laminar flow/ Turbulant flow

Hagen Poiseulle’s formulae

Factors affecting turbulent flow & how. What is the relevance to anaesthetist? Reynolds number

Variable orifice flow meter. Principle and relevance

Diathermy

physiology/pharmac- ICT/ how different anaesthetic agents affect ICT?

Organ donation issues, neonates?

What are the ways of monitoring the inhalation agents?

Do you know what methods are used in your hospital to monitor inhalation agents?

What is infrared? Tell me how the infrared method works?

How can you be sure that your monitor is accurate?

How will you calibrate this equipment?

Tell me about the piezo electric method

How will you make the crystal vibrate?

Is the frequency important?

Tell me about mass spectrometry

How do you identify the gases as they exit the mass spectrometer?

Flow-volume loop
Draw a normal flow-volume loop.
Draw this in the case of an obstructive lung disorder.
Draw this in the case of a restrictive lung disorder.
Draw this in the case of an upper airway obstruction (e.g. laryngeal).
How is flow measured?



Hospital gas supplies
Draw and describe an oxygen tank.
Describe the liquid, pressure and temperature
Evaporating grid?
In the cylinder: what should be the pressure? What volume of oxygen should it contain and what state should it be in?
What type of valve is found on the cylinder?
From what material is the cylinder made?

Describe the properties of a nitrous oxide tank, in terms of: the manifold, pressure and state?
In the cylinder: what should be the values for pressure, volume and filling ratio?
From what material is the cylinder made?
What is the air source?
What is the air pressure?
What is the difference between an air supply used for anaesthesia and one used for other purposes?

Anaesthesia and the kidneys
Draw a normal nephron; show what gets absorbed and where.
What is the effect of anaesthesia on renal function?
What drugs or gases used by anaesthetists might precipitate acute renal failure?

Larynx
Draw a diagram of the larynx.
Describe the sensory and motor nerve supply.
Describe the actions of the laryngeal muscles.
Describe nerve block for the larynx.
Describe the post-surgical and non-surgical causes of stridor.

Discuss the cytochrome p450 superfamily of enzymes; how do they affect anaesthetic drugs and what are the effects of genetic differences between individuals?

Discuss the strategies for avoiding the necessity of a blood transfusion in a patient.

Describe the anatomy of the caudal space, and discuss caudal block.

Discuss hyperbaric oxygen therapy.

One-lung ventilation (OLV):

What are the indications for OLV?
What are the physiological mechanisms/causes of hypoxaemia with intrathoracic surgery?
How should hypoxaemia on OLV be treated?
How would you apply continuous positive airway pressure (CPAP) to the non-dependent lung?
How could the surgeon assist in applying CPAP?

Answer the following questions on electricity:

What is Ohm’s law?
– What is the difference between direct (DC) and alternating current (AC)?
– Draw a diagram demonstrating the differences between AC and DC.
– Does Ohm’s law apply to AC or DC?
– Is the mains supply AC or DC?
– What is mains current frequency?
– Is the mains current frequency safe?
– If the answer to the previous question is “no”, why is it used?
– Discuss the problem of leakage current. By what mechanisms might a patient suffer?

Discuss the safety features of the anaesthetic machine.

Compare sevoflurane and isoflurane.

Describe the sympathetic supply of the eye.

Discuss the management of carbon monoxide poisoning.

What is meant by laminar/turbulent flow?

What is the Hagen-Poiseuille equation?
What is Reynolds number?
Describe the use of the above concepts in medicine.

Define the following terms:

Log dose–response curve
Agonist
Antagonist
Therapeutic index
Partial agonist

List the various types of antagonists.

Compare morphine and buprenorphine.

Describe the structure and function of the acetylcholine receptor.

Describe the oxygen dissociation curve in different types of hypoxia.

Intercostal nerves

List the branches.

Where are they located? (i.e. between which intercostal muscles?)

Where do they arise from?

Why are the 1st, 2nd and 12th intercostal nerves different?

Which nerve supplies the skin over the back?

Describe the nerve supply to the diaphragm.

How is an intercostal nerve block performed (site, volume etc.)?

Describe the location and arrangement of the neurovascular nerve bundle.

When an intercostal nerve block is performed, where and how does the local anaesthetic spread?

What are the complications of an intercostal nerve block?

Adrenaline:

What receptors does it act on?

Where is it secreted from?

How is it metabolised?

How is it synthesised?

Why is it used in local anaesthesia?

What are the systemic effects of adrenaline?

Discuss the physics of ultrasound.
- How is it generated?
- What is the frequency used?
- Are the waves sent continuously?
- What is the Doppler effect?
- What does it measure?
- Describe the uses of ultrasound.
- Describe the various types of echocardiography
- What are their uses?
- How would you measure cardiac output using echocardiography?
- What are the other uses of ultrasound?

Describe the factors that influence intraocular pressure (IOP).
- What is rate of production of aqueous humour?
- Where is it produced?
- Describe the drainage of the aqueous humour, and the use of mydriatics and miotics.
- What are the effects of drugs on IOP?
- What are the effects of suxamethonium on IOP?
- What is sulphur hexafluoride (SF6), and what are its implications for the anaesthetist?

Draw a sketch illustrating the elimination of thiopentone.
- How many compartments is it distributed into?
- What is its alpha half-life, beta half-life, elimination half-life?
- What are its apparent volume of distribution and clearance values?
- To what extent is it protein bound?
- How is it metabolised?
- What is the half-life of pentobarbitone?
- Describe the pharmacodynamics of thiopentone.
- What is its mechanism of action?
- Following thiopentone administration, which decreases first: cerebral metabolic rate or cerebral blood flow?
- What are the implications of using thiopentone in patients with hypovolaemia?
- What are the effects of thiopentone on the respiratory system?
- What are the effects of thiopentone on the renal system?
- How does thiopentone lead to porphyria?
- What is the pH of thiopentone and why is it stored with nitrogen?
- Why does it smell of garlic?

How would you assess the nutrition of patients in the intensive care unit?
- What is the average calorific requirement of a 70 kg adult?
- How would you provide this?
- Which type of foodstuff is best to administer, and why?
- How much carbohydrate and protein should be given?
- What is immunonutrition?
- What else would you give such patients?
- What trace elements would you provide?

Discuss the physical principles underlying haemofiltration and haemodialysis.
- What are the qualities of an ideal membrane?
- What factors affect the amount of fluid you can remove from a patient?
- What else, besides metabolic toxin removal, can haemofiltration be used for?
- What are the complications of haemodialysis?

Describe the innervation of the inguinal area.
- How would you perform a block?

What are the physical properties of nitrous oxide?
- How is it made?
- What is the second gas effect?
- What are the advantages and disadvantages of using nitrous oxide?

Discuss the physiology of muscle contraction (including the interaction of actin and myosin).
- Discuss the incidence, genetics, features, and reasons for muscle features of myotonia.

Describe the physical principles behind magnetic resonance imaging (MRI).
- What are the advantages and disadvantages of MRI compared with computed tomography?
- Which patients are not suitable for MRI and why?
- Where is the MRI scanner usually located in the hospital and why?
- What problems are associated with MRI?

Define drug tolerance.
- Describe the different ways in which tolerance can occur and give examples.

Draw a diagram of the epidural space.
- What is found in this space?

Describe the pathophysiology of diabetic ketoacidosis (DKA).
- What is the anion gap?
- When would you take a patient to theatre with DKA?

Why do you require a scavenging system?
- Can you name any other methods of preventing pollution?
- What are the normal acceptable levels of various anaesthetic gases the theatre environment?
- Is it an international system?
- Name the normal parts of the active and passive scavenging system?
- What are the advantages and disadvantages of each?
- What is the Cardiff inhaler?
- What are its advantages and disadvantages?
- Describe the toxicity associated with nitrous oxide (NO)?
- Give details of how NO causes megaloblastic anaemia and subacute combined degeneration of the spinal cord?

Describe the anatomy of the cervical plexus.
- Describe the technique for performing cervical plexus block for carotid endarterectomy(both superficial and deep).
- What are the complications of performing this block?
- Describe local anaesthetic toxicity.
- What are the maximum doses that can be used for local anaesthetics?
- What level of bupivacaine causes convulsions?
- What are the advantages and disadvantages of performing carotid endarterectomy with the patient asleep and under local anaesthetic?

What are the effects of the following anaesthetic drugs on cerebral blood flow (CBF)?
- Premedication with benzodiazepines.
- Opiates.
- Induction agents.
- Volatile agents.
- Muscle relaxants.
- What other factors affect CBF?
- Draw a graph of mean arterial pressure/O2/CO2 and CBF.
- Describe ways of reducing intracerebral pressure intraoperatively and postoperatively.
- Describe the mechanism of action of drugs such as mannitol and acetazolamide.

Describe the mechanism of blood clot formation when a blood vessel is injured.
- What other protective mechanisms are triggered?
- What mediators are released?
- What is Virchows triad?
- Draw a flow chart showing the sequence of events from platelet activation through to clot formation.
- What mediators are released by the platelets?
- Show on this chart where heparin works.
- Which patients will be at high risk for deep vein thrombosis (DVT)?
- How can DVT be prevented, pharmacologically and non-pharmacologically?
- How effective are calf compressors (give a percentage)?
- What is the mechanism of action of heparin, low-molecular weight heparin (LMWH), warfarin and protamine?
- What is the difference between heparin and LMWH?

Discuss the physics of MRI.

Discuss the anatomy of the ulnar nerve.

Discuss the oxygen dissociation curve for normal haemoglobin.
- How does this change in the case of sickle cell haemoglobin?
- Discuss the diagnosis of sickle cell disease.

Discuss the classification of opioid receptors, and their endogenous ligands.