Drug Metabolism

BT_GS 1.11  Describe the mechanisms of hepatic and non-hepatic metabolism of drugs….


T / F   a phase 1 reaction exposes a polar group on the parent molecule, rendering it more water soluble

T / F  all phase 1 reactions are catalysed by the CYP450 enzymes

T / F  adding (conjugating) glucuronide to the parent molecule is an example of a phase 2 reaction

T / F  phase 2 reactions decrease the activity of the parent compound

T / F  CYP2D6 metabolises codeine to morphine – this enzyme is absent in 1% of caucasians


Is pharmacogenetic testing the “new frontier” of pharmacology? Your patients might have seen websites like this one from the Mayo clinic. Some patients are already coming to hospital with their “genetic printout” stating which drugs they should have!


BT_PO 1.82a  Outline basic cellular physiology, in particular …. energy production by metabolic processes in cells

BT_PO 1.83  Describe the physiological consequences of starvation


T / F  ketones are produced from the oxidation of free fatty acids

T / F  the important role of ketones is as an alternative fuel source to glucose for the brain – this decreases the protein catabolism which occurs via gluconeogenesis

T / F  lipolysis is stimulated by insulin, adrenaline, and cortisol

T / F  ketones provide a source of acetyl-CoA for use directly in the TCA cycle (structurally, ketones consist of actetyl groups)

T / F  in poorly nourished patients (frail elderly, alcoholics etc), a short period of fasting can induce starvation ketoacidosis


I’m not sure that taking ketone pills is a good idea!!

Now that you have thought about ketones….
i) find out if any of the glucometers in your hospital can also measure ketones (if not, how else could you diagnose ketosis?) 
ii) how would you treat starvation ketoacidosis in a non-diabetic?


IV Fluids – Crystalloids

IT_GS 1.5   Describe the chemical composition of crystalloids and colloids used in clinical practice and their effects when used in volume replacement


salt being produced at Shark Bay, Western Australia


T / F   the osmolarity of Hartmann’s solution is 255 mOsm/L, which is slightly lower than plasma

T / F   lactate is included in Hartmann’s because it gets metabolised to bicarbonate in the liver

T / F   5% glucose is a way of giving free water without causing haemolysis

T / F   5% glucose and “4% and a fifth” are iso-osmolar but hypo-tonic

T / F   if one litre of 0.9% saline is given rapidly IV, half of it will remain in the intravascular space after 4 hours

IV Fluids – Albumex

IT_GS 1.5   Describe the chemical composition of crystalloids and colloids used in clinical practice and their effects when used in volume replacement

stiff peaks2

The word albumin is derived from the Latin albus, meaning “white” (in reference to the white of an egg). Albumin is the most abundant egg white protein (although it’s ovalbumin – not quite the same as human serum albumin). Ever wondered why you can get “stiff peaks” to form when you beat egg whites? Click here to find out.

T / F   “Albumex 4” contains 4 g/L of albumin

T / F   Albumex is not a human blood product, because it is manufactured by recombinant DNA techniques

T / F   Albumex contains 150 mmol/L Na+ and 150 mmol/L Cl-

T / F   Albumex is rendered free of possible virus transmission by pasteurisation (heating to 60 degrees C for 10 hours)

T / F   the half life of albumin in the circulation is 48 hours

Medical Latin

We use Latin abbreviations all the time….. do you know the meanings of any of these terms?


T / F    PRN is the abbreviation for pro re nata which means “never actually given”

T / F    “stat” is short for statim which means “melodramatic”

T / F    “Q” (as in Q4H) is short for quaque, which means “every”

T / F    “PO” is the abbreviation for per os, meaning “through the mouth” – NOT “go away”

T / F    “TDS” (ter die sumendum) and “TID” (ter in die) are equally acceptable for “three times a day”


For those sitting the written exam on Tuesday – all the very best!!!

Ventilation / Perfusion (V/Q) Relationships

BT_PO 1.26 Discuss normal ventilation-perfusion matching

BT_PO 1.29 Discuss ventilation-perfusion inequalities, venous admixture and the effect on oxygenation and carbon dioxide elimination


T / F   the V/Q ratio at the apex of the upright lung is 3.3, because the apex receives most of the alveolar ventilation

T / F   in a conscious person lying on their left side, the left lung will receive more ventilation AND perfusion than the right lung

T / F   in an anaesthetised ventilated patient lying on their left side, the left lung will receive more ventilation AND perfusion than the right lung

T / F   atelectasis results in an increase in alveolar dead space, which can cause hypercapnoea

T / F   a decrease in cardiac output can decrease mixed venous PO2 – this will magnify the hypoxaemia produced by any alveolar shunt

Nitrous Oxide

BT_GS 1.27 Describe the pharmacology of nitrous oxide


T / F   nitrous oxide does not support combustion

T / F   nitrous oxide acts synergistically with volatile agents to produce anaesthesia

T / F   nitrous oxide does not cause any peripheral vasodilation

T / F   nitrous oxide acts on GABA receptors in the brain

T / F   nitrous oxide use is associated with post-operative MI

Serotonin Syndrome

BT_PO 1.102 Discuss the clinical features and management of serotonin syndrome


T / F   all serotonin receptors are ligand gated ion channels

T / F   tramadol, pethidine, fluoxetine, amphetamines and amitriptyline are all potentially serotonergic

T / F   monoamine oxidase inhibitors are not serotonergic

T / F   features of serotonin syndrome include: CNS excitation; hyperthermia; and hyper-reflexia

T / F   treatment is usually supportive, although cyproheptadine is a potential antidote


BT_SQ 1.5 Describe basic physics applicable to anaesthesia, in particular:
…. principles of humidification and use of humidifiers ….


T / F   during quiet breathing, air reaching the carina is close to 37 degrees C and 100% relative humidity

T / F   at 37 degrees C, air can hold a maximum of 44 mg/L of water vapour

T / F   during expiration, water vapour condenses onto the airway mucosa

T / F   absolute humidity depends upon both the temperature and the atmospheric pressure

T / F   a HME can warm inspired gases to about 30 degrees C, but this takes about 20 minutes

Historical Perspectives on Anatomy and Physiology

It’s easy to falsely assume that anatomy has been an unchanging science, which has “always” existed. This is far from the truth. Furthermore, all advances in understanding of physiology have followed later, often centuries after the accurate anatomical descriptions were made.

Consider respiratory physiology. The process we call “gas exchange” was still being debated in the 1920’s. Many physiologists at the time proposed a mechanism whereby oxygen was actively transported into the blood from the alveoli!

The fact that air contains a mixture of separate gases (one of which is oxygen) was not understood until the late 1700’s! Until oxygen was discovered, no one understood why breathing and living were connected.

Andreas Vesalius (1514-1564) was probably the first to realise that the life of an experimental animal could be sustained, if the lungs were repeatedly inflated with air. To do this experiment, he used fireside bellows and a tracheotomy. Vesalius is depicted on the ANZCA coat of arms, holding a bellows, as a tribute to him as a founder of respiratory physiology. Of course, he had no idea that air contained oxygen – his work preceded the discovery of oxygen by 200 years. Vesalius is also hailed as the father of anatomy – he did accurate human dissections that overturned centuries of erroneous teaching.

Leonardo da Vinci (1452-1519) is also credited with many anatomical discoveries. However, he also struggled to understand function. Consider his description of the mechanics of breathing: “When the lung has driven out the wind and is so diminished in size by an amount equal to the wind which has left it, one ought then to consider from where the space of the capsule [pleura] of the diminished lung attracts to itself the air which fills it on its enlargement, since in nature there is no vacuum.” Here, da Vinci was hindered by the philosophical view of Galen that “nature abhors a vacuum” (horror vacui), although his thought process is remarkable given that he was basically coming up with these theories from scratch.

It’s so interesting to read about the history of discoveries in science (especially those that have a direct influence on our clinical work). AFTER the exam, I would recommend Chapter 34 of Nunn (8th edition). This chapter is available only in the on line edition.