CICM SAQ 2015.2 Q19


  • a) Interpret the three pharmacodynamic (PD) profiles, labelled Scenario 1, Scenario 2 and Scenario 3, shown below.
  • b) For each PD profile, describe how you would optimise the dose and/or frequency of antibiotic if prescribing:
    • i) a beta lactam
    • ii) an aminoglycoside
Scenario 1
Scenario 2
Scenario 3


Answer and interpretation

a) Interpret the three pharmacodynamic (PD) profiles

Scenario 1

  • Drug concentration does not reach MIC
  • Ineffective dose

Scenario 2.

  • Drug concentration is well above MIC
  • Repeat dose maintains the concentration above MIC but increases the AUC: MIC ratio.

Scenario 3

  • Peak drug concentration is well above MIC
  • Significant period of interval between doses where drug level is below MIC

b) For each PD profile, describe how you would optimise the dose and/or frequency of antibiotic if prescribing:

Methods to optimise:

(i) Beta Lactam agents:

Scenario 1

  • Increase dose
  • More frequent dosing
  • Consider continuous infusion after an appropriate loading dose

Scenario 2

  • Decrease dose
  • Less frequent dosing intervals
  • Continuous infusion

Scenario 3

  • More frequent dosing interval
  • Continuous infusion

(ii) Aminoglycosides

Scenario 1

  • Increase dose

Scenario 2

  • Prolong dosing interval
  • Therapeutic drug monitoring to avoid drug toxicity

Scenario 3

  • No change
  • Could consider higher dose
  • Pass rate: 75%
  • Highest mark: 8.0
Exams LITFL ACEM 700

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Chris is an Intensivist and ECMO specialist at the Alfred ICU in Melbourne. He is also a Clinical Adjunct Associate Professor at Monash University. He is a co-founder of the Australia and New Zealand Clinician Educator Network (ANZCEN) and is the Lead for the ANZCEN Clinician Educator Incubator programme. He is on the Board of Directors for the Intensive Care Foundation and is a First Part Examiner for the College of Intensive Care Medicine. He is an internationally recognised Clinician Educator with a passion for helping clinicians learn and for improving the clinical performance of individuals and collectives.

After finishing his medical degree at the University of Auckland, he continued post-graduate training in New Zealand as well as Australia’s Northern Territory, Perth and Melbourne. He has completed fellowship training in both intensive care medicine and emergency medicine, as well as post-graduate training in biochemistry, clinical toxicology, clinical epidemiology, and health professional education.

He is actively involved in in using translational simulation to improve patient care and the design of processes and systems at Alfred Health. He coordinates the Alfred ICU’s education and simulation programmes and runs the unit’s education website, INTENSIVE.  He created the ‘Critically Ill Airway’ course and teaches on numerous courses around the world. He is one of the founders of the FOAM movement (Free Open-Access Medical education) and is co-creator of litfl.com, the RAGE podcast, the Resuscitology course, and the SMACC conference.

His one great achievement is being the father of three amazing children.

On Twitter, he is @precordialthump.

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