Question 27

A 60-year-old patient is admitted to ICU following a MET call 7 days post emergency repair of a ruptured abdominal aortic aneurysm. Blood cultures grew Staphylococcus aureus and Enterobacter cloacae on day 5. On admission the patient is confused, restless and diaphoretic. The blood pressure is 60/40 mmHg and heart rate is 148 beats/min.

a) List the most likely sources of the bacteraemia. (30% marks)

b) Outline your management plan for the septic shock. (70% marks)

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College answer

Many candidates had a poor structure to their answer. Despite being 30% of the marks, many candidates had limited list of sources in part a). Answers were often lacking any detail in the resuscitation of the patient, which was required based on the scenario presented.


a) is a bug hunt: an exercise of guessing what the examiners are thinking. The writer of the question would have had some idea of what they thought were appropriate sources to list, and you have to guess what these were. When playing a game of Where's The Source, there are many methods of listing possible options, all of which are equally valid because they represent mnemonics and aide-mémoires. Observe:

  • CNS
    • Unlikely, but meningitis? (S.aureus)
  • Orofacial
    • Nasogastric tube associated sinusitis (S.aureus)
    • Periodontal infection (could be either S.aureus or E.cloacae)
  • Skin and soft tissue
    • Invasive devices (CLAB, S.aureus)
    • Cellulitis (S.aureus)
  • Thoracic
    • Lungs (VAP, could be either S.aureus or E.cloacae)
    • Valves (endocarditis, S.aureus)
  • Abdominal
    • Endovascular graft (could be either S.aureus or E.cloacae)
    • Ischaemic gut (E.cloacae)
    • Psoas abscess (could be either S.aureus or E.cloacae)
    • Intraabdominal collection, if the repair was open (E.cloacae)
  • Pelvic
    • Urinary tract (E.cloacae)
    • Genital tract (E.cloacae)
    • Rectum, eg. bowel management system (E.cloacae)
  • Upper limb
    • Peripheral cannula sites (S.aureus)
  • Lower limb
    • Infected foot ulcers (if the patient had an abdominal aortic aneurysm, one might surmise that their circulatory system is not in a pristine condition, and there may be some peripheral vascular disease which is commonly associated with unhealing lower limb ulcers)
    • Pressure areas (there should not be any that could be attributed to the ICU stay, but the stem does not mention anything about the patient's background)

b) is also, to some extent, an exercise in guessing what the examiners were thinking. Obviously the content of their minds remains inscrutable, but we can guess that "detail in the resuscitation of the patient" was required, and from previous SAQs such as Question 1 from the second paper of 2014, where a detailed management plan is laid out. 

  • Resuscitation
    • Establish IV access (PIVCs to begin with, but ultimately this patient needs a new central line)
    • Retrieve blood cultures (two sets)
    • Commence fluid resuscitation with crystalloid (20ml/kg bolus, if you believe that sort of thing)
    • Concurrently support blood pressure with noradrenaline or metaraminol
    • Insert invasive arterial monitoring to assist titration of vasoactive agents
      • Aim for MAP > 65 and use lactate measurements to guide further reassessment
      • Reassess fluid responsiveness and administer further fluid boluses as needed
    • If fluid responsiveness decreases and the patient remains unstable hemodynamically and/or with raised lactate:
      • Bedside TTE to determine contractility and chamber filling
      • If the filling is adequate and contractility is vigorous, a vasopressin  infusion can be commenced and "stress dose" steroids can be considered
      • If the contractility is globally poor, septic cardiomyopathy should be considered and inotropes commenced (with a heart rate of 148, this is unlikely, but this rate could represent some sort of arrhythmia and contractility may still be an issue)
  • Specific management
    • Immediately start antibiotics that target the known organisms
      • Meropenem for the E.cloacae, as many of these will be resistant to extended spectrum β-lactams
      • Vancomycin for the S.aureus, which can potentially deescalate to cephazolin once the sensitivities are established
    • Remove old lines
    • Collect cultures of the the sputum and urine
    • Scan the chest abdomen and pelvis with a contrast CT (because that's how you investigate S.aureus bacteraemia anyway), but also to explore the possibility that the aortic graft might be infected
      • Consult the vascular surgical team regarding this possibility
    • Consider a TOE if the CT reveals no collections, or (even worse) reveals multiple collections suggestive of emboli
  • Supportive management
    • The patient should remain nil-by-mouth
    • ​​​​​​​If the confusion and restlessness do not resolve enough for the CT to be possible, the patient may required sedation or even intubation
    • Anticoagulants and aspirin should be withheld, in case explantation of the graft may be imminent


Vogel, Todd R., Rebecca Symons, and David R. Flum. "The incidence and factors associated with graft infection after aortic aneurysm repair." Journal of Vascular Surgery 47.2 (2008): 264-269.