Question 17

College Answer

Primary problem not fixed:

Untreated focus of infection/ inadequate primary source control e.g. pancreatic abscess, infected pseudocyst.

New septic site e.g. central line/ hospital acquired pneumonia / cholecystitis, urinary tract.

Systematic approach i.e. Hypovolaemic / obstructive / cardiogenic / distributive +/- endocrine etc.

• Hypovolaemia or hidden bleeding
• E.g. From surgical site/ peptic ulcer, “third space” losses (e.g. ascites from peritonitis)
• Undiagnosed or new “obstructive shock”:

• Tension pneumothorax / Pericardial effusion / gas trapping (auto PEEP) / pleural effusions / pulmonary emboli
• Severe Intra abdominal hypertension
• Dysrhythmia e.g. SVT, junctional rhythm etc.
• New myocardial ischaemia
• New/ undiagnosed cardiac valve pathology
• Severe adrenal / pituitary / thyroid dysfunction.
• Drug reaction / anaphylaxis

• Electrolyte abnormalities such as hypophosphataemia and hypocalcaemia (the latter particularly with pancreatitis)

Technical:

CVL fallen out or not in a central vein / no pressors in the infusion bag

Measurement error – e.g. arterial line not zeroed/under or over damped, transducer height, wrong NIBP cuff size etc.

Miscellaneous:

Radial / central arterial monitoring discrepancy with severe vasoconstriction

Upper limb vascular disease (radial arterial line) or obstruction (e.g. dissection or aorto-occlusive disease: femoral arterial line)

Anti hypertensive drugs taken as part of patients usual medications

Discussion

This question does not rely on published evidence, but rather tests the candidate's ability to reason through shock in a systematic fashion.

If one were to approach it like a normal list of differentials, it would look like this:

Measurement artifact

• Arterial line is incorrectly zeroed
• Wrong sized cuff being used for NIBP

Vascular causes

• CVC has fallen out or is extravasating
• There is cardiac dysfunction due to MI, i.e. a cardiogenic shock - an ECG and TTE are warranted.
• The patient is hypovolemic, and requires more fluid - bedside static and dynamic methods of fluid responsiveness could be employed to rule this out.
• Air embolism (line-related)

Infectious causes

• A new infection may be brewing. Cultures and a septic work-up are warranted.

Inflammatory causes

• SIRS secondary to pancreatitis
• SIRS secondary to systemic hypoperfusion
• Capillary leak syndrome

Drug-induced causes

• Inappropriate drug administration - is there even any noradrenaline in that infusion bag?
• Anaphylactic drug reaction -review allergy history and examine for a rash; look for eosinophilia and send off a mast cell tryptase level.

Traumatic causes

• CVC insertion has resulted in a retroperitoneal, pleural or mediastinal hematoma
• The pancreatic pseudocysts has eroded into the splenic artery aneurysm, and the patient is exsanguinating into the abdomen
• Either way, an FBC and abdominal ultrasound would rapidly exclude these causes

Endocrine causes

• Untreated hypothyroidism
• Untreated absolute adrenal insufficiency
• Relative adrenal insufficiency
  • One would send TFTs and a random serum cortisol, then start "stress dose" steroids.
• Hypocalcemia may be causing vasoplegia.
• Hypocalcemia and hypophosphataemia may be contributing to poor cardiac contractility.
  • One would send a CMP and replace the relevant electrolytes

If one were to approach it like any shock, it would look like this:

• Artifactual shock
  • Art line inappropriately zeroed
  • Wrong size NIBP cuff
• Technical error
  • CVC is extravasating vasopressors
  • Vasopressor infusion was improperly prepared
• Obstructive shock
  • Cardiac tamponade
  • Tension pneumothorax
• Distributive shock
  • Septic shock
  • Anaphylactic shock
  • Post-bypass vasoplegia
• Hypovolemic shock
  • Haemorrhage
  • Inadequate fluid resuscitation

Rivers, Emanuel, et al. "Early goal-directed therapy in the treatment of severe sepsis and septic shock." New England Journal of Medicine 345.19 (2001): 1368-1377.

Jones, Alan E., et al. "The effect of a quantitative resuscitation strategy on mortality in patients with sepsis: a meta-analysis." Critical care medicine 36.10 (2008): 2734.

Kumar, Anand, et al. "Duration of hypotension before initiation of effective antimicrobial therapy is the critical determinant of survival in human septic shock*." Critical care medicine 34.6 (2006): 1589-1596.

Early Goal-Directed Therapy Collaborative Group of Zhejiang Province. "The effect of early goal-directed therapy on treatment of critical patients with severe sepsis/septic shock: A multi-center, prospective, randomized, controlled study." Zhongguo wei zhong bing ji jiu yi xue= Chinese critical care medicine= Zhongguo weizhongbing jijiuyixue 22.6 (2010): 331.

Yealy, Donald M., et al. "A randomized trial of protocol-based care for early septic shock." The New England journal of medicine 370.18 (2014): 1683-1693.

Power, GSarah, et al. "The Protocolised Management in Sepsis (ProMISe) trial statistical analysis plan." Critical Care and Resuscitation 15.4 (2013): 311.

Delaney, Anthony P., et al. "The Australasian Resuscitation in Sepsis Evaluation (ARISE) trial statistical analysis plan." Critical Care and Resuscitation 15.3 (2013): 162.

Marik, Paul E. "Early Management of Severe Sepsis: Concepts and Controversies." CHEST Journal 145.6 (2014): 1407-1418.

Peake, Sandra L., et al. "Goal-directed resuscitation for patients with early septic shock." The New England journal of medicine 371.16 (2014): 1496.

Yealy, Donald M., et al. "A randomized trial of protocol-based care for early septic shock." The New England journal of medicine 370.18 (2014): 1683-1693.