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FACP. Colegio de médicos de Tarragona Nº 4305520 / fgcapriles@gmail.com




Monday, April 11, 2016

Why we fail at hemodynamics

Resultado de imagen de pulmcrit
PulmCrit - April 11, 2016 - By Josh Farkas
Use of Swan-Ganz catheterization in heart failure is increasing, despite evidence-based recommendations to the contrary (Pandey 2016). This trend may reflect increased utilization of advanced therapies in heart failure (e.g., LVADs). With a resurgence of the Swan, a resident recently asked me: why don’t we use the Swan to guide sepsis resuscitation? Answering this question forced me to recognize that many problems with the Swan continue to haunt us today when using our new darling, bedside echocardiography.
  • First reason we fail: The flaw of averages
  • Second reason we fail: The Swan’s Curse
  • Bedside echocardiography: The curse continues
  • Responsiveness: The cure for the Swan’s curse
    • Although echocardiography is safer than Swan-Ganz catheterization, it is susceptible to some of the same cognitive errors.
    • Our understanding of how medications affect hemodynamics is based on the average response of groups of patients. Unfortunately, it may be incorrect to assume that an individual patient will respond similarly to the average (“Flaw of averages”).
    • Most variables obtained from either Swan-Ganz catheterization or bedside echocardiography are static variables. These describe the current state of the patient’s hemodynamics, but don’t predict how the patient will respond to various interventions. Unfortunately, there is a natural tendency to base therapeutic decisions on static variables which are easily observable (“Swan’s Curse”).