By Marcy Phipps, RN, a regular contributor to this blog. Her essay, “The Soul on the Head of a Pin,” was published in the May 2010 issue of AJN.

Black Hole Paradox/ Angel’s Gate, via Flickr

We’ve been using a new piece of hemodynamic monitoring equipment in our ICU. Considered minimally invasive, it uses an arterial line to measure fluid balance status by measuring stroke volume variation (SVV). The derived values are useful in guiding fluid resuscitation, and are based on a principle with an interesting and contradictory name. Instead of pulsus paradoxus (variations in arterial pressure during spontaneous breaths), the SVV is calculated based on reverse pulsus paradoxus (variations in arterial pressure during mechanical, positive pressure ventilation).

I’m a “numbers” person. From a scientific perspective, I totally get this. But the concept of monitoring hemodynamics using a principle described as a reverse paradox is unsettling. I don’t want paradoxes, especially reverse paradoxes, to exist in nursing; I don’t need or want circular logic to confound and muddle my days. And yet, as I’ve considered paradoxes in general, I’ve found nursing-related situations that seem to fit the definition:

  • Administration of a benzodiazepine, intended to relieve agitation, which instead results in increased agitation.
  • Titration of an inotrope, with the goal of increasing cardiac output, with the unexpected outcome of decreased blood pressure.
  • The impression that a vented patient is relatively oriented, only to find out after they’re extubated that they’re actually completely disoriented.

Reverse paradoxes are harder to find, and I could only find one:

  • A patient is pronounced brain dead, so there’s death, and the family opts for organ donation, so there’s life, and then the organs are rejected prior to procurement . . . so there’s death.

It could be argued that none of my examples are really paradoxes. They’re adverse reactions, misinterpretations, or unfortunate events. Perhaps the only real paradox here is this: When Kussmaul suggested the name “pulsus paradoxus” in 1863, he was describing findings that are physiologically explainable today, and not considered paradoxical. I’ve been preoccupied with the reverse of a paradox that’s not really a paradox, and questioning logic in science, to no avail.

Science remains scientific, regardless of how much I overthink it.

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