floors, ceilings, and SAGE wisdom

A persistent false dichotomy in critical care (and all of medicine, for that matter) is that one either provides rigid guideline-based care, or tailors care to the each individual.

However, as we all know:

(Sorry if you hate the prequels)

Reality is more interesting than the either/or mindset, fortunately. As we try to better identify patients who may respond to therapies, or those who may have features that make them less likely to benefit from guideline-driven care, it’s important to establish a firm foundation on the best available evidence.

Cue SAGE

SAGE (Severe ARDS: Generating Evidence), a US multi-center observational cohort of nearly 2,500 patients across 29 centers, evaluated ventilation and adjunctive treatment practices in patients with moderate to severe ARDS. For a nice summary of key findings, see this thread by first author Nida Qadir.

The authors found significant variability in ARDS management across centers. Importantly, only early adherence to lung protective ventilation was associated with decreased mortality rate, and adherence varied from 0-65% across the sites. Use of adjunctive therapies also varied widely.

A few other items I found interesting:

  • Nearly 1/4 of patients in the cohort received tidal volumes over 8 ml/kg predicted body weight
    • In fact, 3.5x more patients received high tidal volumes than prone positioning!
  • Only about half of all patients had plateau pressures measured on day 1
  • Pulmonary vasodilators (a therapy still in search of a meaningful benefit in ARDS) were used twice as frequently as prone position ventilation, the adjunctive therapy with the strongest evidence base.

Floors and Ceilings

Reasons for this practice variability are likely complex, but I suspect have little to do with intentionally personalized medicine. In my institution, we observed improvement in ARDS outcomes when care was standardized. There were many factors to its success, but one aspect was simplifying the choices one may make when caring for a patient with moderate-to-severe ARDS.

Sometimes, the best thing we can do is decrease the amount of confusing inputs to a system:

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Both lung protective ventilation and prone positioning are technically easy to implement and are low cost (especially when compared to other adjunctive therapies such as pulmonary vasodilators and ECMO), and probably have the largest impact on mortality.

This does not mean there isn’t room for personalization, but the physiologic rationale has to be strong. Did some patients in SAGE receive pulmonary vasodilators to rescue a failing right ventricle? This would be reasonable, to me, but only after applying RV-protective ventilation and proning.

Just as in zentensivism, where clinical mastery is a prerequisite, the essentials of ARDS management must be mastered and consistently implemented before artisanal care can be attempted. Evidence-based practice should not be viewed as a threat to personalization, but instead the important starting point for care.

Indeed, it is the floor which we build from, and not a ceiling to constrain us.

Notes

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