Page 28 - Hall et al (2015) Principles of Critical Care-McGraw-Hill

Introduction xxvii

TABLE 2 Therapeutic Goals in AHRF intuition focuses on the important variable; otherwise you might
end up with a very well conducted scientific study that concludes
1980 2005 erroneously that the intervention had no effect on outcome. In the
Seek least PAOP/CVP Conservative fluid management guise of critical thinking and right reason, the scientific method may
--- Adequate CO ---↓ Ventilator time cause us to falsify effective treatment.
1 ---Absent prerenal oliguria ---↓ ICU time For all its contributions, the scientific method has provided enough
---Absent lactic acidosis --- Without ↑ organ dysfunction incomplete or erroneous explanations of reality to make us wary. Many
J Clin Investig. 1981;67 9 N Engl J Med. 2006;354 8
ascribe the birth of science to the publication of Issac Newton in 1687 of
Seek least PEEP Higher PEEP not better than lower PEEP The Mathematical Principles of Natural Philosophy. For about 250 years
--- 90% saturation in ARDS thereafter, scientists probed nature with this ingenious theory or way
2 --- Adequate hemoglobin N Engl J Med. 2004;351 16 of thinking to reveal more and more discoveries of how nature works.
But in the last century, science revealed the world of subatomic physics
--- Nontoxic Fi O 2
J Appl Physiol. 1984;57 13 which moved by different forces not explained by Newtonian Laws, in a
Seek least VT Low VT (6 mL/kg) world of sub atomic particles requiring a different set of laws describing
---Absent acidosis ---↓ Mortality “quantum physics.” Despite 100 years of focused research, we have yet
3 Am Rev Resp Dis. 1990;142 14 ---↓Time on ventilator to develop a unified theory to explain both classical and quantum phys-
---↓ Time in ICU ics. Though we may just be slow the possibility arises that the scientific
N Engl J Med. 2000;342 15 method is wrong. 21,22 Similarly, formulation of the laws of heredity of
the species by Charles Darwin emphasizes “survival of the fittest” to
account for the range of creatures in the world. Recently, the data and
interpretations of heredity put forward 50 years earlier by Lamarck
demonstrated beyond a doubt that development of new structure and
patients in the ICU is a belief until the clinical study demonstrates its function is promoted by the environment of the species. Accordingly,
utility in patients, no matter how long it takes. Darwin’s theory is now questioned as incomplete or even wrong and has
Yet, clinical intuition should play a role until controlled clinical been altered while we went looking for a more comprehensive theory. 21,22
studies are performed. In the case reports and textbook guidelines And the co-discoverer of the double-helix, Frances Crick, insisted that
describing treatment goals in AHRF 13-15 we used the least PEEP all reproduction was explained by the arrangement and duplication of
achieving its goals (see Table 2) and coupled that with the least four nucleic acids. This dictum excluded, even ridiculed, scientists pre-
tidal volume preventing unacceptable acidosis. 13,14,16 As indicated senting data suggesting influence on the expression of the nucleic acids
in Table 2, the therapeutic goals were supported by subsequent by cell membranes, cytoplasmic substances, and extracellular influences.
multicenter clinical trials, 17,18 conducted 25 years later, while all our The new science of epigenetics is reversing the Crick dictum and its
patients were being ventilated with smaller VT and goal directed interpretation to explain these extracellular effects. 22
PEEP. This practice of ventilating patients with ALI with small I cited these three important theories with demonstrated error so
VT was based on the intuition that if our patient’s lungs were 80% that we all, scientists and believers alike, may retain skepticism about
flooded, we better give smaller VT or we will injure the aerated scientific evidence and its interpretation. Nonscientists need not feel
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units further. triumphant about these short falls of science, for it is a strength of the
How many other standards of Critical Care cause similar dam- scientific method to make itself vulnerable to criticism by obtaining
age until disproven? This important question got greater attention accurate, reproducible data and interpreting these data in clear unequiv-
than it deserves when a multicentered trial of low tidal volume ocal language. This scientific candor helps the scientific community
ventilation was halted by the concern that one patient group did not revise erroneous theories as the most rapid approach to new knowledge.
receive care according to the “best current standard of practice,” as
arbitrary as that standard may be. 19
4. This study illustrates another limit on science. The first protocol NEUROSCIENCE, MYSTICAL EXPERIENCES, AND BELIEF
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intervention occurred on average 43 hours after admission to the When we consider the limitations of belief, we do not compare errors for
ICU. Thereafter, conservative fluid management was associated with they are hard to detect in the softer language of belief. Instead, we look
a return to spontaneous breathing in 5 days by 255/500 patients, but for outcomes of belief which, if true, provide enhancement of under-
only 200/500 patients receiving liberal fluids resumed spontaneous standing sprinkled around the surface of science. In this sense, there is
breathing. Accordingly, 55 patients were spared ventilator therapy no war of worldviews for these two modes of inquiry are not competing
by conservative fluid balance in the first 5 days, and no further dif- for the same prize. Instead, they arrive at truth from different points
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ference was seen between groups after 5 days. It seems that most of view: science looks outward to describe accurately how the world
of the benefit of conservative fluid management occurs early, and works, while belief looks inward with consciousness to find meaning
this study nearly missed and almost certainly underestimated it, by and purpose. Choosing to see these processes as antagonistic perpetu-
taking so long to get started. A careful look at Fig. 1 in reference ates the human trait of arguing about which approach is best, whereas
10 explains the delay, for so many controlled variables take time more knowledge is achieved when the participants admit that each has
to organize. This early therapeutic effect was evident in our canine something to offer the other in the search for knowledge.
studies when the reduction in PAOP was effected 1 hour after the In an extraordinary interview, Joseph Campbell tells Bill Moyers about
injury, and promptly stopped further edema accumulation and its the power of myth. A key concept is how myth exposes and explains
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effect to increase Q /Q and reduce compliance further. 11,12 In a ret- the mysteries of life, most often inner mysteries through introspection.
S
T
rospective study of 40 patients with ARDS, the group with reduced The far-fetched mechanisms said to underlie these mysteries lead many
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PAOP had the effect measured already by 24 hours from admission, scientists to skepticism and disbelief. But these same scientists need to
so one might expect a greater beneficial effect of conservative fluids recall that many hypotheses to explain reality were equally outrageous
than was observed in the multicenter trial. Indeed, we reported an before being put to the test without being falsified. Accordingly, it is not
increase in survival from 29% to 75% in the low PAOP group. It scientific to reject beliefs before they are falsified.
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seems possible to obscure therapeutic effects by delaying the inter- In his discussion of the physiology of spiritual experience, Andrew
vention until all the controls are in place. One cannot help but think Newberg outlines his attempt to elucidate the underpinnings of the spir-
it wise to lighten up on the controls in large clinical studies when itual experience using single photon emission computed tomography
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