Can capillary refill time (CRT) replace serum lactate as a resuscitation
target in septic shock?
Leave it to the South Americans to try to figure this one
out… ¡Vamonos Amigos!
This was an RCT conducted in 28 ICU’s in Chile, Argentina,
Uruguay, Ecuador and Colombia. (¿Valididad externa?)
424 adult patients were randomised to a resuscitation protocol
aimed at either normalising CRT vs. normalising or decreasing lactate levels.
The study was powered to detect an absolute reduction of 28-day
mortality by 15%. Of course, this is crazy… nothing would be expected to work
this well. As such, this study was always at a high risk of a type II error (i.e.
not finding a difference when one truly exists). ¿Vamonos?
Out of interest, the CRT involved training and standardisation
as follows
...CRT was measured by applying firm pressure to the
ventral surface of the right index finger distal phalanx with a glass microscope
slide. The pressure increased until the skin was blank and then maintained for
10 seconds. The time for return of the normal skin color was registered with a
chronometer, and refill time greater than 3 seconds was defined as abnormal.
Once again, the primary outcome was all cause mortality at
28 days. There were lots of prespecified secondary outcome measures.
¿Resultados?
By day 28, a total of 35%
in the CRT group vs 43 % in the lactate group had died (hazard ratio, 0.75
[95% IC, 0.55 to 1.02]; P=.06; risk difference,
-8.5% [95% CI, -18.2% to 1.2%]
P value was 0.06. Therefore, a negative study…
This highlights the silly dichotomous nature that we
attribute to P values. Less than 0.05 means “something important” whereas above
0.05 means nothing… totalmente loco amigo.
0.05 has always been a single arbitrary cut-off of
probability. It tells us nothing about the effect size, whether a study was
powered correctly or whether the outcomes are clinically important. It doesn’t
tell us about bias, confounding, reverse causality or if the correct statistical analysis was
used. The reverence we
hold to P values must stop!
In the end, this study produces quite a bit of noise in favour
of capillary refill time as a target for resuscitation. But perhaps it
highlights the lack of utility of lactate. To be fair, we would never use a single
marker in isolation. So perhaps this is all a bit silly… almost as silly as the
title, ANDROMEDA-SHOCK trial.
¡Olé!
Covering
Hernandez G, Ospina-Tascon G Damiani LP, et al. Effect of a
Resuscitation Strategy Targeting Peripheral Perfusion Status vs Serum Lactate
Levels on 28-Day Mortality Among Patients with Septic Shock: The
ANDROMEDA-SHOCK Randomized Clinical Trial. JAMA. 2019;321:654-64. [link to
article]
No comments:
Post a Comment