Research Design, Biostatistics, and Literature Evaluation
Can aid in determining short-term goals. Example: Selecting an initial dose of loop diuretic
according to the home medication dose and current therapeutic goal of urinary output
Primary literature on which to base treatment decisions for all clinical scenarios may not exist.
Protocols are intended to synthesize the best available evidence and standardize a series of treatment
options to reduce variability and error while maximizing treatment effect. Examples: Sterile technique
for central line placement, heparin or insulin infusions, and sepsis bundles.
is key.
Determine the homogeneity of various studies on the same topic (e.g., early goal-directed therapy
for septic shock) and confounding variables that influence the interpretation of results. Study design
affecting the screening and time to treatment for subjects compared with actual practice, improvements
in the processes of usual care over time, etc.
Resource use
Drug shortages
Fiscal
Complexity
Familiarity
Lack of consensus (e.g., sepsis 1-hour bundle)
Practice Case
Questions 7 and 8 pertain to the following case.
You are reading a study that evaluated the use of hydrocortisone versus placebo for lowering C-reactive protein
(CRP) in patients with ARDS at 3 days after enrollment. The authors concluded that they would need to enroll
100 patients to achieve 90% power to find a decrease in CRP of 10 mg/L, assuming a baseline concentration of
35 mg/L and an ฮฑ level of 0.05. They enroll 50 patients in the hydrocortisone group and 51 patients in the pla-
cebo group. The median [interquartile range] CRP concentrations in the intervention and placebo groups are 23
[19โ31] and 29 [20โ40], respectively (p<0.05). The percentages of patients achieving a CRP decrease of at least
10 mg/L in the intervention and placebo groups are 15% and 18%, respectively (p>0.05).
Which is your biggest concern with interpreting the validity of this study?
steroid use in ARDS.
Which best describes the NNT for achieving a CRP decrease of at least 10 mg/L in this study?