Research Design, Biostatistics, and Literature Evaluation

Learning Objectives

Identify factors influencing the conduct of essential

critical care research.

tests for a set of data.

Apply concepts of research design and analysis to

clinical care.

4F-PCC Four-factor prothrombin complex concentrate

CI

Confidence interval

CRP

C-reactive protein

ICU

Intensive care unit

IRB

Institutional review board

NPV

Negative predictive value

OR

Odds ratio

PPV

Positive predictive value

QI

Quality improvement

RR

Relative risk

Self-Assessment Questions

Answers and explanations to these questions may be

found at the end of this chapter.

Investigators are planning a clinical trial to

determine the optimal resuscitation fluid for trauma

patients. This study will seek to determine whether

administering crystalloid fluid, such as lactated

Ringer solution, or a transfusion strategy involving

packed red blood cells in the trauma field improves

survival to hospital discharge. The investigator

team has consulted with various ethics scholars to

identify relevant issues to be addressed in the trial

design. Which issue is most relevant to the ethical

conduct of this study?

identify the optimal end point and study population

to test the effectiveness of a novel drug compound

for septic shock. The novel drug compound is a

recombinant protein that mediates the inflammatory

cascade of sepsis and has had impressive results for

all etiologies of septic shock in preclinical animal

studies. Historical estimates of septic shock mortal-

ity are 35%–40% in previous studies from the past

10 years; this guides the investigators to calculate

a required sample size of ~800 patients to achieve

80% power. A more recent study of septic shock

reported 28-day mortality to be 20% in the standard

treatment arm. Which best describes the rationale

for selecting a study population or primary end

point?

without a high level of comorbid conditions at

baseline to limit confounders.

to include patients with sepsis, not just septic

shock, to show a 28-day mortality benefit.

be larger than earlier studies to increase likeli-

hood of obtaining power.

patients with septic shock caused by pneumo-

nia to test a relevant study population.

A quality improvement (QI) initiative is imple-

mented to improve antimicrobial dosing for patients

with septic shock presenting to the emergency

department. As the pharmacy representative, you

have worked with the pharmacy operations team to

ensure that an appropriate selection of antimicrobial

agents and doses is available in the automated drug-

dispensing machines. Which factor will be most

important in showing the effectiveness of this QI

initiative?

the QI initiative.

bring awareness to the initiative.