Changes in host gene expression to differentiate between systemic inflammation and infection after major surgery (PAX study)

Despite preventive measures, a considerable number of surgical patients suffer
from a postoperative infection. The incidence of postoperative infection
exceeds 30% in patients undergoing major noncardiac surgery such as pancreatic
or esophageal cancer. Postoperative infections are associated with poor health
and death after surgery, and increased healthcare costs. Diagnosis of surgical
patients with an infection at an early stage would enable prompt intervention,
but effective biomarkers are currently lacking.
Surgical trauma activates the innate immune system and triggers a
systemic inflammatory response syndrome (SIRS) in up to 50% of patients over
the course of the first 7 postoperative days. This increases risk for infection
as well as complicates its early diagnosis, which now relies primarily on
clinical features and unspecific biomarkers of inflammation (e.g. C-reactive
protein, leucocyte count, fever, tachycardia). Differentiation between SIRS and
postoperative infection is thus challenging, and the diagnostic uncertainty
that results from this may cause delays in interventions to prevent a patient
from deteriorating to organ dysfunction or eventually death.
Changes in host gene expression may provide additional diagnostic
information for postoperative infection. A recent study identified infection in
surgical patients in advance of clinical diagnosis, and reliably differentiated
infected from non-infected patients, by using blood leukocyte transcriptomics.

Primary Objective: To study the early diagnostic performance of specific gene
signatures for differentiation of patients having postoperative infection (A1)
or sepsis (A2) from non-infected patients having postoperative SIRS (B1) and
non-infected patients having an uncomplicated postoperative course (B2)

Multicenter observational cohort study

In each patient blood samples will be drawn for analysis on the following time
points: after induction for anaesthesia, directly postoperative and on
postoperative day 1 - 7. For each sample 2.5 ml of blood is taken. In a total
of 9 samples this results in a cumulative volume of 22.5 ml. Whenever possible,
blood samples will be drawn simultaneously with routine perioperative
laboratory testing. In case of admission to the Intensive Care Unit blood
samples will be collected using an arterial line. There are no direct risks or
benefits for patients included in the study.