Unresponsive Low Mixed Venous Oxygen Saturation During Early Intensive Care Unit Stay is Associated With Increased...

The aim of the study was to determine if unresponsive mixed venous oxygen saturation (SvO₂) values during early postoperative hours are associated with postoperative organ dysfunction.

A single-center retrospective observational study.

A university hospital.

A total of 6,282 adult patients requiring cardiac surgery who underwent surgery in a University Hospital from 2007 to 2020.

A pulmonary artery catheter was used to gather SvO₂ samples after surgery at admission to the intensive care unit (ICU) and 4 hours later. For the analysis, patients were divided into 4 groups according to their SvO₂ values. The rate of organ dysfunctions categorized according to the SOFA score was then studied among these subgroups.

The crude mortality rate for the cohort at 1 year was 4.3%. Multiple organ dysfunction syndrome (MODS) was present in 33.0% of patients in the early postoperative phase. During the 4-hour initial treatment period, 43% of the 931 patients with low SvO₂ on admission responded to goal-directed therapy to increase SvO₂ >60%; whereas, in 57% of the 931 patients, the low SvO₂ was sustained. According to the adjusted logistic regression analyses, the odds ratio for MODS (4.23 [95% CI 3.41-5.25]), renal- replacement therapy (4.97 [95% CI 3.28-7.52]), time on a ventilator (2.34 [95% CI 2.17-2.52]), and vasoactive-inotropic score >30 (3.62 [95% CI 2.96-4.43]) were the highest in the group with sustained low SvO₂.

Patients with SvO₂ <60% at ICU admission and 4 hours later had the greatest risk of postoperative MODS. Responsiveness to a goal-directed therapy protocol targeting maintaining or increasing SvO₂ ≥60% at and after ICU admission may be beneficial.