Outcomes Associated with a Screening and Treatment Pathway for Occult Hypoperfusion Following Cardiac Surgery

Abstract

Introduction: Routinely monitored parameters such as blood pressure (BP) and heart rate may not reliably detect per- fusion abnormalities. However, central venous oxygen saturation (ScvO2) and lactate levels can detect occult hypoper- fusion (OH) and identify patients at risk for complications. The study objective was to assess the impact of an OH treatment pathway on morbidity and length of stay (LOS) post coronary bypass and valve surgery. Methods: This is a prospective cohort observational study following the implementation of a treatment pathway for OH, defined by ScvO2 2 mMol/L with systolic BP ≥ 90 mmHg. Initial treatment included volume resuscitation and/or blood transfusion, followed by additional interventions when ScvO2 remained hours postoperatively. Primary outcomes were intensive care unit (ICU)/hospital LOS and complications. Results: Comparing 53 patients managed by the OH pathway against 21 historical controls, median ICU LOS was 40.4 vs. 49.2 hours (p = 0.122), median hospital LOS 9.2 vs. 11.0 days (p = 0.0093), ICU readmission rate 7.5% vs. 28.6% (p = 0.026), and complication rate 26.4% vs. 47.6% (p = 0.101). Repeat lactate was checked 18 hours postoperatively in 47 of the 53 patients. Comparing 33 patients with repeat lactate at goal ( 2 mMoL/L) with 14 patients not at goal, median ICU LOS was 35.3 vs. 68.4 hours (p = 0.061), median hospital LOS 8.9 vs. 11.2 days (p = 0.058), median length of mechanical ventilation (LOMV) 13.3 vs. 28.4 hours (p = 0.0038), and complication rate 15.2% vs. 50.0% (p = 0.025). Conclusions: An OH screening and treatment pathway following cardiovascular surgery was associated with signifi- cantly shorter hospital LOS and lower ICU readmission rate. Among the OH pathway patients, achieving lactate goal 18 hours postoperatively was associated with significantly shorter LOMV and lower complication rate.