Correlation between shock index and postoperative outcomes for patients undergoing on-pump coronary artery bypass graft surgery (an observational study)

Introduction Shock index (SI) is defined as a ratio of heart rate and systolic blood pressure. It was originally employed to evaluate hemorrhage and acute circulatory failure. Recently, SI has been used as a morbidity and mortality predictor in various fields. An elevated SI was associated with higher morbidity. Objective To detect the sensitivity and specificity of SI in predicting major cardiac events. Methods We randomly enrolled 100 patients who were set to undergo on-pump coronary artery bypass graft (CABG) surgery in the study. The primary outcome was to detect the sensitivity and specificity of SI to predict the occurrence of major adverse cardiac events, occurrence of acute kidney injury (AKI) and the need for ventilator support for >48 h. The secondary outcome was to correlate between SI and need of inotropic support, length of hospital stay and in-hospital mortality. Results The main findings of our study were the presence of a good correlation between SI and occurrence of postoperative cardiovascular (CV) collapse, AKI and prolonged postoperative mechanical ventilation after on-pump CABG as primary outcomes as well as the presence of a significant correlation between the occurrence of in-hospital mortality and morbidities and high values of SI as secondary outcomes. Conclusions We believe that SI has a good prediction of postoperative CV collapse, AKI and prolonged postoperative mechanical ventilation >48 h.

Automated summary

The study found a good correlation between shock index (SI), which is the ratio of heart rate and systolic blood pressure, and postoperative cardiovascular complications, acute kidney injury, and prolonged mechanical ventilation. SI was also significantly correlated with in-hospital mortality and complications.