Background and Aims Total knee arthroplasty is a very common surgical procedure in daily practice and its number is constantly increasing. Some studies have reported that general anaesthesia was associated with greater hemodynamic instability, but this paradigm has since been disputed. The aim of this study is to evaluate intraoperative hemodynamic stability during total knee arthroplasty according to the type of anaesthesia. The hypothesis is that hemodynamic stability is better preserved during spinal anaesthesia (SA) compared to general anaesthesia (GA).

Methods Adults undergoing primary total knee arthroplasty were retrospectively selected over a period of 10 years. Primary outcome was the presence of a hemodynamic instability defined by a norepinephrine infusion started when the variation of patient‘s blood pressure exceeded 30% of its baseline value for more than 5 minutes. Secondary outcomes included mean intraoperative dose of ephedrine, mean blood loss, and mean volume of fluid administered. Demographic data and anaesthetic strategy were extracted. Patients receiving SA versus GA were compared for the different variables.

Results Demographic data are displayed in table 1. Patients under SA received less ephedrine (p<0.0001), less infusion of norepinephrine (p<0.0001) and less intraoperative fluids (p<0.0001) than patients under GA, while blood loss was similar between groups (p=0.29) (table 2).

Conclusions Patients under SA have a better intraoperative hemodynamic stability, as they required less vasopressors than patients under GA.