Hemodynamic Stability Between Spinal and General Anesthesia in Patient Undergoing Primary Total Knee Arthroplasty: A Retrospective Study.

BACKGROUND

Total knee arthroplasty (TKA) is a common surgical procedure that may be associated with blood loss. The aim of this study is to evaluate intraoperative hemodynamic stability during TKA under general (GA) or spinal anesthesia (SA).

METHODS

Any adult undergoing primary TKA under GA or SA was retrospectively selected over a 10-year period and compared. The primary outcome was the presence of intraoperative hemodynamic instability, defined by starting a norepinephrine infusion, as the variation of the patient's blood pressure exceeded 30% of its baseline value for more than 5 min. Secondary outcomes included intraoperative dose of ephedrine, phenylephrine, blood loss, and volume of fluid administered. Demographic and intraoperative anesthetic variables associated with norepinephrine use were entered in a multivariate logistic regression model.

RESULTS

The analysis included 1,441 patients; 59% received a SA. 3.6% of patients under SA required a norepinephrine infusion versus 10.4% under GA (p < 0.001). Ephedrine administered was lower in the SA group (mean dose 19 mg vs. 31 mg, p < 0.001), while phenylephrine was not statistically different (414 μg for SA and 481 μg for GA, p = 0.09). Intraoperative blood loss was identical in both groups (402 mL for SA and 415 mL for GA, p = 0.35), while mean intraoperative fluid income was higher in the GA group (862 mL vs. 725 mL, p < 0.001). Variables associated with norepinephrine use were GA and age, among others.

CONCLUSIONS

GA requires more norepinephrine infusion compared to SA in patients during primary TKA, suggesting intraoperative hemodynamic stability is better preserved during neuraxial anesthesia.