The effect of general versus spinal anesthesia on perioperative innate immune function in patients undergoing total hip arthroplasty.

Background: Increasing evidence shows that postoperative innate immune dysregulation is associated with delayed recovery and infectious complications. The aim of this study was to compare the effects of general versus spinal anesthesia on innate immune function during and after total hip arthroplasty (THA).

Methods: This comparative matched cohort study used data from two single-center randomized-controlled trials. Patients from the control group of the HIPPO study received general anesthesia and were matched to control patients from the MAGIC study who received spinal anesthesia in a 2:1 ratio (general(n = 18); spinal(n = 9)). Immune function was assessed by determination of ex vivo cytokine production capacity upon whole blood stimulation with E. coli lipopolysaccharides (LPS) and measurement of plasma cytokines and danger-associated molecular patterns (DAMPs).

Results: In the general anesthesia group, ex vivo cytokine production capacity of IL-1β was significantly lower shortly after induction (p = 0.02) and both IL-1β and IL-6 were significantly lower at the end of surgery compared to the spinal anesthesia group (p = 0.002 and p = 0.02, respectively). On postoperative day 1 (POD1), no differences were observed. Plasma cytokine concentrations did not differ between the spinal and general anesthesia group at most timepoints, except for IL-10 at the end of surgery (p = 0.04) and TNF on POD1 (p = 0.04), which were higher in the general anesthesia group. Plasma concentrations of DAMPs did not differ between the groups.

Conclusions: General anesthesia has a transient impact on innate immune function in patients undergoing THA, but the clinical significance of anesthesia-induced innate immune dysregulation might be limited as no differences were observed on POD1.

Trial Registration: The HIPPO study (NCT05562999, date of registration 2022-10-03) and MAGIC study (NCT05723406, date of registration 2023-02-10) are registered at ClinicalTrials.gov.