[Translated article] Transient haemodynamic changes following tourniquet release in total knee arthroplasty: A multicenter retrospective study

Abstract

Background

The release of a pneumatic tourniquet during total knee arthroplasty (TKA) causes an abrupt increase in blood flow to the lower limb, which may result in transient haemodynamic instability. The aim of this study was to quantify the magnitude and duration of these changes in a real-world clinical setting.

Methods

A multicenter retrospective observational study was conducted including 149 patients undergoing primary TKA under pneumatic tourniquet ischaemia. Systolic (SBP), diastolic (DBP), and mean arterial pressure (MAP), heart rate (HR), respiratory rate (RR), and oxygen saturation (SpO₂) were recorded at three time points: baseline (pre-release), 3 min (T3), and 6 min (T6) after tourniquet release. Statistical analysis was performed using repeated-measures ANOVA or the Friedman test, according to data distribution, with p < 0.05 considered statistically significant.

Results

Following tourniquet release, a significant immediate decrease in SBP and DBP was observed (p < 0.001), with mean reductions of 19.8% and 21.2%, respectively, at T3. HR showed a mild but significant increase (p = 0.012). SpO₂ decreased slightly (p = 0.034) without clinical relevance. Transient arrhythmias were recorded in 8.7% of patients. At 6 min post-release, all parameters returned to baseline values.

Conclusion

Tourniquet release during TKA is associated with transient haemodynamic changes and early recovery. These findings support the need for reinforced monitoring in patients classified as ASA III and/or with ischaemia times longer than 85 min, and provide a rationale for future prospective studies incorporating advanced haemodynamic monitoring.

Level of evidence

Level III, retrospective study.