Korean J Anesthesiol.  2012 Feb;62(2):154-160. 10.4097/kjae.2012.62.2.154.

Relation between preoperative autonomic function and blood pressure change after tourniquet deflation during total knee replacement arthroplasty

• Huh IY
• Kim DY
• Lee JH
• Shin SJ
• Cho YW
• Park SE

• KMID: 2236295
• DOI: http://doi.org/10.4097/kjae.2012.62.2.154

Abstract

BACKGROUND
Tourniquets are used to provide a bloodless surgical field for extremities. Hypotension due to vasodilation and bleeding after tourniquet deflation is a common event. Hemodynamic stability is modulated by the autonomic nervous system (ANS). Heart rate variability (HRV) is a sensitive method for detecting individuals who may be at risk of hemodynamic instability during general anesthesia. The purpose of this study was to investigate ANS function to predict hypotension after tourniquet deflation.
METHODS
Eighty-six patients who underwent total knee replacement arthroplasty (TKRA) were studied. HRV, systolic blood pressure variability (SBPV) and baroreflex sensitivity (BRS) were analyzed. We assigned two groups depending on the lowest systolic blood pressure (SBP) or mean BP (MBP) after tourniquet release (Group H; SBP < 80 mmHg or MBP < 60 mmHg, Group S; SBP > 80 mmHg and MBP > 60 mmHg).
RESULTS
Fifteen patients developed severe hypotension and ten patients were treated with ephedrine. Of the parameters of HRV, SBPV, and BRS, only BRSSEQ was significant being low in Group H. BRS and high-frequency SBPV were correlated with the degree of MBP change after tourniquet deflation.
CONCLUSIONS
Preoperative low BRS is associated with hypotension after tourniquet deflation, suggesting the importance of baroreflex regulation for intraoperative hemodynamic stability.

Keyword

Baroreflex sensitivity; Heart rate variability; Hypotension; Systolic blood pressure variability; Tourniquet deflation

MeSH Terms

Anesthesia, General
Arthroplasty
Arthroplasty, Replacement, Knee
Autonomic Nervous System
Baroreflex
Blood Pressure
Ephedrine
Extremities
Heart Rate
Hemodynamics
Hemorrhage
Humans
Hypotension
Tourniquets
Vasodilation
Ephedrine