Cardiovascular Effects of Tourniquet Application with Cardiac Cycle Efficiency: A Prospective Observational Study

Area of Science:

• Anesthesiology
• Cardiovascular Physiology
• Surgical Innovation

Background:

• The effect of surgical tourniquets on cardiac efficiency is not well understood.
• Tourniquets are commonly used in orthopedic surgery, particularly for total knee arthroplasty (TKA).
• Different anesthesia techniques may influence the cardiovascular response to tourniquet application.

Purpose of the Study:

• To assess the impact of tourniquets on cardiac cycle efficiency (CCE).
• To compare the effects of general anesthesia (GA) and combined spinal epidural anesthesia (CSEA) on CCE during TKA.
• To analyze cardiac energy parameters under different anesthesia and tourniquet conditions.

Main Methods:

• Prospective observational study of 43 patients undergoing elective unilateral TKA.
• Patients were divided into two groups: GA (n=22) and CSEA (n=21).
• Cardiac energy parameters, including CCE, were measured at multiple time points: pre-anesthesia, pre-tourniquet, during tourniquet inflation, and post-deflation.

Main Results:

• CCE significantly decreased more in the GA group compared to the CSEA group upon tourniquet inflation.
• dP/dt and Ea (measures of cardiac contractility and workload) increased more in the GA group.
• Post-deflation, CCE increased in the GA group, while dP/dt and Ea decreased, indicating compensatory changes.

Conclusions:

• Tourniquet application reduces cardiac efficiency, likely due to compensatory cardiovascular responses.
• CSEA appears to mitigate the negative impact of tourniquets on cardiac efficiency compared to GA.
• CSEA may be a preferred anesthetic choice for TKA when tourniquet use is necessary to preserve cardiac function.