A new tourniquet system that determines pressures in synchrony with systolic blood pressure in knee surgery.

This study reports the results of the clinical use of a new tourniquet system for surgery related to knee joint that can determine tourniquet pressure in synchrony with systolic blood pressure (SBP). We prospectively applied additional pressure of 100 mmHg based on the SBP recorded just before infiltration of tourniquet in 163 consecutive procedures, which consisted of 73 TKA related surgeries, 42 arthroscopic related surgeries, 20 ACL reconstructed surgeries, 15 ORIF, and 13 other surgeries. After the infiltration, the tourniquet pressure was automatically synchronized with the SBP. The interval of the measurement of blood pressure was every 2.5 min. The average durations of the operation and tourniquet use were 56 (range 6-134) and 56 (range 8-125) min, respectively. The average initial systolic tourniquet pressure was 207 mmHg (range 178-302). The average maximum changes during surgery were 37 mmHg (range 2-102) systolic and 23 mmHg (range 5-67) diastolic. The average maximum systolic pressure changes during 2.5 min interval were 20 mmHg (range 5-97). All cases kept a good operative field without measurable bleeding and there were no postoperative complications. Sixty-eight (42%) cases had a lower intra-operative SBP than the initial value. Since a tourniquet should be applied at the lowest pressure, and for the shortest amount of time possible, the new system appears to be practical and reasonable for maintaining a bloodless surgical field, as compared to conventional tourniquets, which maintain the initial pressure between 300 and 350 mmHg.