Discussion
pain
REGRESSION, MINOR
Tourniquet pressure reduction using the LOP technique has been applied in previous studies [The present study showed that, in minor hand surgery, using LOP to determine RTP as the tourniquet pressure can significantly decrease cuff pressure from the standard 250 mmHg. Although the difference was only 22 mmHg, however, the lower pressure in the RTP group resulted in significantly less pain and discomfort. The average of RTP in our study was slightly higher than the previous studies that reported an average of arterial occlusion pressure of 200 mmHg because there was not added a safety margin, which is a remain controversial [In our study, using the LOP technique to determine RTP, which optimizes cuff pressure, the bloodless surgical field was maintained as same as standard 250 mmHg during the operation, which was comparable to previous studies [Although the average of tourniquet time in RTP group was higher than standard group, 16 min in the RTP group and 14.5 min in the standard group, however, there was no significant difference. An average of the tourniquet time in this study it seems to be slightly higher than usual for minor hand surgery because a surgeon who performed the procedures was an Orthopaedic resident that would be represent a general orthopedic surgeon.Creating a motionless field was found in the RTP group, which has not been reported in previous studies. This means that the optimal tourniquet pressure provides no difference in creating a bloodless field and provides comparable overall quality of the surgical field. Therefore, the results of our study showed that determining the optimal tourniquet pressure using RTP in the upper limb is practical and satisfactory.We performed the multiple regression analysis in order to adjust the confounding factors (age, BMI and SBP) and also predict RTP from LOP. The formula was based on the recommended RTP prediction (Predicted RTP = Predicted LOP + Safety Margin). For predicted LOP = 63.41 + (0.31*age) + (0.65*BMI) + (0.42*SBP). Safety Margin was determined by plus 50 mmHg for LOP 90–130 mmHg, plus 75 mmHg for LOP 131–190 mmHg and plus 100 mmHg for LOP above 190 mmHg. This correlation is considered as the optional method to determine RTP when there is no LOP measurement equipment available.Tourniquet position for upper limb surgery have been debated between using arm and forearm tourniquet. The previous studies showed no significant difference in patient pain, physiological response, tourniquet time, bloodless field or length of operation. However, the arm tourniquet was less obstruction [The strengths of this study were that it was a double-blinded randomized controlled trial, with balanced prognostic factors, well-controlled confounders and adequate sample size. However, there are couple limitations including subjectivity of the surgical field evaluation outcome and many surgeons responsible for the operation. Moreover, to measure the LOP the automatic equipment is required.