This study was designed to illustrate the role imposed by adenosine release in pathogenesis of tourniquet pain through the use of its receptor antagonist theophylline and to evaluate the possibility of reduction administered dose of local anesthetic. The study comprised 60 patients allocated into control group (Group C; n=20) received 200mg of xylocaine 2% in 40ml normal saline and study group (Group T; n=40) primed with theophylline (4mg/kg) in 20ml normal saline injected while the proximal tourniquet was inflated, 5-min later, the distal one is inflated then the proximal tourniquet was deflated and 150mg (Group T1; n=20) or 200mg (Group T2; n=20) of xylocaine 2% in 20 ml were injected. Four-point verbal analogue scale (VbAS) was used for intraoperative evaluation of tourniquet and surgical site pain; postoperative pain was assessed using visual analogue scale (VAS). Duration of postoperative analgesia and type of analgesia used were defined. No patient complained of severe tourniquet pain and the analgesic effect extended till deflation of tourniquet in 5 patients received theophylline. The VrAS records showed a significant decrease in group T2 compared to control; while, in group T1 mean score was non-significantly decreased compared to control group. Only 7 patients reported mild operative site pain; 3 in control and 4 in T1 groups. Mean postoperative VAS significantly decreased and duration of analgesia was significantly increased in theophylline groups with significant difference in favor of group T2. It could be concluded that local adenosine release secondary to tourniquet application plays a prominent role in induction of tourniquet pain and patients priming with theophylline prior to administration of IVRA solution could ameliorate this effect and enables the reduction of administered dose of local anesthetic. |
