Few data are available for the PI as a tool for evaluation of peripheral block success in pediatric patients. Furthermore, there is currently no cut-off value defined for the accuracy of the PI in the detection of successful block.

modify plan for intraoperative and postoperative analgesia. Perfusion index is an assessment of the pulsatile strength at a monitoring site; it is calculated by means of pulse oximetry by expressing the pulsatile signal as a percentage of the non pulsatile signal by a specialized probe, both of which are derived from the amount of infrared light absorbed.PI can provide useful information about the peripheral perfusion status of the patients and works as an index for sympathetic stimulation. Recent study suggested that PI could be used as an early and sensitive indicator to assess the development of sympathectomy induced by brachial plexus block in conscious adults; it is more sensitive than other parameters such as changes of skin temperature gradients or mean arterial pressure (MAP)

Inclusion Criteria:

Age group: (3-14) years old. ASA class I-II

Exclusion Criteria:

• Patients with age below 3 year or older than 14 years. Parent refusal. Patients with apparent infection at site of needle insertion. Patients with any coagulation disorder. Patients with known neuropathy or brachial plexus injury. Patients with any cardiac, hepatic, renal or neurological disease

59 pediatric patients scheduled for elective upper extremity procedures will receive general anesthesia and trained anesthesiologist will perform ultrasound guided supraclavicular brachial plexus block on the ipsilateral side of the procedure.