Validation of Peripheral Perfusion Index in Predicting Successful Supraclavicular Brachial Plexus Block for Upper Extremity Procedures in Children.

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)