Plethysmographic variability index and perfusion index in patients with axillary brachial plexus nerve catheters: An observational study

Axillary nerve blocks are commonly using for forearm and hand surgery. Especially for finger replacement it has been shown continuous plexus blockade improves microcirculation. Addition to that benefit continuous blockade provides adequate analgesia. In this study perfusion index (PI) and plethysmographic variability index (PVI) changes were used to evaluate in blocks success. The PVI and PI values were detected by a Radical-7TM finger pulse oximetry device (Massimo Corp, USA) in both fingers of 50 plastic surgery patients, who received an axillary brachial plexus catheter before surgery. Data recorded at baseline, during catheter replacement, after catheter replacement, and before surgery. All periods hemodynamic data, visual analog scala, Ramsey sedation score and patient satisfaction score were collected. In all 110 patients blocks were successfully applied, PI values in blocked arm increased after local analgesic application (during catheter replacement), (P < .05), PVI values were decreased in the same period but there were no statistical significance. The PI increases after peripheral plexus blockade and may be used as an indicator for successful block placement in awake patient. And also, it may be used as an indicator for catheter effectiveness after surgery. But PVI values cannot detect that kind of relation with nerve blockade.