Perfusion Index Variability During Epidural Labor Analgesia

This prospective, single-centre observational study evaluates changes in the peripheral Perfusion Index (PI) - a non-invasive parameter derived from the pulse-oximetry photoplethysmographic waveform - in women receiving epidural, or combined spinal-epidural (CSE) with intrathecal opioid only, analgesia during vaginal labor. Epidural-induced sympathetic block causes vasodilation and compensatory changes in peripheral vascular resistance, which alter peripheral perfusion and therefore PI. PI is recorded together with routinely monitored haemodynamic, obstetric and analgesia-related variables (including pain intensity on the Numeric Rating Scale, NRS) from before block placement until after delivery. The aims are: to describe the pattern and magnitude of PI changes during labor analgesia and the parameter's usefulness in this dynamic clinical setting; to assess the correlation between PI changes and reported pain; and to evaluate whether PI (its change or the absence of change) can help identify ineffective blocks early - for example those caused by catheter malposition or by sacral sparing in the second stage of labor. All measurements are non-invasive and consistent with the current standard of perinatal care.