Perfusion Index Variability During Epidural Labor Analgesia
Variability of the Peripheral Perfusion Index (PI) During Epidural Analgesia for Labor: A Single-Centre Prospective Observational Study
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.
Study Overview
Status
Conditions
Intervention / Treatment
Detailed Description
Background: The Perfusion Index (PI) is the ratio of the pulsatile (AC) to the non-pulsatile (DC) component of light absorption in the photoplethysmographic waveform recorded during pulse oximetry, expressed as a percentage. Originally used as an indicator of pulse-oximeter signal quality, PI is now recognised as a non-invasive measure of peripheral perfusion. Because both signal components are influenced chiefly by vascular tone and vascular-bed filling, PI changes across clinical states. Spontaneous vaginal labor involves changes in cardiac output, peripheral resistance and blood redistribution, and therefore in PI. Neuraxial (epidural) analgesia further modifies PI: the sympathetic block it produces causes vasodilation and compensatory changes in peripheral resistance in non-blocked regions, altering peripheral perfusion. These changes can be captured systemically by the finger pulse oximeter routinely used to monitor labor analgesia. Analysing PI during epidural monitoring may therefore provide clinically useful information about correct block placement, drug distribution in the epidural space across successive stages of labor, and thus analgesic effectiveness.
Design and population: Prospective observational study. Participants are patients admitted to the labor ward of the Department of Obstetrics and Gynaecology, Gynaecologic Oncology and Gynaecologic Endocrinology, University Clinical Centre in Gdańsk, who receive epidural analgesia during vaginal delivery - either as the sole regional technique or as combined spinal-epidural (CSE) analgesia. For CSE, only intrathecal opioids may be administered (the standard approach in these patients); intrathecal local anaesthetic is an exclusion criterion. Both spontaneous-onset and induced labors are eligible.
Recorded haemodynamic parameters: PI is recorded automatically together with peripheral oxygen saturation (SpO2). Additional parameters recorded with standard monitors are arterial blood pressure, maternal heart rate (HR) and fetal heart rate (FHR). Monitoring begins before placement of the regional block.
Measurement schedule: Parameters are recorded every 5 minutes for the first 30 minutes after administration of local anaesthetic (LA) into the epidural space, and every 15 minutes thereafter. When bolus LA doses are given into the epidural space, 5-minute recording is resumed for 30 minutes from the time of administration. Data are archived as printouts from the labor-ward telemetry system.
Regional block data: The type of block and the doses/volumes and concentrations of all administered drugs are recorded with exact times. For drugs given by infusion, the flow rate per unit time and the time range for each rate are recorded.
Additional clinical data: Ramsay sedation score; correct block function assessed by cold sensation test; pain intensity on the Numeric Rating Scale (NRS); motor block on the Bromage scale; stage of labor and cervical dilation; body position; and any need to adjust catheter depth or replace the catheter. When reported pain exceeds NRS 4, pain location is additionally recorded. Intravenous drugs and fluids (dose and time), obstetric data (operative vaginal delivery with forceps or vacuum, episiotomy, conversion to caesarean section) and basic demographics (age, gestational week, number of previous pregnancies) are recorded, together with relevant comorbidities and medications to allow later subgroup analyses. Data are archived on a dedicated form or in the patient's anaesthesia chart.
Recording duration: Recording runs from before placement of the regional block until 30 minutes after delivery. If delivery is completed by caesarean section, recording continues until the patient is transferred to the operating room.
Non-invasive nature and standard of care: All recorded parameters are obtained non-invasively. PI - the study's object of interest - is recorded with the pulse oximeter that forms part of standard monitoring of patients receiving regional labor analgesia. The scope and frequency of monitoring are consistent with the applicable Polish organisational standard of perinatal care and with the procedures of the University Clinical Centre in Gdańsk.
Study Type
Enrollment (Estimated)
Contacts and Locations
Study Contact
- Name: Tomasz Jasiński, MD PhD
- Phone Number: +48 58 349 32 80
- Email: tjasinski@uck.gda.pl
Study Locations
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Pomeranian Voivodeship
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Gdansk, Pomeranian Voivodeship, Poland, 80-322
- University Clinical Centre in Gdańsk , Drpartment of Anesthesiology nd Intensive Therapy and Department of Obstetrics and Gynaecology, Gynaecologic Oncology and Gynaecologic Endocrinology
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Contact:
- Tomasz Jasiński, MD PhD
- Phone Number: +48 349 32 80
- Email: tjasinski@uck.gda.pl
-
-
Participation Criteria
Eligibility Criteria
Ages Eligible for Study
Accepts Healthy Volunteers
Genders Eligible for Study
Sampling Method
Study Population
Women in spontaneous or induced vaginal labor, admitted to the labor ward of the Department of Obstetrics and Gynaecology, Gynaecologic Oncology and Gynaecologic Endocrinology, University Clinical Centre in Gdańsk, who receive epidural or opioid-only combined spinal-epidural analgesia.
Description
Inclusion Criteria:
- Use of epidural analgesia (epidural block, or combined spinal-epidural block) during spontaneous vaginal delivery.
- Signed informed consent to participate in the study.
Exclusion Criteria:
Administration of local anaesthetic into the intrathecal (subarachnoid) space as part of combined spinal-epidural analgesia.
Study Plan
How is the study designed?
Design Details
- Observational Models: COHORT
- Time Perspectives: PROSPECTIVE
Cohorts and Interventions
Group / Cohort |
Intervention / Treatment |
|---|---|
|
Women receiving epidural labor analgesia
Patients in spontaneous or induced vaginal labor receiving epidural analgesia as the sole regional technique, or combined spinal-epidural analgesia with intrathecal opioid only. |
Neuraxial labor analgesia administered as part of routine care; local anaesthetic ± opioid via the epidural catheter (bolus and/or infusion), with exact drugs, doses, concentrations, volumes, infusion rates and times recorded. In the CSE subgroup only intrathecal opioid is given (intrathecal local anaesthetic is excluded). |
What is the study measuring?
Primary Outcome Measures
Outcome Measure |
Measure Description |
Time Frame |
|---|---|---|
|
Change in peripheral Perfusion Index (PI) during epidural labor analgesia
Time Frame: From before neuraxial block placement until 30 minutes after delivery (typically up to several hours of labor).
|
Peripheral Perfusion Index (%), recorded non-invasively from a finger pulse oximeter, tracked across the course of labor. PI is recorded before block placement and then every 5 minutes for the first 30 minutes after epidural local-anaesthetic administration, every 15 minutes thereafter, with 5-minute recording resumed for 30 minutes after each epidural bolus. The pattern and magnitude of PI change relative to the pre-block baseline are assessed. |
From before neuraxial block placement until 30 minutes after delivery (typically up to several hours of labor).
|
Secondary Outcome Measures
Outcome Measure |
Measure Description |
Time Frame |
|---|---|---|
|
Correlation between Perfusion Index change and pain intensity (NRS
Time Frame: From before neuraxial block placement until 30 minutes after delivery.
|
Association between changes in PI and self-reported pain intensity on the Numeric Rating Scale (NRS, 0-10) during epidural labor analgesia. NRS ≤ 4 is regarded as acceptable analgesia; pain location is additionally recorded when NRS > 4. Unit of Measure : repeated-measures correlation coefficient |
From before neuraxial block placement until 30 minutes after delivery.
|
|
Change in Perfusion Index associated with catheter malposition
Time Frame: From before neuraxial block placement until 30 minutes after delivery.
|
Magnitude of the change in PI (%) around events of epidural catheter malposition. Malposition is identified clinically by the need for catheter depth adjustment or replacement. Unit of Measure - Perfusion Index (%) |
From before neuraxial block placement until 30 minutes after delivery.
|
|
Change in Perfusion Index associated with sacral sparing in the second stage of labor
Time Frame: From before neuraxial block placement until 30 minutes after delivery.
|
Magnitude of the change in PI (%) in cases of sacral sparing, identified clinically by inadequate sacral analgesia in the second stage of labor (cold sensation test and NRS > 4 in the sacral distribution). Unit of Measure - Perfusion Index (%) |
From before neuraxial block placement until 30 minutes after delivery.
|
|
Perfusion Index across maternal body positions during epidural labor analgesia
Time Frame: From before neuraxial block placement until 30 minutes after delivery.
|
Peripheral Perfusion Index (%) recorded in the maternal body positions adopted during labor (e.g., supine with lateral tilt, lateral decubitus, sitting), to describe the effect of body position on PI. Unit of Measure - Perfusion Index (%) |
From before neuraxial block placement until 30 minutes after delivery.
|
Collaborators and Investigators
Sponsor
Study record dates
Study Major Dates
Study Start (Estimated)
Primary Completion (Estimated)
Study Completion (Estimated)
Study Registration Dates
First Submitted
First Submitted That Met QC Criteria
First Posted (Actual)
Study Record Updates
Last Update Posted (Actual)
Last Update Submitted That Met QC Criteria
Last Verified
More Information
Terms related to this study
Keywords
Additional Relevant MeSH Terms
Other Study ID Numbers
- OI-EPI-1
Plan for Individual participant data (IPD)
Plan to Share Individual Participant Data (IPD)?
Drug and device information, study documents
Studies a U.S. FDA-regulated drug product
Studies a U.S. FDA-regulated device product
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