Pupillary Light Reflex to Predict Post-Spinal Hypotension in Elective Cesarean Delivery

June 25, 2026 updated by: Tarik Saber Sarhan, Al-Azhar University

Pupillary Light Reflex for Predicting Hypotension Risk After Spinal Anesthesia for Elective Cesarean Section: A Prospective Observational Cohort Study

This prospective observational cohort study investigates whether pre-anesthetic pupillary light reflex (PLR) parameters can predict the risk of hypotension following spinal anesthesia in women undergoing elective cesarean section. Spinal anesthesia-induced hypotension is common, with reported incidence rates of 50-90%, and current predictors such as baseline blood pressure and BMI have limited accuracy. PLR, a sensitive marker of autonomic nervous system balance, may offer a simple, objective, and non-invasive tool for identifying patients at higher risk. The study evaluates pupillary reaction latency and other PLR parameters and correlates them with post-spinal blood pressure changes to determine their predictive value.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Not yet recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

Spinal anesthesia is the standard technique for elective cesarean delivery, yet it is frequently associated with maternal hypotension due to sympathetic blockade. According to the study protocol, spinal anesthesia-induced hypotension (SAIH) occurs in 50-90% of cases, and currently available predictors-including baseline blood pressure, BMI, and block height-demonstrate limited accuracy (AUC <0.65). The pupillary light reflex (PLR) is a sensitive indicator of autonomic nervous system balance, and pupillary reaction latency may reflect parasympathetic conduction efficiency. As noted in the protocol, no published studies have evaluated PLR as a predictor of hypotension after spinal anesthesia in obstetric patients.

This prospective observational cohort study aims to determine whether pre-anesthetic PLR parameters, particularly pupillary reaction latency, can predict the occurrence and severity of hypotension following spinal anesthesia for elective cesarean section. Additional pupillometry parameters-including baseline diameter, constriction velocity, and minimum diameter-will also be assessed. Measurements are obtained using a handheld pupillometer after 5 minutes of dark adaptation, with three readings taken at 60-second intervals.

Following spinal anesthesia with hyperbaric bupivacaine and fentanyl, maternal blood pressure is monitored every 5 minutes for the first 20 minutes. The primary outcome is hypotension, defined as a >20% decrease in systolic blood pressure. Secondary outcomes include severe hypotension, vasopressor requirements, maternal symptoms, and neonatal Apgar scores and umbilical artery pH.

Statistical analysis includes ROC curve evaluation, Youden's index for cutoff determination, and multivariate logistic regression. The study involves no interventions beyond routine care, and pupillometry is non-invasive and safe. Findings may support the development of a novel, objective, and clinically useful predictor for SAIH in obstetric anesthesia.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Observational

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
200

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult

Accepts Healthy Volunteers

Yes

Sampling Method

Non-Probability Sample

Study Population

Pregnant women (ASA II), aged 18-45 years, with term singleton pregnancies undergoing elective cesarean section under spinal anesthesia at Al-Azhar University Hospital, Damietta. Participants are evaluated using pre-anesthetic pupillometry and routine perioperative monitoring.

Description

Inclusion Criteria:

ASA II Term pregnancy ≥37 weeks Singleton pregnancy Elective cesarean section Age 18-45 years Written informed consent

Exclusion Criteria:

Emergency cesarean section Hypertensive disorders Diabetes mellitus Cardiovascular disease Neurological or autonomic disorders Ophthalmic disease Medications affecting autonomic function BMI >40 kg/m² Failed spinal anesthesia

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

Cohorts and Interventions

Group / Cohort

Group / Cohort

A group or subgroup of participants in an observational study that is assessed for biomedical or health outcomes.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Elective Cesarean Section Cohort
Pregnant women (ASA II, term ≥37 weeks) undergoing elective cesarean section under spinal anesthesia. Participants undergo pre-anesthetic pupillometry and routine perioperative monitoring. No interventions are administered beyond standard clinical care.
Other: Not applicable- observational study
This study does not involve any investigational drugs, devices, or therapeutic interventions. Pupillometry is a non-invasive measurement performed as part of the observational assessment and is not considered an intervention.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Incidence of Hypotension After Spinal Anesthesia
Time Frame: 0-20 minutes after spinal anesthesia
Hypotension defined as a >20% decrease in systolic blood pressure from baseline within the first 20 minutes after spinal anesthesia administration. Blood pressure is measured every 5 minutes as per protocol.
0-20 minutes after spinal anesthesia

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Incidence of Severe Hypotension
Time Frame: 0-20 minutes after spinal anesthesia
Severe hypotension defined as systolic blood pressure <80 mmHg or requiring vasopressor administration.
0-20 minutes after spinal anesthesia
Total Vasopressor Dose Administered
Time Frame: Intraoperative period (first 20 minutes post-spinal)
Total amount of vasopressor medication administered to treat hypotension following spinal anesthesia.
Intraoperative period (first 20 minutes post-spinal)
Maternal Symptoms Associated With Hypotension
Time Frame: Intraoperative period
Assessment of maternal symptoms including nausea, vomiting, dizziness, or discomfort associated with hypotension.
Intraoperative period
Neonatal Apgar Scores
Time Frame: 1 minute and 5 minutes postpartum
Apgar scores at 1 and 5 minutes after delivery.
1 minute and 5 minutes postpartum
Umbilical Artery pH
Time Frame: Immediately after delivery
Measurement of umbilical artery blood pH to assess neonatal acid-base status.
Immediately after delivery

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Al-Azhar University

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
June 28, 2026

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
September 30, 2026

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
October 31, 2026

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
June 25, 2026

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
June 25, 2026

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
July 1, 2026

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
July 1, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
June 25, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
June 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • DFM-IRB 00012367- 26-06-005

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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