Spinal Induced Hypotension in Cesarean DeliveryNCT06885593
Femoral Vein Collapsibility Index and Post-Spinal Hypotension in Pregnant Women: Impact of Position
A study testing Supine Position and Left Lateral Tilt Position in people with Spinal Induced Hypotension in Cesarean Delivery, run by Mehmet Sarı at 1 site in Turkey (Türkiye).
Trial summary
This study aims to improve the safety of spinal anesthesia for pregnant patients undergoing elective cesarean delivery. Specifically, the investigators are investigating whether ultrasound measurements of a vein in the groin (the right common femoral vein, or RCFV) can help predict the risk of low blood pressure… Read more about this study
- Who is it for?
- Ages 18 years and older, women only
- Conditions the study is for
- Spinal Induced Hypotension in Cesarean Delivery
- What is being tested?
- Supine Position and Left Lateral Tilt Position
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 100 participants
- Where
- 1 siteTurkey (Türkiye)
- Study dates
- 1 May 2025to 31 Aug 2026
- Phase
- Interventional
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- Women only
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- ASA 2
- Uncomplicated pregnancy
- Height between 150 cm-180 cm
- Signed the informed consent form
- 8 hours of fasting before the operation
- Patients who refuse normal delivery
Who cannot join
- Obstetric comorbidities affecting caval compression of the aorta
- Transverse development
- Fetal macrosomia
- Uterine anomaly
- Polyhydramnion
- Oligohydroamnion
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- Membrane ruptures
- Intrauterine growth retardation
- Mothers with hyperactive lung disease
- Those with autonomic neuropathy
- Kidney failure
- Smokers
- Severe scoliosis or kyphosis
- Multiple pregnancy (twins, triplets,...)
- Those who do not reach T6 sensory block level after 10 minutes
- Those undergoing general anesthesia or IV analgesics for any reason
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Turkey (Türkiye)1 site
Bezmialem Vakıf Univeristesi Dragos Hastanesi Yalı, Kennedy Cd. No:16.
Istanbul, 34844
Kazım Karaaslan Head of Department, Medical Doctor, Professor, +905055213865, kkaraaslan@bezmialem.edu.tr
Mehmet SARI, Medical Doctor
About this study
Official title: "Can Femoral Vena Cava Collapsibility Index Predict Post-spinal Hypotension in Pregnant Women in Left Lateral Tilt Position?"
This study aims to improve the safety of spinal anesthesia for pregnant patients undergoing elective cesarean delivery. Specifically, the investigators are investigating whether ultrasound measurements of a vein in the groin (the right common femoral vein, or RCFV) can help predict the risk of low blood pressure (hypotension) after spinal anesthesia. The main question it aims to answer is:
Can femoral vena cava collapsibility index predict post-spinal hypotension in pregnant women in left lateral tilt position?
Before receiving spinal anesthesia, participants will undergo a brief and painless ultrasound examination of the RCFV in the groin area while lying in a specific position."
Read the detailed description
Post-spinal hypotension (PSH) is defined as a systolic arterial blood pressure (SBP) decrease of more than 20% from baseline or an SBP drop below 100 mmHg. This reduction in blood pressure may compromise uteroplacental perfusion, leading to fetal hypoxia and acidosis. PSH is the most common complication in obstetric anesthesia, with an incidence of up to 95% in healthy women. Despite extensive research, the most effective strategy to maintain hemodynamic stability remains under investigation. Various methods, including crystalloid and colloid fluid loading, leg wrapping, head-down tilt, and vasopressor use, have been explored for both treatment and prevention.
The sympatholytic effect of spinal anesthesia induces vasodilation, exacerbating maternal hypotension due to the gravid uterus compressing the inferior vena cava (IVC). This compression reduces venous return and subsequently decreases the IVC diameter.
Current recommendations for term pregnant women undergoing cesarean delivery advocate for a left lateral tilt position to prevent aortocaval compression (ACC), maternal hypotension, and fetal compromise . In the supine position, the IVC is nearly completely obstructed at term up to its bifurcation. However, most women experience only minimal hemodynamic effects due to compensatory mechanisms such as venoconstriction in the lower extremities and collateral circulation via the paraspinal and azygos veins. Clinically significant hemodynamic compromise, known as supine hypotensive syndrome, occurs in approximately 8-10% of term pregnancies, likely due to insufficient compensatory responses .
The right common femoral vein (RCFV), a continuation of the right external iliac vein, is a tributary of the IVC. Because the RCFV is superficially located, it can be easily visualized using a high-frequency ultrasound probe. Importantly, the RCFV is situated distal to the site of aortocaval compression, making it a potential surrogate marker for hemodynamic changes.
Study Hypothesis This study hypothesizes that the peak velocity and collapsibility index of the RCFV in the inguinal region, measured in the left lateral 15-degree tilt position, reflect the degree of aortocaval compression. These parameters may help identify pregnant women at high risk of post-spinal hypotension during elective cesarean delivery.
- Being tested
- Supine Position, Left Lateral Tilt Position
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Supine PositionDiagnostic test
All ultrasonography (USG) procedures will be performed by the same anesthesiologist using a Ultrasound device before the start of spinal anesthesia (SA) and after baseline blood pressure and heart rate have been measured. Patients will be placed in supine and left lateral tilt (LLT) positions. After at least 3 minutes in each position, ultrasound of the inferior vena cava (IVC) and femoral vein (FV) will be performed. The oblique probe will be placed below the xiphoid. Anteroposterior diameters and peak velocities of the IVC will be measured 2-3 cm below the IVC-right atrium For standardization purposes, measurements of the right femoral vein will be used in the study. The FV will be visualized with B-mode ultrasound 2-5 cm below the level of the inguinal ligament where the femoral artery is best palpated, without applying any pressure that may affect the FV diameter.
Supine PositionDiagnostic test
All ultrasonography (USG) procedures will be performed by the same anesthesiologist using a Ultrasound device before the start of spinal anesthesia (SA) and after baseline blood pressure and heart rate have been measured. Patients will be placed in supine position. After at least 3 minutes in each position, ultrasound of the inferior vena cava (IVC) and femoral vein (FV) will be performed. The oblique probe will be placed below the xiphoid. Anteroposterior diameters and peak velocities of the IVC will be measured 2-3 cm below the IVC-right atrium For standardization purposes, measurements of the right femoral vein will be used in the study. The FV will be visualized with B-mode ultrasound 2-5 cm below the level of the inguinal ligament where the femoral artery is best palpated, without applying any pressure that may affect the FV diameter.
Left Lateral Tilt PositionDiagnostic test
All ultrasonography (USG) procedures will be performed by the same anesthesiologist using a Ultrasound device before the start of spinal anesthesia (SA) and after baseline blood pressure and heart rate have been measured. Patients will be placed in left lateral tilt (LLT) position. After at least 3 minutes in each position, ultrasound of the inferior vena cava (IVC) and femoral vein (FV) will be performed. The oblique probe will be placed below the xiphoid. Anteroposterior diameters and peak velocities of the IVC will be measured 2-3 cm below the IVC-right atrium For standardization purposes, measurements of the right femoral vein will be used in the study. The FV will be visualized with B-mode ultrasound 2-5 cm below the level of the inguinal ligament where the femoral artery is best palpated, without applying any pressure that may affect the FV diameter.
| Study group | Role | What they receive |
|---|---|---|
| Supine Position | Sham comparator | All ultrasonography (USG) procedures will be performed by the same anesthesiologist using a Ultrasound device before the start of spinal anesthesia (SA) and after baseline blood pressure and heart rate have been measured. Patients will be placed in supine position. After at least 3 minutes in each position, ultrasound of the inferior vena cava (IVC) and femoral vein (FV) will be performed. The oblique probe will be placed below the xiphoid. Anteroposterior diameters and peak velocities of the IVC will be measured 2-3 cm below the IVC-right atrium For standardization purposes, measurements of the right femoral vein will be used in the study. The FV will be visualized with B-mode ultrasound 2-5 cm below the level of the inguinal ligament where the femoral artery is best palpated, without applying any pressure that may affect the FV diameter. Receives: Diagnostic Test: Supine Position; Diagnostic Test: Left Lateral Tilt Position |
| Left Lateral Tilt Position | Active comparator | All ultrasonography (USG) procedures will be performed by the same anesthesiologist using a Ultrasound device before the start of spinal anesthesia (SA) and after baseline blood pressure and heart rate have been measured.
Patients will be placed in left lateral tilt (LLT) positions. After at least 3 minutes in each position, ultrasound of the inferior vena cava (IVC) and femoral vein (FV) will be performed. The oblique probe will be placed below the xiphoid. Anteroposterior diameters and peak velocities of the IVC will be measured 2-3 cm below the IVC-right atrium For standardization purposes, measurements of the right femoral vein will be used in the study. The FV will be visualized with B-mode ultrasound 2-5 cm below the level of the inguinal ligament where the femoral artery is best palpated, without applying any pressure that may affect the FV diameter. Receives: Diagnostic Test: Supine Position; Diagnostic Test: Left Lateral Tilt Position |
What is being measured
The primary outcome is the main question the study is designed to answer.
Number of Participants with Post-Spinal Hypotension
Post-Spinal Hypotension Measured by Systolic and Diastolic Blood Pressure and Heart Rate Changes Following Spinal Anesthesia in Supine and Left Lateral Tilt Positions Systolic Blood Pressure, Diastolic Blood Pressure, and Heart Rate are now presented as separate outcome measures, each with its own unit of measure.
Measured: 40 minute
Secondary outcomes (1)
Number of Participants with time of onset of maternal hypotension, symptomatic hypotension, incidence of bradycardia, cumulative ephedrine requirements, patient satisfaction
Secondary maternal outcomes recorded from the induction of spinal anesthesia (SA) to delivery include: time of onset of maternal hypotension (time from SA to first hypotension episode); symptomatic hypotension (hypotension with nausea, vomiting, and/or dizziness); severe hypotension (systolic arterial pressure [SAP] <70% of baseline); minimum recorded SAP; cumulative duration of hypotension (total minutes of SAP <90 mmHg or diastolic BP <60 mmHg); minimum heart rate (HR); incidence of bradycardia (HR <50 bpm); atropine use for bradycardia; cumulative ephedrine requirements (total ephedrine dose administered); and patient satisfaction (rated on a Likert scale from 1-5).
Measured: 24 hours
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted20 Mar 2025
- Study start1 May 2025 (estimated)
- Primary completion30 Apr 2026 (estimated)
- Study completion31 Aug 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (2)Papers the sponsor has linked to this study.
- Other trials for Spinal Induced Hypotension in Cesarean DeliveryStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Prevention
- Allocation
- Non-randomised
- Intervention model
- Crossover
- Model description
- All ultrasonography (USG) procedures will be performed by the same anesthesiologist using a Ultrasound device before the start of spinal anesthesia (SA) and after baseline blood pressure and heart rate have been measured. Patients will be placed in supine and left lateral tilt (LLT) positions. After at least 3 minutes in each position, ultrasound of the inferior vena cava (IVC) and femoral vein (FV) will be performed. The oblique probe will be placed below the xiphoid. Anteroposterior diameters and peak velocities of the IVC will be measured 2-3 cm below the IVC-right atrium For standardization purposes, measurements of the right femoral vein will be used in the study. The FV will be visualized with B-mode ultrasound 2-5 cm below the level of the inguinal ligament where the femoral artery is best palpated, without applying any pressure that may affect the FV diameter.
- Masking
- Quadruple blind
- Who is masked
- Participant, Care provider, Investigator, Outcomes assessor
- Enrolment
- 100 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Mehmet Sarı
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor-investigator, Mehmet Sarı, Bezmialem Vakif University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06885593
- Sponsor's protocol ID
- 2025/7
- Status last verified
- Mar 2025
- First submitted
- 10 Mar 2025
- Last updated
- 20 Mar 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Undecided
Publications
Yao SF, Zhao YH, Zheng J, Qian JY, Zhang C, Xu Z, Xu T. The transverse diameter of right common femoral vein by ultrasound in the supine position for predicting post-spinal hypotension during cesarean delivery. BMC Anesthesiol. 2021 Jan 20;21(1):22. doi: 10.1186/s12871-021-01242-8.
PubMed 33472587Lal J, Jain M, Rahul, Singh AK, Bansal T, Vashisth S. Efficacy of inferior vena cava collapsibility index and caval aorta index in predicting the incidence of hypotension after spinal anaesthesia- A prospective, blinded, observational study. Indian J Anaesth. 2023 Jun;67(6):523-529. doi: 10.4103/ija.ija_890_22. Epub 2023 Jun 14.
PubMed 37476444