Restrictive vs Liberal Intraoperative Fluid Strategy and Postoperative Outcomes After Elective Cesarean Section

A Prospective Randomized Controlled Trial Comparing Restrictive and Liberal Intraoperative Fluid Strategies on Postoperative Nausea and Vomiting and Gastrointestinal Recovery After Elective Cesarean Section Under Spinal Anesthesia

Spinal anesthesia for elective cesarean section is frequently associated with hemodynamic instability and postoperative complications such as postoperative nausea and vomiting (PONV) and delayed gastrointestinal recovery. Although intraoperative fluid administration is routinely used to prevent spinal-induced hypotension, the optimal fluid strategy remains unclear. Both restrictive and liberal fluid approaches may influence maternal hemodynamics and postoperative outcomes through different physiological mechanisms.

This prospective, single-center, randomized controlled trial aims to compare restrictive (≤3 mL/kg/h) and liberal (>3 mL/kg/h) intraoperative crystalloid fluid strategies in patients undergoing elective cesarean section under spinal anesthesia. The primary outcome is the incidence of PONV within the first 24 hours postoperatively. Secondary outcomes include postdural puncture headache (PDPH), time to first flatus, hypotension frequency, and vasopressor requirements.

Study Overview

• Status: Recruiting
• Conditions: Cesarean Section; Postoperative Ileus; Postoperative Nausea and Vomiting (PONV); Gastrointestinal Recovery; Postdural Puncture Headache (PDPH)
• Intervention / Treatment: Other: Restrictive intraoperative crystalloid fluid strategy (≤3 mL/kg/h); Other: Liberal intraoperative crystalloid fluid strategy (>3 mL/kg/h)

Detailed Description

Spinal anesthesia is the preferred anesthetic technique for elective cesarean section; however, it is frequently associated with sympathetic blockade-induced hypotension. Intraoperative crystalloid administration is commonly used to mitigate hemodynamic instability, yet the optimal fluid strategy remains controversial. Liberal fluid administration may reduce the incidence or severity of hypotension but can contribute to tissue edema, including gastrointestinal wall edema, potentially delaying the recovery of bowel function. Conversely, restrictive fluid strategies may limit fluid overload but could increase vasopressor requirements and compromise splanchnic perfusion. The balance between these approaches and their influence on postoperative maternal outcomes has not been clearly established.

Postoperative nausea and vomiting (PONV) remains one of the most common and distressing complications following cesarean section. Hemodynamic fluctuations, vasopressor use, and visceral perfusion changes may all contribute to its development. In addition, delayed gastrointestinal recovery and postdural puncture headache (PDPH) are relevant postoperative outcomes that may be influenced by intraoperative fluid management.

This prospective, single-center, parallel-group randomized controlled trial is designed to compare two intraoperative crystalloid fluid strategies in patients undergoing elective cesarean section under spinal anesthesia. Patients will be randomized in a 1:1 ratio to receive either a restrictive (≤3 mL/kg/h) or a liberal (>3 mL/kg/h) intraoperative fluid approach. All other anesthetic procedures, spinal technique, and perioperative management will be standardized according to institutional protocol.

The primary outcome of the study is the incidence of PONV within the first 24 postoperative hours. Secondary outcomes include the incidence and severity of PDPH, time to first flatus as a marker of gastrointestinal recovery, frequency of hypotension, and vasopressor requirements. Intraoperative hemodynamic parameters and fluid administration data will be recorded prospectively.

The study aims to clarify whether intraoperative fluid volume influences postoperative maternal recovery and to contribute evidence toward optimizing perioperative fluid management in elective cesarean section.

• Study Type: Interventional
• Enrollment (Estimated): 160
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Pınar Erdoğan, Assoc. Prof.; Phone Number: +905233646954; Email: pinar.erdogan@ohu.edu.tr
• Study Contact Backup: Name: Seval Kılbasanlı, MD; Phone Number: +905057246364; Email: pinar.erdogan@ohu.edu.tr

Study Locations

• Turkey (Türkiye)
  • Merkez
    • Niğde, Merkez, Turkey (Türkiye), 51240
      • Recruiting
      • Niğde Ömer Halisdemir University Hospital
      • Contact: Pınar Erdoğan, Assoc. Prof.; Phone Number: 05233646954; Email: drpinarerdogan@gmail.com

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Female patients aged 18-45 years
• ASA physical status II
• Scheduled for elective cesarean section under spinal anesthesia
• Provision of written informed consent

Exclusion Criteria:

• Emergency cesarean section
• Preeclampsia or eclampsia
• Known cardiac failure
• Known renal failure
• Known hepatic failure
• Coagulopathy
• Contraindication to spinal anesthesia
• Conversion to general anesthesia
• Major technical complications during spinal anesthesia
• Refusal to participate

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Double

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Restrictive intraoperative fluid strategy (≤3 mL/kg/h); Participants undergoing elective cesarean section under spinal anesthesia will receive intraoperative crystalloid at a target average infusion rate of ≤3 mL/kg/h. Standardized spinal anesthesia technique and intraoperative management will be applied. Hypotension will be treated according to the predefined rescue protocol (e.g., ephedrine and/or additional fluid bolus as clinically indicated).	Other: Restrictive intraoperative crystalloid fluid strategy (≤3 mL/kg/h); Intraoperative crystalloid administration targeting an average rate of ≤3 mL/kg/h during elective cesarean section under spinal anesthesia.
Active Comparator: Liberal intraoperative fluid strategy (>3 mL/kg/h); Participants undergoing elective cesarean section under spinal anesthesia will receive intraoperative crystalloid at a target average infusion rate of >3 mL/kg/h. Standardized spinal anesthesia technique and intraoperative management will be applied. Hypotension will be treated according to the predefined rescue protocol (e.g., ephedrine and/or additional fluid bolus as clinically indicated).	Other: Liberal intraoperative crystalloid fluid strategy (>3 mL/kg/h); Intraoperative crystalloid administration targeting an average rate of >3 mL/kg/h during elective cesarean section under spinal anesthesia.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Incidence of postoperative nausea and vomiting (PONV)	Occurrence of nausea and/or vomiting within the first 24 hours after surgery, recorded as present or absent.	0-24 hours postoperatively

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Incidence and severity of postdural puncture headache (PDPH)	Occurrence of postdural puncture headache (PDPH) within 72 hours postoperatively. Severity will be assessed using a standardized pain scale (e.g., numerical rating scale).	24-72 hours postoperatively
Time to first flatus	Time (in hours) from the end of surgery to the first reported passage of flatus.	Up to 72 hours postoperatively
Frequency of intraoperative hypotension	Number of hypotensive episodes defined as systolic blood pressure <90 mmHg or a decrease >20% from baseline.	Intraoperative period
Total intraoperative vasopressor dose	Cumulative dose of ephedrine administered during surgery.	Intraoperative period

Collaborators and Investigators

• Sponsor: Nigde Omer Halisdemir University
• Investigators: Principal Investigator: Pınar Erdoğan, Assoc Prof, Niğde Ömer Halisdemir University Hospital

Study record dates

Study Major Dates

• Study Start (Actual): March 4, 2026
• Primary Completion (Estimated): January 30, 2027
• Study Completion (Estimated): January 30, 2027

Study Registration Dates

• First Submitted: February 23, 2026
• First Submitted That Met QC Criteria: February 23, 2026
• First Posted (Actual): February 27, 2026

Study Record Updates

• Last Update Posted (Actual): March 10, 2026
• Last Update Submitted That Met QC Criteria: March 7, 2026
• Last Verified: March 1, 2026

More Information

Terms related to this study

• Keywords: Hypotension; Postoperative Nausea and Vomiting; Cesarean Section; Spinal Anesthesia; Postdural Puncture Headache; Intraoperative Fluid Therapy; Restrictive Fluid Strategy; Liberal Fluid Strategy; Gastrointestinal Recovery; Vasopressor Use
• Additional Relevant MeSH Terms: Brain Diseases; Central Nervous System Diseases; Nervous System Diseases; Vascular Diseases; Cardiovascular Diseases; Postoperative Complications; Pathologic Processes; Signs and Symptoms, Digestive; Headache Disorders; Vomiting; Headache Disorders, Secondary; Nausea; Pathological Conditions, Signs and Symptoms; Signs and Symptoms; Hypotension; Postoperative Nausea and Vomiting; Post-Dural Puncture Headache
• Other Study ID Numbers: 2025/154

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: Individual participant data (IPD) will not be publicly shared due to institutional policies and ethical considerations related to patient confidentiality. De-identified data may be made available upon reasonable request to the corresponding investigator, subject to approval by the institutional ethics committee and data protection regulations.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No