Renal Functions in Preeclamptic Pregnant Women Using Neutrophil Gelatinase-associated Lipocalin (NGAL) and Standard Renal Function Tests

Evaluation of the Effect of Spinal Anesthesia-Induced Hypotension on Renal Functions in Preeclamptic Pregnant Women Using Neutrophil Gelatinase-associated Lipocalin (NGAL) and Standard Renal Function Tests

Acute kidney injury (AKI) is a significant postoperative complication. Risk factors for AKI include impaired renal perfusion, decreased functional renal reserve, as well as advanced age, peripheral arterial disease, diabetes mellitus, renovascular disease and congestive heart failure. Mean arterial pressure (MAP) below 55-60 mmHg has been associated with postoperative AKI. Traditional diagnostic criteria for AKI include increased serum creatinine levels and oliguria. However, creatinine levels do not rise until more than half of renal function is lost. Serum and urine NGAL levels rise earlier-within 24-48 hours-making it a promising early biomarker.

In our study, hypotension is defined as systolic blood pressure <100 mmHg or a >30% decrease in MAP. Patients requiring ephedrine under these conditions will be evaluated as the hypotension group and compared with non-hypotensive patients in terms of NGAL, BUN (blood urea nitrogen), creatinine, and GFR (Glomerular Filtration Rate) values at baseline and at the 4th postoperative hour.

Study Overview

• Status: Not yet recruiting
• Conditions: Anesthesia; Acute Kidney Failure; Preeclampsia (PE); Spinal Anesthesia Induced Hypotension; Spinal Aneshtesia

Detailed Description

All patients were informed about the study in the preoperative period and written informed consent was obtained before the procedure. The following data were recorded: age, sex, weight, height, BMI (Body Mass Index), comorbidities, regular medications, ASA (American Society of Anesthesiologists) classification, gestational age, history of preeclampsia in previous pregnancies, hemodynamic values and laboratory results. After being admitted to the cesarean operating room, patients were monitored according to the ASA guidelines using standard monitoring methods (non-invasive arterial blood pressure measurements at 2-minute intervals, 3-lead ECG (Electrocardiogram) and pulse oximetry). A peripheral intravenous line was established via the dorsum of the hand and Ringer's lactate was infused at a rate of 10 mL/kg/h. All patients received oxygen via nasal cannula at a rate of 3-4 L/min.

Blood samples were collected from the patients before spinal anesthesia and at the 4th postoperative hour. The samples were centrifuged at 4000×g for 10 minutes in the biochemistry laboratory and then transferred into Eppendorf tubes and stored at -80°C in a deep freezer until the day of analysis. NGAL levels were measured using an ELISA (Enzyme-Linked ImmunoSorbent Assay) method with a commercial kit (USCN, China) at the Biochemistry Laboratory of Ankara Bilkent City Hospital. Each sample was measured in duplicate, and the mean values were used for evaluation. The intra-assay and inter-assay coefficients of variation (CV%) for the kit were determined to be <10% and <12%, respectively. At the 4th postoperative hour, blood samples were also analyzed for BUN, creatinine, and GFR levels, which were recorded accordingly.

• Study Type: Observational
• Enrollment (Estimated): 46

Contacts and Locations

• Study Contact: Name: Cahide Çağlayan, Dr; Phone Number: +905547542106; Email: cahide.gulsen@hotmail.com
• Study Contact Backup: Name: Nihan Aydın Güzey; Phone Number: +905056496231; Email: nihanaydinguzey@gmail.com

Study Locations

• Turkey
  • Ankara, Turkey, 06800
    • Ankara City Hospital
    • Contact: Ankara City Hospital; Phone Number: +905549542106; Email: cahide.gulsen@hotmail.com

Participation Criteria

Eligibility Criteria

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

• Sampling Method: Non-Probability Sample

Study Population

Preeclamptic pregnant women aged 18 to 45 years, classified as ASA II-III, who volunteered to participate, were scheduled for cesarean section, and received spinal anesthesia were included in the study.

Description

Inclusion Criteria:

• Patients classified as ASA physical status II-III
• Pregnant women aged 18-45 years, diagnosed with preeclampsia and scheduled for elective cesarean section, will be included in the study.

Exclusion Criteria:

• Patients who are unable to read, understand, or sign the informed consent form
• Patients with a diagnosed renal disease
• Patients who do not wish to participate in the study
• Patients with ASA physical status greater than III
• Patients younger than 18 or older than 45 years
• Patients requiring sedation or undergoing general anesthesia
• Patients with cardiac instability
• Patients with known arrhythmias

Study Plan

How is the study designed?

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort
CASE GROUP; During the operation, heart rate (HR) and peripheral oxygen saturation (SpO₂) were continuously monitored. Systolic arterial pressure (SAP), diastolic arterial pressure (DAP), and mean arterial pressure (MAP) were measured and recorded every 2 minutes for the first 15 minutes, then every 5 minutes thereafter. Hypotension was defined as a ≥30% decrease in MAP from baseline or systolic blood pressure <100 mmHg. Patients who developed hypotension within the first four measurements were included in the hypotension group. Patients who developed hypotension in later measurements were excluded from the study to avoid confusion with bleeding-related hypotension. A 5 mg bolus of ephedrine was administered to raise the MAP to 80% or more of the baseline level within 60 seconds. Surgical duration, amount of fluids administered, duration and number of hypotensive episodes, total dose of ephedrine, estimated blood loss, use of additional uterotonics or tranexamic acid, neonatal weight, and Apgar.
CONTROL GROUP; During the operation, the patient's heart rate (HR) and peripheral oxygen saturation (SpO₂) were continuously monitored. Systolic arterial pressure (SAP), diastolic arterial pressure (DAP), and mean arterial pressure (MAP) were measured and recorded every 2 minutes for the first 15 minutes, and then every 5 minutes thereafter. Patients whose MAP did not decrease by 30% or more from the baseline value were considered the control group

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
ID: TABED 2/170/2024 Change in Plasma NGAL Levels Before and After Spinal Anesthesia	To assess whether spinal anesthesia-induced hypotension in preeclamptic patients leads to early kidney injury, based on changes in plasma NGAL (neutrophil gelatinase-associated lipocalin) levels.	Before spinal anesthesia and at postoperative 4th hour

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Renal Function Parameters Post-Spinal Anesthesia	Evaluation of postoperative serum urea levels to assess renal function in the early postoperative period.	Postoperative 4th hour
Comparative Timing of NGAL and Creatinine in Detecting AKI	To compare the timing of elevation between plasma NGAL and serum creatinine for early detection of acute kidney injury in preeclamptic patients.	NGAL measured before and 4 hours after anesthesia; creatinine at 4 hours
Intraoperative Hemodynamic Monitoring	Measurement of hemodynamic parameter systolic arterial pressure [SAP] at specified time points during the operation to evaluate the cardiovascular effects of spinal anesthesia in preeclamptic patients.	Measurements recorded at 2, 4, 6, 8, 10, 12, 14, 20, 25, 30, 35, 40, 50, and 55 minutes after spinal anesthesia initiation.
Intraoperative Hemodynamic Monitoring	Measurement of hemodynamic parameter diastolic arterial pressure [DAP] at specified time points during the operation to evaluate the cardiovascular effects of spinal anesthesia in preeclamptic patients.	Measurements recorded at 2, 4, 6, 8, 10, 12, 14, 20, 25, 30, 35, 40, 50, and 55 minutes after spinal anesthesia initiation.
Intraoperative Hemodynamic Monitoring	Measurement of hemodynamic parameter mean arterial pressure [MAP] at specified time points during the operation to evaluate the cardiovascular effects of spinal anesthesia in preeclamptic patients.	Measurements recorded at 2, 4, 6, 8, 10, 12, 14, 20, 25, 30, 35, 40, 50, and 55 minutes after spinal anesthesia initiation.
Intraoperative Hemodynamic Monitoring	Measurement of hemodynamic parameter heart rate [HR] at specified time points during the operation to evaluate the cardiovascular effects of spinal anesthesia in preeclamptic patients.	Measurements recorded at 2, 4, 6, 8, 10, 12, 14, 20, 25, 30, 35, 40, 50, and 55 minutes after spinal anesthesia initiation.
Intraoperative Hemodynamic Monitoring	Measurement of hemodynamic parameter oxygen saturation [SpO₂] at specified time points during the operation to evaluate the cardiovascular effects of spinal anesthesia in preeclamptic patients.	Measurements recorded at 2, 4, 6, 8, 10, 12, 14, 20, 25, 30, 35, 40, 50, and 55 minutes after spinal anesthesia initiation.
Renal Function Parameters Post-Spinal Anesthesia	Evaluation of postoperative serum creatinine levels to assess renal function in the early postoperative period.	Postoperative 4th hour
Renal Function Parameters Post-Spinal Anesthesia	Evaluation of postoperative eGFR levels to assess renal function in the early postoperative period.	Postoperative 4th hour

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Incidence of Spinal Anesthesia-Related Hypotension	Number and percentage of patients who experience hypotension (defined as a >20% decrease from baseline systolic blood pressure) following spinal anesthesia.	Within the first 30 minutes after spinal anesthesia
Total Intraoperative Vasopressor Requirement	otal dose of vasopressors (e.g., ephedrine or phenylephrine) administered to treat spinal-induced hypotension.	Intraoperative period

Collaborators and Investigators

• Sponsor: Nihan Aydin Guzey
• Collaborators: Ankara City Hospital Bilkent
• Investigators: Principal Investigator: Nihan Aydın Güzey, Ankara City Hospital Bilkent

Study record dates

Study Major Dates

• Study Start (Estimated): June 8, 2025
• Primary Completion (Estimated): September 22, 2025
• Study Completion (Estimated): October 20, 2025

Study Registration Dates

• First Submitted: May 26, 2025
• First Submitted That Met QC Criteria: June 8, 2025
• First Posted (Actual): June 11, 2025

Study Record Updates

• Last Update Posted (Actual): June 11, 2025
• Last Update Submitted That Met QC Criteria: June 8, 2025
• Last Verified: June 1, 2025

More Information

Terms related to this study

• Keywords: Hypotension; Preeclampsia; NGAL; AKI; Creatinine
• Additional Relevant MeSH Terms: Urogenital Diseases; Vascular Diseases; Cardiovascular Diseases; Male Urogenital Diseases; Kidney Diseases; Urologic Diseases; Female Urogenital Diseases; Female Urogenital Diseases and Pregnancy Complications; Pregnancy Complications; Hypertension, Pregnancy-Induced; Pre-Eclampsia; Acute Kidney Injury; Hypotension; Renal Insufficiency
• Other Study ID Numbers: TABED 2/170/2024

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

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