An observational study in Perioperative Care, Fluid Therapy and Monitoring, Physiologic, sponsored by Wonkwang University Hospital. Completed at 1 site in South Korea. Open to participants aged 19 Years and older, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-08-14.
Sponsored by Wonkwang University Hospital · Observational
This study will compare two operating-room monitors-stroke volume variation (SVV, from the arterial line) and the Pleth Variability Index (PVI, from the pulse oximeter)-to see which one more accurately predicts whether giving a small fluid bolus will improve the heart's pumping during laparoscopic major abdominal surgery. Adults having elective surgery under general anesthesia will receive two small, timed 250-mL crystalloid infusions as part of routine care (one before and one after creation of the pneumoperitoneum). The research team will record SVV and PVI values just before and three minutes after each infusion while keeping these readings hidden from the clinicians so that usual care is not changed. No experimental drugs or devices are used. The main goal is to learn which index better identifies "fluid responsiveness," so future care can be safer and more consistent. Potential risks are minimal and relate to the small fluid boluses (temporary changes in blood pressure or heart rate); the test stops if the anesthesiologist has any safety concerns. There is no direct benefit to participants, but results may help guide fluid therapy for similar patients in the future. The study is being conducted at a single academic hospital in the Republic of Korea and plans to enroll about 300 adults.
Background and rationale. Goal-directed fluid therapy during laparoscopic major abdominal surgery remains variable because dynamic preload indices perform inconsistently under pneumoperitoneum and positional changes. Stroke Volume Variation (SVV, derived from the arterial pressure waveform) and the Pleth Variability Index (PVI, derived from the pulse oximeter) are both widely available and non-drug, non-investigational monitors. A head-to-head, paired accuracy study using standardized fluid challenges can clarify which index better identifies fluid responsiveness in this setting.
Objectives. Primary: Compare the diagnostic accuracy (area under the ROC curve, AUROC) of SVV vs PVI for predicting fluid responsiveness to a small crystalloid bolus during laparoscopic major abdominal surgery.
Key secondary objectives: (1) determine optimal decision thresholds and report sensitivity, specificity, predictive values, and likelihood ratios; (2) compare calibration and classification performance (Youden index, net reclassification); (3) assess effect modification by pneumoperitoneum status, body mass index, ventilation parameters, and vasoactive use; (4) describe peri-bolus hemodynamic changes.
Design and setting. Prospective, single-center, paired diagnostic-accuracy cohort. Adults undergoing elective laparoscopic major abdominal surgery under general anesthesia are enrolled. Each participant undergoes up to two standardized 250-mL crystalloid fluid challenges delivered over \~3 minutes at two time points when feasible: (A) before insufflation and (B) after establishment of pneumoperitoneum at a hemodynamic steady state. Because both indices are recorded around the same fluid challenges, each participant serves as his/her own control.
Index tests. SVV (from the arterial pressure monitor) and PVI (from the pulse-oximetry monitor) are captured immediately before ("pre-bolus") and at \~3 minutes after each bolus. Index values are recorded by trained research staff and kept masked from anesthesia clinicians to avoid influencing usual care.
Reference standard and definition of fluid responsiveness. The reference standard is change in stroke volume index (SVI) or cardiac index derived from arterial pulse contour analysis. Fluid responsiveness is defined a priori as a ≥10% increase in SVI after the 250-mL bolus. Sensitivity analyses will use a 15% threshold and will repeat analyses with cardiac index. If signal quality is inadequate or a clinical safety concern arises, the test is aborted and data flagged.
Anesthesia and peri-bolus standardization. Ventilation is volume-controlled with tidal volume \~6-8 mL/kg predicted body weight and PEEP according to institutional practice; settings and pneumoperitoneum pressure/position are recorded. Vasoactive drugs and additional fluids are allowed as clinically indicated but are time-stamped; fluid challenges for research are not given when active titration of vasoactives makes a stable baseline impossible.
Participants. Inclusion: adults (≥18 years), ASA I-III, elective laparoscopic major abdominal surgery, arterial line in place, informed consent. Exclusion: clinically significant arrhythmia (e.g., atrial fibrillation with irregular R-R), severe valvular disease, intracardiac shunts, pregnancy, severe right-heart failure, inability to obtain reliable arterial or plethysmographic waveforms, or any condition in which a fluid challenge is judged unsafe by the anesthesiologist.
Outcomes. Primary outcome: AUROC of SVV vs PVI for predicting fluid responsiveness. Secondary outcomes: sensitivity/specificity at prespecified thresholds (e.g., SVV 12-13%, PVI 13-15%), decision-curve analysis, subgroup AUROC by pneumoperitoneum status, and immediate hemodynamic responses (MAP, HR).
Sample size and power. The study plans to enroll \~300 adults, yielding up to \~600 evaluable fluid challenges. Assuming a fluid-responsive rate of \~40%, this sample provides >80% power to detect a paired AUROC difference of \~0.08-0.10 between SVV and PVI at α=0.05 using DeLong's test with clustering by subject.
Statistical analysis. ROC curves for SVV and PVI are constructed using clustered bootstrap resampling at the patient level (≥2000 replicates). AUROCs are compared with paired DeLong tests. Threshold performance metrics include exact 95% CIs with patient-clustered bootstrap. Mixed-effects logistic regression (random intercept for patient) will estimate adjusted odds of fluid responsiveness per unit change of each index; prespecified covariates include pneumoperitoneum status, BMI, tidal volume per kg, PEEP, and vasoactive use. Missing index or reference values are minimized; if >5% are missing, multiple imputation will be performed in sensitivity analyses. All analyses follow a prespecified statistical analysis plan.
Safety and risk/benefit. Risks relate to small fluid boluses (transient blood pressure or heart-rate changes, fluid accumulation in vulnerable patients). The bolus is withheld or stopped for any safety concern. No experimental drugs or investigational devices are used; all monitors are standard of care. Participants are unlikely to benefit directly, but the results may improve future intraoperative fluid management.
Confidentiality and data handling. Data are captured on a secure electronic case-report form with coded identifiers. Only the research team has access. Results will be presented in aggregate without personal identifiers and disseminated in peer-reviewed venues.
Regulatory status. This is not an FDA-regulated drug or device investigation and is conducted under institutional review board approval at a single academic hospital in the Republic of Korea.
134 studies on the registry are indexed under Pneumoperitoneum; 28 are open to participants now.
This study's enrollment of 300 is above the median of 59 across 48 observational studies indexed under Pneumoperitoneum.
Browse Pneumoperitoneum studies →Wonkwang University Hospital is the lead sponsor of 26 studies on the registry; 1 is open to participants now.
Counted across the registry records on this site, refreshed daily.
Adults undergoing elective laparoscopic major abdominal surgery at a single academic hospital.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
The anaesthetists’ scale of health before surgery: I is healthy, II has a mild illness that is under control, III a severe one, IV a severe illness that is a constant threat to life. V and VI are used for the critically ill and for organ donors.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
ASA physical status
The anaesthetists’ scale of health before surgery: I is healthy, II has a mild illness that is under control, III a severe one, IV a severe illness that is a constant threat to life. V and VI are used for the critically ill and for organ donors.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Adults undergoing elective laparoscopic major abdominal surgery under general anesthesia at a single academic hospital. Each participant may receive up to two standardized 250-mL crystalloid fluid challenges (pre- and post-pneumoperitoneum). SVV and PVI are recorded around each bolus; no assignment or experimental treatment.
Device: Stroke Volume Variation (SVV) monitoring · Device: Pleth Variability Index (PVI) monitoring
Non-investigational physiologic monitoring. SVV derived from the invasive arterial pressure waveform using a commercially available platform. Used as an index test; values recorded immediately before and \~3 minutes after a standardized 250-mL crystalloid bolus at up to two time points (pre- and post-pneumoperitoneum). Readings are masked to clinicians; operation per usual care.
Also known as: SVV, Arterial pressure waveform analysis, FloTrac, EV1000, HemoSphere, Edwards Lifesciences
Non-investigational pulse-oximetry-derived index. PVI obtained from a commercial monitor. Used as a paired index test; values recorded immediately before and \~3 minutes after each 250-mL crystalloid bolus (up to two time points). Readings masked; monitor used within standard care.
Also known as: PVI, Pleth variability Index, Pulse oximetry-derived variability, Masimo, Radical-7
Area under the ROC curve (AUROC) of stroke volume variation (SVV) and Pleth Variability Index (PVI) for predicting fluid responsiveness to a 250-mL crystalloid bolus
Index tests: pre-bolus SVV (arterial waveform-derived) and PVI (pulse-oximetry-derived). Reference standard: fluid responsiveness defined as a \>=10% increase in stroke volume index measured about 3 minutes after the 250-mL crystalloid bolus using arterial pulse contour analysis. ROC curves will be built for SVV and PVI to discriminate responders vs non-responders; AUROCs will be compared with a paired DeLong test with patient-level clustering. Unit: AUROC (0-1; higher indicates better discrimination).
Time frame: Intraoperative: from the pre-bolus baseline to ~3 minutes after each standardized 250-mL crystalloid bolus (up to two episodes per participant: before and after pneumoperitoneum).
Sensitivity of prespecified SVV thresholds for predicting fluid responsiveness
Proportion of fluid challenges in which SVV \> 13% correctly identifies fluid responsiveness (≥10% increase in stroke volume index after a 250 mL bolus).Unit of Measure: Percent of fluid challenges (%)
Time frame: Intraoperative: pre-bolus baseline to about 3 minutes after each 250 mL bolus (up to two boluses).
Specificity of prespecified SVV thresholds for predicting fluid responsiveness
Proportion of fluid challenges in which SVV ≤ 13% correctly identifies non-responsiveness. Unit of Measure: Percent of fluid challenges (%)
Time frame: Intraoperative: pre bolus baseline to about 3 minutes after each 250 mL bolus (up to two episodes per participant).
Sensitivity of prespecified PVI threshold for predicting fluid responsiveness
Description: Proportion of fluid challenges in which PVI \> 15% correctly identifies fluid responsiveness (≥10% increase in stroke volume index). Unit of Measure: Percent of fluid challenges (%)
Time frame: Intraoperative: pre bolus baseline to about 3 minutes after each 250 mL bolus (up to two episodes per participant).
Specificity of prespecified PVI threshold for predicting fluid responsiveness
Proportion of fluid challenges in which PVI ≤ 15% correctly identifies non-responsiveness. Unit of Measure: Percent of fluid challenges (%)
Time frame: Intraoperative: pre bolus baseline to about 3 minutes after each 250 mL bolus (up to two episodes per participant).
Optimal cutoffs for SVV using Youden index
Data-driven SVV threshold (%) that maximizes the Youden index (sensitivity + specificity - 1) for predicting fluid responsiveness. Unit of Measure: Percent (%)
Time frame: Intraoperative: pre bolus to about 3 minutes post bolus.
Optimal cutoffs for PVI using Youden index
Data-driven PVI threshold (%) that maximizes the Youden index for predicting fluid responsiveness. Unit of Measure: Percent (%)
Time frame: Intraoperative: pre bolus to about 3 minutes post bolus.
Percent change in stroke volume index after a fluid bolus
Percent change in stroke volume index from pre-bolus baseline to about 3 minutes after each 250 mL bolus; subgroup analyses will compare periods before vs. after pneumoperitoneum. Unit of Measure: Percent change (%)
Time frame: Intraoperative: pre bolus baseline to about 3 minutes after each 250 mL bolus.
Change in mean arterial pressure after fluid challenge
Absolute change in mean arterial pressure (mmHg) from pre-bolus baseline to about 3 minutes after each 250 mL bolus. Unit of Measure: Millimeters of mercury (mmHg)
Time frame: Intraoperative: pre bolus to about 3 minutes post bolus.
Change in heart rate after fluid challenge
AAbsolute change in heart rate (beats per minute) from pre-bolus baseline to about 3 minutes after each 250 mL bolus.
Time frame: Intraoperative: pre bolus to about 3 minutes post bolus.
Incidence of any predefined hemodynamic adverse event within 10 minutes of a study bolus
Number of participants experiencing at least one predefined hemodynamic adverse event (hypotension requiring vasopressor, tachycardia requiring treatment, new arrhythmia, etc.) within 10 minutes after each study bolus, divided by the total number of participants. Unit of Measure: Percent of participants (%)
Time frame: From bolus start to 10 minutes after each bolus during surgery.
Ran from Jul 2026 to primary completion in Jul 2026, 0 months.
Of 26 observational studies under Pneumoperitoneum, half reached primary completion within 11 months of starting (the median), counting those still running; a quarter within 5 and three quarters within 17. This study's 0 months is below that.
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This study is completed, as verified in Aug 2026. You cannot join it, but the record below documents what was studied.
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Wonkwang University Hospital