This observational study investigates the predictors of Pleth Variability Index (PVI) changes in euvolemic patients undergoing laparoscopic-assisted vaginal hysterectomy (LAVH). The primary objective is to quantify changes in PVI (ΔPVI) across six intraoperative time points associated with positional shifts. Secondary objectives include identifying key predictors of significant PVI change (ΔPVI ≥ 5%), such as passive leg raising, Trendelenburg position, body mass index (BMI), and intraabdominal pressure. Additional variables including perfusion index, mean arterial pressure, bispectral index, skin temperature, age, and anesthetic agent will be evaluated as potential modulators. Findings aim to support individualized fluid management strategies in LAVH.
This prospective, single-center observational cohort study evaluates dynamic intraoperative changes in the Pleth Variability Index (PVI) in 50 adult female patients undergoing elective laparoscopically assisted vaginal hysterectomy (LAVH) at Wonkwang University Hospital. After establishing euvolemia with a 500 mL Volulyte preload (Fresenius Kabi GmbH) over 30-50 minutes, no further intraoperative fluid boluses are given. Anesthesia is induced with propofol (2 mg/kg), fentanyl (1-2 μg/kg), and rocuronium (0.6 mg/kg), and maintained with sevoflurane or desflurane titrated to a bispectral index (BIS) of 40-60. Pneumoperitoneum is set at 12-15 mmHg, and positional maneuvers include 30° passive leg raising, 15° Trendelenburg, and 15° reverse Trendelenburg. Monitoring devices and data acquisition: * \*\*Masimo Radical-7\*\* pulse oximeter (PVI, perfusion index \[PI\]) * \*\*Invasive arterial line\*\* (mean arterial pressure \[MAP\]) * \*\*BIS sensor\*\* (BIS) * \*\*Skin temperature probe\*\* (forearm, °C) calibrated pre-case Measurements are recorded at six standardized time points (baseline; post-induction; post-passive leg raising; post-pneumoperitoneum; post-Trendelenburg; post-reverse Trendelenburg). Continuous waveforms are averaged over 30 s epochs. Primary endpoint is the absolute change in PVI (ΔPVI) relative to baseline. Secondary analyses include: * Multivariable logistic regression for predictors of ΔPVI ≥ 5% * Multivariable linear regression for continuous ΔPVI prediction * Correlation analyses of ΔPVI with intraabdominal pressure (mmHg) and body mass index (kg/m²) * Sensitivity analysis of PI reliability (intraclass correlation coefficient) across skin temperature thresholds * Descriptive statistics for frequency of vasopressor (ephedrine) use All analyses are performed using SPSS v29.0 with p \< 0.05 considered statistically significant (Bonferroni correction applied for repeated measures).
Study Type
OBSERVATIONAL
Enrollment
50
"PVI is continuously monitored using the Masimo Radical-7 pulse oximetry device to evaluate respiratory variation in the plethysmographic waveform amplitude during laparoscopic-assisted vaginal hysterectomy (LAVH). No fluid intervention is applied; device use is for observational measurement of fluid responsiveness."
Wonkwang University School of Medicine Hospital
Iksan, Jeollabuk-do, South Korea
ΔPVI (Change in Pleth Variability Index)
Absolute change in PVI (%) at each of six intraoperative time points relative to baseline.
Time frame: Intraoperative period (~60-90 minutes)
Proportion of patients with significant ΔPVI ≥ 5%
Percentage of participants exhibiting a ΔPVI ≥ 5% at any intraoperative time point.
Time frame: At any of the six predefined intraoperative time points: • Post-induction • Post-passive leg raising • Post-pneumoperitoneum • Post-Trendelenburg • Post-reverse Trendelenburg • End of surgery (within 60-90 minutes after induction of anesthesia)
Effect of intraabdominal pressure on ΔPVI
Correlation coefficient (r) between intraabdominal pressure (mmHg) and magnitude of ΔPVI.with magnitude of ΔPVI during pneumoperitoneum and Trendelenburg position. Multivariable linear regression is used.
Time frame: At post-pneumoperitoneum and post-Trendelenburg time points (20-45 minutes after anesthesia induction)
Effect of body mass index on ΔPVI
Correlation coefficient (r) between BMI (kg/m²) and magnitude of ΔPVI.measurements during LAVH. Data analyzed using subgroup comparison between stable and decreased skin temperature conditions.
Time frame: ΔPVI measured at post-pneumoperitoneum and post-Trendelenburg time points (20-45 minutes after anesthesia induction)
Change in mean arterial pressure (MAP)
Absolute change in MAP (mmHg) at the six predefined time points.
Time frame: MAP measured at six predefined intraoperative time points: • Baseline • Post-induction • Post-passive leg raising • Post-pneumoperitoneum • Post-Trendelenburg • Post-reverse Trendelenburg (Total duration: ~90 minutes after anesthesia induction)
Change in perfusion index (PI)
Absolute change in PI (unitless) at the six predefined time points.
Time frame: MAP measured at six predefined intraoperative time points: • Baseline • Post-induction • Post-passive leg raising • Post-pneumoperitoneum • Post-Trendelenburg • Post-reverse Trendelenburg (Total duration: ~90 minutes after anesthesia induction)
Change in bispectral index (BIS)
Absolute change in BIS (unitless) at the six predefined time points.
Time frame: MAP measured at six predefined intraoperative time points: • Baseline • Post-induction • Post-passive leg raising • Post-pneumoperitoneum • Post-Trendelenburg • Post-reverse Trendelenburg (Total duration: ~90 minutes after anesthesia induction)
Influence of skin temperature on PI reliability
Difference in intraclass correlation coefficient of PI measurements between stable (≤ ± 1 °C) and decreased (\> 1 °C drop) skin temperature conditions.
Time frame: MAP measured at six predefined intraoperative time points: • Baseline • Post-induction • Post-passive leg raising • Post-pneumoperitoneum • Post-Trendelenburg • Post-reverse Trendelenburg (Total duration: ~90 minutes after anesthesia induction)
Frequency of vasopressor use
Number and percentage of patients requiring ephedrine bolus due to MAP \< 70 mmHg during the observation period.
Time frame: MAP measured at six predefined intraoperative time points: • Baseline • Post-induction • Post-passive leg raising • Post-pneumoperitoneum • Post-Trendelenburg • Post-reverse Trendelenburg (Total duration: ~90 minutes after anesthesia induction)
This platform is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional.