Correlation of Perfusion Index and Inferior Vena Cava Collapsibility Index in Preoperative Patients: A Prospective Analytical Study

Introduction: Noninvasive monitoring methods are increasingly being explored to avoid complications associated with invasive techniques in perioperative or critical care settings for optimal hemodynamic management.The perfusion index (PI) derived from pulse oximetry reflects peripheral perfusion, while the inferior vena cava (IVC)-collapsibility index (CI) measured by ultrasonography is a useful indicator of intravascular volume status.The present study aimed to evaluate the correlation between PI and IVC-CI and to assess their relationship with mean arterial pressure (MAP).Methods: This prospective analytic study included adult preoperative patients with American Society of Anesthesiologists (ASA) physical status I and II who fulfilled the inclusion criteria.Perfusion index was recorded using pulse oximetry, and IVC diameters were measured using bedside ultrasonography to calculate IVC-CI.Mean arterial pressure was estimated using noninvasive blood pressure measurement.Spearman's correlation coefficient was used for the determination of the correlation between PI and IVC-CI, MAP and PI, and MAP and IVC-CI.Results: A total of 119 adult patients aged 33.06 ± 12 (mean ± SD) years, belonging to ASA physical status I and II, and posted for elective surgical procedures were included in this study.The baseline MAP was 92.98 ± 11.32 mmHg.There were no participants with PI < 0.03, and the baseline PI was 2.63 ± 2.11 (mean ± SD).The preoperative mean ± SD maximum (IVCmax) and minimum (IVCmin) IVC diameter measurements were 1.58 ± 1.36 and 1.03 ± 1.41 cm, respectively.The correlation coefficient (r) was -0.012 between PI and IVC-CI (p = 0.893), -0.070 between PI and MAP (p = 0.447), and 0.054 between IVC-CI and MAP (p = 0.561).Conclusions: The present study found no significant correlation between PI and IVC-CI.A positive correlation was observed between IVC-CI and MAP, in contrast to the inverse relationship observed between PI and MAP, but these findings were not statistically significant.