Comparative efficacy of finger versus forehead Plethysmographic Variability Index monitoring in pediatric surgical...

The Plethysmographic Variability Index can be measured by both finger and forehead probes. Vasoconstriction may jeopardize the reliability of finger PVI measurements in pediatric patients undergoing surgery. However, forehead vasculature exhibits more marked resistance to alterations in the vasomotor tonus.

Our aim was to compare the Plethysmographic Variability Index measured via finger or forehead probes in mechanically ventilated pediatric surgery patients in terms of their ability to predict fluid responsiveness as well as to determine the best cut-off values for these two measurements.

A total of 50 pediatric patients undergoing minor elective surgery were included after provision of parental consent and ethics committee approval. Perfusion index measured at the finger or forehead and Plethysmographic Variability Index monitoring comprised the primary assessments. Hemodynamic parameters monitored included perfusion index, Plethysmographic Variability Index, and cardiac output. A ≥ 15% increase in cardiac output following passive leg raise maneuver was considered to show fluid responsiveness. Two groups were defined based on fluid responsiveness: Group R (responsive) and Group NR (non-responsive). Student's t-test, Mann-Whitney U test, DeLong test, and ROC were used for statistical analysis.

The area under curve for finger and forehead Plethysmographic Variability Index prior to passive leg raise maneuver were 0.699 (p = .011) and 0.847 (p < .001), respectively. The sensitivity for finger and forehead measurements at a cut-off value of ≤14% was 92.9% and 96.4%, and 45.4% and 72.7%, respectively.

Although forehead and finger Plethysmographic Variability Index monitoring were similarly sensitive in predicting fluid responsiveness in pediatric surgical patients, the former method provided higher specificity. The best cut-off value for PVI measurements with forehead and finger probes was found to be 14%.