The plethysmographic variability index does not predict fluid responsiveness estimated by esophageal Doppler during kidney transplantation: A controlled study

Research is ongoing to find a noninvasive method of monitoring, which can predict fluid responsiveness in patients undergoing kidney transplantation. To compare the responses to fluid challenges with the Pleth Variability Index, a noninvasive dynamic index derived from plethysmographic variability (Radical 7 pulse oximeter; Masimo Corporation, Irvine, CA), and the esophageal Doppler, the criterion standard. Observational study. University hospital; study from May 2011 and May 2012. Forty-eight patients with end-renal function were included and 44 analyzed. Patients with cardiac failure were not eligible. Fluid challenges were administered during maintenance of general anesthesia but before skin incision and repeated if the patient was deemed to be a “responder” (increase in stroke volume ≥10%). The primary endpoint was to assess if the Pleth Variability Index is an accurate predictor of fluid responsiveness. Among 76 fluid challenges, 38 were considered as positive (increase in stroke volume measured by Doppler ≥10%). Pleth Variability Index was similar at baseline between responders and nonresponder patients. Fluid challenges were associated with a significant decrease in Pleth Variability Index in overall cases (12 [8–14] vs 10 [6–17], P = .050), but it was not able to discriminate between responders (12 [8–15] vs 10 [5–15], P = .650) and nonresponders (11 [6–16] vs 8 [5–14], P = .047). The area under the Receiver Operating Characteristic curve for Pleth Variability Index was 0.49 (0.36–0.62). Pleth Variability Index is not an accurate predictor of fluid responsiveness during kidney transplantation.