Clinical investigation of plethysmographic variability index: A derivative index of pulse oximetry in anesthetized dogs

Paranjape, Vaidehi V. M.S., Purdue University, August 2014. Clinical Investigation of Plethysmographic Variability Index: A Derivative Index of Pulse Oximetry in Anesthetized Dogs. Major Professor: Jeff C. Ko. Plethysmographic Variability Index (PVI) is a derivative index of pulse oximetry that allows evaluating an individual's intravascular volume status. Perfusion Index (PI) represents the strength of pulse signal at the anatomic site of measurement from which PVI is calculated using changes in PI over respiratory cycles. Plethysmographic Variability Index has been used to detect hypovolemia and predict fluid responsiveness in mechanically ventilated human patients however, fewer studies are available in spontaneously breathing patients. The use of PVI has not been explored extensively in dogs so far. The goals of this study were to establish a common range for PVI and assess relationship of the PVI, PI and various clinical variables in the anesthetized spontaneously breathing dogs. Values of PVI and PI derived from Masimo pulse oximetry were obtained at 5, 10, 15 and 20 minutes after anesthetic induction but before surgical stimulation together with cardiorespiratory variables that included heart rate, blood pressures (systolic, mean and diastolic blood pressures), respiratory rate and hemoglobin saturation of oxygen (SpO2) in 73 dogs with ASA 1-3 status admitted to the Purdue Teaching Hospital.