title: On better estimating and normalizing the relationship between clinical parameters: comparing respiratory modulations in the photoplethysmogram and blood pressure signal (DPOP versus PPV).
abstract: DPOP (ΔPOP or Delta-POP) is a noninvasive parameter which measures the strength of respiratory modulations present in the pulse oximeter waveform. It has been proposed as a noninvasive alternative to pulse pressure variation (PPV) used in the prediction of the response to volume expansion in hypovolemic patients. We considered a number of simple techniques for better determining the underlying relationship between the two parameters. It was shown numerically that baseline-induced signal errors were asymmetric in nature, which corresponded to observation, and we proposed a method which combines a least-median-of-squares estimator with the requirement that the relationship passes through the origin (the LMSO method). We further developed a method of normalization of the parameters through rescaling DPOP using the inverse gradient of the linear fitted relationship. We propose that this normalization method (LMSO-N) is applicable to the matching of a wide range of clinical parameters. It is also generally applicable to the self-normalizing of parameters whose behaviour may change slightly due to algorithmic improvements.
authors.affiliation: Covidien Respiratory & Monitoring Solutions, Edinburgh EH26 0PJ, UK.
authors.forename: Paul S
authors.initials: PS
authors.lastname: Addison
authors.affiliation: Covidien Respiratory & Monitoring Solutions, Edinburgh EH26 0PJ, UK.
authors.forename: Rui
authors.initials: R
authors.lastname: Wang
authors.affiliation: Department of Anesthesiology, The Ohio State University Wexner Medical Center, Columbus, OH 43210, USA.
authors.forename: Alberto A
authors.initials: AA
authors.lastname: Uribe
authors.affiliation: Department of Anesthesiology, The Ohio State University Wexner Medical Center, Columbus, OH 43210, USA ; Department of Neurological Surgery, The Ohio State University Wexner Medical Center, Columbus, OH 43210, USA.
authors.forename: Sergio D
authors.initials: SD
authors.lastname: Bergese
mesh_terms: D000465:Algorithms; D001794:Blood Pressure; D001795:Blood Pressure Determination / Q000379:methods*; D006801:Humans; D020896:Hypovolemia / Q000175:diagnosis; D016018:Least-Squares Analysis; D016014:Linear Models; D010092:Oximetry / Q000379:methods; D017156:Photoplethysmography / Q000379:methods*; D012044:Regression Analysis; D015203:Reproducibility of Results; D012119:Respiration; D056152:Respiratory Rate; D012815:Signal Processing, Computer-Assisted