title: Algorithmic Summaries of Perioperative Blood Pressure Fluctuations.
abstract: Automated perioperative measurements such as cardiovascular monitoring data are commonly compared to established upper and lower thresholds, but could also allow for more complex interpretations. Analyzing such time series in extensive electronic medical records for research purposes may itself require customized automation, so we developed a set of algorithms for quantifying different aspects of temporal fluctuations. We implemented conventional measures of dispersion, summaries of absolute gradients between successive values, and Poincaré plots. We aggregated the severity and duration of hypotensive episodes by calculating the average area under different mean arterial pressure (MAP) thresholds. We applied these methods to 30,452 de-identified MAP series, and analyzed the similarity between alternative indices via hierarchical clustering. To explore the potential utility of these propositional metrics, we computed their statistical association with presumed complications due to cardiovascular instability. We observed that hierarchical clustering reliably segregated features that had been designed to quantify dissimilar aspects. Summaries of temporary hypotension turned out to be significantly increased among patient subgroups with subsequent signs of a complicated recovery. These associations were even stronger for measures that were specifically geared to capturing short-term MAP variability. These observations suggest the potential capability of our proposed algorithms for quantifying heterogeneous aspects of short-term MAP fluctuations. Future research might also target a wider selection of outcomes and other attributes that may be subject to intraoperative variability.
authors: Medical Informatics, University Erlangen-Nuremberg, Germany.
authors: Dennis
authors: D
authors: Toddenroth
authors: Medical Center for Information and Communication Technology, University Hospital Erlangen, Germany.
authors: Thomas
authors: T
authors: Ganslandt
authors: Medical Informatics, University Erlangen-Nuremberg, Germany.
authors: Caroline
authors: C
authors: Drescher
authors: Dept of Anaesthesiology & Intensive Care, University Hospital Erlangen, Germany.
authors: Thomas
authors: T
authors: Weith
authors: Medical Informatics, University Erlangen-Nuremberg, Germany.
authors: Hans-Ulrich
authors: HU
authors: Prokosch
authors: Dept of Anaesthesiology & Intensive Care, University Hospital Erlangen, Germany.
authors: Juergen
authors: J
authors: Schuettler
authors: Dept of Anaesthesiology & Intensive Care, University Hospital Erlangen, Germany.
authors: Tino
authors: T
authors: Muenster
mesh_terms: D000465:Algorithms; D062186:Arterial Pressure / Q000502:physiology; D001794:Blood Pressure / Q000502:physiology*; D057286:Electronic Health Records; D005858:Germany; D006801:Humans; D008991:Monitoring, Physiologic; D063868:Patient Outcome Assessment; D059035:Perioperative Period; D013997:Time Factors