title: Cardiorespiratory instability in monitored step-down unit patients: using cluster analysis to identify patterns of change.
abstract: Cardiorespiratory instability (CRI) in monitored step-down unit (SDU) patients has a variety of etiologies, and likely manifests in patterns of vital signs (VS) changes. We explored use of clustering techniques to identify patterns in the initial CRI epoch (CRI1; first exceedances of VS beyond stability thresholds after SDU admission) of unstable patients, and inter-cluster differences in admission characteristics and outcomes. Continuous noninvasive monitoring of heart rate (HR), respiratory rate (RR), and pulse oximetry (SpO2) were sampled at 1/20 Hz. We identified CRI1in 165 patients, employed hierarchical and k-means clustering, tested several clustering solutions, used 10-fold cross validation to establish the best solution and assessed inter-cluster differences in admission characteristics and outcomes. Three clusters (C) were derived: C1) normal/high HR and RR, normal SpO2(n = 30); C2) normal HR and RR, low SpO2(n = 103); and C3) low/normal HR, low RR and normal SpO2(n = 32). Clusters were significantly different based on age (p < 0.001; older patients in C2), number of comorbidities (p = 0.008; more C2 patients had ≥ 2) and hospital length of stay (p = 0.006; C1 patients stayed longer). There were no between-cluster differences in SDU length of stay, or mortality. Three different clusters of VS presentations for CRI1were identified. Clusters varied on age, number of comorbidities and hospital length of stay. Future study is needed to determine if there are common physiologic underpinnings of VS clusters which might inform clinical decision-making when CRI first manifests.
authors.affiliation: The University of Texas at Austin, 1710 Red River St., Austin, TX, 78701, USA. ebose@nursing.utexas.edu.
authors.forename: Eliezer L
authors.initials: EL
authors.lastname: Bose
authors.affiliation: Department of Critical Care Medicine, University of Pittsburgh Schools of Medicine, Pittsburgh, USA.
authors.forename: Gilles
authors.initials: G
authors.lastname: Clermont
authors.affiliation: Auton Lab, Carnegie Mellon University Robotics Institute, Pittsburgh, USA.
authors.forename: Lujie
authors.initials: L
authors.lastname: Chen
authors.affiliation: Auton Lab, Carnegie Mellon University Robotics Institute, Pittsburgh, USA.
authors.forename: Artur W
authors.initials: AW
authors.lastname: Dubrawski
authors.affiliation: Department of Acute and Tertiary Care, University of Pittsburgh Schools of Nursing, Pittsburgh, USA.
authors.forename: Dianxu
authors.initials: D
authors.lastname: Ren
authors.affiliation: Department of Acute and Tertiary Care, University of Pittsburgh Schools of Nursing, Pittsburgh, USA.
authors.forename: Leslie A
authors.initials: LA
authors.lastname: Hoffman
authors.affiliation: Department of Critical Care Medicine, University of Pittsburgh Schools of Medicine, Pittsburgh, USA.
authors.forename: Michael R
authors.initials: MR
authors.lastname: Pinsky
authors.affiliation: Department of Acute and Tertiary Care, University of Pittsburgh Schools of Nursing, Pittsburgh, USA.
authors.forename: Marilyn
authors.initials: M
authors.lastname: Hravnak
mesh_terms: D000328:Adult; D000368:Aged; D016000:Cluster Analysis; D015331:Cohort Studies; D015897:Comorbidity; D003422:Critical Care / Q000379:methods*; D005260:Female; D006339:Heart Rate; D006760:Hospitalization; D006801:Humans; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic / Q000295:instrumentation* / Q000379:methods; D010092:Oximetry; D010343:Patient Admission; D015203:Reproducibility of Results; D056152:Respiratory Rate; D012815:Signal Processing, Computer-Assisted; D055986:Vital Signs
keywords: Cardiorespiratory instability; Cluster analysis; Non-invasive monitoring