title: Prone positioning decreases cardiac output and increases systemic vascular resistance in neonates.
abstract: OBJECTIVE
  To evaluate the cardiovascular response to short-term prone positioning in neonates.
  
  
  METHODS
  In this prospective study, we continuously monitored heart rate (HR), stroke volume (SV) and cardiac output (CO) by electrical velocimetry in hemodynamically stable neonates in each of the following positions for 10 min: supine, prone and back-to-supine position. Skin blood flow (SBF) was also continuously assessed on the forehead or foot using Laser Doppler technology. Systemic vascular resistance (SVR) index was calculated as mean blood pressure (BP)/CO. Data were analyzed using repeated measures analysis of variance.
  
  
  RESULTS
  Thirty neonates (gestational age: 35±4 weeks; postmenstrual age: 36±3 weeks) were enrolled. HR did not change in response to positioning. However, in prone position, SV, CO and SBF decreased and SVR index increased from 1.5±0.3 to 1.3±0.3 ml kg(-1) (mean ±s.d., P<0.01), 206±44 to 180±41 ml kg(-1) min(-1) (P<0.01), 0.54±0.30 to 0.44±0.29 perfusion units (P<0.01) and 0.25±0.06 to 0.30±0.07 mm Hg ml(-1) kg(-1) min(-1) (P<0.01), respectively. After placing the infants back-to-supine position, SV, CO, SBF and SVR index returned to baseline. The above pattern of cardiovascular changes was consistent in vast majority of the studied neonates.
  
  
  CONCLUSIONS
  Short-term prone positioning is associated with decreased SV, CO and SBF and increased calculated SVR index.
authors.affiliation: 1] Division of Neonatology and the Center for Fetal and Neonatal Medicine, Department of Pediatrics, Children's Hospital Los Angeles, Los Angeles, CA, USA [2] The LAC+USC Medical Center, Los Angeles, CA, USA [3] Keck School of Medicine, University of Southern California, Los Angeles, CA, USA.
authors.forename: M
authors.initials: M
authors.lastname: Ma
authors.affiliation: 1] Division of Neonatology and the Center for Fetal and Neonatal Medicine, Department of Pediatrics, Children's Hospital Los Angeles, Los Angeles, CA, USA [2] The LAC+USC Medical Center, Los Angeles, CA, USA [3] Keck School of Medicine, University of Southern California, Los Angeles, CA, USA.
authors.forename: S
authors.initials: S
authors.lastname: Noori
authors.affiliation: Department of Biomedical Engineering, University of Southern California, Los Angeles, CA,USA.
authors.forename: J-M
authors.initials: JM
authors.lastname: Maarek
authors.affiliation: 1] Department of Biomedical Engineering, University of Southern California, Los Angeles, CA,USA [2] Department of Psychiatry and Behavioral Science, University of Southern California, Los Angeles, CA, USA.
authors.forename: D P
authors.initials: DP
authors.lastname: Holschneider
authors.affiliation: Department of Anesthesiology, University of California Los Angeles, Los Angeles, CA,USA.
authors.forename: E H
authors.initials: EH
authors.lastname: Rubinstein
authors.affiliation: 1] Division of Neonatology and the Center for Fetal and Neonatal Medicine, Department of Pediatrics, Children's Hospital Los Angeles, Los Angeles, CA, USA [2] The LAC+USC Medical Center, Los Angeles, CA, USA [3] Keck School of Medicine, University of Southern California, Los Angeles, CA, USA [4] Sidra Neonatology Center of Excellence, Department of Pediatrics, Sidra Medical and Research Center, Doha, Qatar.
authors.forename: I
authors.initials: I
authors.lastname: Seri
mesh_terms: D002302:Cardiac Output / Q000502:physiology*; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D007231:Infant, Newborn / Q000502:physiology*; D017078:Laser-Doppler Flowmetry; D008297:Male; D016684:Prone Position / Q000502:physiology*; D011446:Prospective Studies; D012867:Skin / Q000098:blood supply; D013318:Stroke Volume / Q000502:physiology; D016683:Supine Position / Q000502:physiology; D014655:Vascular Resistance / Q000502:physiology*