title: Baroreflex dysfunction in sick newborns makes heart rate an unreliable surrogate for blood pressure changes.
abstract: Cerebral pressure passivity (CPP) in sick newborns can be detected by evaluating coupling between mean arterial pressure (MAP) and cerebral blood flow measured by near infra-red spectroscopy hemoglobin difference (HbD). However, continuous MAP monitoring requires invasive catheterization with its inherent risks. We tested whether heart rate (HR) could serve as a reliable surrogate for MAP in the detection of CPP in sick newborns.
  
  
  
  Continuous measurements of MAP, HR, and HbD were made and partitioned into 10-min epochs. Spectral coherence (COH) was computed between MAP and HbD (COHMAP-HbD) to detect CPP, between HR and HbD (COHHR-HbD) for comparison, and between MAP and HR (COHMAP-HR) to quantify baroreflex function (BRF). The agreement between COHMAP-HbD and COHHR-HbD was assessed using ROC analysis.
  
  
  
  We found poor agreement between COHMAP-HbD and COHHR-HbD in left hemisphere (area under the ROC curve (AUC) 0.68) and right hemisphere (AUC 0.71). Baroreflex failure (COHMAP-HR not significant) was present in 79% of epochs. Confining comparison to epochs with intact BRF showed an AUC of 0.85 for both hemispheres.
  
  
  
  In these sick newborns, HR was an unreliable surrogate for MAP required for the detection of CPP. This is likely due to the prevalence of BRF failure in these infants.
authors: Divison of Fetal and Transitional Medicine, Children's National Health System, Washington, DC.
authors: Rathinaswamy B
authors: RB
authors: Govindan
authors: Divison of Fetal and Transitional Medicine, Children's National Health System, Washington, DC.
authors: Tareq
authors: T
authors: Al-Shargabi
authors: Division of Neonatology, Children's National Health System, Washington, DC.|Department of Pediatrics, The George Washington University School of Medicine and Health Sciences, Washington, DC.
authors: An N
authors: AN
authors: Massaro
authors: Divison of Fetal and Transitional Medicine, Children's National Health System, Washington, DC.
authors: Marina
authors: M
authors: Metzler
authors: Division of Neonatology, Children's National Health System, Washington, DC.|Department of Pediatrics, The George Washington University School of Medicine and Health Sciences, Washington, DC.
authors: Nickie N
authors: NN
authors: Andescavage
authors: Divison of Fetal and Transitional Medicine, Children's National Health System, Washington, DC.
authors: Radhika
authors: R
authors: Joshi
authors: Divison of Fetal and Transitional Medicine, Children's National Health System, Washington, DC.
authors: Rhiya
authors: R
authors: Dave
authors: Divison of Fetal and Transitional Medicine, Children's National Health System, Washington, DC.|Department of Pediatrics, The George Washington University School of Medicine and Health Sciences, Washington, DC.
authors: Adre
authors: A
authors: du Plessis
mesh_terms: D019540:Area Under Curve; D062186:Arterial Pressure; D017704:Baroreflex; D015415:Biomarkers; D001794:Blood Pressure; D057785:Catheters; D002560:Cerebrovascular Circulation; D006339:Heart Rate; D006439:Hemodynamics; D006454:Hemoglobins / Q000032:analysis; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature / Q000502:physiology; D008991:Monitoring, Physiologic; D011312:Pressure; D012372:ROC Curve; D012680:Sensitivity and Specificity; D013053:Spectrophotometry
chemical_list: D015415:Biomarkers; D006454:Hemoglobins