Elevated Diastolic Closing Margin Is Associated with Intraventricular Hemorrhage in Premature Infants.
OBJECTIVE
To determine whether the diastolic closing margin (DCM), defined as diastolic blood pressure minus critical closing pressure, is associated with the development of early severe intraventricular hemorrhage (IVH).


METHODS
A reanalysis of prospectively collected data was conducted. Premature infants (gestational age 23-31 weeks) receiving mechanical ventilation (n = 185) had ∼1-hour continuous recordings of umbilical arterial blood pressure, middle cerebral artery cerebral blood flow velocity, and PaCO2 during the first week of life. Models using multivariate generalized linear regression and purposeful selection were used to determine associations with severe IVH.


RESULTS
Severe IVH (grades 3-4) was observed in 14.6% of the infants. Irrespective of the model used, Apgar score at 5 minutes and DCM were significantly associated with severe IVH. A clinically relevant 5-mm Hg increase in DCM was associated with a 1.83- to 1.89-fold increased odds of developing severe IVH.


CONCLUSIONS
Elevated DCM was associated with severe IVH, consistent with previous animal data showing that IVH is associated with hyperperfusion. Measurement of DCM may be more useful than blood pressure in defining cerebral perfusion in premature infants.
Section of Neonatology, Department of Pediatrics, Texas Children's Hospital/Baylor College of Medicine, Houston, TX. Electronic address: cjrhee@texaschildrens.org.
Christopher J
CJ
Rhee
Section of Neonatology, Department of Pediatrics, Texas Children's Hospital/Baylor College of Medicine, Houston, TX; Department of Obstetrics and Gynecology, Texas Children's Hospital/Baylor College of Medicine, Houston, TX.
Jeffrey R
JR
Kaiser
Section of Neonatology, Department of Pediatrics, Texas Children's Hospital/Baylor College of Medicine, Houston, TX.
Danielle R
DR
Rios
Department of Anesthesiology, Texas Children's Hospital/Baylor College of Medicine, Houston, TX; Department of Critical Care Medicine, Texas Children's Hospital/Baylor College of Medicine, Houston, TX; Department of Pediatrics, Texas Children's Hospital/Baylor College of Medicine, Houston, TX.
Kathleen K
KK
Kibler
Department of Anesthesiology, Texas Children's Hospital/Baylor College of Medicine, Houston, TX; Department of Critical Care Medicine, Texas Children's Hospital/Baylor College of Medicine, Houston, TX; Department of Pediatrics, Texas Children's Hospital/Baylor College of Medicine, Houston, TX.
R Blaine
RB
Easley
Department of Anesthesiology, Texas Children's Hospital/Baylor College of Medicine, Houston, TX; Department of Critical Care Medicine, Texas Children's Hospital/Baylor College of Medicine, Houston, TX; Department of Pediatrics, Texas Children's Hospital/Baylor College of Medicine, Houston, TX.
Dean B
DB
Andropoulos
Department of Academic Neurosurgery, Addenbrooke's Hospital, University of Cambridge, Cambridge, United Kingdom.
Marek
M
Czosnyka
Department of Academic Neurosurgery, Addenbrooke's Hospital, University of Cambridge, Cambridge, United Kingdom.
Peter
P
Smielewski
Department of Academic Neurosurgery, Addenbrooke's Hospital, University of Cambridge, Cambridge, United Kingdom.
Georgios V
GV
Varsos
Section of Cardiology, Department of Pediatrics, Texas Children's Hospital/Baylor College of Medicine, Houston, TX.
Craig G
CG
Rusin
Department of Biostatistics, University of Arkansas for Medical Sciences, Little Rock, AR.
C Heath
CH
Gauss
Department of Biostatistics, University of Arkansas for Medical Sciences, Little Rock, AR.
D Keith
DK
Williams
Department of Anesthesiology, Texas Children's Hospital/Baylor College of Medicine, Houston, TX; Department of Critical Care Medicine, Texas Children's Hospital/Baylor College of Medicine, Houston, TX; Department of Pediatrics, Texas Children's Hospital/Baylor College of Medicine, Houston, TX.
Ken M
KM
Brady
D001783:Blood Flow Velocity / Q000502:physiology; D001794:Blood Pressure / Q000502:physiology*; D002543:Cerebral Hemorrhage / Q000209:etiology* / Q000503:physiopathology*; D015331:Cohort Studies; D003971:Diastole; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D007235:Infant, Premature, Diseases / Q000209:etiology* / Q000503:physiopathology*; D008297:Male; D020768:Middle Cerebral Artery / Q000502:physiology; D012121:Respiration, Artificial; D014469:Umbilical Arteries / Q000502:physiology
arterial blood pressure; cerebral blood flow; critical closing pressure