title: Does helmet CPAP reduce cerebral blood flow and volume by comparison with Infant Flow driver CPAP in preterm neonates?
abstract: OBJECTIVE
  We compared neonatal helmet continuous positive airway pressure (CPAP) and the conventional nasal Infant Flow driver (IFD) CPAP in the noninvasive assessment of absolute cerebral blood flow (CBF) and relative cerebral blood volume changes (DeltaCBV) by near-infrared spectroscopy.
  
  
  METHODS
  A randomized crossover study in a tertiary referral NICU.
  
  
  METHODS
  Assessment of CBF and DeltaCBV in 17 very low birth weight infants with respiratory distress (median age 5 days) treated with two CPAP devices at a continuous distending pressure of 4 mbar.
  
  
  RESULTS
  Neonates were studied for two consecutive 60-min periods with helmet CPAP and with IFD CPAP. Basal chromophore traces enabled DeltaCBV changes to be calculated. CBF was calculated in milliliters per 100 grams per minute from the saturation rise integral and rate of rise O(2)Hb-HHb. Median (range) CBF with helmet CPAP was 27.37 (9.47-48.20) vs. IFD CBF 34.74 (13.59-60.10)(p=0.049) and DeltaCBV 0.15 (0.09-0.28) with IFD and 0.13 (0.07-0.27) with helmet CPAP (NS). Using helmet and IFD CPAP, the neonates showed no difference in mean physiological parameters (transcutaneous carbon dioxide and oxygen tension, pulse oximetry saturation, heart rate, breathing rate, mean arterial blood pressure, desaturation rate, axillary temperature).
  
  
  CONCLUSIONS
  Assessing CBF and DeltaCBV measured by near-infrared spectroscopy with two CPAP devices revealed no differences in relative blood volume, but CBF was lower with helmet CPAP. Greater active vasoconstriction and/or passive capillary and/or venous vessel compression seem the most likely reason, due to a positive pressure around the head, neck, and shoulders by comparison with the airway pressure.
authors.affiliation: Department of Pediatrics, University of Padova, Neonatal Intensive Care Unit, Padua, Italy. zaramella@pediatria.unipd.it
authors.forename: Patrizia
authors.initials: P
authors.lastname: Zaramella
authors.forename: Federica
authors.initials: F
authors.lastname: Freato
authors.forename: Nicoletta
authors.initials: N
authors.lastname: Grazzina
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Saraceni
authors.forename: Andrea
authors.initials: A
authors.lastname: Vianello
authors.forename: Lino
authors.initials: L
authors.lastname: Chiandetti
mesh_terms: D000704:Analysis of Variance; D001776:Blood Circulation Time; D001810:Blood Volume; D002560:Cerebrovascular Circulation; D045422:Continuous Positive Airway Pressure / Q000295:instrumentation* / Q000379:methods; D018592:Cross-Over Studies; D004867:Equipment Design; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D019102:Infant, Very Low Birth Weight; D007363:Intensive Care Units, Neonatal; D008297:Male; D008397:Masks; D012127:Respiratory Distress Syndrome, Newborn / Q000503:physiopathology / Q000628:therapy*; D018709:Statistics, Nonparametric; D016896:Treatment Outcome