title: Pharyngeal pressure with high-flow nasal cannulae in premature infants.
abstract: OBJECTIVE
  The aim of this study was to measure pharyngeal pressures in preterm infants receiving high-flow nasal cannulae.
  
  
  METHODS
  A total of 18 infants were studied (median gestational age 34 weeks, weight 1.619 kg). A catheter-tip pressure transducer was introduced into the nasopharynx. Flow was sequentially increased to a maximum of 8 l min(-1) and decreased to a minimum of 2 l min(-1).
  
  
  RESULTS
  There was a strong association between pharyngeal pressure and both flow rate and infant weight (P<0.001, r (2)=0.61), but not mouth closure. This relationship could be expressed as pharyngeal pressure (cm H(2)O)=0.7+1.1 F (F=flow per kg in l min(-1) kg(-1)).
  
  
  CONCLUSIONS
  High-flow nasal cannulae at flow rates of 2 to 8 l min(-1) can lead to clinically significant elevations in pharyngeal pressure in preterm infants. Flow rate and weight but not mouth closure are important determinants of the pressure transmitted.
authors.affiliation: Department of Paediatrics, Mercy Hospital for Women, Melbourne, VIC., Australia. dominic.wilkinson@rch.org.au
authors.forename: D J
authors.initials: DJ
authors.lastname: Wilkinson
authors.forename: C C
authors.initials: CC
authors.lastname: Andersen
authors.forename: K
authors.initials: K
authors.lastname: Smith
authors.forename: J
authors.initials: J
authors.lastname: Holberton
mesh_terms: D002404:Catheterization; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D015931:Intensive Care, Neonatal; D008297:Male; D008954:Models, Biological; D010102:Oxygen Inhalation Therapy / Q000379:methods*; D010614:Pharynx / Q000502:physiology*; D012119:Respiration; D012121:Respiration, Artificial / Q000379:methods*