title: Effect of flow rate, humidifier dome and water volume on maximising heated, humidified gas use for neonatal resuscitation.
abstract: OBJECTIVE
  Dry, cold gas is used for neonatal resuscitation, contributing to low admission temperatures and exacerbation of lung injury. Recently, a method of heating and humidifying neonatal resuscitation gases has become available. We aimed to determine the optimal flow rate, humidifier chamber and water volume needed to reach 36°C, and near 100% humidity at the patient T-piece in the shortest possible time.
  
  
  METHODS
  A T-piece resuscitator was connected via a heated patient circuit to a humidifier chamber. Trials were performed using different gas flow rates (6, 8 and 10L/min), humidification chambers (MR290, MR225) and water volumes (30g, 108g). Temperature was recorded at the humidifier chamber (T1), distal temperature probe (T2) and the T-piece (T3) over a 20min period at 30s intervals. A test lung was added during one trial.
  
  
  RESULTS
  No significant difference existed between flow rates 8L/min and 10L/min (p=0.091, p=0.631). T3 reached 36°C and remained stable at 360s (8L/min, MR225, 30mL); near 100% RH was reached at 107s (10L/min, MR225, 30mL). T3 and humidity reached and remained stable at 480s (10L/min, MR290, 30mL). Target temperature and humidity was not reached with the test lung.
  
  
  CONCLUSIONS
  It is possible to deliver heated, humidified gases in neonatal resuscitation in a clinically acceptable timeframe. We suggest the set-up to achieve optimal temperature and humidity for resuscitation purposes is 10L/min of gas flow, a MR290 humidification chamber, and 30mL of water.
authors.affiliation: Department of Newborn Services, Mater Mothers' Hospital, Australia. Electronic address: rayfarley@doctors.org.uk.
authors.forename: R C
authors.initials: RC
authors.lastname: Farley
authors.forename: K
authors.initials: K
authors.lastname: Gibbons
authors.forename: L A
authors.initials: LA
authors.lastname: Jardine
authors.forename: A D
authors.initials: AD
authors.lastname: Shearman
mesh_terms: D004867:Equipment Design; D005740:Gases; D006801:Humans; D006813:Humidity; D007231:Infant, Newborn; D012151:Resuscitation / Q000295:instrumentation* / Q000379:methods*; D013696:Temperature; D014867:Water
chemical_list: D005740:Gases; D014867:Water
keywords: Heated Gas; Humidification; Neonatal; Resuscitation; T-Piece resuscitator; Temperature control