• Closed and open breathing circuit function in healthy volunteers during exercise at Mount Everest base camp (5300 m).

      McMorrow, R C N; Windsor, J S; Hart, N D; Richards, P; Rodway, G W; Ahuja, V Y; O'Dwyer, M J; Mythen, M G; Grocott, M P W; UCL Centre for Altitude Space and Extreme Environment Medicine, UCL Institute of Child Health, University College London, London, UK. mcmorrow.roger@gmail.com (Anaesthesia, 2012-08)
      We present a randomised, controlled, crossover trial of the Caudwell Xtreme Everest (CXE) closed circuit breathing system vs an open circuit and ambient air control in six healthy, hypoxic volunteers at rest and exercise at Everest Base Camp, at 5300 m. Compared with control, arterial oxygen saturations were improved at rest with both circuits. There was no difference in the magnitude of this improvement as both circuits restored median (IQR [range]) saturation from 75%, (69.5-78.9 [68-80]%) to > 99.8% (p = 0.028). During exercise, the CXE closed circuit improved median (IQR [range]) saturation from a baseline of 70.8% (63.8-74.5 [57-76]%) to 98.8% (96.5-100 [95-100]%) vs the open circuit improvement to 87.5%, (84.1-88.6 [82-89]%; p = 0.028). These data demonstrate the inverse relationship between supply and demand with open circuits and suggest that ambulatory closed circuits may offer twin advantages of supplying higher inspired oxygen concentrations and/or economy of gas use for exercising hypoxic adults.
    • Oxygenation with T-piece versus self-inflating bag for ventilation of extremely preterm infants at birth: a randomized controlled trial.

      Dawson, Jennifer A; Schmölzer, Georg M; Kamlin, C Omar F; Te Pas, Arjan B; O'Donnell, Colm P F; Donath, Susan M; Davis, Peter G; Morley, Colin J; Newborn Services, The Royal Women's Hospital, Melbourne, Australia. jennifer.dawson@thewomens.org.au (The Journal of pediatrics, 2011-06)
      To investigate whether infants < 29 weeks gestation who receive positive pressure ventilation (PPV) immediately after birth with a T-piece have higher oxygen saturation (SpO₂) measurements at 5 minutes than infants ventilated with a self inflating bag (SIB).
    • A randomised crossover study of low-flow air or oxygen via nasal cannulae to prevent desaturation in preterm infants.

      Hensey, Conor C; Hayden, Eoghan; O'Donnell, Colm Patrick Finbarr; Department of Neonatology, The National Maternity Hospital, Dublin, Ireland. (2013-09)
      To compare the efficacy of low-flow oxygen, low-flow air and sham treatment given via nasal cannulae in preventing desaturation (falls in oxygen saturation (SpO2)) in preterm infants.