Dr John Rutherford Dr Mahboob Khan Dumfries & Galloway Royal Infirmary

1. Does ultrasound measured distance from front of abdomen to spine correlate with depth of breathing? Dr John Rutherford Dr Mahboob Khan Dumfries & Galloway Royal Infirmary

2. Introduction • To compare ventilation with facemask and LMA ventilation • Need a method of assessing ventilation that is not dependent on measuring exhaled gas… • Rechner et al. described measuring abdominal movement Paed Anesth 2007; 17: 609-610 • We didn’t have their equipment…

3. Methods • Local research ethics approval • Information sent to children and parents when booking for surgery • Consent • Age <16 years • GA involving LMA

4. Exclusions; reflux, language difficulties or lack of consent • Age • Weight • Height

5. IV or inhalational induction then LMA • Ventilated at 5, 10 and 15 cmH2O • M mode ultrasound with curvilinear probe (Sonosite MicroMaxx) and pneumotachograph for tidal volumes with Datex Ohmeda Aestiva

6. Analysis • Changes in upper abdominal distance analysed with paired T-tests using Microsoft Excel Office 2003

7. Results • 31 children and parents approached • 7 refused consent • 1 not read the information • 1 unable to communicate in English • 1 active respiratory tract infection • 21 consented but unable to see spine in one child

8. Age range 1 – 11 years • Male to female 9 to 12 • AP distances similar for pressure regardless of age of child • T-test 5-10 cmH2O p< 0.005 • 10-15 cmH2O p< 0.0001 • 5-15 cmH2O p< 0.0001 • Difference in tidal volume +/- probe = 2.6%

9. 10 15 5

10. Limitations • Same location of probe • Same angle of probe • However the equipment is widely available in the UK

11. Questions? ?

12. Acknowledgements • Dr Petr Hrobar, consultant radiologist • Dr Gwen Baxter, R&D department • Dr Alastair Baxter, consultant paediatric anaesthetist • We are not aware of any conflict of interest