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 cmH 2 O 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 cmH 2 O p< 0.005 –10-15 cmH 2 O p< 0.0001 –5-15 cmH 2 O p< 0.0001 Difference in tidal volume +/- probe = 2.6%

9. 5 1015

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