Results and Discussions Pressure and alarms of aestiva5

1. Are ventilators with an American or a European breathing bag safe to prevent accidental volutrauma?Steven M. Cnudde, M.D1., Jan Paul J Mulier, M.D1., Ph.D., Thomas Deckmyn, M.D2. 1Dep of Anaesthesiology, AZ St Jan AV Brugge, Belgium2Dep of Anaesthesiology, AZ St Lucas Brugge, Belgium • Results and Discussions • Pressure and alarms of aestiva5 • The USA breathing bag has a maximum pressure of 34 cmH20. • The EUR breathing bag has a maximum pressure of 46 cmH20. • Airway pressure stayed above 20 cm H20 for more then 10 seconds in all three ventilators. • Discussion: • Healthy ASA I patients and children with a high total lung compliance might have hyperinflation at a continous airway pressure of 20 cmH20. • APL valve and alarms below 20 cmH20 makes manual ventilation impossible. • Correct alarm and APL setting could not prevent hyperinflation in case of human error. • Conclusion: • 1. The tested ventilators are dangerous to very dangerous. • 2. Correct alarm and APL setting are important but only vigilance remains the cornerstone of safety. • 3. Technical improvement is possible to prevent hyperinflation and would be ideal to protect every ventilator with a manual ventilation mode. • Background: • The APL valve protects against high airway pressures. • At induction: Fresh gas flow high. • The APL valve at maximum (facilitating face mask ventilation). • Dangerous: if ventilation mode remains manual. • Airway pressure rises very fast and causes volutrauma if no immediate reaction occurs. • Goal of the study: • Evaluation of 3 ventilators: • Aestiva 5 from Datex-Ohmeda • Julian from Draeger • Neptune from Medec • in the manual ventilation mode, without manual compression • Materials and methods: • The airway pressure is measured and the time when an alarm went off. • Two types of breathing bags (2l.) are connected for manual ventilation: • An European type (Ch Medical, Ltd) latex free balloon • An USA type (Vital signs, Inc) latex free balloon • Fresh gas flow at 12 l/min. Airway pressure alarm at maximum level. • The artificial lung (Pulmo-Sim apparatus from Blease) with a compliance of 23 ml/cm H20. • At T0 the ventilator is switched to a manual ventilation mode without compression of the breathing bag. • The airway pressure is monitored. • The time when the alarms went off are noted by a high frequency pulse given on the pressure transducer. • A ventilator is considered • dangerous if the airway pressure stayed above 20 cm H20 for more than 10 seconds and • very dangerous if no alarm did go off in that time. Anesthesiology 2006; 105: A932 ,Annual Meeting ASA October 14-18, 2006 McCormick Place-Chicago, Illinois