The Science Journal of the American Association for Respiratory Care

2008 OPEN FORUM Abstracts

ARE WE ABLE TO PROVIDE A STEADY OXYGEN FLOW ON NON INVASIVE MECHANICAL VENTILATION SYSTEMS WITH A NEW GENERATION OXYGEN CONCENTRATOR?

Rodrigo S. Adasme1, Alejandra P. Martinez1, Camilo Navarro1, Hernan Polanco1, Juan E. Romero1, Adrian Knight2



Background: The feasiblility of keeping a positive pressure&oxygen-dependent patient at home has been fulfilled in our Private and Public Health Systems. High costs,availability ,complications and the risk of handling oxygen cylinders have been assessed .Alternative systems for providing oxygen at home are preferred. Oxygen concentrators meet several requirements: lower costs, improved transfer and fewer risks, but their system of oxygen delivery does not bear back pressure. All this make them unable of delivering oxygen to positive pressure system with the actual concentrators.

Objectives: To compare flow and FiO2 in CPAP and BiPAP when oxygen is being delivered from a wall outlet or from an ultimate generation oxygen concentrator.

Materials and methods: We used a non invasive mechanical ventilator Respironichs ST 30, with CPAP(5,6 and 8 cms H2O)and BiPAP(8/4 and 12 /6cms H2O) by connecting a conventional NIMV circuit of 120 cm and Φ;2O cms. At the end limb, a 6 mm exhalatory port was connected as well as a test lung. Oxygen injection was done by an swivel connector and a silicone near the equipment. FiO2 was measured between the exhalatory portal and the test lung with a Hudson RCI 5801 oxygen analyzer. Flow was measured near to BiPAP prior to the input of oxygen by means of a Ferraris Haloscales Wright respimeter. Oxygen measured flows were:O,5-1-1,5-2 and 3 l/min.These were delivered from the wall outlet by a Compensated pressure Torphe flowmeter and followed by a Sequal Eclipse concentrator with a compensated-variable resistance-flowmeter.Three measurements(1 min each)were done for each parameter under study.

Results: On TABLE 1 we can observe the average values,SD for flow and Fi02 with oxygen delivered from wall outlet or from the Eclipse concentrator according to the different values of NIMV under study. Non parametric data analysis are similar and no significant difference was obtained.

Conclusion: We have evidenced similar values of flow and Fi02 with oxygen being delivered from the wall outlet or from an Eclipse oxygen concentrator. Further in-depth studies are needed to recommend this method of oxygen delivery in NIMV, as a different way to administrate positive pressure with oxygen at home