The Science Journal of the American Association for Respiratory Care

2011 OPEN FORUM Abstracts


Thomas J. Cahill, Cynthia C. White, Robert Campbell; Respiratory Care Division, Cincinnati Children's Hospital Medical Center, Cincinnati OH, OH

Introduction: The Trilogy 202 (Philips-Respironics, Murrysville, PA) allows ventilation with both active and passive circuit types. In Volume modes (VC), the Trilogy behaves differently with each circuit. We designed a bench study to evaluate volume delivery and measurement accuracy of the Trilogy 202 in VC at different lung mechanics and leaks. Methods: The Trilogy 202 was used to ventilate a TTL test lung (Michigan Instruments, MI) in A/C with both a passive and active circuit. Ventilator settings: rate- 12, FiO2 .21, PEEP 5 cmH2O, and a Ramp flow pattern. Resistance of 5 cmH2O/L/Sec was used in all test conditions. VT/Ti combinations of 250ml < 0.6s, and 500 ml < 0.9s were set with Compliance of 20, 40, and 60 ml/cmH2O. VT of 50ml < 0.3s was used with C of 20 only. Measurements were made at six leak rates created with a series of stopcocks. Delivered VT (Del-VT) was measured at the proximal airway with an NM3 Monitor (Philips, Carlsbad, CA). VTE and leak rate were recorded from the Trilogy display for 6 breaths. Del-VT was compared with set VT and the Trilogy VTE. Results: With the passive circuit, Del-VT was within 10% of set VT and the Trilogy VTE was within 10% of Del-VT at all zero leak conditions. At 50ml VT, Del-VT was < 85% of set VT at leak 1 and 5; and was < 30% of set VT at leak 2. VTE displayed on the Trilogy was within 10% of Del-VT at every leak. At 250ml VT, Del-VT was < 88% of set VT at leak 4 and 5 at each C. At leak 5 and C-60, the Trilogy VTE was < 88% of Del-VT and all other VTE measurements were within 10% of Del-VT . At 500ml VT, Del-VT was < 73% of set in all leak 5 conditions and the VTE display was < 90% of Del-VT in leak 5 at C-60 and C-40 and in leak 4 at C-60. With the active circuit, the Del-VT was within 10% of set VT for 50 and 250ml settings, as was the VTE display within 10% of Del-VT . At 500ml VT, Del-VT was < 88% of set and displayed VTE was < 14% of the Del-VT. Del-VT was < set VT by 27% at leak1, 54% at leak 2, and 66% at leak 3. Discussion: In VC, the Trilogy compensates for leaks < 30 L/min with passive circuit use and delivers increased VT compared to the active circuit. Measurement of VTE on the Trilogy accurately reflects Del-VT when leak is < 30 L/min.
Sponsored Research - None