2007 OPEN FORUM Abstracts
THE AFFECT OF IN-LINE MEDICATION DELIVERY IN REGARDS TO PATIENT-VENTILATOR TRIGGER SYNCHRONY
K. E. Barbarisi1, S. Richey1, S. Kirby2
Background: Patients on mechanical ventilation may receive medications delivered via aerosol in-line with the patient-ventilator circuit. Some ventilators are not outfitted with a nebulizer port which propels the aerosolized medication and compensates for the additional added flow. Consequently, an external flow source must be used to drive the nebulizer. Hypothesis- Utilizing an external flow source to deliver aerosolized medications will affect patient-ventilator trigger synchrony.
Methods: A simulated spontaneous breathing model was utilized consisting of a dual chamber, double TTL test lung (Michigan Instruments). One test lung (driver) was powered by a Puritan Bennett 840 (PB840) ventilator (Tyco HealthCare, LLC.) using two “models” to generate spontaneous breathing of a second test lung connected to another PB840 with the following settings: Spontaneous Mode, Pressure Support 5 cmH2O, PEEP 5 and baseline trigger 2Lpm (flow trigger testing) and 2 cmH2O (pressure trigger testing).
Driver Model 1: “Decreased Respiratory Drive” ACPC, PC 5cmH2O, RR 12, I-time of 1.0 second, Rise time 1%, and PEEP of zero.
Driver Model 2: “Vigorous Respiratory Drive” ACPC, PC 25cmH2O, RR 12, I-time of 1.0 second, Rise time 60%, and PEEP 5.
A Hand Held Nebulizer device was placed 18 inches proximal to the “Y” on the inspiratory limb and was connected to a flow-meter.
Test conditions consisted of allowing the spontaneous model, set on the baseline trigger setting to capture all 12 breaths with no trigger asynchronies. Once this was established the external flow-meter was turned on at 8 lpm, and the ventilator was observed for failure to trigger and/or inspiratory delay time asynchrony.
Results: (table 1) Model 1: Out of 38 trigger titrations (19 Flow, 19 pressure, 2.0-to-0.2, 0.1 increments) there was 38 trigger asynchronies. There was no statistical difference when comparing a flow or pressure trigger in regards to failure to trigger (p 0.17) and inspiratory delay time asynchronies (p 0.17).
Model 2: The ventilator was able to capture all breaths without any failure to trigger or inspiratory time delay asynchronies.
Conclusion: The results of this study validate that introducing an external flow source into the inspiratory limb of the patient ventilator circuit; the additional flow can generate trigger asynchronies in patients with a decreased respiratory drive.
|Trigger Titrations (lpm or cmH2O)||Flow||Pressure|
ASYNCHRONIES: Fail to trigger= FT, Inspiratory delay time= D