The Science Journal of the American Association for Respiratory Care

2012 OPEN FORUM Abstracts

THE INDEPENDENT EFFECT OF THREE INLINE SUCTION ADAPTERS AND LUNG COMPLIANCE CHANGE ON AMPLITUDE AND DELIVERED TIDAL VOLUME DURING HIGH FREQUENCY OSCILLATORY VENTILATION IN AN ADULT PATIENT WITH ARDS: BENCH MODEL.

AUTHORShreya J. Thacker, Lynda T. Goodfellow, Robert Harwood, Ralph Zimmerman; Respiratory Therapy, Georgia State University, Atlanta, GA

Introduction: The technique of instituting High Frequency Oscillatory ventilation to ventilate the lungs at volumes less than anatomical dead space to avoid high pressures is used widely. Apart from HFOV, pulmonary hygiene too forms the cornerstone in maintaining appropriate pulmonary pressures. Suctioning has been studied extensively to cause loss of tidal volume on patients receiving mechanical ventilation and adding dead space to the ventilatory circuit. Owing to this, suctioning procedures have been avoided for long periods of time to prevent derecruitment of alveoli. This leads to secretion retention and high alveolar pressures. Thus to maintain adequate tidal volumes and to prevent the suboptimal use of suctioning during HFOV, research is required to understand the mechanics between the ventilator and the ventilatory circuit. Purpose: The study answered the following research questions: 1. Effect of three inline closed suction adapters on delivered tidal volume with varying lung compliance 2. Effect of varying compliance on the amplitude delivered by HFOV 3. Effect of compliance on tidal volume delivered by HFOV. Method: An in vitro bench model using high fidelity breathing simulator (ASL 5000, IngMar Medical) simulating an adult patient with ARDS was set up with 3100B SensorMedic high frequency ventilator. The simulation included varying the compliance for each lung at 50, 40, 30 and 20cmH2O while maintaining fixed resistance of 15 cmH2O/L/sec. The ventilator was set to: power of 6, frequency of 5, inspiratory time of 33%, bias flow of 30 LPM and FiO2 of 50%. The breathing simulator was connected with the high frequency ventilator using a standard HFOV circuit. Fourteen French Kimberly Clark (T and Elbow adapters) and Air-Life suction catheters (Y adapter) were placed in-line with the circuit. Each run lasted for 1 minute after achieving stable state conditions. Results: Analysis showed that Air-Life suction catheters caused the least lost in tidal volume when placed in line with high frequency circuit. Also a direct correlation between amplitude and lung compliance was seen. Lastly, the study did not show a statistically significant change in tidal volume with changes in lung compliance. Conclusion: 1. Choice of in-line suction system to be placed in line with the ventilator is one of the many determinants of change in tidal volume during HFOV. 2. Lung compliance changes lead to associated changes in amplitude delivery by HFOV. Sponsored Research - None