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

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 By Shreya J. Thacker Introduction: The use of high frequency oscillatory ventilation is increasing in treatment of acute respiratory distress syndrome over the past decade. The technique of HFOV of ventilating the lungs at volumes less than the anatomical dead space calms the clinical concerns surrounding ventilating stiff ARDS lungs with high pressures and volumes. This largely reduces the probability of barotraumas and/or atelectrauma. Purpose: The study was on an in vitro bench model that answered the following research questions: 1. The effect of three inline closed suction adapters on delivered tidal volume during HFOV with varying lung compliance 2. The effect of varying compliance on the amplitude delivered by HFOV; and 3. The 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 the following parameters: power of 6, frequency (f) of 5, inspiratory time (Ti) of 33%, bias flow (BF) of 30 LPM and oxygen concentration of 50%. The breathing simulator was connected with the high frequency ventilator using a standard HFOV circuit and a size 8.0mm of endotracheal tube. Fourteen French Kimberly Clark suction catheters (with T and Elbow adapters) and AirLife suction catheters (Y adapter) were placed in-line with the circuit successively to carry out the study. Each run lasted for 1 minute after achieving stable state conditions. This approximated to 300 breaths. The data was collected from the stimulator and stored by the host computer. Data Analysis: The data was analyzed using SPSS v.11 to determine the statistical significance. A probability value (P value) of ≤ 0.001 was considered to be statistically significant. Results: The data analysis showed that Air-Life Y-adapter suction catheters caused the least lost in tidal volume when placed in line with HFOV and hence proved to be the most efficient. The study also showed a direct relationship between amplitude and lung compliance i.e. an increase in lung compliance caused an associated increase in amplitude (power setting remaining unaltered). Lastly, the study did not show a statistically significant change in tidal volume with changes in lung compliance. Future studies may be required to further evaluate the clinical significance of the same. Conclusion: 1. Many factors affect delivery of tidal volume during high frequency ventilation and thus it is not constant. Choice of in-line suction system to be placed in line is one of the determinants of the same. 2. Lung compliance changes lead to associated changes in amplitude delivery by HFOV. This should be adjusted as patient condition improves by altering the power settings to ensure optimal ventilation and to avoid trauma to the lungs. THE INDEPENDENT EFFECT OF THREE INLINE SUCTION ADAPTERS AND LUNG COMPLIANCE CHANGE ON AMPLITUDE AND DELIVERED TIDAL VOLUME DURING HIGH FREQUENCY OSCILLATORY VENTILTION IN AN ADULT PATIENT WITH ARDS: BENCH MODEL By Shreya J. Thacker A thesis Presented in Partial Fulfillment of Requirements for the Degree of Masters of Science In Health Sciences In Division of Respiratory Therapy At Byrdine F. Lewis School of Nursing and Health Professions Georgia State University Atlanta, Georgia 2011