The Science Journal of the American Association for Respiratory Care

2010 OPEN FORUM Abstracts

EFFECTS OF MUCUS CLEARANCE ON THE DIFFERENCES OF RHEOLOGICAL PROPERTY AND DRIVING PRESSURE DURING HIGH FREQUENCY CHEST WALL OSCILLATION (SMARTVESTTM).

Tetsuo Miyagawa1, Yuusaku Takeda2, Tomomi Ichiba1,3, Yuuta Kasuga4, Mari Nomoto5, Aiko Taguchi6; 1Division of Respiratory Care, Graduate School of Nursing and Rehabilitation Sciences, Showa University, Yokohama, Japan; 2Department of Physical Therapy, Kanagawa Neurosurgery Clinic, Yokohama, Japan; 3Department of Physical Therapy, Faculty of Health Sciences, Kyorin University, Tokyo, Japan; 4Department of Physical Therapy, Ichigao Karion Hospital, Yokohama, Japan; 5Department of Physical Therapy, Musashino Yoowakai Hospital, Tokyo, Japan; 6Department of Physical Therapy, Kawasaki kyodo Hospital, Kawasaki, Japan

Background:High frequency chest wall oscillation (HFCWO) is commonly used for airway clearance. The volume of mucus moved has been thought to be greatest at frequencies between 10Hz and 20Hz, especially 13Hz. However it is not clear that effects of mucus clearance on the rheological properties and driving pressure. The purpose of this study is to clarify differences of airway clearance efficacy depend on mucus property and driving pressure. Method: Twenty-four normal subjects participated in the study. Mucus stimulants (MS) were prepared using thickener 1, 2, 3 and 4% (Toromi Perfect TM, Nisshin Oillio Company) and the pressure controls of SmartVestTM (Electomed Inc.) were driven 20, 30 and 40. MS rheological studied were measured using Rheometer MARS (Thermo Scientific HAAKE).They were quiet breathing into the endotracheal tubes having internal diameter of 7mm during SmartVestTM. We measured peak expiratory flow rate (PEFR), peak expiratory pressure (PEmax) and effortless breathing using modified Borg scale on each driving pressure, also measured clearance velocity of each MS. Data analysis was performed using software SPSS Statistics 17.0. Results: The higher setting pressure controls droved, the more PEFR and PEmax increased (p < 0.05). The lower viscoelasticity of MS had, the faster clearance velocity moved in table 1 (p < 0.05). There was the negative correlative relationship between viscoelasticity of MS and clearance velocity(6.813Hz: r=-0.49~-0.73, p < .0001) (10Hz: r=-0.42~-0.64,p < 0.0001),(stress dependency: r=-047~-0.75,p < 0.001). When the driving pressure increased, the clearance velocity improved in the lower viscoelasticity of MS (1% and 2%). However, the clearance velocity did not increase in the higher viscoelasticity of MS (3% and 4%) in spite of higher driving pressures. The subjects were tolerable on each driving pressure, had nothing in effort breathing using modified Borg scale (from very weak to weak). Conclusions The lower viscoelasticity of MS had, the faster clearance velocity moved during HFCWO. However, the clearance velocity did not increase in the higher viscoelasticity of MS in spite of higher driving pressures. Sponsored Research - None Table 1 : The clearance velocity of mucus stimulants