ALS and Airway Clearance (ALSAC) Is There a Best Therapy for Airway Clearance in Patients With ALS

Study Purpose:

Patients will receive one of three respiratory therapy interventions for airway clearance assistance: 1) High frequency chest wall oscillation (HFCWO) and mechanical insufflation/exsufflation (MIE), 2) HFCWO or 3) MIE. The study period will be six months and include three clinic visits, baseline and follow-up visits at 3 and 6 months, and 6 monthly home visits by the respiratory therapist.

Study Status:

Not recruiting


Amyotrophic Lateral Sclerosis , Respiratory Muscle Weakness

Study Type:


Type of Intervention:


Intervention Name:

High Frequency Chest Wall Oscillation, Mechanical insufflation/exsufflation




Study Chair(s)/Principal Investigator(s):

Donna Gardner, DrPH, University of Texas Health San Antonio ID:


Neals Affiliated?


Coordinating Center Contact Information

Full Study Summary:

The proposed project includes both the HFCWO and MIE and will capitalize on the specific goals of each therapy and address the problem as a whole rather than piece-meal. The HFCWO aims to mobilize the secretions to the pharynx to allow the patient to expel the secretions. However, many patients diagnosed with ALS are unable to expel the secretions due to atrophied expiratory muscles. The HFCWO device uses a small air compressor with a vest that wraps around the chest to induce airflows to pull secretions from the walls of the airways, thin the secretions and move them up the airways towards the larger airways and pharynx. The MIE, a noninvasive therapy, removes secretions in patients who have an ineffective cough because the peak cough flows are less than 270 L/min. This device applies a positive pressure to the airway and rapidly switches to a negative pressure applied to the airway. The rapid switch between the two types of pressure simulates a natural cough, thus assisting with expulsion of the secretions. Logically, the two mechanisms of action of these devices should work synergistically to produce effective airway clearance to keep the lungs clear, healthy and reduce the risk of infections from stagnant secretions. Respiratory infections are especially serious for patients with ALS because the patient is not able to recuperate from infections as quickly as a person without ALS. The objective is to determine if changing the use of existing respiratory therapy devices can improve the physical and psychosocial health and quality of life for patients diagnosed with ALS and caregivers.

Study Sponsor:

The University of Texas Health Science Center at San Antonio

Estimated Enrollment:


Estimated Study Start Date:

01 / 25 / 2012

Estimated Study Completion Date:

09 / 17 / 2017

Posting Last Modified Date:

11 / 04 / 2021

Date Study Added to

07 / 01 / 2021

Minimum Age:

21 Years

Maximum Age:


Inclusion Criteria:

1. Age 21 and above,

2. Probable or definite ALS diagnosis,

3. Peak Cough Flow of <160L/min or complain of issues clearing airway secretions

4. Caregiver must also consent to participate

Exclusion Criteria:

1. Current use of HFCWO or MIE

2. Tracheostomy

3. Congestive heart failure

4. All contraindications for the HFCWO

5. Head and/or neck injury that has not been stabilized;

6. Active hemorrhage with hemodynamic instability;

7. Uncontrolled hypertension;

8. Active or recent gross hemoptysis; and

9. All contraindications for the MIE

10. History of bullous emphysema;

11. Known susceptibility to pneumothorax;

12. Pneumomediastinum; and

13. Recent barotrauma

14. Frontal Temporal Dementia (FTD) - suspected or diagnosed . FTD is a form of dementia found in about 20% of Familial ALS. This dementia interferes with the ability to follow commands and follow through with therapies due to forgetfulness.

15. Patients not able to provide informed consent.

University of Texas Health San Antonio

San Antonio, Texas 78229
United States