The Science Journal of the American Association for Respiratory Care

1998 OPEN FORUM Abstracts

FIVE THINGS I LEARNED THIS YEAR ABOUT AIRWAY CLEARANCE TECHNIQUE

Jeffrey L. Tarnow, RRT The Medical Center at the University of California, San Francisco

Patients with pulmonary disease often have increase mucus production, leading to cough and expectoration. The goal of respiratory care include the promotion of coughing and the removal of excess bronchial secretions, which is traditionally done by CPT, which is considered the GOLD standard for secretion clearance.

There are many alternatives to conventional chest physiotherapy (CPT). At the University of California in San Francisco (UCSF) we teach many different methods of secretion clearance. As of to date, there are no studies to demonstrate superiority of one method over the other.

Here is a very brief description of four alternatives; ABI Vest(tm) (formally The ThAIRapy(r) Vest), Intrapulmonary Percussion Ventilation (IPV), Flutter(r) (Osculating PEP), and TheraPEP(r) Positive Expiratory Pressure Therapy (PEP).

ABI Vest(tm) is based on high-frequency chest wall oscillation (HFCWO). It is indicated for patients with a large volume of respiratory secretions. The vest generates HFCWO through the use of a pneumatic vest which encircles the thorax and oscillates the chest wall 5 to 25 times per second. So in theory these vibrations cause transient increases in airflow in the airways, resulting in improved gas-liquid interactions and the movement of mucus.

IPV delivers high-flow jets of gas to the airways by a pneumatic flow interrupter at a rate of 100-300 cycles/min. The duration of percussion is controlled by the patient or caregiver. Once the patient has learned to use the device correctly, the drive pressure is slowly increased until significant chest excursion is seen. An aerosol generator is in-line to deliver medications. The physiologic basis for its potential effectiveness is unknown, but it is presumed to be enhanced mucociliary clearance through bronchodilation from combination of increased airway distending pressure and bronchodilators.

Flutter(r) is a small handheld unit that is used to facilitate the removal of secretion. It is shaped like a pipe with a mouthpiece at one end, plastic protective perforated cover at the other end, and high density stainless steel ball resting in a plastic circular cone on the inside. The principle of this device is based on its ability to vibrate the airway walls (loosening mucus), decrease the collapsibility of the airways, and accelerate airflow, thus facilitating movement of mucus up the airways. The Flutter(r) produces a range of oscillation frequencies between 6-20 Hz. These vibrations, coupled with increases in expiratory pressure and airflow, facilitate the clearance of secretions.

TheraPEP(r) is a fixed-orifice flow resistor device that is dependent on the patients expiratory flows through the desired size orifice to achieve an expiratory pressure between 10-20cm H20. PEP is a self-contained unit, it doesn't require a pressurized gas source. Similar to pursed-lip breathing, PEP creates back pressure within the airways and thus preventing and resolving airway collapse during expiration.

The 44th International Respiratory Congress Abstracts-On-DiskĀ®, November 7 - 10, 1998, Atlanta, Georgia.

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