The Science Journal of the American Association for Respiratory Care

Foreword

July 2002 / Volume 47 / Number 7 / Page 759

New Horizons in Respiratory Care: Airway Clearance Techniques

It was an honor to co-chair the 17th Annual New Horizons Symposium at the American Association for Respiratory Care's International Respiratory Congress in San Antonio, Texas, on December 2, 2001. The New Horizons Symposium has been a landmark feature of the meeting for 17 years. This full-afternoon session provides a comprehensive, focused, and multi-dimensional exploration of a key aspect of the practice of respiratory care, usually reviewing areas of evolving clinical practice. In many instances the manuscripts from the symposium are then published in a special issue of RESPIRATORY CARE.

Airway mucus is a critically important host defense. Normal mechanisms for mobilization of secretions include mucociliary transport, autocephalad flow (secretions moving toward the central airway during normal breathing), and cough. Mucus hypersecretion and impaired mucus clearance can be serious problems, leading to discomfort, dyspnea, airway obstruction, atelectasis, infection, bronchiectasis, and pulmonary disability. As respiratory care has evolved as a profession, airway secretion clearance has always been part of our scope of practice.1-4 Terms such as "bronchial hygiene" and "pulmonary toilet" have been used to characterize the process of assisting patients to clear airway secretions. Too often, however, those terms have been associated only with postural drainage, percussion and vibration, or mechanical aspiration of the airways in acutely ill patients.

Over the past 40 years we have come to better understand the mechanisms of airway clearance in health and disease, and this has led to the development of devices and techniques to assist in secretion removal. The amount and quality of evidence from rigorously conducted, randomized clinical trials in support of these diverse techniques varies widely.5 However, most of the techniques are based on physiologic rationale and are at least supported by case studies.2

This year's New Horizons Symposium began with a review of the "Physiology of Airway Mucus Clearance" (Bruce Rubin). The major bronchial hygiene techniques were reviewed in "Positioning Versus Postural Drainage" (Jim Fink), "Airway Physiology, Autogenic Drainage, and Active Cycle of Breathing" (Craig Lapin), "Positive Pressure Techniques" (Jim Fink), and "High-Frequency Oscillation of the Airway and Chest Wall" (Mike Mahlmeister and Jim Fink). Kathy Davidson discussed "Airway Clearance Strategies for the Pediatric Patient" and presented strategies for introducing these techniques as the patient develops from infancy through to adulthood. Robert Lewis then reviewed key practice considerations for the intubated patient in or out of the intensive care unit in "Airway Clearance Techniques for the Patient with an Artificial Airway." Dr Rubin's review of "The Pharmacologic Approach to Airway Clearance: Mucoactive Agents" then summarized the state of the art for medical management of secretion retention.

As we concluded the symposium it was clear that we had not addressed one potentially valuable method of airway clearance: ultra-low-frequency airway oscillation, better known as the Insufflator/Exsufflator (Fig. 1). This device has been studied for more than 50 years. Evidence suggests that it is an effective method to assist airway clearance in debilitated patients or in those with severe neuromuscular weakness.

Fig 1

The symposium participants agreed that although there may be few data to unequivocally support the use of many of these techniques, there is strong observational evidence that suggest that many of these techniques can have a role in mobilizing secretions, reducing dyspnea, and helping patients maintain patent airways. Selection of a "best" technique is currently more of an art than a science and depends greatly on the patient's underlying condition, level of functioning and understanding, and ability and willingness to perform the technique and integrate it into normal daily routines. For the clinician, the decision diagrams in Figure 2 represent one approach for technique selection. Education is key to the success of any technique. The better a patient understands a technique the better chance the patient has of adopting it appropriately.

Fig 2

Future research needs to better define and refine techniques in use and to incorporate good study designs in well-powered clinical trials that use meaningful outcomes. As an example, although often measured, the volume of expectorated sputum is of limited or no value in determining the clinical effectiveness of these devices and techniques. Measuring the frequency of protocol-defined exacerbations, antibiotic use, unplanned physician visits, hospitalizations, or missed days of work or school appears to be of greater clinical and scientific relevance. The more that we as a profession invest in learning, teaching, and studying these techniques, the greater the chance that our patients can benefit from their use.

James B Fink MSc RRT FAARC
Fellow, Respiratory Science
Aerogen Incorporated
San Francisco, California

Bruce K Rubin MEngr MD FAARC
Department of Pediatrics
Wake Forest University School of Medicine
Winston-Salem, North Carolina

References

  1. Fink JB. Bronchial hygiene and lung expansion. In: Fink JB, Hunt J, editors. Clinical practice of respiratory care. Philadelphia: Raven-Lippincott; 1999.
  2. Fink JB, Hess DR. Secretion clearance techniques. In: Hess DR, MacIntyre NR, et al, editors. Respiratory care: principles and practices. Philadelphia: WB Saunders; 2002.
  3. American Association for Respiratory Care. AARC Clinical Practice Guideline: Postural drainage therapy. Respir Care 1991;36(12):1418-1426.
  4. Fink JB, King M. Mechanical methods of mucus clearance, In: Rubin B, Van der Schans CP, editors. Therapy for mucus clearance disorders: lung biology in health and disease. New York: Marcel Dekker (in press).
  5. Hess DR. The evidence for secretion clearance techniques. Respir Care 2001;46(11):1276-1292.

Correspondence: Dean R Hess PhD RRT FAARC, Department of Respiratory Care Services, Massachusetts General Hospital, 55 Fruit Street, Ellison 401, Boston MA 02114-2696. Email: dhess@partners.org.

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