Chest Physiotherapy and Cystic Fibrosis: Forced Expiration Technique
The FET, as defined by Pryor and Webber (1979) consists of one or two forced expirations, or huffs, followed by relaxation and breathing control. As secretions reach the upper airways, one or two huffs or coughs are required to expectorate. The FET is thought to assist secretion movement by manipulating thoracic pressures and airway dynamics. Forced expiratory maneuvers with an open glottis produce lower thoracic pressures and result in equal pressure points. During a forced expiratory maneuver, compression and collapse occur only in the airways “downstream” (toward the mouth) from the equal pressure points. As the lung volume decreases, these equal pressure points move toward the alveoli, permitting enhanced expiratory linear velocity of airflow to mobilize secretions. canadian neighbor pharmacy viagra
This technique can be performed by the patient independently or may be used in conjunction with an assistant giving percussion or vibration. Comparisons of the independent and assisted regimens showed significantly better results in sputum clearance and pulmonary function for the independent regimen Further, Pryor and Webber compared the independent regimen of treatment, with and without FET, over four consecutive days in a group of CF and a group of asthmatic patients. A significantly greater amount of sputum was produced and improvements in FEVi occurred in the groups using PD with FET. In the asthmatic group, there was no evidence to suggest that the FET aggravated airway obstruction.
The FET appears to be misunderstood by various clinicians and researchers thus leading to poor application and outcome when used with patients The breathing control component of the technique is essential, especially since CPT treatment that does not include breathing control can result in broncho-spasm and alterations in oxygenation.
The FET has become an essential part of the ACBT established by Webber (1988) This regimen consists of a combination of techniques performed in sequence. The sequence consists of breathing control, three to four thoracic expansion exercises, breathing control, two to three thoracic expansion exercises, breathing control, one to two huffs, and breathing control. Manual techniques such as percussion or vibration may be superimposed during the thoracic expansion exercises. The ACBT can be performed in gravity-assisted positions or sitting and has been shown to improve lung function. It has not been associated with hypoxemia in acutely ill CF patients.