Treatment of the pulmonary disease is based on a regular program to clear secretions, 
antibiotic therapy, bronchodilator therapy, oxygen administration, and (in the late phases) lung 
transplantation. 
1.3.1 Secretion Clearance Therapy: Physical measures to increase clearance of lower airway 
secretions have been used to decrease the risk of infection in cystic fibrosis. For more than 30 
years, a twice-daily program of chest percussion and postural drainage has been routine therapy 
and it has been associated with an increase in survival rate. More recently, this approach has 
been augmented with newer maneuvers, such as positive expiratory pressure breathing (PEP 
mask), autogenic drainage, and physical exercise. 
1.3.2 Antibiotic Therapy: Antibiotic therapy is a mainstay of treatment. Young patients 
suffer mainly from Staphylococcal infection and may be treated with oral antibiotics, such as 
cephalexin or Co-trimoxazole. Patients with established Pseudomonas aeruginosa infection 
frequently require hospital admission for intravenous treatment with anti-pseudomonal drugs. 
This usually takes the form of combination therapy with a beta lactam drug and an aminoglyco- 
side. These hospital admissions may last 10 to 14 days, or longer, and have been shown to be 
associated with a decrease in sputum bacterial density and improvement in pulmonary function 
(Regelmann, 1990). Outpatient treatment of chronic Pseudomonas infection has been hampered 
by the lack of potent oral anti-pseudomonal agents although the quinolones, such as ciprofloxacin 
and ofloxacin have shown some promise (Rubio, 1990). More recently, home therapy with 
intravenous antibiotics has emerged as an effective therapy with financial and social benefits. 
1.3.3 Respiratory Support Therapy: Eventually, progressive obstructive pulmonary disease 
and diffuse bronchiectasis result in hypoxemia, especially at night and with exercise. 
Supplemental oxygen is used in an attempt to reduce pulmonary hypertension and forestall the 
development of cor pulmonale. Partial pressures of carbon dioxide (CO 2 ) in arterial blood do 
not usually increase until late in the disease. Since the prognosis for successful weaning and 
extubation of CF patients on mechanical ventilators is poor (Davis, 1978), mechanical ventilation 
is not usually used to prolong life in cystic fibrosis. 
1.3.4 Bronchodilator Therapy: Bronchodilator treatment appears to be helpful in up to 30% 
of patients with cystic fibrosis. However, bronchodilators need to be used judiciously because 
some patients have a paradoxical decrease in flow rates following therapy (Landau and Phelan, 
1973). 
1.3.5 Lung Transplantation: For patients with very advanced lung disease and a poor life 
expectancy, lung transplantation has been used. Initially, this was developed using heart-lung 
transplantation (Smyth et.al., 1991). More recently, bilateral single lung transplants have been 
developed (Pasque et.al., 1990). These have prolonged life in a small number of cases, and the 
two-year survival rate is 50-60%. However, the numbers of organs available for transplantation 
are few and it is unlikely that most CF patients will benefit from this mode of therapy. 
1.4 New Pharmacological Therapies in Cystic Fibrosis: Many new therapies are being 
developed to ameliorate the progressive pulmonary disease of cystic fibrosis in the hope of 
improving life expectancy. These therapies include the use of an aerosolized antiproteases to 
inhibit neutrophil elastase, such as secretory leukocyte protease inhibitor (McElvaney et.al., 
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