Pulmonary Disorders II

intestine, but primarily the lung (Chest 2004;125:1-39)

CF is a recessive disorder caused by a mutation in the cystic fibrosis transmembrane conductance regulator

(CFTR). CFTR controls the movement of chloride and bicarbonate across the cell membranes of many

organs throughout the body (e.g., lungs, gastrointestinal tract, pancreas) (Chest 2018;154:383-93).

sodium and fluid through the epithelial sodium channel (ENaC), which creates a viscous mucus (Chest

2018;154:383-93). The pH of this mucus is more acidic, which impairs ciliary clearance and the function

of phagocytic cells (Int J Mol Sci 2022;23:3513).

Chronic therapy has been developed to target specific CFTR mutations, and such therapies may be seen

in the ICU as home medications. Several of these agents have important drug-drug interactions as either

substrates or inducers of CYP3A4 (Chest 2018;154:383-93).

Social Determinants of Health in CF (Expert Rev Respir Med 2016;10:967-77)

The term socioeconomic status, defined as access to education, material goods and services, social

support, and position in society, contributes to differences in outcomes among patients with CF

through varying exposure to allergens, quality of nutrition, chronic stress levels, and ability to self-

manage disease, as well as access to medical care.

Patients of a lower socioeconomic status have higher morbidity and mortality rates. Their disease

progression related to lung function and nutrition are adversely affected as well.

Definitions and significance

There is no universally accepted definition for pulmonary exacerbations of CF (Respir Care

2020;65:233-51).

Acute exacerbations include symptoms of increased cough, sputum production, shortness of breath,

weight loss, and a decline in lung function.

Pulmonary exacerbations of CF can have a significant impact on quality of life and disease

progression. About 25% of patients with an exacerbation will not completely recover lung function

Staphylococcus aureus is the most common organism isolated from birth to teenage years.

Methicillin resistant Staphyloccocus aureus (MRSA) becomes more common in the 11–30 years

of age range.

Pseudomonas aeruginosa has a prevalence rate of around 15% from birth to teenage years, but

rapidly increases in prevalence after 17 years of age. Greater than 60% of adults with CF in the

United States are infected with P. aeruginosa.

Stenotrophomonas maltophilia

Achromobacter xylosoxidans

Burkholderia cepacia complex

Nontuberculous mycobacteria

Antibiotic therapy for pulmonary exacerbations of CF

Antibiotic dosing is challenging because of the altered pharmacokinetics in patients with CF.

Patients with CF can be distinguished by their large volume of distribution and augmented renal

clearance.