Respiratory System Function and Sounds

Study Notes

Ventilation: Movement of air into and out of the lungs.
Perfusion: Movement of blood into and out of the capillary beds and to other organs.
Diffusion: Movement of gases between the air spaces in the lungs and the bloodstream.

Wheezing: Whistling, musical sound caused by narrow or obstructed airways.
- Asthma:
- COPD (Chronic Obstructive Pulmonary Disease) including chronic bronchitis
- Sleep Apnea:
- CHF (Congestive Heart Failure) and GERD (Gastroesophageal Reflux Disease)
- Bronchiectasis, bronchiolitis, lung cancer, anaphylaxis
Crackles: Discontinuous, high-pitched sounds heard during inspiration.
- COPD (Chronic Obstructive Pulmonary Disease) including chronic bronchitis
- Asbestosis:
- Idiopathic pulmonary fibrosis:
Stridor: Monomorphic sound indicating narrowing of the larynx
- Status Asthmaticus:
- Choking/Foreign Body: Obstruction of the larynx or trachea

Obstructive Lung Diseases: Characterized by decreased FEV1 (Forced Expiratory Volume in 1 second) and decreased FEV1/FVC (Forced Vital Capacity) ratio.
- Asthma
- COPD: (Emphysema and Chronic Bronchitis)
- Cystic Fibrosis
- Bronchiectasis
Restrictive Lung Diseases: Characterized by increased or normal FEV1/FVC ratio.
- Sarcoidosis
- Pneumoconiosis: (Berylliosis, Byssinosis, Asbestosis )
- Idiopathic pulmonary fibrosis

Inconsistent Asthma: Uses short-acting beta-agonists (SABAs) 1-2 times or less during the daytime in a week and wakes up less than 2 times a month.
Mild Persistent Asthma: Uses SABAs >2 times or more in a week and wakes up 3-4 times a month.
Moderate Persistent Asthma: Daily symptoms, uses SABAs every day, and wakes up more than 5 times a month.
Severe Persistent Asthma: Uses SABAs 2-3 times a day, wakes up every night, and has continuous symptoms.

Pulmonary Function Tests: Measure the amount and speed of air a person can inhale and exhale.
- Spirometry: Measures lung volumes and flow rates.
- Plethysmography: An airtight box that patients sit or stand in to conduct the test.
Peak Flow: Monitors the response to treatment (usually used for asthma)
- The maximum speed at which a person can exhale.
Incentive Spirometry: A device used to help patients breathe deeply after surgery or illness. It encourages them to take slow, deep breaths to help improve lung function.

Pseudomonas aeruginosa: Most common bacterial infection in patients with cystic fibrosis.
- Treatment: Fluoroquinolones and aminoglycosides (e.g., Levofloxacin and Gentamycin)

Floating Stools: Due to pancreatic insufficiency.
Infertility: Men experience infertility, and women have decreased fertility.
Meconium Ileus: Obstruction of the intestines in newborns.
Salty-Tasting Skin: Infants with cystic fibrosis may have salty-tasting sweat.

Autosomal Recessive Disorder: Both parents must carry the gene for a child to inherit the disease.
Most Common Lethal Genetic Disease in the White Population: Cystic fibrosis is the most common lethal genetic disease in people of European descent.
**CFTR Gene: ** The CFTR gene on chromosome 7 regulates chloride channels, impacting the flow of sodium, chloride, and bicarbonate.

Symptoms:
- Chronic bacterial infections of the lungs, leading to bronchiectasis.
- Pancreatic insufficiency with malabsorption of fat and fat-soluble vitamins, causing oily stools (steatorrhea).
- Infants may have salty-tasting skin and excessive sweating.
- Hyponatremia and elevated lipase levels.
CXR (Chest X-ray): Hyperinflation, bronchial wall thickening, atelectasis, and bronchiectasis.

Elevated Sweat Chloride Test: Sweat chloride levels greater than 60 mmol/L on two separate visits confirm cystic fibrosis.
Genetic Screening: Genetic testing confirms the diagnosis.