Respiratory Disorders

Act of breathing requires two processes

• ventilation

• respiration

Ventilation

movement of air in and out of the lung

• ventilation = mechanical

Respiration

exchange of oxygen and carbon dioxide across cell wall membranes

• alveoli is like a balloon - as you inhale → expands → thinner → greater diffusion

Mechanics of respiration

• Lung movement is entirely passive, result of external forces

• Pressure is inversely related to volume, air moves from high pressure to low

• Respiration reflects rhythmic fluctuations between alveolar pressure and the atmospheric pressure

Upper airway tract

• Nose, paranasal sinuses, pharynx, tonsils, adenoids, larynx, trachea

• warms and humidifies air + filters

Lower airway tract

• Lungs which contain the bronchial and alveolar structures.

• Stored in the thoracic cage-an airtight chamber with distensible walls.

• R bronchus is shorter and wider

• Branches divide into subsegmental bronchi, bronchioles, terminal bronchioles, and respiratory bronchioles

• Respiratory bronchioles divide into alveolar ducts, alveolar sacs, and alveoli

Alveoli Type 1

• 95%

• serve as a barrier between the air and alveolar surface

Alveoli Type 2

• 5%

• make type 1 cells and surfactant

• surfactant reduces surface tension

Alveolar macrophages

phagocytic cells that ingest foreign matter

Alveoli are surrounded by

a pulmonary capillary network

• distance of less than 1 mm

Lung circulation

• Oxygen travels from the alveolus into the capillary blood to the cells of the body, carbon dioxide passes out of the blood into the alveolus for passage to the external environment.

• This gas exchange is the process called Respiration

• Alveolar-capillary membrane is ideal for gas exchange due to its thinness and large surface area.

FOr gas exchange

perfusion and ventilation

Ventilation and perfusion balance and imbalance

V/Q perfusion ration should be 1:1 blood to gas

imbalance result in hypoxia

Ventilation (2)

• Inhalation is an active process, diaphragm is primary muscle of breathing, also includes external intercostal muscles and scalene muscles.

• Exhalation is passive process, relaxation of diaphragm and intercostal muscles

• Compliance-yielding to pressure, ease with which lungs can be stretched while taking in air.

• Elasticity is determined by musculature and bones of the thoracic cage

Control of respiration

• Chemoreceptors feed data to medulla oblongata and pons

• Increase in depth and rate of ventilation when CO2 levels increase

• Decrease in depth and rate of ventilation when the CO2 levels decrease

• Peripheral chemoreceptors located in the carotid bodies and aortic arch (freshly oxygenated blood)

respond to low arterial blood oxygen levels

• COPD patients rely on hypoxic drive for breathing so they depend on peripheral chemoreceptors for control of ventilation—they become hypercapnic

• Neural receptors are stretch receptors in airways that respond to changes in pressure. J receptors located in alveolar walls respond to shallow breathing (pulmonary edema, pneumonia)

CHanges with Aging

• Thoracic cage becomes rigid from cartilage calcification, osteoporosis of the ribs, arthritic changes in the joints of the ribs

• Kyphosis (hunch back)

• Increase in anteroposterior diameter of the chest

• Increased size of the pores of Kohn - (interalveolar connections or alveolar pores) discrete holes in walls of adjacent alveoli

• Decreased elasticity of alveolar sacs

Coughing reflex can be impaired by

• weakness

• paralysis of resp muscles

• prolonged inactivity

• NG

• Depressed function of brain’s medullary center (anesthesia, brain disorder)

Coughing reflex stimulated by

• mucus

• blood

• pus

• airborne irritant (smoke, gas)

• asthma gas reflux, infection, and some meds (ACE inhibitors)

Sputum

Productive cough

• Bacterial infection: thick and change in color (yellow, green, rust)

• Viral bronchitis: thin

• Lung tumor: pink-tinged

• Pulmonary edema: profuse pink frothy

• Lung abscess, bronchiectasis, or infection: foul-smelling, bad breath

Sputum Collection

• In early AM, RT frequently obtains

• Must be deep, not saliva

• Keep collection chamber at bedside

• Note color, consistency, odor, quantity, obvious blood

• Can be save in refrigerator if not sent to lab right away

Pulmonary symptoms

Dyspnea-discomfort when breathing

• Tachypnea-increased respiratory rate

• Hypoxemia- low blood Oxygen

• Hyperpnea-increased depth of respiration

• Orthopnea- SOB when lying flat

• Productive cough-sputum production

• Paroxysmal cough-periodic forceful episodes; frequent violent coughing making it hard for patient to breathe

• Hemoptysis-blood or blood-tinged sputum, usually frothy with air bubbles, alkaline in pH, and bright red

• Wheezing-high pitched whistling sound when air passes through narrowed or obstructed airways

Adventitious Lung sounds

• Crackles

• Rhonchi-low pitched continuous sounds heard over lungs in partial airway obstruction (can be heard with or without a stethoscope)

• Wheezes-high pitched whistling sound (bronchospasm, asthma, airway constricted)

• Pleural friction rub-grating, rubbing, creaking

Diagnostic For respiratory Disorders

• Sputum for gram stain, cultures, cytologic examination

• Chest radiographs

• Computed tomography

• Fluroscopy-observe movement in the area

• MRI

• Ventilation-perfusion lung scan-pattern of radioactivity after inhalation of radio-nucleotides (pulmonary embolism)

• Thoracoscopy- incision made in pleural cavity between ribs

• Bronchoscopy- direct inspection of larynx, trachea, and bronchi

• Thoracentesis- aspiration of pleural fluid

• Biopsy

Labs for Respiratory Disorders

ABG

• To provide information of oxygenation, ventilation, and acid-base balance

CBC

• RBC to assess overall oxygen-carrying capacity

• WBC to assess for infection, immune system dysfunction

• Hgb to assess cells oxygen-carrying capacity

Acid-Base Lab Values

• pO2: 80-100 mmhg

• pCO2: 35-45 mmHg

• HCO3: 22-25 meq/L

• pH: 7.35-7.45

• O2 sat: 95-99%

CO2 Critical Levels Respiratory Lab

• < 15: s/s include deep vigorous breathing and flushed skin

• AKI, hyperventilation, starvation/ metabolic acidosis

  • Treatment: sodium bicarb 2NaHCO3- Na2 + HCO3- H+ H2O + CO2

• > 40: pt is at risk with excessive vomiting, gastric suctioning, shallow breathing

• Airway obstruction, asthma, bronchitis, hypoventilation, Tb, post-surgery

  • Treatment: encourage slow/deep ventilation, may need Narcan/reversals

Compensaiton

• blood gas compensation is the body’s attempt to maintain a normal pH level in the blood when there is a disturbance in the level of oxygen and carbon dioxide

• Respiratory and renal systems compensate with CO2 and HCO3 to correct the pH

• Full compensation results in normal/corrected pH

• partial results in a slightly less abnormal pH

• If respiratory issue → kidneys fixes

  • acid high → excrete H+, retain HCO3

  • alkalosis high → excrete HCO3, retain H+

• If metabolic → respiratory fixes

  • acidosis → excrete CO2

  • Alkalosis → retain CO2

Lactic Acid Respiratory Lab

• Evaluate tissue oxygenation/acidosis

• Critical > 31

• At risk when insufficient oxygen in tissues and decreased blood flow result in a build up of LA from anaerobic glycolysis.

  • Asthma, Asphyxiation, MI, Heart failure, hemorrhage, pulmonary edema/embolism, Sepsis

  • Treatment: monitor and treat electrolyte imbalance, administer O2, Abx,

Respiratory Risk Factors

• Smoking!!!!

• single most important contributor to lung disease

• Exposure to infectious agents

• pollution & allergens

• Predisposition to genetic disorders

• Asthma, lung CA, cystic fibrosis

• Past pulmonary illnesses

• Childhood allergies, frequent colds, influenza, TB

• Environmental irritants

• dust, fumes, gases, coal dust, allergen

ATELECTASIS

• Closure of collapse of the alveoli, most often seen on x-ray.

• Acute or chronic

• Obstructive: most common, air is blocked by a foreign body, tumor, or retained secretions. Can be caused by some surgical procedures (upper abdomen, thoracic, or open heart)

• Non-obstructive: caused by reduced ventilation

• S/S cough, dyspnea, sputum production, anxious, orthopnea, cyanosis, tachypnea, tachycardia, decreased breath sounds, and hypoxemia.

• Prevention: frequent turning, early mobilization, managing secretions, enhanced lung expansion

Acute Tracheobronchitis

• Acute inflammation of the mucous membranes of the trachea and the bronchial tree

• Follows a viral infection if not adequately treated

• S/S mucopurulent sputum, cough, sternal soreness, fever, chills, headache, malaise, night sweats.

• Abx may be needed depending on the severity, sputum purulence, and results of the sputum culture.

• Increase fluids, cool or steam humidifiers, mild analgesics, high fowlers, cough effectively, and rest.

Pneumonia

• Four categories:

• S/S consolidation on x-ray, fever, sputum production, pleural effusions, tachycardia, orthopnea, malaise,

diaphoretic,

• *Aspiration PNA= entry of endogenous or exogenous substances into the lower airway

• Prevention: flu vaccine

• Treatment: antibiotics, hydration, antipyretic, warm moist humidified air, antihistamines, rest, and nasal

decongestants.

• Severe complications includes hypotension, septic shock, and respiratory failure

Pneumonia Categories

• Community-acquired (CAP) usually caused by viral infections (flu)

• Health care-associated (HCAP) often caused by MDROs

• Hospital-acquired (HAP) develops >48 hours after admittance

• Ventilator-associated (VAP) HAP plus the presence of an ET tube

Pleural Effusion

• Accumulation of pleural fluid in the plural space (between the parietal and visceral pleurae of the lung).

• Thoracentesis may be preformed to remove the fluid and send to lab

• Empyema occurs when thick purulent fluid accumulates within the plural space.

• Chest tube may be inserted to drain the empyema

Aspiration

• Inhalation of a foreign material into the lungs. Can cause PNA

• S/S tachycardia, dyspnea, central cyanosis, hypertension, hypotension, and potentially death.

• High risk when the protective airway reflexes are compromised (GERD, dysphagia, esophageal strictures, tracheoesophageal fistula, decreased LOC)

• Prevention: extubation, high fowlers when eating/drinking, soft diet, small bites, keep chin tucked and head turned when swallowing.

• *Straws should not be used

Pulmonary Embolism

• Blockage of pulmonary blood flow

• causes: DVT/thrombus, or emboli from fat/air/amniotic fluid/septic (endocarditis)

• S?S: dyspnea, poor perfusion, hypoxemia, tachycardia, tachypnea, hypotension

  • will lead to R. ventricle failure

• Dx: CT pulmonary angiogram, Echo (R. ventricle hypertrophy)

• Tx: warfarin, Xarelto, TPA, embolectomy

• Prevention: SubQ heparin, SCDs, IVC filter