Lecture 3 - Pulmonary System

Ventilation

• Gas (O2) and Carbon dioxide (CO2) transport into and out of the lungs

• mechanical process by which the gases are moved in and out of the lungs

Respiration

• gas exchange across the alveolar-capillary and capillary-tissue interfaces

• act of gas exchange occurring in the lungs relating to facilitating movement of O2 into blood and CO2 out of the blood

To accomplish ventilation and respiration into this system is regulated by…

neural, chemical, non-chemical mechanisms

Medullary respiratory center

• in the brainstem

• responsible for the rhythmicity of breathing

• controls autonomic ventilation

Pneumotaxic center

• located in pons

• controls ventilation rate and depth

cerebral cortex

• sends impulses directly to the motor neurons of ventilatory muscles

• mediates voluntary ventilation

arterial levels of CO2,H+, and O2 can modify…

rate and depth of respiration

Chemoreceptors on carotid arteries and aortic arch respond to…

either rise in CO2 and H+ or fall in O2

When chemoreceptors get stimulated, impulses are sent to …

respiratory centers causing an increase or decrease of respiration

• rate

• depth

• both

Increase in PCO2 = ?

increase in ventilation rate

• helps increase amount of CO2 exhaled = decreases PCO2 levels in arterial blood

Medulla primarily responds to a rise in…

PCO2 and H+

in relaxed inhalation…

diaphragm contracts and descends

in relaxed expiration…

diaphragm relaxes and the elastic recoil of the lungs, chest wall, and abdominal structures compress the lungs and expels air

apnea

absence of ventilation >= 10 seconds

bradypnea

a decreased ventilation rate with a regular rhythm; <10 breaths per min in adults

hyperpnea

increased depth of ventilation at a normal rate and rhythm

hyperventilation

increased rate and depth of ventilation resulting in decreased PCO2

hypoventilation

decreased rate and depth of ventilation resulting in decreased PCO2

orthopnea

dyspnea that occurs in a flat supine position. relief occurs with more upright sitting or standing

tachypnea

rapid ventilation rate >20 breaths per minute

palpation

• Assess for tracheal deviation or shifts

• Presence, location, and reproducibility of pain or tenderness

• Skin temperature and edema

• Presence of bony abnormalities, rib fractures, or both

• Chest wall expansion and symmetry

• Muscle activity of the chest wall, diaphragm, and accessory muscle use

SpO2 (Oximetry) can be affected by…

• poor circulation (cool digits)

• movement of sensor cord

• cleanliness of sensors

• nail polish

• jaundice

• skin pigmentation

• shock states

• severe hypoxia

when SpO2 is <90%…

collaboration with medical team regarding patient considerations is warranted

ABG analysis examines…

• acid-base balance (pH)

• Ventilation (PaCO2 levels)

• Oxygenation (PaO2 levels)

• Bicarbonate (HCO3)

Disturbances in acid-base balance can be caused by…

pulmonary or metabolic dysfunction

Respiratory Acidosis

• decreased pH

• increased PCO2

• normal HCO3

Respiratory Acidosis causes

• respiratory depression (drugs, CNS, ALS, GBS, MD)

• pulmonary disease (inadequate mechanical ventilation)

• kyphoscoliosis

• extra thoracic tumors

• circulatory disorders

• shock

• heart failure

Respiratory Acidosis presentation

• anxiety, confusion, fatigue/lethargy, dyspnea, somnolence

Respiratory Acidosis clinical implications

• assess vital signs, breathing pattern, respiratory status

• consider underlying cause

• ABG trend

• medical stability

  • K+ values (hyper)

respiratory alkalosis

• increased pH

• decreased PCO2

• normal HCO3

respiratory alkalosis causes

• hyperventilation (emotions, pain, fever, excessive mechanical ventilation)

• salicylates

respiratory alkalosis presentation

dizziness, dyspnea, paresthesia, chest pain, confusion, seizure

respiratory alkalosis clinical implications

same as acidosis

metabolic alkalosis

• increased pH

• normal PCO2

• increased HCO3

metabolic alkalosis causes

• sodium bicarbonate overdose

• prolonged vomiting

• nasogastric drainage

• cystic fibrosis

metabolic alkalosis presentation

confusion, dyspnea, weakness, cardiac arrhythmias, muscle spasms

metabolic alkalosis clinical implications

• monitor vital signs and cardiac rhythm during PT intervention

• symptom-based approach to treatment

metabolic acidosis

• decreased pH

• normal PCO2

• decreased HCO3

metabolic acidosis causes

diabetes, shock, renal failure, intestinal fistula

metabolic acidosis presentation

dyspnea, confusion, somnolence, respiratory muscle fatigue, tachyarrythmias

metabolic acidosis clinical implications

• monitor vital signs and cardiac rhythm during PT intervention

• symptom-based approach to treatment

• in the case of renal failure, may need to coordinate PT intervention around dialysis

Clinical presentation of CO2 retention

• Altered mental status

• Lethargy

• Drowsiness

• Coma

• Headache

• Hypertension

• Diaphoresis

• Tremor

• Redness of skin, sclera, or conjunctiva

normal PaO2

80-100 mmHg

normal PaCO2

35-45 mmHg

normal pH

7.35-7.45

normal HCO3

21 - 86 mEg/liter

Obstructive pulmonary conditions

• are characterized by decreased airflow out of the lungs as a result of narrowing of the airway lumen

• increased dead space, decreased surface area for gas exchange

• COPD

COPD

• describes airflow limitation that is not fully reversible

• diagnosis is confirmed with spirometric testing

examples of obstructive disorders

• COPD

• Asthma

• Chronic Bronchitis

• Emphysema

• Cystic fibrosis

• Bronchiectasis

Restrictive pulmonary conditions

• characterized by low lung volumes that result from

  • decreased lung compliance and distensibility

  • increased lung recoil

  • results in increased work of breathing

examples of restrictive pulmonary conditions

• atelectasis

• pneumonia

• pulmonary edema

• adult respiratory distress syndrome (ARDS)

• pulmonary embolism (PE)

• interstitial lung disease

• lung contusion

Restrictive extrapulmonary conditions are…

disorders or trauma occurring outside of the visceral pleura pleural effusion

pneumothorax

when air enters the pleural space

• type of restrictive extrapulmonary condition

hemothorax

type of pleural effusion characterized by the presence of blood in the pleural space from damage to the pleura and great or smaller vessels

Flail chest

double fracture of three or more adjacent ribs, resulting in this segment separating from the rest of the ribcage

Empyema

pleural effusion in which there is a presence of anaerobic bacterial pus in the pleural space, resulting from underlying infection

MSK changes of thoracic cage can occur with….

• ankylosing spondylitis

• rheumatoid arthritis

• kyphoscoliosis

• pregnancy

• obesity

• cervical/thoracic spinal cord injury

• GBS

Nebulized medications are optimally active…

15-20 min after administration

• plan therapy sessions for max medication benefit

PT intervention goals

• promote independence in functional mobility

• maximize gas exchange

• increase aerobic capacity

• increase respiratory muscle endurance

• educate patients of their pulmonary condition

parameters for restrictive lung disease

• RR = <40 breaths/min; able to speak comfortably (rapid, shallow breathing and decreased Inhale:Exhale ratios of 1:2, and approaching 1:1, are common with activity

• HR = 60-120 beats/min (caution if >120)

• pulse oximetry: >90%; generally require increased amounts of supplemental O2

parameters with COPD

• RR = <30 breaths/min; able to speak comfortably (increased Inhale;Exhale ratios of 1:3 - 1:5; instruct in pursed lip breathing to prevent air trapping during exercise and activity)

• HR = 60-120 beats/min (caution if >120)

• pulse oximetry = >90% at rest (with or without supplemental O2)

  • O2 use is often needed with moderate to advanced disease, but use should be judicious.

  • Overoxygenation may decrease the hypoxic drive to breathe; SpO2 target with activity in the acute setting is generally 88% to 92%