GAS EXCHANGE

• Gas Exchange

  Oxygen transport to cells and carbon dioxide transport away from cells through ventilation and diffusion
• Alveoli

  where gas exchange happens
• Perfusion

  Arterial blood flow through tissues, and blood pumped by the heart
• Physiology of Breathing

  1. Drive to breathe depends on level of CO2 in arterial blood

  2. When level rises, receptor sites in medulla and pons stimulate increase in rate and/or depth of ventilation (NOT the decrease of O2 in bloodstream)

  3. Receptor sites in aortic arch and carotid arteries monitor O2 levels

  4. Quality of breathing: effort involved in taking a breath, sounds that occur

  5. Effective breathing requires a patent airway (open, free of obstruction)
• Hypoxemia


  Decreased level of oxygen in the blood
• Hypoxia


  Decreased delivery of oxygen to tissues
• Ability of respiratory system to deliver O2

  • Inflated, well-oxygenated alveoli
  • Well-perfused capillaries
• VQ Ratio (ventilation/perfusion)

  The concentrations of O2/CO2 to move across membrane
• Alteration in VQ Ratio

  ventilation alterations: Alveolus blocked by sputum, inflammation, atelectasis, fluid volume excess.

  perfusion alteration: Blood clots, plaque buildup and emphysemic alveoli interfere with capillary blood flow.
• Respiratory Assessment

  • HX (current/past/meds/smoking)
  • Pallor
  • Nail beds
  • Nasal flaring
  • Work of breathing/SOB
  • Neuro (ALOC), difficulty speaking/raspy
  • Respiratory rate (full breath in/out)
  • Pulse ox (correlate w hx and assessment)
  • Breath sounds
  • Accessory muscle use
  • Chest symmetry
  • Positioning (tripod, orthopnea)
  • Cough (productive/non productive, how often, activity related)
  • Sputum
  • Chest pain
  • Restlessness, irritable, fatigue early sign of hypoxia
• Diagnostic Tests

  • ABG's, sputum testing
  • Chest xray, Thoracic CT, Pulmonary Angiogram & VQ scans, Pulmonary Function Tests (PFTs), Bronchoscopy, Thoracentesis
• Diagnostic Tools

  • Incentive Spirometry, Peak Expiratory Flow Rate (PEFR)
• Bronchial sounds


  Loud, high-pitched, heard over trachea, longer on exhalation than inhalation
• Bronchovesicular sounds


  Medium loudness and pitch, heard on each side of sternum, between scapulae, equal in duration during inhalation and exhalation
• Vesicular sounds


  Soft, low-pitched, heard over peripheral lung fields (bases), typically longer on inhalation than exhalation
• Adventitious Breath Sounds

  • Rhonchi: coarse, low-pitched, continue through inspiration, blockage of large airway passages
  • Stridor: high pitched sound in trachea & larynx, suggests narrowing of passage (croup)
  • Crackles: high pitched popping sounds, inspiration sound associated with fluid, associated with atelectasis: collapse of all or part of lung, obstruction is primary cause
  • Wheezing: high pitched whistling most often on expiration but can in inspiration also, narrowing of bronchi
  • Pleural rub: low pitched crackling sound during inspiration and expiration, pleural inflammation causes surfaces to slide
• Nail clubbing and Barrel chest result of chronic cardiovascular or respiratory disease
• Respiratory Assessment: Recognize Cues

  • Laboratory: RBC, ABG, Sputum specimens
  • Imaging: Chest x-rays, CT
  • Other noninvasive diagnostic assessments: Pulse ox, Capnometry and capnography, Pulmonary function tests (PFTs), Exercise training
• PCO2

  Hypercarbia (capnia), Hypocarbia (capnia)
• SaO2

  Pulse ox (% of hemoglobin carrying oxygen)
• Increase in pH (alkalotic)


  Kidneys excrete bicarb
• Decrease in pH (acidic)


  Kidneys retain bicarb
• Independent Nursing Interventions


  • Monitor vital signs, lab values, fluid status (improving or decompensating)
  • Monitoring activity intolerance (space periods of activity with period of rest)
  • Promoting secretion clearance/suctioning
  • Deep breathing exercises
  • Encouraging smoking cessation
  • Assisting with ADLs
  • Positioning (High Fowler's)
• Chest Tube Management

  • treat condition in which air or fluid cause lung collapse
  • trauma, pressure changes, coughing, airplanes, procedures, illness/cancer
  • hemothorax / pneumothorax
  • inserted under emergency conditions
  • remains in place of 2-5 days
  • vaseline gauze readily available
• Signs & Symptoms of Chest Tube Insertion

  • Sudden sharp pleuritic pain, worsened by breathing, coughing
  • Decreased or absent breathing sounds over the affected side
  • Asymmetrical chest wall movement
  • SOB
  • Cyanosis
• Factors that affect healthy respiratory system


  • Hypertension & atherosclerosis
  • Infectious illness of respiratory tract
  • Hemoglobin disorders interfere with effective respiratory function
  • Some medications affect respiratory rate, depth
  • Inflammation, infection, sputum production, compromised airflow alter respiratory health
  • Modifiable risk factors: obesity, T2DM, smoking, stress and anxiety
• health promotion:

  • Vaccination encouraged to decrease transmission of preventable diseases
  • management of environmental air quality may decrease concentration fo respiratory irritants
• Respiratory System in Children

  • Infant's airway is approximately 4mm, in contrast to an adult's 20mm
  • Infants are obligate nose breathers until approx. 3 months
  • Retractions (accessory muscle use) are common in children
  • Babies born after 36 weeks gestation have sufficient surfactant to prevent alveoli from collapsing after every exhalation
  • Prone to foreign body/choking
  • the size of little finger = trachea estimate
• Respiratory System in Pregnancy

  • Pregnancy raises diaphragm, decrease ability to expand lungs, Respiratory rate increase to keep us with increased O2 needs, Chest circumference increases, Changes to upper respiratory mucosa increase likelihood of developing nasal stuffiness, nosebleeds
  • Monitor oxygenation status during labor to prevent adverse effects on baby's oxygenation status
  • Prolonged supine positioning may be harmful to fetus
  • Check pregnancy status to make sure medication is safe for fetus
• Physiologic Changes in Aging

  • Increased risk of developing respiratory infections
  • Increased risk of sleep apnea diminished strength of respiratory muscles. May result in weaker cough
  • Changed to cough reflex → increased risk of choking on food
  • Increased incidence of gastroesophageal reflux → increased risk of aspiration of food = increases risk of pneumonia
  • Expect decreased breath sounds, inspiratory crackles common
  • Vesicular breath sounds with longer inspiratory phase may reflect respiratory alteration with obstructive component (COPD. asthma)
  • Pneumonia may not present with fever but with atypical symptoms
  • Frequent suctioning: due to decreased gag/cough reflex. Use lower suction pressure
• ABG's 


  to test the amount of O2 in arterial system
• label the image below

  A) pharynx

  B) larynx

  C) trachea

  D) diaphgram

  
• label the image below.

  A) bronchioles

  B) alveolo

  C) left

  D) right

  E) 3

  F) 2

  
• label the image below.

  A) alveoli

  B) capillaries

  
• label the image below.

  A) normal

  B) physiologic shunting

  C) dead space

  
• fill in the blanks of the table.

  A) pH

  B) hydrogen

  C) 7.35-7.45

  D) PaCO2

  E) 35-45

  F) PaO2

  G) oxygen

  H) 80-100

  I) HCO3

  J) Bicarb

  K) 22-26

  
• fill in the blanks of the image below.

  A) alkalosis

  B) acidosis

  C) alkalosis

  D) acidosis

  
• oxygen therapy

  • purpose: relieves hypoxemia and hypoxia
  • hypoxemia: low levels of oxygen in the blood
  • hypoxia: decreased tissue oxygenation
• oxygen therapy

  • purpose: relieves hypoxemia and hypoxia
  • hypoxemia: low levels of oxygen in the blood
  • hypoxia: decreased tissue oxygenation
  • goal: use lowest fraction of inspired oxygen for acceptable blood oxygen level without causing harmful side effects
• fill in the blanks for this O2 therapy?

  A) 24-45