13) Respiration Flashcards
What is respiration?
- Mechanism the body uses to exchange gases between atmosphere and blood
- Involves ventilation, diffusion, and perfusion
What is ventilation?
- Movement of gases in and out of the lungs
What is diffusion in respiration?
- Movement of oxygen and carbon dioxide between alveoli and red blood cells
What is perfusion in respiration?
- Distribution of red blood cells to and from pulmonary capillaries
How is ventilation assessed?
- By determining respiratory rate, depth, and rhythm
How are diffusion and perfusion assessed?
- By determining oxygen saturation
How is breathing normally regulated?
- Respiratory center in brainstem regulates involuntary control
- Adults breathe smoothly 12-20 times per minute
What regulates ventilation?
- Levels of CO2, O2, and hydrogen ion concentration in arterial blood
- CO2 level is most important factor
How does elevated CO2 affect breathing?
- Causes respiratory control system to increase rate and depth
- Removes excess CO2 (hypercarbia) by increasing exhalation
How is ventilation controlled in chronic lung disease patients?
- Chemoreceptors become sensitive to low arterial O2 (hypoxemia)
- Signal brain to increase ventilation rate and depth
Why can high oxygen levels be dangerous for chronic lung disease patients?
- Low arterial O2 provides stimulus to breathe
- High oxygen removes this stimulus
What is involved in moving the lungs and chest wall during breathing?
- Muscular work
- Inspiration is an active process
What happens during inspiration?
- Respiratory center sends impulses through phrenic nerve
- Diaphragm contracts, abdominal organs move down/forward
- Increases length of chest cavity to move air into lungs
How much does the diaphragm and ribs move during inspiration?
- Diaphragm moves about 1 cm
- Ribs retract upward 1.2-2.5 cm from midline
What is the tidal volume?
- Amount of air inhaled during a normal, relaxed breath
- 500 mL
What happens during expiration?
- Diaphragm relaxes
- Abdominal organs return to original positions
- Lung and chest wall return to relaxed position
- A passive process
What is eupnea and what interrupts it?
- Eupnea is normal rate and depth of ventilation
- Interrupted by sighing (prolonged deeper breath)
- Sigh expands small airways/alveoli not ventilated normally
How is normal respiration assessed?
- By recognizing normal thoracic and abdominal movements
- Chest wall gently rises and falls
- No visible accessory muscle use
- Abdomen rises and falls slowly with diaphragm
What is required for accurate respiratory assessment?
- Observation and palpation of chest wall movement
- No special equipment needed, but measurement must not be haphazard
Why is noting sudden changes in respiration character important?
- Respiration is tied to function of numerous body systems
- All variables need consideration when changes occur
- Example: Abdominal trauma may injure phrenic nerve affecting diaphragm
How should respiratory rate be assessed during nursing assessment?
- Try not to let patient know you are assessing their respiration
- Patient may consciously alter rate and depth if aware
- Best time is immediately after pulse, with hand on wrist over chest/abdomen
What should be considered when assessing respiration?
- Patient’s usual ventilatory rate and pattern
- Influence of any disease/illness on respiratory function
- Relationship between respiratory and cardiovascular function
- Influence of therapies on respiration
What are the objective respiratory measurements?
- Rate of breathing
- Depth of breathing
- Rhythm of ventilatory movements
What should the nurse observe when counting respiratory rate?
- Both inspiration and expiration