Respiratory Regulation, Pulse Oximetry, and Effects of Breath-Holding and Hyperventilation

Which gas is the main factor in minute-to-minute regulation of respiration?

PCO2 (carbon dioxide)

What does a pulse oximeter measure?

Blood oxygen saturation (SpO2), pulse rate, and perfusion

How does a pulse oximeter work?

It shines light through the finger and measures how much light is absorbed to estimate oxygen levels

What is the normal range of SpO2?

95%-100%

What is hypoxemia?

Low oxygen levels in the blood (typically below 90%)

What conditions can cause hypoxemia?

Lung disease, heart problems, high altitude, airway obstruction

What happens to breathing after holding your breath?

Breathing becomes deeper and faster

What happens to arterial O2 during breath holding?

Remains relatively stable

What happens to arterial CO2 during breath holding?

Increases

What happens to blood pH during breath holding?

Decreases (becomes more acidic)

How does exercise affect breath-holding time?

It decreases

What happens to CO2 production during exercise?

Increases

What happens to O2 use during exercise?

Increases

What happens to hydrogen ion concentration during exercise?

Increases

How does hyperventilation affect O2 levels?

Stays about the same

How does hyperventilation affect CO2 levels?

Decreases

How does hyperventilation affect blood pH?

Increases (becomes more basic)

Why is there little urge to breathe after hyperventilation?

CO2 levels are low, delaying the trigger to breathe

How does breathing into a bag affect CO2 levels?

Increases

How does breathing into a bag affect pH?

Decreases (more acidic)

Why are breath-holding times different under different conditions?

Because CO2 and O2 levels vary based on activity

Which regulates breathing more, O2 or CO2?

CO2

Does oxygen saturation change significantly during breath holding?

No

Does oxygen saturation change significantly during hyperventilation?

No

What happens to breathing rate after breath holding?

Increases

What happens to breath depth after breath holding?

Increases

What is the purpose of increased breathing after breath holding?

Restore CO2, O2, and pH to normal

What happens to breathing after hyperventilation?

Rate and depth adjust to restore CO2 levels

What is the Valsalva maneuver?

Forceful exhalation against a closed airway

How does the Valsalva maneuver affect venous return?

Decreases

How does the Valsalva maneuver affect stroke volume?

Decreases

What happens to pulse strength during the Valsalva maneuver?

Decreases

What happens to pulse strength after the Valsalva maneuver?

Increases, then returns to normal

If blood becomes acidic, how does respiration change?

Respiration rate increases

During breath holding, what happens to CO2?

Increases

During breath holding, what happens to pH?

Becomes more acidic

During breath holding, what happens to O2?

Remains relatively stable

During breath holding, what happens to the urge to breathe?

Increases

Reading aloud demonstrates what type of control of breathing?

Voluntary control

After breath holding, how does respiratory rate compare to normal?

Greater than normal

After breath holding, how does breath magnitude compare to normal?

Greater than normal