Hyper and hypo ventilation with PaCO2 levels

  1. 0
    i'm confused..... in my book it states
    hyperventilation occurs when the paco2 is less than 35 mmhg and hypoventilation occurs when the paco2 is greater than 45 mmhg. that doesn't make sense to me.

    is this a mistake or am i missing something?
  2. 47 Comments so far...

  3. 1
    It's backwards.
    tokmom likes this.
  4. 2
    Quote from osteward
    i'm confused..... in my book it states
    hyperventilation occurs when the paco2 is less than 35 mmhg and hypoventilation occurs when the paco2 is greater than 45 mmhg. that doesn't make sense to me.

    is this a mistake or am i missing something?
    wait... when you hyperventilate, you are blow off your co2 so the levels are going to be low.
    when you hypoventilate, you are retain the co2, so the levels would be higher. this is also when you would have respiratory acidosis... right?
    or am i confused now?
    lol
    crazytonurse and Esme12 like this.
  5. 3
    That's what I figured.... If you have increased CO2 then you would be acidosis so you would want to "blow off" more CO2 (hyperventilation) and if you have decreased CO2 then you are alkalosis and would want to retain more CO2 (hypoventilation)
    tokmom, Esme12, and Hygiene Queen like this.
  6. 0
    Ok, I think it's just a mistake in the book (Potter and Perry fundamentals) because in my med surg book (iggy as I call it) says the exact opposite.
  7. 3
    Quote from Osteward
    Ok, I think it's just a mistake in the book (Potter and Perry fundamentals) because in my med surg book (iggy as I call it) says the exact opposite.
    Yes, because low CO2 doesn't cause hyperventilation, but low CO2 is a result of hyperventilation.
    Alikatz, GrnTea, and LaughingRN like this.
  8. 0
    Hyperventilation is breathing in excess of what the body means blowing off too much CO2 thereby LOWERING the CO2 level beneath 35 mmhg. Hyperventilation is breathing that is deeper and more rapid than normal. It causes a decrease in the amount of a gas in the blood (called carbon dioxide, or CO2). This decrease will cause a patient to be lightheaded, have a rapid heartbeat, and be short of breath. It also can lead to numbness or tingling in your hands or feet, anxiety, fainting, muscles spasms and cramping, and sore chest muscles.Hyperventilation causes the carbon dioxide level in the blood to decrease. This lower level of carbon dioxide reduces blood flow to the brain, which may result in the following nervous system and emotional symptoms.
    • Weakness
    • Fainting
    • Dizziness
    • Confusion
    • Agitation
    • A feeling of being outside yourself
    • Seeing images that aren't there
    • Feeling as if you can't breathe
    Overbreathing can also cause the calcium levels to drop in your blood, which may result in the following nervous system symptoms:
    • Numbness and tingling (usually in both arms or around the mouth)
    • Spasms or cramps of the hands and feet
    (Carpal Pedal syndrome....Hand or foot spasms: MedlinePlus Medical Encyclopedia)
    • Muscle twitching
    Many different factors can cause chest symptoms with hyperventilation syndrome. Normally, breathing is relaxed. If a person over breathes, the lungs become overinflated. Without thinking about it, the person might use the chest muscles to expand the rib cage. This extra muscle work will feel like shortness of breath, and the person will have difficulty taking a deep breath. The chest muscles will become tired, just like the legs tire after a long run. The lowered carbon dioxide levels in the blood can cause squeezing of the airways, which then results in wheezing.
    Hyperventilation Causes, Symptoms, Treatment - Hyperventilation Symptoms on eMedicineHealth

    When you are breathing too fast or taking frequent deep breaths you blow off too much C02 there fore DECREASING CO2 levels dropping them below 35 mmhg.
    Medscape: Medscape Access Hyperventilation Syndrome requires registration but it's free and a great resource.

    HYPOVENTILATION

    The respiratory system serves a dual purpose: delivering oxygen to the pulmonary capillary bed from the environment and eliminating carbon dioxide from the blood stream by removing it from the pulmonary capillary bed. Metabolic production of carbon dioxide occurs rapidly. Thus, a failure of ventilation promptly increases the levels of carbon dioxide measured by arterial blood gas analysis (PaCO2) greater than 45mmHg. Medscape: Medscape Access
    Hypoventilation Syndromes
    Alveolar hypoventilation is defined as insufficient ventilation leading to an increase in PaCO2 (ie, hypercapnia).

    hypoventilation (also known as respiratory depression) occurs when ventilation is inadequate(hypo means "below") to perform needed gas exchange. By definition it causes an increased concentration of carbon dioxide (hypercapnia) and respiratory acidosis.

    Medscape: Medscape Access Hypoventilation Syndromes Treatment & Management

    Breathing too slow or with peroid of apnea (as in sleep apnea) caused the CO2 levels to rise and cause a desreased LOC leading to a condition called CO2 narcosis.Hypoventilation Treatment | Hypoventilation Syndrome

    All medscape requires registraiton but it is free and holds a TON of information.
    I hope this helps and your book was right.......
    Last edit by Esme12 on Mar 19, '12 : Reason: sp
  9. 1
    Quote from ScottE
    It's backwards.
    Hey Scott...read the question again.
    Last edit by Esme12 on Mar 19, '12
    Hygiene Queen likes this.
  10. 0
    Okay soooo.....

    Low PaCO2 levels stimulate you to hypoventilate which compensates and ends up increasing CO2 levels

    High PaCO2 levels stimulate you to hyperventilate which compensates and ends up decreasing CO2 levels

    ??? right?
  11. 1
    low pco2 levels are a by product due to another source whether it is metabolic acidosis, as in the setting of diabetic ketoacidosis, to help off set the acidosis by hyperventilating to produce bicarbonate (very simply put) to compensate for the acidosis or in the setting someone is hyperventilating from anxiety groping the pco2 levels and ph causing a alkaloid state causing vasodilation dropping of ca+ levels causing numbness of the hands and face and muscle spasms. low pco2 levels don't have a hypoventilation stimuli to drop them as does elevated pco2 level stimulate you to breathe. the treatment of the underlying causative factor prevails here. low pco2 levels don't necessarily "cause" you to hypoventilate.

    high pco2 levels stimulate you to breathe except in the presence of copd and co2 retainers. elevated pco2 will stimulate and increased respiratory drive to "blow off" the excess pco2 to normal levels not necessarily "hyperventilate"

    you really should register for the medscape on the links i provided. it is free and is an excellent reference and informational site........what i have linked for you will, i think, clarify this confusion for you.

    this may help as well...... http://allnurses.com/general-nursing...ol-662475.html

    ch 40 oxygenation.pdf‎
    Hygiene Queen likes this.


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