respiratory practical questions Flashcards
what happens to co2 levels after hyperventilation
co2 decreases when one hyperventilates.
hyperventilation is when one takes deep breaths to fill the lungs, which dilute co2 in the blood and this decreases end tidal co2 measured at end expiration
would you expect to see a change in oxygen saturation during hyperventilation
no as in a young and healthy individual oxygen saturation is 98-100% so hyperventilation will make no difference
after a period of light headedness a subject may report feeling dizzy. why is this
during hyperventilation one is taking deep breaths to fill the lungs which reduces co2 levels in the blood
co2 is a vasodilator so if the levels are decreased this will result in vasoconstriction which in turn will reduce blood flow to the brain which leads to dizziness
what effect does hyperventilation have on the ability to hold your breath
hyperventilation reduces co2 levels in the blood. breath hold is starting at a lower co2 level which means it will take longer for the person to reach the threshold level that triggers the breath hold to end
the level of co2 at the end of the breath hold is variable across individuals.
predict the changes in end tidal carbon dioxide and oxygen saturation at the end of the breath hold following hyperventilation
if a person performs a breath hold for as long as they can after hyperventilating the end tidal pco2 will be the same as the breath hold performed when they did not hyperventilate
what do vitalographs measure
vital capacity
forced vital capacity
forced expiratory volume in one second
how would forced vital capacity in an elderly patient differ from in a young and healthy patient
lung volume measured is reduced compared to younger adults because the lung loses elasticity over time which means it is harder to force the volume of air out of the lung
how does end tidal co2 change if the subject held their breath for as long as possible
the end tidal pco2 value would increase
predict how oxygen saturation would change after a 90 second breath hold and explain your answer by referring to oxyhaemoglobin dissociation curve
after a 90 second breath hold, the oxygen saturation would be decreased. in a young and healthy individual, his decrease would be minimal.
the oxyhameoglobin curve illustrates that a drop in po2 to less than 60mmhg can occur before there is a decrease in oxygen saturation
what is the respiratory exchange ratio
the ratio between carbon dioxide output from the body and oxygen uptake by the body
peak expiratory flow rate
the highest rate of airflow attained during a forced vital capacity expiration
respiratory quotient
the ratio of the amount of carbon dioxide produced by metabolism to the amount of oxygen consumed
mixed expired gas
the gas mixture obtained when all expired gas collected. mixture of anatomical dead space and alveolar gas
blood gas abnormalities values
arterial hypoxemia - arterial po2 is less than 80mmhg
hypoxia - arterial po2 is less than 60mmHg
hypercapnia - arterial pco2 is greater than 40
hypocapnia - arterial pco2 is less than 35mmHg
atelectasis
obstruction of ventilation due to mucous plugs, airway oedema, foreign bodies and tumours in the airways
