oxygen – Flashcards

• there is a decrease in ventilation V as well as a decrease in perfusion Q

patient has pulmonary emboli and emphysema)

• V always exceeds Q

some ventilation will always be wasted and

• ventilation encounters little or no perfusion (perfusion decreases)

Q is in excess of V

• blood is bypassed or "shunted" without picking up oxygen

• doesn't receive any ventilation

there is more blood flow then there is ventilation - or - • ventilation decreases (seen in obstructive and restrictive lung diseases)

• is not uniformly negative around the lungs

• alveoli in the apices are more distended as well as having a more negative intrapleural pressure

because the alveoli in the apices have a greater negative intrapleural pressure (more distention), the more open these alveoli become

• alveoli in the bases are less distended as well as having a less negative intrapleural pressure

because the alveoli in the bases have a less negative intrapleural pressure (less distention), the less open theses alveoli become

Shunting Obstructive lung diseases (ie. asthma bronchitis emphysema) Restrictive lung disorders (ie. pneumonia pulmonary fibrosis various occupational exposures) Hypoventilation for any reason

Pulmonary emboli Partial or complete obstruction of the pulmonary artery Extrinsic pressure on pulmonary vessels (ie. Pneumothorax hydrothorax or tumor) Destroyed pulmonary vessels (ie. Emphysema or decreased cardiac output

oxygen carbon dioxide and pH levels of the pulmonary capillary unit • the blood leaving the capillary unit will have a lower than normal level of oxygen • the blood leaving the capillary unit will have a higher than normal level of CO2

• hyperventilation - increase in ventilation causes respiratory alkalosis "blowing off CO2" • pulmonary emboli partial or complete obstruction of the pulmonary artery extrinsic pressure on pulmonary vessels (ie. Pneumothorax hydrothorax or tumor) destroyed pulmonary vessels (ie. Emphysema decreased cardiac output)

•(PAO2 and PaO2 increases) oxygen leaving the capillary unit will be high •(PACO2 and PaCO2 decreases) CO2 leaving the capillary unit will be low • (pH increase) leaning to a more alkalytic acid base balance

Ratio of CO2 transferred (added to alveoli from blood) Oxygen Absorbed (into blood from alveoli) For every 4 ml CO2 (added to alveoli from pc blood) 5 ml of oxygen (diffuses into pulmonary capillary blood) This is called the "Respiratory Exchange Ratio" (RER or RE) = 0.8 the meaning of the symbols VO2 and VCO2

oxygen consumed during respiration (oxygen the fuel used in cellular metabolism that converts glucose into ATP)

is the ratio of CO2 produced (CO2 waste product that is produced after cellular metabolism)

Ratio of CO2 Produced (VCO2) / Oxygen Consumed (VO2) 200 ml of carbon dioxide produced (metabolism) / 250 ml of oxygen consumed (by tissues) This is called the "Respiratory Quotient" or (RQ) = 0.8