What is the alveolar air equation?
The alveolar gas equation is a formula used to approximate the partial pressure of oxygen in the alveolus (PAO2):PAO2=(PB−PH2O)FiO2−(PaCO2÷R)where PB is the barometric pressure, PH2O is the water vapor pressure (usually 47mmHg), FiO2 is the fractional concentration of inspired oxygen, and R is the gas exchange ratio.
What is the meaning of alveolar air?
Alveolar gas is a mixture of inspired air, fully saturated with water vapor, and carbon dioxide that diffuses from the blood. At the end of each expiration about 2000–2500 ml of air remain in the lung.
What is K in alveolar ventilation?
V’A = Alveolar Ventilation Rate. V’CO2 = Rate of carbon dioxide exhalation. PaCO2 = Partial pressure of arterial carbon dioxide. K = Unit correction factor.
How is the alveolar gas equation derived?
By the total pressure for example the partial pressure of carbon dioxide in alveolar gas is equal to the fractional concentration of co2 in the alveoli.
How do you remember the alveolar gas equation?
Alveolar gas equation – YouTube
What does R stand for alveolar gas equation?
respiratory quotient
The alveolar gas equation (AGE) is well known. and relates the alveolar concentration of oxy- gen FAO2 (or equivalently partial pressure. PAO2) to three variables: FIO2, FACO2 and the. respiratory quotient (R).
What is the difference between alveolar air and inspired air?
b) Alveolar air has a lower PCO2 than inspired air. d) Alveolar air has a higher PH2O than inhaled air. Hemoglobin releases the same amount of oxygen to all the tissues regardless of variations in their metabolic rate.
Is alveolar air and expired air same?
As expiration progresses the expired air becomes a mixture of ‘dead space’ air and alveolar air and that the last part of the expired air is pure alveolar air. The expired air, therefore, is richer in O2 but poorer in CO2 as compared to alveolar air.
How is PO2 calculated in alveoli?
The alveolar gas equation is used to calculate alveolar oxygen partial pressure: PAO2 = (Patm – PH2O) FiO2 – PACO2 / RQ.
Is PO2 and PAO2 the same?
PO2 , SaO2 , CaO2 are all related but different.
If the lungs are normal, then PaO2 is affected only by the alveolar PO2 (PAO2), which is determined by the fraction of inspired oxygen, the barometric pressure and the PaCO2 (i.e., the alveolar gas equation).
Why is the alveolar gas equation important?
The alveolar gas equation helps us in calculating the alveolar and arterial PO2 gradient (A-a) difference. If more than required FiO2 is given, it can lead to an increase in PO2 within the alveoli, and, if given for long periods of time, this can lead to lung injury.
How do you calculate alveolar o2?
The alveolar gas equation is of great help in calculating and closely estimating the partial pressure of oxygen inside the alveoli. The alveolar gas equation is used to calculate alveolar oxygen partial pressure: PAO2 = (Patm – PH2O) FiO2 – PACO2 / RQ.
What do you mean by inspired air?
air enters the lungs (inspiration), provided the larynx is open; when the air pressure within the alveoli exceeds atmospheric pressure, air is blown from the lungs (expiration). The flow of air is rapid or slow in proportion to the magnitude of the pressure difference.
Why is the a difference between inspired and expired air?
The expired air differs from inspired air qualitywise in the following aspects: It contains less oxygen. It contains more water vapour. It contains more carbon dioxide.
Why expired air has less CO2 than alveolar air?
Since carbon dioxide is expired, the partial pressure of carbon dioxide within the lungs should be greater than that of the expired air. Therefore during expiration, the carbon dioxide concentration in the alveolar air is greater than that in the expired air.
What does pO2 stand for?
partial pressure of oxygen
pO2 (partial pressure of oxygen)
What does PCO2 stand for?
partial pressure of carbon dioxide
The partial pressure of carbon dioxide (PCO2) is the measure of carbon dioxide within arterial or venous blood. It often serves as a marker of sufficient alveolar ventilation within the lungs. Generally, under normal physiologic conditions, the value of PCO2 ranges between 35 to 45 mmHg, or 4.7 to 6.0 kPa.
What is the PCO2 in alveolar air?
The partial pressure of carbon dioxide (PCO2) is the measure of carbon dioxide within arterial or venous blood. It often serves as a marker of sufficient alveolar ventilation within the lungs. Generally, under normal physiologic conditions, the value of PCO2 ranges between 35 to 45 mmHg, or 4.7 to 6.0 kPa.
What is difference between alveolar air and inspired air?
a) Alveolar air has a higher PN2 than inspired air. b) Alveolar air has a lower PCO2 than inspired air. d) Alveolar air has a higher PH2O than inhaled air. Hemoglobin releases the same amount of oxygen to all the tissues regardless of variations in their metabolic rate.
What is difference between inspired and expired air?
Hint: The air that moves out of the chest during the process of expiration is called expired air while inspired air is the air that enters the lungs during the process of inspiration, provided the larynx is open.
What are the 3 types of respiration?
Respiration is the process of gas exchange between the air and an organism’s cells. Three types of respiration include internal, external, and cellular respiration.
What is the definition of inspiration and expiration?
Inspiration and expiration are two processes involved in respiration. Inspiration is the process of taking in of the air and expiration is the breathing out of the air. During inspiration, there is an increase in the volume of the thoracic area.
Why is there less oxygen in alveolar air?
Recall that the respiratory system works to humidify incoming air, thereby causing the air present in the alveoli to have a greater amount of water vapor than atmospheric air. In addition, alveolar air contains a greater amount of carbon dioxide and less oxygen than atmospheric air.
What is the name for PO2?
PO 2: Phosphorus dioxide, a gaseous free radical that plays a role in the chemiluminescence of phosphorus and phosphine.
Is PO2 and PaO2 the same?