If a patient is receiving an FIO2 of .70 on a day when the barometric pressure is 748 mm Hg and if the PaCO2 is 50 mm Hg

When calculating the partial pressure of oxygen (P_AO₂) in the alveoli, why do we remove the water vapor pressure and the P_ACO2.

If a patient is receiving an FIO2 of .70 on a day when the barometric pressure is 748 mm Hg and if the PaCO2 is 50 mm Hg, what is the patient’s alveolar oxygen tension (PAO2).

Solutions

Expert Solution

When the inspired air reaches the alveoli, there is an addition reduction of PO₂( partial pressure of oxygen) due to the humidification and alveolar pressure of CO₂ .That is why, we remove the partial pressure of water vapour and carbon dioxide while calculating partial pressure of oxygen in the alveoli( PACO₂) .

To find the alveolar oxygen tension of the patient( PAO₂) , the given values are:

FiO₂ ( fractional concentration of oxygen) = 0.70

P_B ( barometric pressure) =748 mm Hgthe patient's

PaCO₂( partial pressure of CO₂)=50 mm hg

We know that ,

P_H2O ( partial pressure of water vapour) =47 mmHg

R ( respiratory quotient)=0.8( even though R=0.825)

The standard equation for finding alveolar partial pressure,

PAO₂ =FiO₂(P_B -P_H2O) -(PACO₂/R)

Applying values of the patient,

PAO₂ =0.70(748-47) -(50/0.8)

=(0.70×701) -62. 5

=491-62.5

 =428.5 mmHg

Therefore, the patient's alveolar oxygen tension is 428.5mmHg

Nightingale answered 1 year ago

Next > < Previous

Related Solutions

1. Interpret the following values: Systolic pressure 140 mm Hg, diastolic pressure 90 mm Hg, serum...

1. Interpret the following values: Systolic pressure 140 mm Hg, diastolic pressure 90 mm Hg, serum LDL 180 mg/dl, serum HDL 35 mg/dl. Suggest a course of action.

Physical Chemistry 1.At 50°C the vapor pressure of ethyl alcohol is 219.9 mm Hg. If 6...

Physical Chemistry 1.At 50°C the vapor pressure of ethyl alcohol is 219.9 mm Hg. If 6 g of a nonvolatile solute of molecular weight 120 are dissolved in 150 g of water and ethyl alcohol, what will be the relative vapor pressure lowerings in the two solvents? 2.A solution composed of 10 g of a nonvolatile organic solute in 100 g of diethyl ether has a vapor pressure of 426.0 mm at 20 °C. If the vapor pressure of the...

When subjects were treated with a drug, their systolic blood pressure readings (in mm Hg) were...

When subjects were treated with a drug, their systolic blood pressure readings (in mm Hg) were measured before and after the drug was taken. Results are given in the table below. Assume that the paired sample data is a simple random sample and that the differences have a distribution that is approximately normal. Using a 0.05 significance level, is there sufficient evidence to support the claim that the drug is effective in lowering systolic blood pressure? Before After 179 147...

When subjects were treated with a drug, their systolic blood pressure readings (in mm Hg) were...

When subjects were treated with a drug, their systolic blood pressure readings (in mm Hg) were measured before and after the drug was taken. The results are given in the table below. Assume that the paired sample data is a simple random sample and that the differences have a distribution that is approximately normal. Using a 0.050 significance level, is there sufficient evidence to support the claim that the drug is effective in lowering systolic blood pressure? Before: 205 159...

The vapor pressure of ethanol (CH3CH2OH) at 20c is 44 mm Hg, and the vapor pressure...

The vapor pressure of ethanol (CH3CH2OH) at 20c is 44 mm Hg, and the vapor pressure of Methanol (CH3OH) at the same temperature is 94 mm Hg. A mixture of 30.0 g of Methanol and 45.0 g ethanol is prepared and can be assumed to behave ideally. Anwser the following questions concerning this mixture. A) Which component is more volatile? A2) Determine the mole fraction of both components of the liquid mixture? B) Calculate the vapor pressure of methanol and...

pH 7.44 PaCO2 80 mm Hg HCO3- 30 mEq/L a metabolic acidosis with partial respiratory compensation...

pH 7.44 PaCO2 80 mm Hg HCO3- 30 mEq/L a metabolic acidosis with partial respiratory compensation b metabolic alkalosis with partial respiratory compensation c respiratory alkalosis with full renal compensation d metabolic alkalosis with full respiratory compensation pH 7.25 PaCO2 40 mm Hg HCO3- 20 mEq/L a metabolic acidosis with no respiratory compensation b respiratory acidosis with no renal compensation c metabolic acidosis with partial respiratory compensation d respiratory acidosis with partial renal compensation pH 7.31 PaCO2 55 mm Hg...

1a. A sample of argon gas at a pressure of 909 mm Hg and a temperature...

1a. A sample of argon gas at a pressure of 909 mm Hg and a temperature of 23 °C, occupies a volume of 11.2 liters. If the gas is heated at constant pressure to a temperature of 58 °C, the volume of the gas sample will be_______L? 1b. A sample of methane gas at a pressure of 0.535 atm and a temperature of 231 °C, occupies a volume of 479 mL. If the gas is heated at constant pressure until...

The vapor pressure of benzene is 73.03 mm Hg at 25 °C. A nonvolatile, nonelectrolyte that...

The vapor pressure of benzene is 73.03 mm Hg at 25 °C. A nonvolatile, nonelectrolyte that dissolves in benzene is TNT. Calculate the vapor pressure of the solution at 25 °C when 14.83 grams of TNT, C7H5N3O6 (227.1 g/mol), are dissolved in 254.5 grams of benzene. benzene = C6H6 = 78.12 g/mol. VP(solution) =-________mm Hg?

The vapor pressure of ethanol is 54.68 mm Hg at 25 °C. A nonvolatile, nonelectrolyte that...

The vapor pressure of ethanol is 54.68 mm Hg at 25 °C. A nonvolatile, nonelectrolyte that dissolves in ethanol is chlorophyll. Calculate the vapor pressure of the solution at 25 °C when 7.712 grams of chlorophyll, C55H72MgN4O5 (893.5 g/mol), are dissolved in 206.3 grams of ethanol. ethanol = CH3CH2OH = 46.07 g/mol. VP(solution) = ? mm Hg

1. A mixture of hydrogen and oxygen gases, at a total pressure of 874 mm Hg,...

1. A mixture of hydrogen and oxygen gases, at a total pressure of 874 mm Hg, contains 0.316 grams of hydrogen and 8.78 grams of oxygen. What is the partial pressure of each gas in the mixture? PH2 = mm Hg PO2 = mm Hg 2. A mixture of carbon dioxide and hydrogen gases contains carbon dioxide at a partial pressure of 279 mm Hg and hydrogen at a partial pressure of 477 mm Hg. What is the mole fraction of each...

Subjects