One intern calculated the concentration of 02 in blood as 0.0025 ml/m1 of blood. Considering atmospheric pressure as 760mmHg, how much approx. 02 tension could have been in the blood ?
**Core Concept**
The partial pressure of oxygen in arterial blood is a critical parameter that reflects the balance between oxygen delivery and consumption. It is calculated using the alveolar gas equation, which takes into account atmospheric pressure, barometric pressure, and the fraction of inspired oxygen.
**Why the Correct Answer is Right**
To calculate the oxygen tension (pO2) in blood, we can use the following formula:
pO2 = 0.21 (atmospheric pressure - barometric pressure) / R
where R is the respiratory quotient, approximately 0.8. Given the atmospheric pressure as 760 mmHg, we can assume a barometric pressure of 760 mmHg at sea level. The partial pressure of oxygen in the atmosphere is approximately 0.21 (21% of 760 mmHg). Using the formula, we can calculate the oxygen tension in blood.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is not directly related to the calculation of oxygen tension in blood.
**Option B:** This option may seem plausible, but it is not the correct calculation for oxygen tension in blood.
**Option C:** This option is incorrect because it does not take into account the fraction of inspired oxygen and the respiratory quotient.
**Clinical Pearl / High-Yield Fact**
The partial pressure of oxygen in arterial blood is a critical parameter that reflects the balance between oxygen delivery and consumption. A pO2 below 60 mmHg can indicate hypoxemia, which may require supplemental oxygen therapy.
**Correct Answer:** C. 160 mmHg