Quick notes - Changes in Partial Pressure of Oxygen Causes of changes in Partial Pressure of Oxygen Reduced pO2:– Later stages of pregnancy– Altitude– Type 1 respiratory failure (emphysema, PE)– Type 2 respiratory failure (muscle disease, chronic bronchitis– Methaemoglobinaemia Reduced pCO2 occurs in– Normal pregnancy– Hyperventilation– Emphysema– PE– Mild-moderate asthma Increased pCO2:– raised cerebral blood flow– raised acidosis– therefore more acidic urine