Final answer:
Decreased Hbg/Hct leads to a reduced oxygen-carrying capacity, requiring increased cardiac output to maintain oxygen delivery due to conditions like ß-thalassemia and sickle cell anemia.
Step-by-step explanation:
Decreased hemoglobin (Hbg) and hematocrit (Hct) results in decreased oxygen-carrying capacity of the blood, which in turn means that more oxygen is required to achieve the same level of hemoglobin saturation. This phenomenon is often seen in conditions like ß-thalassemia and sickle cell anemia, where the efficiency of oxygen transport is impaired due to abnormal hemoglobin structure or production, resulting in hypoxia. The body compensates for this reduced oxygen-carrying capacity through various physiological changes. For instance, when carbon dioxide (ßCO2) levels rise in the blood, the pH drops, leading to a decrease in the affinity of hemoglobin for oxygen and a rightward shift in the oxygen dissociation curve. This ultimately necessitates an increased cardiac output (ßCO) to deliver the same amount of oxygen to the tissues.