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29 Cards in this Set
- Front
- Back
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What statements are true of oxygen transport? |
-Hemoglobin allows whole blood to carry approximately 20 mL of oxygen per 100 mL of blood at the normal arterial Pa02 of 100 MMHG. - Hemoglobins capacity to carry oxygen is approximately 67 times more than the capacity of plasma alone when Pa02 is 100 MMHG. - A normal cardiac output of 5L/min delivers approximately 1000 ml of oxygen to the body tissues each minute. |
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What term describes the unoxygenated hemoglobin? |
Deoxyhemoglobin |
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What are normal values for hemoglobin saturations and oxygen partial pressures? |
-Arterial oxygen saturation (SA02) is approximately 97.5% -P02 is 100 mmhg at SA02 of 97.5% -Mixed venous oxygen saturation (SV02) is normally 75% |
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What is the conventionally accepted value for hemoglobins oxygen carrying capacity? |
1.34 ml of oxygen per gram of hemoglobin |
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What statements relate to the HBO2 equilibrium curve? |
-Large PO2 changes cause small to minimal changes in oxygen content expecially at the extreme flat right end (60 to 100 MMHG) - Small PO2 changes cause large blood oxygen content changes in the middle steep portion of the curve (20 to 60MMHG) |
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What levels of P02 is associated with a significant oxygen content gain? |
40 to 60MMHG |
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What levels of P02 is associated with sharp decreases in oxygen saturation and content? |
Less than 60MMHG |
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What statements relate to P50? |
-Normally a PO2 of 27MMHG produces an SO2 of 50% - The P50 is a measure of hemoglobins affinity for oxygen - A normal P50 is accurate when the blood temperature is 37ﾟC, Ph is 7.40, and PC02 is 40MMHG |
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What conditions decrease hemoglobins affinity for oxygen? |
-Increased blood PC02 -Decreased blood PH -Increased blood temperature |
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What factors affect oxygen delivery to the tissues? |
-Hemoglobin concentration -Arterial hemoglobin saturation with oxygen -Cardiac output |
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A patient has the following arterial blood gas values while breathing Room air: PA02 = 100 MMHG, SA02 = 0.975, the hemoglobin concentration is 7 g/dL, and the Q is 8 L/min. Will the resting oxygen consumption be affected? |
No, because the D02 is well above the normal resting oxygen consumption |
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What is a true statement of blood transfusion to improve oxygen delivery? |
It is associated with increased mortality |
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What condition is an example of hypoxemia with cyanosis? |
Polycythemia |
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What statement are true of fetal hemoglobin? |
-Hemoglobin present in the fetus has a high affinity for oxygen -HbF of normal term infants has a P50 of approximately 22MMHG -A cyanotic newborn infant has a much lower arterial P02 than an equally cyanotic adult -By 6 months after birth most HbF has been replaced with HbA |
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What are pathological features associated with HbS? |
-Thromboeemboli -Ischemia -Tissue hypoxia |
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Where is the majority of oxygen in the blood? |
Bound to hemoglobin inside the erthrocyte |
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How many times the body tissues resting requirement is oxygen delivery? |
4 times |
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Assuming a concentration of 15 g/dL, what will be the hemoglobins oxygen carrying capacity? |
20.1 mL/dL |
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Under resting conditions what percentage of the arterial oxygen content is extracted by the tissues? |
25% or 5mL/dL |
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What is the effect of high P50? |
Hemoglobins affinity to 02 is decreased |
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What is the name of the phenomenon associated with a decreased affinity of HB for oxygen when PC02 is high? |
Bohr Effect |
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What is the effect of transfusing bank blood stored with an acid-citrate dextrose anticoagulant? |
Decreases O2 availability to tissues |
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What is the normal amount of oxygen extracted by the tissues for each 100 ML of blood? |
5mL/dL |
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What is the normal amount of oxygen delivered to the tissues? |
1000 mL/min |
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What is the normal amount of oxygen consumed by the tissues? |
250 mL/min |
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What is the interpretation of a decrease in the C(a-v)02? |
Reduction of cardiac output |
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What is the minimum desaturated hemoglobin concentration in the capillaries when most observers perceive cyanosis? |
5g/dL |
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What is the best explanation for the presence of peripheral cyanosis? |
Low venous 02 saturation |
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What is the rationale behind using an FIO2 of 1.0 to manage patients with acute CO poisoning? |
FIO2 of 1.0 decreases half life of HBCO |
