Term
| What is the term that describes the movement of gas between the lungs and the body tissues? |
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Definition
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Term
| Diffusion gradient - Area where highest PO2 is found |
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Definition
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Term
| Diffusion gradient - Area where lowest PO2 is found |
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Definition
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Term
| Diffusion gradient - Area where highest CO2 is found |
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Definition
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Term
| Diffusion gradient - Area where lowest CO2 is found |
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Definition
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Term
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Definition
| partial pressure of oxygen |
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Term
| What is the alveolar air equation |
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Definition
| PAO2=FIO2x(PB-47) - (PACO2 / 0.8) |
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Term
| Explain the pulmonary diffusion gradients |
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Definition
| For gas exchange to occur between the alveoli and pulmonary capillaries, a difference in partial pressures (P1-P2) must exist |
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Term
| What is the normal value for PO2 of venous blood returning to the lungs from the right side of the heart |
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Definition
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Term
| What is the normal value for PCO2 of venous blood returning to the lungs from the right side of the heart |
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Definition
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Term
| How much faster does Carbon dioxide diffuse across the alveolar-capillary membrane than does oxygen and why |
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Definition
| 20 times faster, because of its much higher solubility in plasma |
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Term
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Definition
| A quantification of the measurement of variations in the affinity of Hb for oxygen |
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Term
| What is the P50 a partial pressure of |
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Definition
| Oxygen at which the Hb is 50% saturated, standardized to a pH level of 7.4. |
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Term
| What is a normal P50 value |
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Definition
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Term
| WHat conditions cause the HbO2 curve to the right |
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Definition
| conditions that cause a decrease in Hb affinity for oxygen |
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Term
| What conditions cause the HbO2 curve to the left |
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Definition
| conditions that cause an increase in Hb affinity for oxygen |
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Term
| Define the Haldane Effect |
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Definition
| The more oxygen that is bound to a hemoglobin molecule, the less carbon dioxide will bind to that molecule. |
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Term
| What is the important thing to remember about the Haldane Effect |
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Definition
| It causes the blood to pick up carbon dioxide better in areas of low oxygen and vice versa |
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Term
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Definition
| The fact that pH alters the bonding of oxygen to hemoglobin |
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Term
| Describe the Bohr Effect and its influence on the HbO2 Dissociation Curve |
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Definition
| Changes in pH causes a shift in the curve. As the H ion concentration increases, which makes the pH more acidic, which alters the bonding of oxygen to hemoglobin, and therefore shifts the curve to the right |
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Term
| With regard to the Bohr Effect, which shifts the curve to the right, how is it physiologically significant that an alkaline pH will cause a left shift of the curve? |
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Definition
| as blood pH at the tissue is more acidic than at the lungs, so oxygen is more readily unloaded to the tissues. blood pH changes are the strongest of factors that will shift HbO2 curve |
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Term
| What cause a right shift in Dissociation Curve |
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Definition
| Decreased affinity, more tissue oxygenation, increased H+ (lower pH), Increased PCO2, Increased temperature, Increased 2.,3 DPG - If you live RIGHT you'll go UP to heaven |
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Term
| What cause a left shift in Dissociation Curve |
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Definition
| Increased affinity, less tissue oxygenation, Decreased H+ (higher pH), Decreased PCO2, Decreased temperature, Decreased 2,3 DPG |
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Term
| What factors contribute to an increased in hemoglobin's (Hb) affinity for O2 |
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Definition
| acute alkalosis, decreased PCo2, Decreased temperature, low levels of 2,3 DPG, carboxyhemoglobin, methemoglobin, abnormal hemoglobin |
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Term
| What factors contribute to a decrease in hemoglobin's (Hb) affinity for O2 |
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Definition
| Acute acidosis, High CO2, Increased temperature, high levels of 2,3 DPG, abnormal hemoglobin |
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Term
| What is the normal value of the arterial oxygen content of combined O2 (1.34x 15 x SO2) |
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Definition
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Term
| What is the normal value of the venous oxygen content of combined O2 (1.34 x 15 x so2) |
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Definition
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Term
| What is the normal value of the arterial oxygen content of dissolved O2 (PO2 x 0.003) |
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Definition
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Term
| What is the normal value of the venous oxygen content of dissloved O2 |
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Definition
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Term
| WHat is the normal value of the total arterial oxygen content |
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Definition
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Term
| What is the normal value of the total venous oxygen content |
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Definition
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Term
| What is the formula for the total oxygen content of blood |
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Definition
| CaO2 = (0.003x PO2) + (Hbtot x 1.34 x So2) |
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Term
| Calculate the total oxygen content if Po2 is 100 mm Hg, containing 15g/dl and Hb that is 97% saturated with O2 |
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Definition
| CaO2 = (0.003 x 100 mmHg) + (15 g/dl x 1.34 x 0.97) = CaO2 19.8 ml/dl |
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Term
| Cite the primary indicator of hypoventilation |
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Definition
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Term
| What is the amount of oxygen dissolved in the plasma represented by |
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Definition
| the arterial oxygen tension PaO2 - to convert from oxygen tension (partial pressure) to oxygen content in ml/dl, multiply by 0.003 since .003 ml of oxygen will dissolve in one ml of plasma at a temperature of 37 celcius and one torr of ambient pressure. paO2 x 0.003 = CaO2! |
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Term
| Blood carries oxygen in what two forms |
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Definition
| small amount exists in simple physical solution, dissolved in plasma and erythrocyte intracellular fluid; majority is carried in a reversible chemical combination with Hb (hemoglobin) inside the RBC |
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Term
| Hemoglobin saturation formula |
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Definition
| SaO2 = [HbO2/total Hb] x 100 |
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Term
| Calculate the hemoglobin saturation where HbO2 of 15 g/dl Hb of which 7.5g was HbO2 |
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Definition
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Term
| Identify the hemoglobin saturation of the arterial blood that correlates with a PO2 of 65 mmHg |
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Definition
| The HbO2 dissociation curve is shaped in a way such that the flat upper part of teh curve representing the normal operating range for arterial blood, minor changes in PaO2 of this flat portion, have little effect. Therefore 65mmHg PO2 is still 90% |
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Term
| What is Fick Formula for calculating Cardiac Output (both Qt and C.O.) |
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Definition
| Qt = VO2 / [C (a-v) O2 x 10] |
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Term
| Calculate the following using Fick Formula for cardiac output; factor of 10 converts ml/dl to ml/L. Given a normal VO2 of 250 ml/min and a normal C (a-v)O2 of 5 ml/dl |
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Definition
| Qt = 200 ml/min/ (5 ml/dl x 10) ; Qt = 250 ml/min / 5 ml/dl; AT = 5.0 L/min |
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Term
| compare CO affinity to Hb compared to O2 |
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Definition
| CO is more than 200 times greater than it is for oxygen. Even extremely low concentrations of CO represent a loss in carrying capacity. CO with Hb shifts the HbO2 curve to the left furhter impeding oxygen delivery. |
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Term
| What is looked at as the primary measure of ventilation |
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Definition
| PaCO2 = partial pressure of arterial carbon dioxide |
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Term
| How is CO2 transported in the blood and what are the percentages of each |
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Definition
| 1) dissolved in plasma and erythrocyte intracellular fluid - 8%; 2)chemically combined with protein - 12%; 3) Ionized as bicarbonate -80% |
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Term
| How is carbonic acid classified |
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Definition
| it is the only volatile acid of physiologic significance in the body. A volatile acid is one that is in equilibrium with a dissolved gas |
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Term
| What is the primary blood gas component maintained by acid-base balance |
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Definition
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Term
| WHat are normal blood gas ranges |
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Definition
| pH 7.35-7.45; PaCO2 35 - 45 torr; HCO3- 22-25 mEq/L; PaO2 80-100 torr |
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Term
| What are the organs responsible for acid excretion in the body |
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Definition
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Term
| what is the amount of time it takes for the lungs to remove acid from the body vs the time it takes the kidneys to excrete acid |
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Definition
| compared with the ability of the lungs to change blood pco2 in seconds, the renal process is slow requiring hours to days |
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Term
| what is the respiratory and what is the metabolic acid-base components |
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Definition
| CO2 is respiratory and HCO3- is metabolic |
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Term
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Definition
| resists changes in pH when an acid or a base is added to it. Buffer solutions are mixtures of acids and bases. The acid component is the H+ cation, formed when a weak acid dissociates in solution. The base component is the remaining anion portion of the acid molecule , known as the conjugate base. |
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Term
| what is the henderson-hasselbach equation |
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Definition
| pH=6.1 = log [hco3/pco2x.03 |
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Term
| with regard to the henderson-hasselbach equation, what is the normal HCO3 to CO2 ratio |
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Definition
| pH of 7.4 = 20:1 ratio of bicarb to CO2 |
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Term
| identify primary events that cause respiratory acidosis and respiratory alkalosis |
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Definition
| hypoventilation causes respiratory acidosis, hyperventilation causes respiratory alkalosis |
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Term
| describe the process of compensation |
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Definition
| in hypoventilation (respiratory acidosis) the kidneys restore the pH to normal by reabsorbing HCO3, compensatory renal response to hyperventilation (respiratory alkalosis) is urinary eliminatin of HCO3. if a metabolic process lowers or raises HCO3 the lungs compensate by hyperventilation (eliminating CO2) or hypoventilation (retaining CO2) restoring the pH to near normal |
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Term
| WHat are the two ways metabolic acidosis occurs |
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Definition
| fixed (nonvolatile) acid accumulation in the blood or an excessive loss of HCO3 from the body |
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Term
| what regulates the volatile acid content of the blood (CO2) whereas what controls the fixed acid concentration of the blood |
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Definition
| the lungs regulate the volatile acid content of the blood (CO2) whereas the kidneys control the fixed acid concentration of the blood |
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Term
| The larger an acid's equilibrium constant, what happens with regard to H+ |
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Definition
| the more the acid molecule dissociates and yields H+ |
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Term
| What happens in the open bicarbonate buffer system |
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Definition
| H+ is buffered to form the volatile acid H2CO3 which is exhaled into the atmosphere as CO2 |
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Term
| What happens in the closed nonbicarbonate buffer system |
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Definition
| H+ is buffered to form fixed acids which accumulate in the body |
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Term
| What is the difference between bicarbonate buffers and nonbicarbonate buffers |
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Definition
| bicarbonate buffers can buffer only fixed acids, but nonbicarbonate buffers can buffer both fixed and volatile acids |
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Term
| How do the kidneys respond to hypoventilation and how to they respond to hyperventilation |
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Definition
| hypoventilation by reabsorbing bicarbonate, hyperventilation by excreting bicarbonate |
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Term
| how do the lungs respond to metabolic acidosis, alkalosis |
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Definition
| acidosis by hyperventilating, alkalosis hypoventilating |
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Term
| PaCO2 abnormalities characterize which type of acid-base disturbance vs. HCO3 abnormalities |
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Definition
| PaCO2 is respiratory; bicarb is metabolic |
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Term
| WHat does hypochloremia do to the acid-base balance |
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Definition
| forces the kidneys to excrete increased amounts of H+ and K+ to reabsorb Na+, causing alkalosis and hypokalemia |
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Term
| What does hypokalemia do to the acid-base balance |
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Definition
| forces the kidneys to excrete increased amounts of H+ to reabsorb Na+ causing alkalosis |
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Term
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Definition
| When oxygen delivery falls short of cellular needs |
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Term
| Describe the V/Q ratio and cite its normal value |
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Definition
| ventilation perfusion ratio; an ideal ratio of 1.0 indicates that ventilation and perfusion are in perfect balance. High V/Q indicates that ventilation is greater than normal, perfusion is less than normal or both. A low V/Q ratio means ventilation is less than normal perfusion is greater than normal, or both |
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Term
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Definition
| blood flow but no ventilation; venous blood bypasses ventilated alveoli and mixes with freshly oxygenated arterial blood, resulting in what is called a venous admixture |
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Term
| What is the most common cause of hypoxemia in patients with respiratory diseases |
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Definition
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Term
| how can hypoxemia from v/q imbalance be differentiated from hypxemia caused by shunting |
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Definition
| apply the following 50/50 rule: If the oxygen concentration is more than 50 (%) and teh PaO2 is less than 50 mmHg, significant shunting is present; otherwise the hypoxemia is mainly caused by a simple V/Q imbalance |
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Term
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Definition
| when the blood cannot carry enough oxygen, even when enough O2 gets from the lungs to the blood |
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Term
| What is the result of hemoglobin deficiency on oxygen delivery |
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Definition
| hemoglogin carries the vast majority of oxygen, while blood plasma carries very little. if hemoglobin is unable to carry oxygen, the CaO2 will be greatly decreased and the patient will be hypoxic |
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Term
| What does the movement of gases between the lungs and the tissues depnd mainly on? |
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Definition
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Term
| What does the alveolar PCO2 vary directly with and inversely with |
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Definition
| varies directly with carbon dioxide production and inversely with alveolar ventilation |
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Term
| How is alveolar PO2 computed |
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Definition
| using alveolar air equation |
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Term
| With a constant FIO2, what does the alveolar PO2 varies inversely with |
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Definition
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Term
| What is the normal alveolar PO2 |
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Definition
| 100 mmHg, with a mean alveolar PCO2 of approximately 40 mmHg |
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Term
| What does normal mixed venous blood PO2 and PCO2 |
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Definition
| PO2 40 mmHg; PCO2 46 mmHg |
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Term
| What must be in balance for pulmonary gas exchange to be effective |
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Definition
| ventilation and perfusion must be in balance |
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Term
| Why is pulmonary gas exchange less than perfect |
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Definition
| because of normal anatomic shunts and V/Q imbalances |
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Term
| In disease, what is the range of V/Q ratio |
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Definition
| ranges from zero (perfusion without ventilation or physiologic shunting) to infinity (pure alveolar dead space) |
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Term
| How does blood carry oxygen |
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Definition
| small amount in physical solution, greater amount carried in combination with erythrocyte Hb |
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Term
| What is hemoglobin saturation the ratio of |
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Definition
| oxyhemoglobin to total Hb expressed as a percentage |
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Term
| What are the two ways metabolic acidosis occurs |
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Definition
| 1) fixed (nonvolatile) acid accumulation in the blood 2) an excessive loss of HCO3- from the body |
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Term
| What are some examples of the two types of metabolic acidosis |
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Definition
| fixed acid accumulation example is a state of low blood flow in which tissue hypoxia and anaerobic metabolism produce lactic acid. The resulting H+ accumulate and react with HCO3- lowering blood HCO3-. Bicarbonate loss example is severe diarhea in which large stores of HCO3- are eliminated from the body, also causing nonrespiratory acidosis. |
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