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63 Cards in this Set
- Front
- Back
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Calculate partial pressure of humid air Water vapor pp [47mm Hg] atm pp of 760mm Hg oxygen is .21 |
P (gas in humid air) = (p[atm] - P[h2o]) x % of gas (760 - 47) x .21 = 150mmHg --> Bronchial Air (Pio2) @ normal body temps water vapor pressure is 47 |
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Functional residual capacity |
ERV + RV |
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Vital capacity |
ERV + TV + IRV |
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Inspiratory capacity |
TV + IRV |
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Compliance |
delta V / Delta P |
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Decreased compliance diseases |
surfactant and fibrotic lung diseases |
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alveolar ventilation |
VR x ( TV - dead space) normal is 4.2 L/min |
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total pulmonary ventilation aka minute volume |
VR X TV normal is 6L/min |
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VRG (ventral respiratory group) |
includes the botzinger complex with its apparent pacemakers as well as inspiration and active expiration |
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Peripheral chemoreceptors on PO2 |
monitor anything below 60mm Hg triggers an increase in ventilation (in carotid and aortic bodies) |
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Reynold's number determined by? |
larger number more likely to be turbulent 2 (radius of tube) (density of gas) (Velocity) -------------------------------------------------------------- (viscosity of gas) |
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Resistance of airway is proportional to what and inversely proportional to what? |
(n * L)/ r^4 I: length of tube IP: radius or tube |
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Emphysema |
causes abnormal forced expiration by normal maximal inspiration |
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Maximum voluntary ventilation |
125-170 L/min |
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V/Q ratio and normal? |
V= volume of air that reaches the alveoli per unit of time Q= volume of blood that reaches the alveoli per unit of time Normal is .8 |
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V/Q mismatch with emphysema and bronchitis |
emphysema - poorly perfused regions of the lung due to loss of capillaries bronchitis - poorly ventilated due to airway constriction |
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4 causes of hypoxemia |
reduced partial p. of O2 in inspired air alveolar hypoventilation abnormal gas exchange very low cardiac output |
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normal A-a gradient |
(age + 10)/4 |
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A-a gradient used to low vs high |
differentiate between hypoventilation and abnormal gas exchange. low = hypoventilation high = gas exchange problem |
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Alveolar gas equation Alveolar PO2 |
PAO2 = PIO2 ( is 150mmHg) - [PACO2/R] R= .8 If not given PaCO2 normally is 40 mmHg if no lung pathology |
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Diffusion = |
surface area X barrier permeability/distance^2 |
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Will low or high V/Q ration improve with supplemental oxygen |
high V/Q (or dead space) |
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Compensatory mechanisms for High and Low V/Q |
High V/Q can be compensated for by increased alveolar ventilation Low V/Q can be compensated for by hypoxic vasoconstriction |
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Mixed venous blood in systemic capillaries (PO2) In alveolar arterial capillaries (PO2) P02 at mmHg and % saturation |
40 mmHg and 75% saturated to Hb 100 mmHg and 97.5% saturated to Hb |
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CO2 transportation |
70% is in the form of bicarbonate 23% in proteins (carbaminohemoglobin) 7% in the form of plasma |
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Haldane effect |
shift in curve upon binding to oxygen from alveolus, goes right High PO2 in alveolus allows release of CO2 (delivery of CO2 to the lungs) |
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Hypercapnia physiological causes |
decreased minute ventilation decreased alveolar ventilation caused by rapid shallow breathing V/Q mismatch *unable to compensate due to suppression of drug or abnormality of the ventilatory pump (emphysema) |
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Acidosis and Alkalosis what mmHg causes change? |
7.35 and 7.45 .08 pH change for 10mmHg |
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Respiratory acidosis Primary disturbance and compensation |
PaCO2 increases metabolic alkalosis by increasing serum bicarb |
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Respiratory alkalosis Primary disturbance and compensation |
Decrease PaCO2 Metabolic acidosis decrease serum bicarb |
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Metabolic acidosis Primary disturbance and compensation |
Decreasing serum bicarb Respiratory alkalosis decrease PaCO2 |
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Metabolic alkalosis Primary disturbance and compensation |
increasing serum bicarb Respiratory acidosis increasing PaCO2 |
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Ventilatory response to hypoxemia |
minute ventilation increases as PaO2 falls below 60mmHg *when combined with hypercapnia the ventilation response is increased |
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Ventilatory response to hypercapnia |
ventilation increases linearly with acute increases in PaCO2 |
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COPD |
patients with this have trouble eliminating CO2 since elastic recoil is destroyed or airways become thick and inflamed. In COPD patient CO2 is chronically high and hypoxic drive from the peripheral chemoreceptors becomes more important in the drive to breath Oxygen supplement reduce drive to breath |
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Collapse tendency of lungs |
Elastic fibers (1/3) Surface tension (2/3) Aids in expiration |
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Sufactant |
Reduces surface tension Type 2 cells, have less effect at higher lung volumes. Phospholipoprotein. |
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Atelectasis |
areas of the lungs that are collapsed |
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Compliance problems indicated how? |
by a change in resting intrapleural pressures (lack of surfactant, emphysema) |
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Airway resistance problems are indicated how? |
changes in pressures during inflow or outflow but not at rest (asthma, aspiration of a crown) |
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Ventilation pressures with decreased surfactant |
same intra-alveolar pressure EVEN lower intrapleural pressure (more subatmospheric) |
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Asthma ventilation pressures Intra-avleolar pressure Intrapleural pressure |
Intra-avleolar and Intrapleural pressure - higher peaks but same resting values the peaks are due to the flow phase/airway resistance |
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Ventilation pressure with increased Tidal volume |
Intra-alveolar pressure --> increased peaks Intrapleural pressure --> increased peaks but more resting subatmospheric pressure since holding inspiring more air. |
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Diffusion Rate factors |
Solubility ------------- Sqrt (MW) Membrane thickness, surface area, gas pressure difference, diffusion coefficient (solubility and MW) |
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diffusion limited vs perfusion limited |
perfusion limited - the blood PO2 is full saturated and reaches equilibration diffusion limited - never reached equilibrium of saturation, a problem with diffusion. |
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Inspired air vs Alveolar air |
dilution of inspired air by FRC Addition of CO2 and water vapor Removal of O2 by blood |
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At 18,000 ft altitude the barometric pressure decreases by |
half |
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CO2 and O2 pressure gradient |
CO2 is only about a 5 difference (45 --> 40) O2 is about 60 difference (100 --> 40) |
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End-tidal CO2 meter is measured |
Is measured at the nose or at the end of an endotracheal tube. End tidal CO2 is 40 mmHg |
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base or apex receives more tidal volume? |
base due to pleural pressures differences surrounding these regions. More volume change at the base then you will get at the apex. Since it operates lower on the compliance curve. |
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Base or apex as higher blood flow |
base due to the effect of gravity, harder to push blood up into the apices. |
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Ventilation Perfusion Ratio Blood Flow (slope) - dominates where? Ventilation (slope) - dominates where? Match where? |
Blood flow has a steeper declining slope Ventilation has a less of decline Ventilation dominates at apex (>3) Blood flow dominates at base ( <1) Match at rib number 3 |
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Where is V/Q ratio 1 |
at rib number 3 |
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Arterial hypoxia is caused by |
v/q mismatch |
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V/Q extremes are? |
Shunt --> 0 V/ High Q
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Physiologic Dead Space |
Anatomic dead space + alveolar dead space Alveolar dead space from alveoli with little or no blood flow or pulmonary emboli |
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Dissolved oxygen formula |
.003 mls O2/ 100 mls of blood / mmHg so normally .3 mls O2 per 100 mls of blood OR Vol. % since mmHg = 100 or 3mls per L of blood |
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Oxygen attached to hemoglobin formula |
1.34 mls O2 / g Hemoglobin 15 g% normal Hb Concentration [Hb] X 1.34 mls O2/ g Hb X % saturation 15 g X 1.34 mls X .97 = 19.5 vol % |
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20 Vol % is equal to
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20 mls O2 / 100 mls blood |
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Bohr Effect |
Right shift caused by Increased (acidity) H+ / CO2 Curve also shifts right by : Increased temperature and 2,3 -DPG causing oxygen to decrease affinity. |
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CO poisoning |
Binds to ferrous iron of heme group 210X more successfully than O2 --> turn cherry red .1% compete almost equally with O2 for Hb |
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Cyanosis |
Bluish skin color 5 g% deoxygenated hemoglobin (1/3 of hemoglobin is deoxygenated) Reduced blood flow to tissues |
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Chloride shift |
As bicarbonate [] increases within the RBC it begins to diffuse out into the plasma. The resulting negativity within the RBCs induces an inward diffusion of chloride ions from the plasma |
