Term
| The most common cause of decrease inspired O2 is? |
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Definition
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Term
| most common cause of a V/Q mismatch |
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Definition
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Term
| Name four causes of V/Q mistmatch |
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Definition
1. hypoxemia #1cause
2. shunts
3. dead space
4. abnormal distribution of vnetilation and perfusion |
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Term
| Whats the difference between a shunt and dead space |
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Definition
Shunt: There is adequate blood flow but it has to get rerouted becasue you don't have adequate ventilation
Deadspace: There is adequate ventilation that is in area with inadequate blood flow therefore its a deadspace of stagnant air. |
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Term
| Diffusion abnormalities can be caused by? 2x |
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Definition
There is something pathological occuring between the alveoli and capillaries which prevents O2 from crossing over and CO2 from leaving. Causes include
1. Thickened membrane (more space to have to try and pass through from alveloli to capillaries and back (fibrosis,inflammation)
2. decrease surface space of gas exchange airway space. |
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Term
| what is a pulmonary right to left shunt |
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Definition
| When ever there is a lack of venitalted areas then blood will favor bypassing the lugns and going directly to the left lung with unoxygenated blood. |
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Term
| does the fraction of inspired Oxygen change in various altitudes |
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Definition
| NO! It remains 21% or 0.21 (fraction). However what does change is the overall pressure in the air that influences its ability to force its way into your capillaries. More pressure = more gas being forced into lungs. The higher you are the more difficult since less pressure to get O2 in your lungs. |
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Term
| what is the alveolar gas equation for PAO2? REMEMBER ALVEOLAR NOT IN THE AIR |
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Definition
| PAO2= FiO2 (PB-PH20)-PaCO2/0.8 |
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Term
| The parital pressure of O2 in the alveoli is? |
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Definition
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Term
what is the ratio of FiO2 to:
1. O2 in alveoli (PAO2)
2. O2 in the arterial (PaO2) |
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Definition
1. FiO2:PA02 (6x) (Alveoli)
2. FiO2:PaO2 (5x) (Artery) |
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Term
| A-a gradient represents what? |
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Definition
| The difference in parital pressure between O2 in the alveoli and arterial blood |
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Term
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Definition
| <10 mmHg on room air!!! <60 mmHg on 100% |
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Term
| list four neurological or musculoskeleta diseases that may lead to hypoventilation |
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Definition
1. polio
2. guillian barre
3. myasthenia gravis
4. ALS |
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Term
| What law explains why hypoventilation leads to hypoxemia? Explain the science behind htis1 |
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Definition
| When you hypoventilate you decrease the air exchange in the lungs. The goal of breathing to exchange CO2 for O2. CO2 from circulation is extremely concentrated compared to the outside environment. Therefore if you hypoventilate you have higher partial pressures of CO2 stuck in the alveoli which will decrease the partial pressure of O2. Dalton's law explains that the total pressure of a gas = the sum of all its partial pressures. So if CO2 is higher due to low ventilation and clearance than all the other gases must decrease to accomodate this. Therefore O2 goes down and you have hypoxemia. |
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Term
| how do you fix hypoventilation in a patient |
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Definition
1. increase RR
or
2. increase tidal volume on the ventilator |
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Term
Normal ventilation (L/min) Is?
Normal Perfusion (L/min) is?
Therefore normal V/Q is? |
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Definition
Ventilation = 4 liters a minute
Perfusion = 5 Liters a minute
V/Q = Ventilation / Perfusion
V/Q = 4/5 = 0.8. NORMAL V/Q ratio |
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Term
| can a diffusion impairment be the cause of hypercarbia |
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Definition
| NEVER. B/c CO2 difusses 20x better than O2. Since diffusion impairments are from increase wall thickness or decrease surface area then these will do little in CO2 impairment compared to the outstandig effect it will have on O2 diffusion. |
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Term
| name some examples of R-L shunting |
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Definition
1. atelectasis (decrease ventilation to alveoli therefore shunt occurs)
2. PNA (decreae ventilation so shunting)
3. ARDS (decrease airexchange since increase edema and wall thickness)
4. Pulmonary edema (Decresae gas exchhange)
5. ASD if increase pulmonary vasc resistance. Favors R--> L shift in ASD. |
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Term
| The greater the shunt then will increasing O2 have a stronger effect? |
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Definition
| NO. At a shunt of 50% for instance no change in FiO2 will make any difference in the PaO2. Remember shunting means blood is avoiding the alveoli and therefore no matter how much O2 you place in the alveoli it will have limited effects. Also don't forget that at 50% shunt that means theoretically there is only 50% of alveoli still participating in exchange. Now at those remaining 50% alveoli (if person healthy) then High O2 still have to compete with the excessively high CO2 attem;ting to leave the limited airway exchange places. Remember daltons law! If high CO2 then partial pressure of CO2 is high and O2 cannot get into the blood since their pressure is lowered as a result. |
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Term
| A subjective sensation of uncomfortable breathing is called? |
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Definition
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Term
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Definition
| dyspnea when a person is laying down |
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Term
| describe chyne-Stokes respirations |
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Definition
| Abnormal pattern of breathing with periods of Deep and fast breathing followed by periods of apnea |
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Term
| Describe Kussmaul respirations |
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Definition
| DEEP, patterned, sometimes labored breathing associated with severe metabolic acidosis. |
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Term
| Kussmaul respirations can be casued by |
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Definition
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Term
Acute cough is < ____ weeks
Chronic cough is > _____ weeks |
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Definition
Acute cough < 2-3 weeks
Chronic cough > 3 weeks |
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Term
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Definition
| PaO2< 60 mmHg is hypoxemia |
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Term
| normal FEV1 / FVC ratio is |
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Definition
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Term
| the volume of gas exhaled during the first second of forced expiratory maneuver is called |
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Definition
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Term
| the volume of gas that can be exhaled during a forced expiratory maneuver is called? |
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Definition
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Term
| what ratio is used to diagnosis obstructive and restrictive lung disease |
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Definition
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Term
| an index to airway obstruction is what value |
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Definition
| FEF (25-75%) Which is the maximum midexpiratory flow during forced vital capacity. |
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Term
| does a spirogram or flow-volume loop show whether airflow is appropriate for a particular lung volume? |
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Definition
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Term
1 lpm = ___ Fio2
2. 2lpm
3. 3lpm |
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Definition
1 lpm = 24%
2 lpm = 27%
3 lpm = 30% |
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Term
| most common reason for decreased inhaled O2 is from |
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Definition
| decrease ATM pressure. Less pressure to blow O2 into capillaries and diffuse into blood. |
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Term
| decrease ventilation will cause what with regards to ABG |
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Definition
| decrease ventilation means less removal of CO2 and less inspired O2. As a result increasing CO2 will dilute the O2 content and you will have hypercarbia and hypoxemia. |
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Term
| water vapor pressure at 37 is? |
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Definition
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Term
| what is the PAO2 at ATM of 600 with FiO2 of room air and ABC PaCO2 of 40 |
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Definition
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Term
| what are some iatrogenic causes of hypoxemia due to low FiO2 |
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Definition
Iatrogenic cause = relating to illness caused by medical examination or treatment
So what do we do that may actually cause low FiO2 and then hypoxemia. We give GASES! Or we screw up ventilation (drugs like paralytics or sedation) and cause hypoventilation which causes increase CO2 and dilution of O2 pressure (daltons law).
1. Nitrous oxide (more soluble and competes with O2)
2. Nitrogen
3. CO2 (if CO2 partial pressure goes up then O2 partial pressure must go down) |
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Term
| room air, sea level O2 pressure in alveoli is? |
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Definition
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Term
| is PAO2 or PaO2 6x the FiO2 |
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Definition
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Term
| what law relates to the cause/effect of hypoventilation and hypoxemia |
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Definition
| Daltons law: If you hypoventilate too much and let CO2 build up in alveoli then the CO2 partial pressure increases. If this pressure increases then O2 partial pressure must decrease. Remember CO2 will linger wihtout adequate ventilation. CO2 is also 20x more soluble than O2. |
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Term
| Normal ventilation is ___ lpm and normal perfusion is ___ lpm. Therefore normal V/Q is____ |
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Definition
Ventilation = 4 liters /minute
Pefusion (CO) = 5 liters / minute
V/Q = 0.8 |
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Term
| can hypercarbia be from edema or firbrotic airways? |
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Definition
| NO. CO2 is not affected by diffusion abnormalities like O2 is since CO2 is 20x more soluble. |
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Term
| after a build up of CO2 due to disease there are periods of apnea then excessive mechanical correction..this type of breathing is called |
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Definition
| cheyne-stokes respirations |
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Term
| What PaO2 and PaCO2 do you look for when diagnosising a patient with acute respiratory failure |
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Definition
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Term
| two categories (causes) of pulmonary edema |
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Definition
Cardiac or directly related to lung
1. Cardiogenic pulmonary edema
2. injury to lung parenchyma |
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Term
| Does a PE cause dead space or shunt? |
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Definition
| No blood flow, but there is ventilation. So DEAD SPACING occurs due to PE |
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Term
| name four causes of pulmonary HTN |
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Definition
1. OSA
2. HIV
3. Autoimmune disease
4. idiopathic |
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Term
| name the two types of alveolar atelectasis and the differences |
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Definition
1. compression atelectasis
2. Absoprtion atelectasis
Compression is caused by outside pressure pushing down directly onto alveoli. While absorption atelectasis is gradual. |
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Term
| disease that has localized, irreversible dilation of part of the bronchial tree |
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Definition
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Term
| what causes bronchiectasis? What is bronchiectasis? |
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Definition
obstruction of the airway which then causes irreversible dilation of the bronchial tree (pressure exertion trying to get by obstruction) Now secretions can't get up and out due to malformed enlarged airways where cilia are so far apart and mucus has to travel further with less help. This is obviously a obstructive disease. Caused by
1. mucus plugs
2. atelectasis
3. infection
4. cystic fibrosis
5. TB |
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Term
| if a disease is fulminant it means? |
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Definition
| a severe and sudden disease onset |
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Term
| what respiratory disease is fulminant in nature |
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Definition
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Term
| as a CRNA when would you expect to see ARDS onset |
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Definition
| within 24-48 hours of injury or insult |
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Term
| what physiological changes occur in the respiratory system as a result of ARDS |
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Definition
1. inflammation causes endothelial dysfunction, fluid extravasation, impaired drainage of fluid
2. Type II pulmonary epithelial cells are dysfunctional. This means less or no surfactant and high risk for surface tension = atelectasis = shunting. |
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Term
| a bleb rupture is what type of pneumo |
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Definition
| spontaneous primary pneumo |
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Term
| a pneumo that occurs randomly during sleep rest or exercise is what class of pneumo |
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Definition
| primary spontaneous pneumo |
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Term
| what causes secondary spontaneous pneumo? |
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Definition
| anything that is pathological and beyond the normal anatomy of lungs. So COPD is a disease which leads to air trapping and hyperinflation of the lung which increases its risk for rupturing. |
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Term
| what are the categories of restrictive lung disease 3x |
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Definition
1. intrinsic lung disease
2. idiopathic fibrotic disorders
3. extrinsic lung disease |
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Term
| what is restrictive lung disease |
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Definition
| Restrictive lung disease, a decrease in the total volume of air that the lungs are able to hold, is often due to a decrease in the elasticity of the lungs themselves or caused by a problem related to the expansion of the chest wall during inhalation. |
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Term
| With regards to lung volumes seen on spironmetry or PFT what is the difference between restrictive lung disease and obstructive lung disease |
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Definition
OBstructive lung disease:
- air gets trapped and not all of the inhalation volume can get out due to inflammation and narrowing of airways. Overtime this leads to hyper inflaation of airways.
Restrictive lung disease:
- Can get a normal total volume of air in because of either changes of elastic stretch or because chest wall won't allow for full expansion of lungs.
- PFT: decrease TLC, |
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