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29 Cards in this Set
- Front
- Back
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The pulmonary vasculature is the only vascular bed that recieves 100% of ___1____. It is thus a high ___2___, low ___3___ system.
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1) C.O.
2) flow 3) pressure |
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P.A. pressure normally ___1___ during increases in C.O. (exercise). It does this by _____2_____ and ____3_____. These same mechanism allows PVR to remain normal with damage of up to ___% f capillaries.
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1) stays the same
2) dilating capillaries in use 3) Recruiting more capillaries 4) 60% |
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Most of the PVR lies in the ____1____ which are arranged like resistors in ___2___.
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1) capillaries
2) paralell. |
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1) Passive mechanisms of PVR maintenance include...
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1) higher PA and LA pressure passivly dilates capillaries. High lung volume distends extra-alveolar capillary population by radial traction.
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1-2) WHat are the two capillary populations of the lung and how do their resistances change with lung volume (alveolar distension)?
3) at what point do they balance toproduce minimal PVR? |
1) Alveolar capillaries, low resistance at low lung volume, high resistance at high lung volume.
2) Extra-alveolar capillaries in the interstitium. These have high resistance at low lung volume, and low resistance at high lung volume. 3) FRC |
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What is one way that the blood effects PVR?
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viscosity
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1) Local pulmoary vasoconstriction in response to hypoxia is partially mediated by release of what two substances?
2-3) and by inhibition of the voltage gated ___2___ pump on ____3____ cells. |
1) endothelin and serotonin
2) endothelin and serotonin 3) Smooth muscle |
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_____ is synergistic with hypoxia. in that the two together produce more than addative pulmonary vasconstriction.
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acidosis
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In normal humans, the ANS exerts how much control ver pulmonary vessels?
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Little or none
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What is one way that the blood effects PVR?
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viscosity
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1) Local pulmoary vasoconstriction in response to hypoxia is partially mediated by release of what two substances?
2-3) and by inhibition of the voltage gated ___2___ pump on ____3____ cells. |
1) endothelin and serotonin
2) endothelin and serotonin 3) Smooth muscle |
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_____ is synergistic with hypoxia. in that the two together produce more than addative pulmonary vasconstriction.
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acidosis
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In normal humans, the ANS exerts how much control ver pulmonary vessels?
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Little or none
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_____ capillaries act as starling resistors.
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alveolar
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west zone exist mostly because of _____
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gravity
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1) Describe West zone 1 in terms of flow, Pa, Pv, PA
2) Describe West zone 2 in terms of flow, Pa, Pv, PA. 3) Describe West zone 3 in terms of flow, Pa, Pv, PA. 4) Descrive zone 4. 5) What makes zone 4 disappear? |
1) No flow, PA>Pa>Pv
2) Pa>PA>PV. Flow occurs as a funtion of the gradient between artery and alveolus. This changed from zone 1 due to less hydrostatic pressure on the artery wall as we m 3) Pa>Pv>PA flow is present and depends only on the arterovenous pressure gradient. 4) Flow decreases from zone 3 due to increased resistance in extraalveolar vessels due to increased interstitial pressure. 4) Inspiration- tethers open the extraalveolar vesses. |
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how can lung zones be effected by PEEP?
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1) by increasing PA, can change zone 2 to zone 1, or zone 3 to zone 2.
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Define PA HTN
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sustained PA pressure > 25 mmHg at rest or >30 mHg wth LVEDP <15mHg
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There are 5 groups of PA HTN. Name 4 (the last one if miscellaneous).
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Pulmonary Aterty HTn
Pulmonary Venous HTN Pulmonary HTN with hypoxemia Pulmonary HTN due to chronic thomboembolic disease. |
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The normal RV cannot increase PA pressure above....
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40 mHg
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If there is an acute pulmonary HTN (i.e. masive embolus) descrive the hemodynamic consequences?
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RV cannot supply enough PA pressure to put blood through the lungs quickly enough. This results in LV underfilling and a decrease in tissue perfusion. This LV low outut is exacerbated by RV stretch which shifts the IV septum, further decreasing LV preload and increasing LVEDP.
This can also cause exhaustion of the RV in the face of decreased demand and lower blood supply, causing right heart failure. |
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1) How does the body respond to chronic Pulmonary HTN?
2) This adaptation can lead to what symptom? |
1) RV hypertrophy so that it can develop PA pressure higher than the normal max of 40mmHg.
2) Peripheral edema |
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Name 6 things that ca cause PE
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clot
tumor fat amniotic fluid air catheter tip |
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1) if PA pressure is 30-40 mmHg a person probably has _____ pulmonary HTN.
2) if PA pressure is >40 mmHg a person probably has _____ pulmonary HTN. |
1) acute, new onset
2) chronic |
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1-2) in acute PE that is not too bad, CO goes __1__ due to ____2___
3-4) in massive PE, CO goes __3__ due to __4___ |
1) up
2) due to sympathetic tone 3) down 4) Right heart failure |
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People with lung disease have bad hemodynamic response to PE because...
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they have fewer recruitable capillaries, and they other ones are already more dilated. Takes a smaller PE to kill these people.
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In a perfect response to a completely uncomplicted PE, the ______1_____ to the healthy tissue will increase in order to match the necessary increase in ____2____.
3) What effects prevent this ideal, even in healthy people? |
1) V
2)Q 3) Clots elaborate bronchospasm inducing factors which make increaseing V diffcult even in locations remote form the clot. They an also cause atalectasis and loss of surfactant or hemmhorage into alveoli. |
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What anatomical defect can become relevant in the case of PE, and how does it worsen the symptoms?
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PFO can lead to R--> shunt due to increased PA pressures. This directly lowers PaO2 and causes hypoxemia.
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Low CO from a PE leads to decreased ___1____ which exacerbates hypoxemia due to ___2____
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1) mixed venous O2 saturation
2) V/Q mismatch |
