Pulmonary Circulation Flashcards

1
Q

Function of broncial circulation

A
  • protects lung from infarction
  • can “grow into” areas of diseased lung (intercostal arteries
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2
Q

Consequences of bronchial circulation

A
  • usual source of hemopytosis
  • much of arterial flow drains into left atrium = shunt
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3
Q

General characteristics of blood flow/circulation as circuit

A

-R/L sides of heart pump to pulmonary and systemic -capillary beds = source of resistance -driving force ==> voltage = pressure -

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4
Q

Calculating pulmonary vascular resistance

A

PAP (pulm. artery pressure) - LAP (left atrial pressure) = CO * PVR (pulmonary vascular resistance)

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5
Q

Steps in pulmonary circulation

A

-arteries -capillary network -veins

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6
Q

Systemic vs. Pulm

A

-systemic: high resistance vessels, high elastance/low compliance, high pressure system -pulmonary: low resistance, low eslastance/high complaice, low pressure system

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7
Q

Pulmonary artery catheterization

A

-swan-ganz catheter -flow-directed pulmonary catheter -obstruct small pulmonary artery -make static water colum -measure distal pressures

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8
Q

Cardiopulmonary hemodynamics

A

[picture/table]

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9
Q

Impact of gravity on pulmonary pressure

A

-much higher pressure @ base vs. apex -gravity impacts blood pressure but not air pressure -blood flow is intermittent near apex b/c there are points @ which the arterial pressure is lower than alveolar

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10
Q

Physiologic zones of pulmonary blood flow

A
  • Zone 1: PA > Pa > Pv
    • PA = alveolar pressure
    • Pa = arterial pressure
    • Pv = venous pressure
  • Zone 2: Pa > PA > PV
    • Pa = Pv @ diastole
  • Zone 3: Pa > Pv > PA
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11
Q

PA > Pa (Zone 1) : no blood flows

A

-mechanical ventilation -Auto-PEEP (COPD)

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12
Q

Other regulatory mechanisms of pulmonary blood flow

A

-hypoxic pulmonary vasoconstriction -vasoconstriction @ areas w/alveolar hypoxia -serves to preserve V/Q matching

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13
Q

Pulmonary edema

A

-originates in capillaries

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14
Q

Major function of pulmonary circulation

A
  • gas exchange
  • water and solute balance
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15
Q

major determinants of blood flow distribution in lung

A
  • gravity
  • hypoxic vasoconstriction
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16
Q

Major determinants of water and solute balance in lung

A
  • Starling’s Law ==> fluid filtration is determined by difference in hyrostatic pressures inside and outside capillary in balance w/oncotic pressures
17
Q

Major causes of pulmonary edema + general characteristics

A
  • increased hyrdostatic pressure (i.e. in LHF)
    • often occurs rapidly, can respond rapidly to tx
    • sign: Kerley B lines = enlarged lymphatic channels along interlobular septa engorged w/edematous fluid
  • increased permeability of the capillary membrane (i.e. endothelial damage)
    • occurs slowly, slow or no response to tx
    • ARDS/acute lung injury = possible cause
18
Q

Characteristics of ARDS/Acute lung damage

A
  • “Adult respiratory distress syndrome”
  • alveolar/endothelial damage ==> fluid leak into aveoli
    • ==> shunt past fluid-filled alveoli or V/Q mismatch w/poorly ventilated alveoli
  • occurs 6-24 hours after tissue injury
  • possible causes: trauma, inhalation of toxic gas, aspiration, embolism
19
Q

Hydrostatic vs. Non-hydrostatic pulmonary edema

A
  • Hydrostatic
    • Hx of recent/fast onset
    • Sx of HF
    • high LA pressure (pulm. cap wedge pressure)
    • responds to diuretic tx
  • Nonhyrdostatic
    • Hx of slower onset + exposure to traumatic stimulus
    • No Sx of HF
    • normal LA pressure
    • does not respond to diuretics
20
Q

Pulmonary hypertension definition (+equation for Ppa)

A
  • Pulmonary hypertension = pathologic state characterized by an increase in mean pulmonary arterial pressure
  • Normal pulmonary pressure=25/10 with a mean of 15 mmHg
    • mean pressure > 25 mmHg = pulmonary hypertension
  • Ppa- PLA(drop in pressure across pulmonary capillary beds) = CO x PVR ==>
    • Ppa = CO x PVR + PLA
21
Q

Common mechanisms/causes of pulmonary hypertension

A
  1. increased PLA (such as in heart failure or mitral stenosis
  2. increased PVR​​
  3. increased cardiac output
    • ​​not normally a major cause of pulmonary HTN due to increased vessel recruitment and dilation
22
Q

WHO Classification of Pulmonary Hypertension

A
  1. Pulmonary Arterial Hypertension
  2. PH due to Left Heart Disease
  3. PH due to Lung diseases
  4. Chronic thromboembolic pulmonary hypertension
  5. PH w/unclear/multifactorial mechanism