B4.067 Pulmonary Vascular Disease Flashcards
3 major diseases of the pulmonary vessels
pulmonary embolism
pulmonary hypertension
pulmonary edema
normal RA pressure
0-8 mmHg
normal RV pressure
20-30/0-8 mmHg
normal pulm artery pressure
20-30/8-15 mmHg
normal pulmonary artery wedge pressure
8-12 mmHg
how do you get a wedge pressure?
extend catheter through pulm artery until it completely occludes a vessel and the only pressure is the backpressure
how do you calculate pulmonary vascular resistance?
(mean pulm artery pressure - LA pressure) / pulm blood flow
what are the 5 primary classes of pulmonary hypertension
- pulmonary artery hypertension
- left heart disease
- PH with respiratory disease or hypoxia
- chronic thromboembolic disease
- unclear/multifactorial
what does the new classification system emphasize?
similar pathologic findings, similar hemodynamic characteristics, and similar management
what is pulmonary arterial hypertension (PAH)?
sustained elevation of mean pulm arterial pressure of > 25 mmHg
mean pulmonary capillary wedge pressure and/or mean LV end diastolic pressure <15 mmHg
what is the multiple hit hypothesis of the pathogenesis of PAH
primary genetic background + modifier genes + environmental trigger = PAH
what are some examples of environmental triggers of PAH
meth
scleroderma
discuss the pathology of PAH
pulm artery remodeling:
- intimal fibrosis
- medial hypertrophy
- adventitial proliferation
- luminal obliteration
what are some effects of PAH
RV hypertrophy increased central venous pressure peripheral edema JVD SOB
what 3 pathways may target PAH
endothelin
NO
prostacyclin
discuss prostacyclin
activity through cAMP vasodilator inhibits proliferation of vascular smooth muscle decreases platelet aggregation decreased prostacyclin synthase in PAH
discuss endothelin 1
increases intravascular volume and CO by being a potent vasoconstrictor
inhibiting this may help with PAH
what are goals of PAH therapy
dilate blood vessels
help heart
prevent blood clots
decrease scarring/blocked vessels
what are some options for PAH supportive therapy
oxygen
Coumadin
diuretics
treatment of underlying/ co-existing disease
spectrum of treatment options for PAH from least to most intensive
nothing oral meds nebulized meds continuously infused meds gene therapy lung transplant
classes of drugs that help with PAH
prostacyclin
prostacyclin analogues
phosphodiesterase inhibitors (increases NO concentration)
endothelin-receptor antagonists
how do thrombi form?
blood stasis
hyper-coagulable states
vessel wall abnormalities
where do pulmonary emboli originate?
deep veins of the lower extremities or pelvis
upper extremity veins (catheters)
right heart chamber (a fib)
superior vena cava
what is the effect of a pulmonary embolus?
decreases or total cessation of pulm blood flow to the affected distal zone increased PVR (50% occlusion necessary)
what happens when pulm blood flow decreases?
physiologic dead space increased
bronchoconstriction
surfactant production decreases-resulting in atelectasis
arterial hypoxemia
what happens when PVR increases after 50% occlusion occurs?
when mean PAP reaches > 40 mmHg, RV will fail and collapse occurs
what causes death from PE?
cardio collapse, not resp failure
characterize resolution of PEs
resolution occurs rapidly with only a small percentage suffering permanent perfusion defects
what are clinical signs of PE
pain/swelling of extremities (DVT) dyspnea (sudden onset) pleuritic chest pain cough apprehension hemoptysis tachycardia, tachypnea, hypoxia
how do you diagnose DVT
ultrasound
how do you diagnose PE
CT chest
how do you prevent PE
most immobilized hospitalized patients need prophylaxis for DVT
- pharmacological anticoagulants
- mechanical: pneumatic calf compression
how do you treat an acute DVT or PE?
anticoagulation
heparin/warfarin/NOACS
what are supportive therapies for PE?
oxygen to treat hypoxemia
fluid and vasopressors for hypotension and shock
thrombolytics only when shock/cardiac arrest
embolectomy
what are 2 types of pulm edema
cardiogenic
non-cardiogenic
what is the cause of cardiogenic pulm edema
pressure related phenomenon
LV problems, left sided valve problems, pulm vein obstructions
what is the cause of noncaridogenic pulm edema
leaky capillaries
ARDS, HAPE, neurogenic, opiate overdose
how do lungs typically protect themselves from excessive accumulation of fluid into interstitial spaces?
lymphatic drainage into SVC aided by changes in intrathoracic pressure with normal respiration
loose connective tissue located along peribronchovascular space and extending to the level of the bronchiole is capable of storing 2x the normal fluid content of the lungs
gel like matrix of the lung is capable of absorbing additional fluid without affecting interstitial pressures
pathophysiology of pulm edema
decreased lung compliance decreased lung volumes increased airway resistance increased work of breathing V/Q mismatch increased (A-a)O2 gradient hypoxemia
clinical findings of mild pulm edema
dyspnea on exertion
orthopnea
few rales in bases
variable peripheral edema
clinical findings of acute/severe pulm edema
productive cough of frothy blood tinged sputum tachypnea apprehensive peripheral extremities cool, clammy, cyanotic rales, wheezing throughout engorged neck veins tachycardia cardiac enlargement
how to manage cardiogenic edema
improve cardiac function (afterload reduction, inotropes)
eliminate excess fluid
oxygen/ventilator support
advanced therapies : ECMO, LVAD
how to manage non-cardiogenic edema
oxygen/respiratory support
ICU care
advanced support
treat underlying disease
