Pulmonary Circulation Flashcards
how much blood volume flows through the lung per minute on average?
5L/min
What is the average blood pressure in the pulmonary circulation?
15mmHg
What is the average pressure in your right atrium?
2mmHg
What is the average pressure in your right ventricle?
25/0mmHg
What is the average pressure in your left atrium?
5mmHg
What is the average pressure in your left ventricle?
120/0mmHg
What is it called when the pressure in your left atrium becomes greater than the pressure in your pulmonary vein?
Heart failure
How does cardiac cath measure the pressure in the left atrium?
By inserting a cath through the right heart and into the pulmonary artery. Balloon seals all pressure generated from right heart off from the lungs and left heart, allowing us to detect distal pressure. This is called the wedge pressure
How is total resistance preasured?
it is the sum of alveolar and extra-alveolar resistances
What happens during hypoxia?
hypoxic vasoconstriction drives blood away from areas without good gas exchange to areas of that are receiving oxygen
What are the passive controls of pulmonary vascular resistance?
Lung volume and blood pressure. (Gravity is a passive factor that effects both)
what are some potential causes of pulmonary edema?
High capillary pressure (common presentation of left heart failure) Inflammation, Impaired lymphatic drainage High altitude, Drowning
Why doesn’t pulmonary edema begin right away when lungs begin to experience stressors that cause edema?
The ability of the pulmonary lymphatics to increase the rate of lymph flow provides a large reserve before pulmonary edema starts to occur. Once the lymphatics are “overwhelmed”, fluid accumulation starts to occur – first in the interstitial space and may eventually flood the alveoli.
what is a pleural effusion
Pleural effusion, sometimes referred to as “water on the lungs,” is the build-up of excess fluid between the layers of the pleura outside the lungs. The pleura are thin membranes that line the lungs and the inside of the chest cavity and act to lubricate and facilitate breathing
How often does a DVT progress to a PE?
10% of the time. 5,000,000 DVT and 500,000PE/year in US
What are the 3 major factors that contribute to genesis of venous thrombosis?
1) Damage of endothelium of vessel wall
2) Hypercoagulability
3) Stasis
What are some risk factors for epithelial damage?
Inflammation Age > 60 years Malignancy Stress Smoke Obesity Pollutions
What are the most common risk factors for hypercoaguability?
Protein C Deficiency** Protein S Deficiency** Antithrombin III Deficiency** Factor V Leiden: 3-5 times higher risk Prothrombin G20210A Hyperhomocysteinuria Dysfibrinogenemia Familial plasminogen pregnancy
What are some additional risk factors for PE?
major trauma, recent surgery
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What are some things you’d expect to see in the clinical presentation of PE?
Leg pain, swelling, erythema, warmth Dyspnea, chest pain and hemoptysis, shock Sudden Tachypnea, fever, tachycardia Hypotension Crackles, S4, loud P2, JVD, cyanosis
whats do you most commonly see on a CXR when looking at a PE?
nothing, looks normal
What are the most useful tests to diagnose PE?
duplex US, VQ scan, CT, sometimes pulmonary angiography
What are the treatments for PE?
Oxygen
Heparin (APTT 1.5 to 2.5 times normal within 24 hours, Heparin level 0.3 to 0.7)
Warfarin
Massive PE: give thrombolysis therapy via catheter.
how often do you see chronic PE?
4% of survivors have a clot that doesn’t go away or respond to therapy. It can lead to fibrotic changes in vessel wall, treated surgically
What are other types of embolism?
air, fat, amniotic fluid
You can make the diagnosis of pulmonary hypertension when the mean pulmonary artery pressure is greater than _______mmHG.
25mmHg
What is the first part of the body to suffer in a patient with pulm htn?
the right ventricle
what is the criteria to diagnose pulmonary arterial hypertension?
a mean pulmonary arterial pressure >25mmHg AND a pulmonary capillary wedge pressure/left ventricular end-diastolic pressure <15mmHg. So basically the pressure in the pulm artery is elevated, but not in the pulm vein.
What are 5 major categories for patients with pulmonary artery htn?
lung disease/hypoxemia, left heart dz, chronic PE, miscellaneous
what are some common signs/symptoms of patients with PE?
dyspnea, pain on inspiration, tachypnea, chest pain, tachycardia, hypotension, cracles, JVD, cyanosis
what does the ABG usually reveal for a PE patient?
acute respiratory alkalosis due to hyperventilation
What is a lab test you can run to check for DVT or PE?
d-dimer, will be elevated in presence of thrombus
what kinds of preventative options do patients with h/o DVT/PE
typically anticoagulation like Coumadin, vena cava filters (greenfield)
if you see PCWP, what does that mean?
pulmonary capillary wedge pressure
what disease is characterized by right ventricular hypertrophy and eventrual failure resulting from pulmonary dz and associated hypoxia. (Most frequently caused by COPD)
Cor Pulmonale
“Pulmonary hypertension” has several classifications, what are they?
1) Pulmonary arterial htn (PAH)
2) Pulmonary htn owing to left heart dz
3) Pulm htn owing to lung dz and hypoxia
4) chronic thromboembolic pulm htn (CTEPH)
5) pulm htn with unclear unlifactorial mechanism
what is the clinical presentation of pulm htn?
dyspnea, cough, cp, syncope, hemoptysis, pedal edema, “Velcro” crackles, JVD, hepatomegaly, pulsatile liver, ascites, loud P2 (pulmonary valve closing)
Stew has had uncontrolled htn for years. His doctor recently told him that now his left ventricle is enlarged and causing the pressure in his lungs to be high. Would you tell him he had primary or secondary PH?
Secondary, resulting from left heart dz. (Primary PH develops without known cause)
What are some general symptomatic treatment options for pulmonary htn?
General sysmptomatic therapy: Oxygen Diuretics (reduce rt heart edema) Digoxin Coumadin Respiratory Rehab
what are some more aggressive treatments of pulmonary htn?
Vasodilator therapy: ERA, PDE-5 inhibitors and prostacyclin therapy
Surgical treatment:
atrial septestomy
Lung transplant
What is the most important aim of treatment for cor pulmonale?
correction of alveolar hypoxia by administrating O2. Other forms of treatment target underlying disease
