Exam 3: Ventilation And Cardiovascular Function/Dysfunction Flashcards
What are the signs of impaired ventilation?
*Confusion
Cyanosis (late sign)
Clubbing (sign of long-term impaired ventilation).
What is circumoral cyanosis?
Bluish tinge around mouth. Late sign of not enough O2 to tissues.
What is clubbing?
A compensatory mechanism of the body in finger/toes. The tissues grown larger in the hopes of drawing in more O2.
What are early signs of chronic airflow limitation?
Easily fatigued (activity intolerance) Pursed lip breathing Dyspnea Chronic cough Barrel chest (COPD) Tripod position breathing Orthopnea
Why is pursed lip breathing helpful?
It prolongs expiration, which keeps the alveoli open longer (increases CO2-O2 diffusion).
Why does chronic air flow limitation lead to chronic cough?
Coughing helps to pop open alveoli due to the pressure in the thoracic cavity.
Where are the respiratory control centers?
The medulla oblongata and the pons.
What are the central chemoreceptors?
Aka “medullary chemoreceptors”
Primary initiator of Respiratory Rate
Sensitive to CO2 levels and decreased pH.
Tell the respiratory centers to INCREASE respiratory rate when CO2 increases or pH drops. (Allowing the body to blow off CO2 and return to homeostasis).
Where are the peripheral chemoreceptors and what do they do? When are they most important to be aware of, clinically?
Located in the carotid body (carotid artery) and the aortic body (aortic arch).
Monitor O2 levels in arterial blood. When the O2 level drops, they signal the resp center to increase respiratory RATE and DEPTH.
In COPD patients, drop in O2 at peripheral chemoreceptors is the MAIN stimulus for breathing. Over-oxygenation can slow the breathing too much - even stop the drive to breathe.
How do proprioceptors affect respirations? Where are they?
Located in muscles and joints.
Monitor activity and O2 use.
Tell respiratory to increase respiratory RATE when use increases.
How do nociceptors affect our respiratory rate?
Our pain/temp/touch receptors send messages to the resp center to increase our respiratory RATE when stimulated.
What does the Herig-Breuer reflex do? Where is it located?
Stretch receptors. Located in the lungs.
When they reach full compliance (maximum stretch), tell resp centers to SLOW rate and DECREASE depth.
(Via negative feedback loop).
How does surfactant relate to lung compliance?
Without surfactant, our alveoli collapse a little bit and our lung tissue loses its elasticity.
After anaesthesia, you will possibly hear “crackles” (alveoli popping back open).
Why would an increase in temperature increase respiratory rate?
Increase in metabolic activity and dehydration (both associated with higher temps) increase the body’s O2 demand.
The inflammatory response leads to increased lactic acid production, which decreases pH. Faster, deeper breaths blow off more CO2, increasing the body’s pH.
What are the basics of blood oxygenation? (Which ventricle is deoxygenated blood pumped from, what is the structure of the alveoli, what is the process of oxygenation?)
Deoxygenated blood pumped from the R. Ventricle to the Pulmonary arteries.
Pulm. Arteries become a fine meshwork of arterioles around the alveolar sacs.
Gas exchange happens across the alveoli and the pulmonary arterioles via the process of diffusion.
Oxygenated blood returns to the heart (through the pulm vein) and gets pumped to the rest of the body via the L. Ventricle.
What do (alveolar) type I epithelial cells do?
They provide structure and shape to the alveoli, allowing them to stay open.
CO2-O2 exchange happens across these cells.
What do (alveolar) type II epithelial cells do?
Secrete surfactant, which allows for compliance/elasticity of the alveoli.
What do (alveolar) resident macrophages do?
Allow for immediate defense against pathogens and dust
Help grow new tissue in lungs
Help grow new blood supply in lungs (angiogenesis).
CAN reproduce even when the environment is infected/inflamed.
Fun fact: phagocytize tuberculosis and encapsulate it in a granuloma.
About how many hemoglobin molecules does one red blood cell contain? How many ferrous iron discs (Fe2+) per hemoglobin?
Approximately 300 hemoglobin molecules per RBC.
4 Ferrous Irons per hemoglobin.
Why is it important to know what a patient’s Fe2+ levels are? How does this relate to Nitroglycerin?
O2 binds with Fe2+
Nitroglycerin, however, oxidizes Fe2+ to Fe3+, which doesn’t bind to O2 as readily.
Result: worse oxygenation.
If pt is on Nitroglycerin OR sulfonamides (do the same thing) and they are not oxygenating well, look at their Fe2+ levels.
How does carbon monoxide affect O2 binding? How will CO poisoning present?
Carbon monoxide has a much higher affinity for Fe2+ than O2 does. It prevents O2 from binding to the hgb molecule.
Presents as:
Confusion
Nausea/vomiting
Unconsciousness, then death.
What are the pleura and how do they work?
Double-layered sac around the lungs.
Separated by serous fluid, which allows for glide and adherence.
What are the 4 roles of the pulmonary artery?
Bring blood from heart to lungs for gas exchange.
Remove blood clots.
Act as a blood reservoir (500mLs) for the heart.
Make A.C.E in its endothelial cells (for Angio I to Angio II conversion).
What are the bronchial arteries? What do they do?
Bring oxygenated blood to the lung tissue.
Humidify incoming air
CAN undergo angiogenesis to help keep lung tissue alive during a pulmonary embolism.
What are the three things that lung compliance depends on?
Elasticity of lung tissue
Alveolar surface tension
Compliance of the thoracic/chest cage
What is Distensibility (related to lungs)?
Ease of inflation.
What is stiffness (related to lungs)? What makes lung tissue stiff or not stiff?
Resistance to stretch.
Elastin allows for stretch.
Collagen is not stretchy at all.
Collagen replaces elastin in remodeling due to chronic inflammation - lung disease and pulmonary fibrosis. Permanent loss of elasticity.
Increased fluid in the lungs (like in pulmonary edema) leads to a reversible decrease in elasticity.
What does elastic recoil refer to? What common disease results in loss of recoil?
The ability of stretched parts to return to original state/size.
Emphysema results in lungs that are easier to inflate but difficult to deflate due to a loss of elastic recoil.
How does surface tension relate to alveolar function?
Surface tension develops between the liquid film and the air of the alveoli. Increased surface tension = increase in inflation difficulty.
How does surfactant help with breathing?
Lowers surface tension, making inflation easier.
Keeps alveoli dry inside.
What common advice would you give to both post-op patients and immobile patients regarding their breathing?
Breathe Deeply. Increased air volume in lungs spreads the surfactant around.
Shallow breathing from immobility will prevent the spread of surfactant throughout lungs.
Already decreased surfactant (from anaesthesia) will spread more effectively (and sooner) if pt breathes deeply.
What factors increase Hemoglobin’s affinity for O2?
- Presence of each O2 molecule on the hgb further increases hgb’s desire to bind.
- alkalinity (increased pH)
- hypocapnia (decreased CO2)
- decreased body temp
(Makes sense because O2 wants to bind to the molecule in conditions where it won’t take it away from cells that need O2).
What factors decrease hemoglobin’s affinity for O2?
Acidosis (or decreased pH in tissues)
Hypercapnia (or increased CO2 concentration)
Increased temp/fever
(These make sense because tissues in these conditions need O2 to be released to them quickly).
What independent nursing interventions can use use for a patient in respiratory distress?
Turning/repositioning (to move around fluid) Coughing (to increase intrathoracic pressure and open alveoli) Deep breathing (to increase volume)
What interventions would a patient with potential hypoxia/acidosis receive? (Both nursing and from a provider)
O2 supplementation
Improve blood flow (movement?)
Bicarb (acid buffer)
Calcium or sodium blockers (not sure of reasoning yet)
Do nursing interventions typically promote a right shift or a left shift in the oxyhemoglobin assoc/dissoc curve?
Right shift (helps oxygenate cells)
How do oxygen and hemoglobin behave in a right shift?
O2 is more likely to dissociate from hemoglobin
Promotes tissue oxygenation
What independent nursing interventions would help a patient who has a left shift?
Warm the patient Encourage movement (increases CO2 and decreases pH by increasing cellular metabolic activity)
What is anemia? What two components are referred to in the “title” of different types of anemias?
Decreased oxygen-carrying capacity of the blood.
RBC size (macrocytic vs microcytic vs normocytic) Hemoglobin/iron content (hypochromic vs normochromic)
What are the characteristics of macrocytic-normochromic anemia? What is an example?
Large RBCs with normal hemoglobin/iron content.
The quantity of the RBCs is decreased because of their large size - they tend to die within 50-60 days (instead of 120) because pushing through the capillary bed damages them.
Caused by a B12 or folate deficiency (required by the bone marrow to properly form RBCs).
Example: Pernicious anemia
What happens in pernicious anemia? How is it treated?
Parietal cell injury in the stomach (due to autoimmune disorder or a gastric ulcer) prevents the production of INTRINSIC FACTOR.
Intrinsic factor is supposed to attach to B12, forming a complex that allows it to be absorbed by microvilli during digestion. Then it travels to the bone marrow to be used for red blood cell formation.
In pernicious anemia, B12 gets excreted in the stool. Results in a deficiency and abnormal RBCs. Can be treated by B12 injections.
What is microcytic-hypochromic anemia? What does it result from? How is it diagnosed?
Small RBCs and low iron.
RBCs are pulled out of the bone marrow when they are too young.
Insufficient dietary intake of iron can cause this.
Low iron results in RBCs leaving the bone marrow with too little iron to carry O2 in the blood.
Lab values of less than 12 g/dL, but symptoms probably won’t appear until 7-8 g/dL.
Can also test CBC and serum iron levels.
What kind of iron do you want to make for good hemoglobin production?
Ferrous iron (Fe2+)
(Ferric iron, Fe3+, will not produce hemoglobin well).
What are normal hemoglobin and hematocrit levels?
Normal hemoglobin: 12-18 g/dL
Normal hematocrit: 35-50%
What are the symptoms of all anemias?
Fatigue
Weakness
Shortness of breath
Paleness (especially in conjunctiva)
What are the three types of atelectasis and what is the common characteristic they all share?
Compression
Absorption
Surfactant
All are characterized by collapsed alveoli.
What are the symptoms of atelectasis?
Cough Dyspnea Decreased SpO2 Tachypnea Tachycardia Decreased breath sounds Accessory muscle usage Change in level of consciousness Cyanosis
What causes compression atelectasis? How do you treat it and/or prevent it?
Alveoli shrink due to disuse from pressure on the pleural space (high BMI puts pressure on the lungs; immobility = inability to take full, deep breaths).
Both treatment AND prevention: Incentive spirometer (inhalation) - breathing in and holding the ball at a particular space exercises the alveoli, opens the airway and improves oxygenation.
What is absorption atelectasis? How do you prevent it? How would you notice it?
Caused by high flow O2 for too long (10 L/m for 1-2 days). The ratio of nitrogen to oxygen in room air is what keeps the alveoli open. (N=78%).
Prevent with incentive spirometer.
Pt would present with a drop in O2 and crackles.
What is surfactant impairment?
Collapsed alveoli and pulmonary edema because of reduced surfactant and inability to keep the alveoli.
Be aware of this for post-op patients.
Some will also be on high-flow O2 and already at risk for absorption atelectasis.
What is pneumonia? What are its causes, what symptoms will present and what are nursing interventions?
Inflammation in the lower respiratory regions.
Bacterial, viral, ventilator-associated nosocomial/HAI
Colored Sputum differentiates this from other resp problems.
Plus, Fever, productive cough, dyspnea, crackles on INHALATION, pleural pain.
Independent Nursing interventions: Move, turn, cough, breathe deeply.
Dependent: Incentive spirometer, antibiotics.
