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Diag Pro Unit 3
SPC Diagnostic Procedures Unit 3 Exam 2
Question | Answer |
---|---|
What is Deadspace ventilation? | The pattern of how gas is distributed through the lung areas is pulmonary gas distribution. |
Air that goes into regions where gas exchange is not possible is called? | Deadspace |
3 Types of Deadspace? | Anatomic, Alveolar, Physiologic |
Anatomic Deadspace? | Volume of air in the conducting airways from the mouth to the terminal broncioles |
Alvolar Deadspace? | Air that makes it to the alveoli but is not absorbed due to malfunctioning alveoli |
Physiologic Deadspace | Combination of both Anatomic & Alveolar |
The Fowler Method? | aka Nitrogen washout Uses 100% O2 |
The Bohr Method? | Includes the amount of alveolar deadspace Given as a ratio of deadspace to tidal volume |
Closing Volume & Closing Capacity Phase 1? | Gas in upper airway expired (anatomic dead space). |
Closing Volume & Closing Capacity Phase 2? | Expiration of gas in middle airways. Concentration of O2 decreases and N2 increases abruptly |
Closing Volume & Closing Capacity Phase 3? | Alveolar gas is exhaled. The concentrations of O2 and N2 change slowly and evenly. |
Closing Volume & Closing Capacity Phase 4? | Abrupt increase in the concentration of N2 that continues until RV reached. This phase indicates the patient’s Closing Volume and identifies the point at which the airways in the lung bases are closed. |
CV/VC % Male? | 7.7% |
CV/CC % Female? | 8.7% |
CC/TLC % Male? | 24.8% |
CC/TLC % Felame? | 25.1% |
Formula for VD/VT? | (PaCO2-PeCO2)/PaCO2 |
What is the normal range for deadspace? | 20-40% |
High deadspace indicates what? | Deadspace w/o Perfusion |
Formula for VAeff? | f x (VT-VD) |
Normal Range for VAeff? | 3-8 lpm |
Increase VAeff can result in what? | Hyperoxia & Hypocarbia |
Decrease in VAeff can result in what? | Hypoxemia & Hypercampnia |
What is a ventilation scan? | Patient breathes in Xenon 133 a radioactive gas. A scintiscan is made of the lungs, then scintiphotographs are made to record the pattern of the distribution of the Xenon throughout the lung. |
What is a perfusion scan? | Patient is (IV) of a radioactively tagged carrier substance. Isotopes Iodine 131 and techetium 99 are commonly used to tag the carrier substance. The pattern of how these carrier particles lodge in the lung reveals the pattern of pulmonary perfusion. |
V/Q scans are often done to look for what? | Pulmonary Emboli |
What is diffusion? | Where O2 & CO2 are exchanged through the alveolar capillary membrane |
What is the driving force behind the transfers of gasses in the a-c membrane? | Pressure Gradients |
T/F Diffusion defects can produce significant problems with the oxygen levels in the arterial blood. | True |
Why order a diffusion capacity test? | 1. Evaluate extent or progress of pulmonary disease 2. Differ between emphysema, bronchitis, asthma 3. Is systemic disease affecting lungs? 4. Evaluate reactions of amniodorone 5. Determine effect of cardio disease 6. Quantify the lung disease |
Diffusion test is used to measure what? | How well gasses moves across the a-c membrane |
CO has a significant affinity for hemoglobin but how much more? | 210x greater than O2 |
What are the disadvantages of using CO in a diffusion study? | Smokers with high levels of CO and patients w/ significant levels of CO through their enviroment |
What are the 3 DLCO measurement methods? | 1. Single Breath 2. Steady State 3. Rebreathing |
Gas mixture for Single Breath DLCO? | 0.3% CO, 10% Helium, O2, Nitrogen |
What must the patient refrain from doing when trying to obtain an accurate diffusion study? | 1. Smoking at least 24hrs 2. Alcohol at least 4hrs 3. Eating at least 2 hrs 4. Strenuous exercise 5. No sup. O2 at least 5min 6. 20min allowed bwteen Nitrogen washout and DLCO |
Single Breath Method | Simplest Equipment, Moderatly affected by V/Q, difficult for patient, most common method |
Steady State Test | Easiest and natural breathing pattern by patient, calculations are complex, most likely affected by V/Q |
Rebreathing | Least likely affected by V/Q, equipment most complex |
Pulmonary Causes for Decreased DLCO? | Edema, Hypertension, Emphysema, Cystic fibrosis, pneumotitis, sarcoidosis |
Non-Pulmonary causes for Decreased DLCO? | Inflammatory bowel disease, Mixed connective tissue, arthritis, lupus, mitral stenosis, ETOH, drugs, smoking |
Causes for Increased DLCO? | Supine body, polycythemia, left heart failure, L or R cardiac shunt, high altitudes, exercise, pulmonary hemorrhage |
Exhaled FeNO is used for what? | Severity of asthma and success of asthma treatment |