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N4117
Exam II Pulmonary System
| Question | Answer |
|---|---|
| What is ventilation? | Movement of air in and out of the lung alveoli to maintain appropriate concentrations of O2 and CO2. |
| What is respiration? | The process by which alveolar air gases are moved across the alveolar-capillary membrane to the pulmonary capillary bed |
| Define gas transport? | Movement of 02 and Co2 to and from the tissue cells |
| Lung has... | Lobes, and Mediastinum. |
| Name the conducting airways | Trachea, Bronchial tree. |
| Name the gas exchange airways | Bronchioles, and Alveoli |
| How many type of alveoli do we have? | Two types of alveoli, Type I Type II |
| Difussion is determined by? | Lung's surface area available for gas exchange, integrity of alveolar-capillary membrane, Amount of hemoglobin in the blood,Diffusion co-efficient of gas, amount of contact time, Driving pressures. |
| Ventilation is represented by th letter? | V |
| Perfusion is represented by the letter? | Q |
| Ratios of perfusion and ventilation is? | 1.0 |
| Alveoli ventilation rate is? | 4 L/min |
| Pulmonary capillary perfusion rate is? | 5 L/min |
| Normal rate for perfusion & ventilation is? | 0.8 L/min |
| What does V/Q <0.8 mean? | Less ventilation, more perfusion. |
| V/Q <0.8 is indicative of what? | Right to left shunt |
| V/Q <0.8 interpretation? | More deoxygenated blood is returning to the left heart |
| What does V/Q >0.8 mean? | More ventilation, less perfusion. |
| V/Q >0.8 etilogy? | Pulmonary emboli, cardiogenic shock |
| Name V/Q lung zones | Zone I, Zone II, and Zone III |
| In which zone is perfusion highest? | Zone III |
| In which zone is Perfusion Lowest | Zone I |
| Identify PA>Pa>Pv | Pulmonary Alveoli, Pumonary arteriole, Pulmonary venule. |
| Activities in zone I | PA>Pa>Pv (no blood flow)V/Q 1.0, Potential of no perfusion |
| Activities in Zone II | Pa>PA>>Pv (recieves varying blood flow) |
| activities in Zone III | Pa>Pv>PA (constanst blood flow) V/Q = 0.8 to 1.0. Optimal gas exchange area. |
| Zone III is dependent on what? | Gravity (a gravity-dependent area) |
| Why is the positioning of patients very important? | Because of the lung zones & gravity. It aids nurses in helping pts use their best perfused zone |
| How do you position patients with a bad right lungs | Place patient on their left side with the good lung in dependent position |
| How do pulse oximeter measure 02 | Through indirect measurement. Not alway accurate. |
| Gas dissolves in what? | Plasma. |
| Gas bound to what? | Hemoglobin molecules. |
| What does dissociation curve do/tell us? | Describes the ability of Hgb to bind oxygen at normal arterial O2 tension levels and release it at lower PO2 levels. |
| The upper flat portion of dissociation curve tells us what? | Arterial association which protects the body by enabling Hgb to load O2, despite large decreases in PaO2 |
| Example of upper flat portion of dissociation curve | PaO2 is 100 mm Hg yields SaO2 of 98% PaO2 is 60 mm Hg yields SaO2 of 89% |
| What does the lower steep portion of the dissociation curve tell us? | The venous dissociation portion. Protects the body by allowing the tissues to withdraw large amounts of O2 from Hgb |
| Example of lower steep portion of dissociation curve? | PaO2 is 50 mm Hg yields SaO2 of 80% PaO2 is 40 mm Hg yields SaO2 of 70%. |
| *What happens in a "shift to the Right" | Releases 02 more readily to the tissues. (Right = Releases readily or Increases O2) |
| *What is the relationship b/w Hgb & 02 in a "Shift to the right"? | It has less affinity for oxygen. i.e. It Releases the O2 more Readily. |
| *Etiology of a "Shift to the Right"? | Acidosis (pH Reduced), hypeRcapneia (PCO2 increase), feveR, IncRease levels of 2,3- diphosphglycerate (2,3-DPG). |
| *What happens in a "Shift to the Left"? | 02 not dissociated from Hgb, Hgb has more affinity to O2. Decreased O2 delivery to the tissues. ("L" for "Low & hoLd) |
| *Etiology of a "shift to the Left? | AlkaLosis (pH Increase), Low CO2, coLd, Low levels of 2,3-DPG. Increased Level of C02 poisoning. |
| Identify the acronym 2,3-DPG | 2, 3-Diphosphoglycerate |
| What is 2,3-DPG? | An organic phosphate found primarily in RBCs |
| What ability does 2,3-DPG have? | Has the ability to alter the affinity for oxygen |
| When 2,3-DPG level increases in the blood? | Hgb affinity for oxygen is decreased |
| When 2,3-DPG level decreases in the blood? | Hgb affinity for oxygen increases |
| What causes 2, 3-DPG production to increase? | Tissue Hypoxia. |
| *Hypoxic state means? | More 2, 3-DPG |
| When does shunting occur? | When a portion of the venous blood does not participate in gas exchange. |
| How does an Anatomical shunting occur | When the right ventricular blood does not pass thru pulmonary capillaries or if it passes through an airless alveoli |
| What causes an anatomical shuntings | AVMs (alteriousvenous malformation), ARDS, atelectasis, pneumonia, pulmonary edema, pulmonary embolus, vascular lung tumors, intracardiac right to left shunts |
| What cannot help in anatomical shunting? | Increased Fi02 |
| What always stays the same in anatomical shunting? | PcO2 (compensates with increased RR) |
| What is an Intrapulmonary shunting? | Venous blood that flows thru the lungs without being oxygenated due to nonfunctioning alveoli |
| What is an abnormal intrapulmonary shunting | Anything >10% |
| What is life threatning in intrapulmonary shunting? | Anything >30% |
| What is the normal value for intrapulmonary shunting? | 5 ml/dl |
| Name 2 methods used in measuring shunting? | Direct measurement and Estimation |
| How do you do direct measuremnt of shunting? | Give 100% oxygen for 15 minutes. (CaO2 is O2 content of arterial blood - CvO2 which is mixed venous O2 content) = Direct measurement. |
| How many ways to estimate shunting? | 3 |
| How to do the 1st shunting estimation? | Pa02 ÷ PA02 ratio |
| How to do the 2nd shunting estimation | Alveoli - arterial gradient |
| How to do the 3rd shunting estimation | Pa02 ÷ Fi02 ratio |
| Normal intrapulmonary shunting meaurement is? | (Normal is >60%) |
| A - a gradient normal is? | 10-20 mm Hg |
| As patient ages, what happens to the A - a gradient? | It increases |
| PA02 (pulmonary alveoli) - Pa02 (pulmonary arteriol) should always produce what number? | Positive number |
| What is PA02 - Pa02? | Difference in Alveoli to arterial pressure |
| A - a gradient provides what? | Provides an index on the lung's efficiency |
| A large A - a gradient signify? | Lung is the site of the dysfunction. (V/Q mismatching, shunting, diffusion abnormalities) |
| Pao2/Fio2 normal value is what? | Anything > 286 |
| Pao2/Fio2 (PF ratio) < 286 is indicative of what? | Worse lung functions |
| Give two examples of worse lung function calculation? | PaO2 85 ÷ FiO2 1.0 = 85. PaO2 100 ÷ FiO2 0.5 = 200. |
| What causes low 02 tension (Hypoxemia) | High altitudes |
| Etiology of Alveoli hypoventilation (acidosis) | Disorders in the respiratory center, muscles of the respiratory system |
| In hypoventilation, what remains normal? | A - a gradient |
| What is happening in V/Q mismatch? | A - a gradient is increased |
| What does gradient mean? | Difference b/w one level against the other |
| What is the reason to look @ A - a gradient? | To know lung function |
| Type I alveoli cells function | Type I alveoli is for gas exchange |
| Type II alveoli cells function | Type II alveoli is secretory cell, for surfactant production) |
| Anatomy of the lung mainstem | The right mainstem of the lungs is greater and longer with less of an angle than the left mainstem |
| Because of different anatomical structure of the lung, what risks always exists? | Ventilator tubbing enters more often into the right mainstem due to improper placement. |
| Ventilation problem could be what two major types of problem? | Restrictive or Obstructive |
| Restrictive ventilation problems include what? | Lung fibrosis, atelectasis, severe chest pain. |
| Obstructive ventilation problem includes what? | COPD, Asthma, Emphysema. |
| Definition of diffusion? | The movement of molecules from an area of higher concentration to an area of lower concentraion. |
| V/Q ratio of 0.8 means what in a normal healthy person? | More Perffusion than Ventilation. |
| Define gas transport? | The movement of oxygen & carbon dioxide in & out of body tissue. |
| What percentage of O2 is in plasma? | 3% |
| What percantage of O2 is in Hgb? | 97% |
| More 2,3DPG, causes what? | A shift to the right - O2 releases more readily |
| What is the problem with shunting? | The degree is a problem |
| Advantage of shunting estimation | It is unaffected by the changes of the FiO2 |
| Disadvantsge of shunting estimation | You have to directly measure the amount of oxygen in the alveoli |
| In A - a gradient, what are we actually comparing? | The amount of O2 in Alveoli with the amount od O2 in the arterioles |
| What is the normal amount of A - a gradient in healthy 20 years old student (young adult)? | They have a little bit more amount O2 in their alveoli than in the blood (arterioles) |
| Why should A - a gradient always be a positive number? | Becasue we are supposed to have more O2 in the lungs than in the blood |
| The lower the number of PaO2/FiO2 whic is P/F ratio... | The worse the lung function. |
Created by:
nze
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