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NU 624
Final Exam - Viscosity, Flow, Gas Laws
| Question | Answer |
|---|---|
| What are the 2 different types of gas laws? | Ideal and general |
| What do ideal gas laws describe? | Interrelationship between temperature, pressure, and volume |
| What are the three different Ideal Gas Laws? | Boyle’s, Charles’, Gay-Lussac’s |
| What does Boyle’s Law state? | At a constant temperature, gas volume and pressure are inversely proportional |
| How is Boyle’s Law written? | P1V1=P2V2 |
| What does Charles’ Law state? | At a constant pressure, gas volume and temperature are directly proportional |
| How is Charles’ Law written? | V1/T1 = V2/T2 |
| What does Gay Lussac’s Law state? | At a constant volume, gas pressure and temperature are directly proportional |
| What is the equation for Gay Lussac’s Law? | P1/T1 = P2/T2 |
| What does Henry’s Law state? | The amount of gas dissolved in liquid is directly proportional to the partial pressure of the gas over the liquid |
| What is the partial pressure of O2 in the alveoli at room air? | 100 torr |
| If the partial pressure of O2 in the alveoli is 100 torr, what is the partial pressure of O2 in the pulmonary capillary? | 40 torr |
| What is the partial pressure of CO2 in the pulmonary capillaries? | 45 torr |
| What is the partial pressure of CO2 in the alveoli? | Near zero |
| With Henry’s Law, the temperature and amount of dissolved gas in liquid are (directly/indirectly) related. | Indirectly |
| What implication does Henry’s Law have on anesthesia and body temperature? | Hypothermic patients remain anesthetized longer, febrile patients require more anesthesia |
| What does Dalton’s Law state? | Total pressure of a mixture of gases in a closed container at a given temperature is equal to the sum of the pressures of each individual gas |
| What are two ways O2 is carried in blood? | Dissolved in plasma (partial pressure); attached to HgB (SpO2) |
| How many molecules of O2 can one HgB carry? | 4 |
| How much O2 does each gram of hemoglobin carry? | 1.34 ml O2 |
| How much O2 does each dL of plasma contain? | 0.003mL per mmHg |
| At an alveolar partial pressure of 100mmHg, how much O2 does each dL of plasma contain? | 0.3ml O2 (each plasma dL contains 0.003ml O2 per mmHg) |
| What does Avogadro’s Law state? | Equal volumes of gases at the same temperature and pressure contain the same number of molecules, regardless of chemical and physical properties |
| What is Avogadro’s number? | 6.023 x 10 to the 23rd power |
| Avogadro’s number represents the number of gas molecules (any gas) in a volume of _____ liters. | 22.4 |
| What law permits the calculation of the amount of pure substance? | Avogadro’s number |
| What allows for the determination of the molecular weight between gases? | Avogadro’s Law |
| The molecular weights of gases is obtained by comparing the weights of _________. | Equal volumes of gases |
| The resistance a fluid creates to flow can be described by the property of ________. | Viscosity |
| Viscosity is related to ___________ of fluid as it flows through a tube. | Frictional forces |
| When viscosity (increases/decreases), flow decreases. | increases |
| When viscosity (increases/decreases), flow increases. | Decreases |
| Which law governs laminar flow? | Poiseuille’s Law |
| What is laminar flow? | Flow in which all molecules in a tube travel in a parallel path |
| What does Poiseuille’s Law state about the location of a molecule in a tube and speed? | Molecules in the center of a tube move at a greater velocity than those closest to the wall |
| Why do molecules in the center of a tube move at a greater velocity than those closest to the wall? | They have the least amount of adhesive force, or friction, against the walls of the tube |
| Flow is directly proportional to what two properties? | The pressure gradient and radius (to the 4th power) of a tube |
| Flow is inversely proportional to what two properties? | Viscosity of a fluid and length of a tube |
| What variable has the most dramatic effect on flow through a tube? | Tube radius |
| What is the equation for Flow? | [(Pi)(Pressure gradient)(radius to the 4th power)]/[(8)(viscosity)(length of tubing)] |
| How can the anesthetist create a large pressure gradient to improve flow? | Raise the height of the IVF bag |
| Doubling the radius of a tube results in a ________ fold increase in flow. | 16 |
| Identify three situations where turbulent flow can occur. | Molecules encounter walls of a tube in a rough pattern; high velocity; medium to large airways |
| What are 5 clinical implications where Poiseullie’s Law has influence? | 1)airways 2)needle gauge 3)pressure bags 4)ETT 5)blood vessels |
| Turbulent flow is governed by _______ Number. | Reynold's |
| At what Reynold’s number does flow change from laminar to turbulent? | >2000 |
| What are the 5 conditions that favor turbulent flow? | 1)high velocity 2)rough tubing 3)kinks/bends in tubing 4)increased solution density 5)large tube radius |
| What are three variables that are directly proportional to Reynold’s number? | Solution density, linear velocity of flow, tube diameter |
| Flow is (inversely/directly) related to viscosity. | Inversely |
| What is the equation for Reynold’s formula? | Reynolds# = [(linear *v*elocity of the tube)(density of fluid *p*)(tube *d*iameter)]/viscosity |
| What do Reynold’s values above 2000 indicate? | Turbulent flow |
| What do Reynold’s values below 2000 indicate? | Laminar flow |
| Who is the Venturi Effect named after? | Giovanni Battista Venturi |
| What does the Venturi Effect state about fluid pressure? | Fluid that flows through a constricted section of piping or tubing will experience a drop in pressure |
| How are velocity and pressure affected when fluid passes through constricted tubing? | Velocity increases; pressure decreases |
| In what physiologic scenario is the Venturi Effect apparent and describe the relationship? | Aortic regurgitation – After initial stroke volume is released, Venturi Effect draws walls together, transiently obstructing flow and causing a pulsus bisferiens |
| When is a pulsus bisferiens observed? | After the initial stroke volume is released and the walls of the heart are drawn together |
| What does bisferious mean? | Striking twice |
| What does a pulsus bisferiens create? | A double peak per cardiac cycle |
| Where is a pulsus bisferiens best palpated? | Radial artery |
| What are the key characteristics of a pulsus bisferiens and in what conditions is it seen? | Characterized by two strong systolic peaks with a midsystolic dip in-between; seen in aortic regurgitation with stenosis |
| When are Venturi masks useful? | When the provider wants to provide high flows of O2 while controlling the O2 concentration (25-40%) in a spontaneously breathing patient |
| T/F: The Venturi mask requires an airtight seal to function. | F – only requires adequate flow of air/O2 mixture |
| What does the Venturi mask allow control of? | FiO2 |
| O2 at a concentration of _______ percent flows through the constricted tubing of a Venturi mask. | 100% |
| How are nebulizers used with the Venturi effect? | 100% O2 flows past a constriction containing medication, the O2 hits a baffle or ball, the baffle/ball breaks down the medication into fine droplets that are inhaled by the patient |
| What does Bernoulli’s principle state? | For non-viscous fluids, an increase in the speed of a fluid occurs simultaneously with a decrease in pressure |
| Bernoulli’s principle is closely related to the ___________. | Venturi effect |
| State why Bernoulli’s principle is related to the Venturi mask. | As an airway narrows, the flow velocity increases while pressure decreases |
| What are two examples of application of Bernoulli’s principle? | Venturi mask and nebulizers |
| What two principles are closely intertwined in relation to flow and velocity? | Venturi effect and Bernoulli’s principle |