RSPT 1060

1. RSPT 1060 MODULE C Lesson 6 Solutions, Concentrations, & Medication Delivery

2. OBJECTIVES • At the end of this module, the student will be able to… • Define terms associated with solutions, concentrations and medication delivery. • Describe the relationship between matter and mixtures. • Differentiate between a homogeneous and heterogeneous solution. • Give an example of a colloid, suspension and solution found in the human body. • Identify the components of a solution. • Give an example of each of the following solutions: • Gas dissolving in a liquid. • Solid dissolving in a liquid. • List the things that affect solids or liquids dissolving in a liquid.

3. OBJECTIVES • At the end of this module, the student will be able to… • List the things that affect gases dissolving in a liquid. • Differentiate between a dilute, saturated and a supersaturated solution and a precipitate. • Differentiate between osmosis and diffusion. • Explain osmotic pressure and give examples of how it works • Describe the different forms of tonicity • Explain the effects of a hypertonic, hypotonic and isotonic solution as it is injected into the blood stream • Explain the effects of a hypertonic, hypotonic and isotonic solution as it is inhaled into the tracheobronchial tree. • Explain the reason for performing drug calculations in respiratory therapy.

4. OBJECTIVES • At the end of this module, the student will be able to… • Given a bottle of medication, identify the concentration of the drug • Convert a ratio (dilution) solution and a % solution to mg/mL • Perform drug calculations given %weight/volume solutions (%) • Perform drug calculations given ratio solutions (1:100) • Perform calculations using the Universal Formula for solving w/v solutions • Calculate drug dilution problems • Given a medication and a physician order, calculate the dosage or volume required to deliver the ordered amount of medication • Differentiate between Young's Rule, Clarks Rule, Fried's Rule and Body Surface Area for calculating pediatric dosages. • Given an adult dose of medication, use an infant's age in months, child's age in years, weight or body surface area to determine the correct dosage.

5. WEB SITES • http://www.school-for-champions.com/science/chemixtures.htm • http://www.psinvention.com/mixtures.htm • http://en.wikipedia.org/wiki/Mixture • http://en.wikipedia.org/wiki/Molal • http://el.hct.ac.ae/HSci/Pharm/Drugs.html

6. Mixtures MATTER Pure SubstanceMixture (homogeneous) (heterogeneous or homogeneous) elements compounds colloids suspension solutions

7. Heterogeneous mixtures • Heterogeneous – colloid & suspension • Not uniform • Large particles • Concentrations vary throughout • May settle • Can be easily separated by physical means (filtration)

8. Homogeneous mixtures • Homogeneous – solution • Usually transparent • Small (invisible) particles • Will not settle • Uniform concentration throughout • Can be separated by physical means but not easily. (evaporation)

9. Mixtures • Three types: • Colloids • Suspensions • Solutions

10. MIXTURES - Colloid • Examples: Cellular protoplasm, milk, fat in blood, proteins in blood (albumin) • Heterogeneous • Large molecules • Attract and hold water • Usually uniformly dispersed • Usually do not settle • Suspended in a gel

11. MIXTURES - Suspension • Examples: red blood cells in plasma • Heterogeneous • Large particles that float in the liquid • Dispersed by agitation • Willsettle if agitation stops

12. MIXTURES - Solution • Example: Saline (salt + water), medications, electrolytes in body fluids • Homogeneous • Solute evenly dispersed throughout solvent so concentration is same throughout • Solute – smaller quantity dissolved, can be solid, liquid or gas, “active ingredient”. • Solvent – larger quantity, where solute is dissolved. • “Aqueous” solution has water as the solvent.

13. Solutions - Gases in liquids • Ability of a gas to dissolve in a liquid depends upon : • Henry’s Law – dissolving (into) • Graham’s Law – diffusion (through) • Fick’s Law - overall relationships • Surface area • Thickness • Partial pressure • Diffusion coefficient

14. Solutions - Solids & liquids in liquids • Ability of a solute to dissolve in a solvent also depends upon: • Physical properties of solute & solvent (density, solubility coefficient) • Pressure of solute • Temperature of solute & solvent • Presence of other solutes

15. Concentrations of solutions • More or less solute or solvent will change the overall concentration of the solution. • Dilute – small amount of solute in solvent • Saturated – maximum amount of solute in solvent • Precipitate – Excess solute in solvent where some solute settles out at bottom of solvent. • As the concentration changes, the properties of the solution change (freezing point, boiling point…) • Examples: salt on roads, anti-freeze in radiator

16. Concentrations of solutions • Dilute solution with relatively few solute particles. • Saturated solution where the solvent contains all the solute it can hold in the presence of excess solute. (C) Supersaturation solution - Heating the solution dissolves more solute particles.

17. Concentrations of Medications • Concentration can be expressed as: • %weight/volume (g/mL) – solids in liquid (meds) • %vol/vol (mL/mL) – both liquids • %solution • Ratio (weight:volume or g:mL) (meds) • Molal solution • Molar solution • Parts per million or parts per billion (extremely dilute)

18. Medications (drug solutions) • Medications are solutes in solvents. • Calculations help quantify amounts of drug (solute) in sterile water or saline (solvent). • Calculations also help express different concentrations: • %weight/volume (g/mL) – solids in liquid (meds) • Ratio (weight:volume or g:mL) (meds) • Parts per million or parts per billion (extremely dilute)

19. Respiratory Therapy Medications • Preparations: • Multi dose – need to be measured and diluted • Unit dose – already diluted and ready to use • Ultimate Goal of calculating is to know how many cc or mL to administer.

20. Treatment Demonstration • Nebulization of medication • Solute = medication • Solvent = saline or water • Order: 2.5 mg Albuterol in 2.0 mL N/S by hand held nebulizer Q4 hours. • Medication • Drug dosage • Diluent • Method of delivery • Frequency

21. How many mL of drug do we need? Two Ways to Determine: • Dosage on hand = Dosage desired Volume on hand Volume desired DH = DD* Called a weight-volume problem VH VD *Need to have drug in mg/mL format • Universal Drug Calculation: #cc x #% x 10 = #mg *Need to know drug %

22. Weight/Volume Method • Used if we have the medication in a vial that tells us how much of the drug we have in solution. • Expressed as the amount of solid dissolved in a liquid. • “g/mL”

23. Weight/Volume Solutions • Weight/volume solutions are ALWAYS expressed as a % where the percent represents the number of grams of drug in 100ml of solvent. • 0.5% Solution = 0.5 grams per 100 mL • 2.25% Solution = 2.25 grams per 100 mL • In order for us to use this, we must convert the g/100 mL to mg/mL • 0.5% = 0.5 grams per 100 mL OR 500 mg per 100 mL • 2.25% = 2.25 grams per 100 mL OR 2,250 mg per 100 mL

24. Convert % to mg/mL • 1% = ____g / _____ mL = _____mg / _____ mL • 0.4% = ____g / _____ mL = ____mg / _____mL • 0.25% = ____g / ____mL = _____mg / _____mL

25. Medication Problems

26. Respiratory Therapy Medications • Preparations: • Multi dose – need to be measured and diluted • Unit dose – already diluted and ready to use • Ultimate Goal of calculating is to know how many cc or mL to administer.

27. Treatment Demonstration • Nebulization of medication • Solute = medication • Solvent = saline or water • Order: 2.5 mg Albuterol in 2.0 mL N/S by hand held nebulizer Q4 hours. • Medication • Drug dosage • Diluent • Method of delivery • Frequency

28. Medication Example • The physician order states that you are to administer 2.5 mg of albuterol. You have a 0.5% albuterol solution. How much medication (in mL) should you draw up? • How many milligrams are in a 0.5% solution?

29. Medication Example Continued DH = DD500 mg = 2.5 mg VH VD 100 mL x mL By cross-multiplying:

30. Universal Drug Calculation If you know the % of the solution, you can use the Universal Drug Calculation: #cc x #% x 10 = #mg

31. Medication Example • The physician order states that you are to administer 2.5 mg of albuterol. You have a 0.5% albuterol solution. How much medication (in mL) should you draw up? #cc x #% x 10 = #mg

32. Practice • Sibberson’s Practical Math For Respiratory Care: Chapter #6, Sample Problems Second Set, page 72. • May skip step in Sample Problem First Set.

33. Medication Order • Isuprel 5 mg of a 1:100 mL solution in 2mL normal saline by small volume nebulizer Q4 hours. • Medication • Drug dosage • Diluent • Method of delivery • Frequency

34. Ratio Solutions • In this scenario, you are given the concentration of the medication not as a percentage, but rather as a ratio. • The ratio is expressing the concentration as a weight/volume relationship. • One Gram in some amount of mL of solution

35. Ratio Solutions • Ratio solutions = 1 gram/??? mL • 1:100 = 1 gram per 100 mL • 1:200 = 1 gram per 200 mL • Convert to mg/mL • 1:100 = 1000 mg per 100 mL • 1:200 = 1000 mg per 200 mL

36. Convert to mg/mL • 1: 200 = ____g / _____ mL = ____g / 100 mL = ____% = _____mg / _____ mL • 1:1000 = ____g / _____ mL= ____g / 100 mL = ____% = ____ mg / _____mL • 1:400 = ____g / ____mL = ____ g / 100 mL = ____% = _____mg / _____mL Ratios are always ____g / ______mL

37. Medication Example • The physician orders 5 mg of Isuprel. You have a 1:100 solution. Determine how much medication (in mL) to give. • What concentration of drug do you have? • 1:100…What does that mean?

38. Medication Example DH = DD1000 mg = 5 mg VH VD 100 mL x

39. Universal Drug Calculation Need to convert the ratio to a percentage.1:100 = 1/100 = .01 = .01 * 100% = 1%

40. Universal Drug Calculation • The physician orders 5 mg of Isuprel. You have a 1:100 solution. Determine how much medication to give (#mL). • 1:100 = 1% solution

41. Practice • Sibberson’s Practical Math For Respiratory Care: Chapter #6, Sample Problems Fourth Set, page 72. • May skip step in Sample Problem Third Set.

42. Pressures in solutions • Solutes in solvents exert a pressure • Two kinds of pressure gradients exist: • Diffusion • The passive movement from an area of high concentration to one of lower concentration • Osmotic • The movement of water from an area of low concentration to an area of high concentration.

43. Diffusion • Solute pushing across a semi-permeable membrane • Solute can move across membrane • The movement will continue until there is an equilibrium in concentrations.

44. Osmotic pressure • Solvent (usually water) moving across a semi-permeable membrane • Solute cannot move across membrane. • The movement will continue until there is an equilibrium in concentrations.

45. Solvent movement is indicated by arrows through the membranes.

46. Osmotic pressure • Pressure that exists in the body because of a solvent moving across a semi-permeable membrane. • Solute cannot move across membrane. • Attempting to have equal concentrations on both sides of membrane. Cell shrinks Solution 0.9% Cell 0.5% Solution 0.9% Cell 0.5% Water Movement

47. Tonicity • Def: The amount of osmotic pressure in a solution. • Isotonic – having the same concentration as that of the body fluids (such as 0.9% “normal” saline) • Hypertonic – higher concentration that cause cells to shrink (crenation) • Hypotonic – lower concentration that cause cells to swell (hemolysis)

48. Hypertonic • Higher concentration that cause cells to shrink (crenation) Fluid moves from cells into vasculature IV 3% saline 0.9% 0.9% 0.9% 3% Cells shrink - crenation

49. Hypotonic • Lower concentration that cause cells to swell (hemolysis) Fluid moves into cells from vasculature IV 0.45% saline 0.9% 0.9% 0.9% 0.45% Cells swell - hemolysis

50. Changing concentrations • C1 x V1 = C2 x V2 • Use this calculation when the concentration of a medication or solution is too strong and needs to be diluted. • NOTE: Adding more solvent • Does not change the amount of solute (amount of medication) • Does decrease the concentration • Does decrease tonicity & osmotic pressure