2Exogenous Surfactant Administration Indicated for surfactant deficiency, such as in infant respiratory distress syndrome and following lung lavage
3Exogenous Surfactant Administration Produced synthetically or naturallyAdministered by direct instillation into the trachea
4Exogenous Surfactant Administration DrugResponse TimeAdministrationPreparationSide effectsSyntheticColfosceril(Exosurf)Slow in onset(severalhours)During CMVbreath, twodivided dosesReconstitutedNo proteins to stimulate immune responseNaturalBeractant(Survanta)Rapid onset(5 – 30 min)Four divided dosesRefrigeratedsuspensionProteins may elicit immune response
5SurfactantSurfactant is a complex substance containing phospholipids and a number of apoproteins. This essential fluid is produced by the Type II alveolar cells, and lines the alveoli and smallest bronchioles. Surfactant reduces surface tension throughout the lung, thereby contributing to its general compliance. It is also important because it stabilizes the alveoli. Laplaces Law tells us that the pressure within a spherical structure with surface tension, such as the alveolus, is inversely proportional to the radius of the sphere. That is, at a constant surface tension, small alveoli will generate bigger pressures within them than will large alveoli. Smaller alveoli would therefore be expected to empty into larger alveoli as lung volume decreases. This does not occur, however, because surfactant reduces surface tension, more at lower volumes and less at higher volumes, leading to alveolar stability and reducing the likelihood of alveolar collapse. Surfactant is formed relatively late in fetal life; thus premature infants born without adequate amounts experience respiratory problems associated with immature lungs
6SurfactantThe baby presents with retractions (inward movement of intercoastals on inspiration), grunting (an attempt to increase FRC with back pressure), cyanosis, and tachypnea. Babies born with insufficient surfactant are determined to have a disease called RDS (respiratory distress syndrome) or Hyaline Membrane Disease. Surfactant can be distilled into the lungs following birth manually down an ETT.
7SurfactantCommon Surfactants Used: Infasurf (synthetic), Survanta (modified natural bovine lung extract), Exosufr neonatal, Curosurf (Pig extract)Classification: Natural or synthetic surfactant used to treat prematurely of the lung as demonstrated by RDS.How it works: The active component colfosceril palmitate (dipalmitoylphosphatidylcholine) is the major surface active component of natural lung surfactant and acts by forming a stable film that stabilizes the terminal airways by lowering the surface tension of the pulmonary fluid lining them. The lowered surface tension prevents alveolar collapse at end-inspiration; the hysteresis effect equalizes the distension of adjacent alveoli and hence prevents over distension which might result in alveolar rupture and pulmonary air leak.
8SurfactantDelivery Device: Through endotracheal tube, instilled with tracheal adapter, surfactant is drawn up in syringe and instilled down ETT directly into lungs.Doses: A dose of 5ml/kg birth weight of reconstituted Exosurf Neonatal, If the baby is still intubated, a second equal dose should be given 12 hours later by the same route. Survanta- 4cc/Kg given initially, second dose 2cc/Kg. Curosurf- 2.5 cc/Kg, second dose is the same; third dose is 1.25 cc/kg.Administration of exogenous surfactants rapidly improves oxygenation and lung compliance. Following administration, patients should be monitored so that oxygen and ventilatory support can be modified.
9Medication frequency BID= twice a day Ad lib= as desired TID= three times a dayQ4PRN= every 4 hours as neededQID= four times a dayQh= every hourQD= once a dayNS= normal salineQS= every shiftm.l.= militerQ4=every 4 hoursMg= miligramsQ6= every 6 hoursNPO= nothing per mouthHS= At bed timePRN= AS NEEDEDEX: Albuterol 2.5 mg and 2.5 ml NS Q4 and Q2 PRN for wheezing. Oximeter check QS
11Mixtures MATTER Pure Substance Mixture (homogeneous) (heterogeneous or homogeneous)elements compounds colloids suspension solutions
12Heterogeneous mixtures Heterogeneous – colloid & suspensionNot uniformLarge particlesConcentrations vary throughoutMay settleCan be easily separated by physical means (filtration)
13Homogeneous mixtures Homogeneous – solution Usually transparent Small (invisible) particlesWill not settleUniform concentration throughoutCan be separated by physical means but not easily. (evaporation)
15MIXTURES - ColloidExamples: Cellular protoplasm, milk, fat in blood, proteins in blood (albumin)HeterogeneousLarge moleculesAttract and hold waterUsually uniformly dispersedUsually do not settleSuspended in a gel
16MIXTURES - Suspension Examples: red blood cells in plasma HeterogeneousLarge particles that float in the liquidDispersed by agitationWill settle if agitation stops
17MIXTURES - SolutionExample: Saline (salt + water), medications, electrolytes in body fluidsHomogeneousSolute evenly dispersed throughout solvent so concentration is same throughoutSolute – 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.
18Solutions - 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 relationshipsSurface areaThicknessPartial pressureDiffusion coefficient
19Solutions - 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 soluteTemperature of solute & solventPresence of other solutes
20Concentrations of solutions More or less solute or solvent will change the overall concentration of the solution.Dilute – small amount of solute in solventSaturated – maximum amount of solute in solventPrecipitate – 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
21Concentrations 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.
22Concentrations of Medications Concentration can be expressed as:%weight/volume (g/mL) – solids in liquid (meds)%vol/vol (mL/mL) – both liquids%solutionRatio (weight:volume or g:mL) (meds)Molal solutionMolar solutionParts per million or parts per billion (extremely dilute)
23Medications (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)
24Respiratory Therapy Medications Preparations:Multi dose – need to be measured and dilutedUnit dose – already diluted and ready to useUltimate Goal of calculating is to know how many cc or mL to administer.
25Treatment Demonstration Nebulization of medicationSolute = medicationSolvent = saline or waterOrder: 2.5 mg Albuterol in 2.0 mL N/S by hand held nebulizer Q4 hours.MedicationDrug dosageDiluentMethod of deliveryFrequency
26Weight/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 mL2.25% Solution = 2.25 grams per 100 mLIn order for us to use this, we must convert the g/100 mL to mg/mL0.5% = 0.5 grams per 100 mL OR 500 mg per 100 mL2.25% = 2.25 grams per 100 mL OR 2,250 mg per 100 mL
27Weight/Volume Solutions milligrams per ml.0.5% solution contains ……. 5mg/ml1% solution contains ………. 10mg/ml2% solution contains ………. 20mg/ml3% solution contains ………. 30mg/ml4% solution contains ……… 40mg/ml1:100 solution is 1%1:200 solution is .5%1:1000 solution is .05%
28ExampleHow many milligrams are in 2 ml of a 3% solution?30mg/ml • 2ml = 60mg.Since 3% = 30 mg/ml and the question asks how much of this is in 2 ml, we simply multiply 30 by 2
29Respiratory Therapy Medications Preparations:Multi dose – need to be measured and dilutedUnit dose – already diluted and ready to useUltimate Goal of calculating is to know how many cc or mL to administer.
30Treatment Demonstration Nebulization of medicationSolute = medicationSolvent = saline or waterOrder: 2.5 mg Albuterol in 2.0 mL N/S by hand held nebulizer Q4 hours.MedicationDrug dosageDiluentMethod of deliveryFrequency
31Medication ExampleThe 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?
32Medication OrderIsuprel 5 mg of a 1:100 mL solution in 2mL normal saline by small volume nebulizer Q4 hours.MedicationDrug dosageDiluentMethod of deliveryFrequency
33Ratio Solutions Ratio solutions = 1 gram/??? mL 1:100 = 1 gram per 100 mL1:200 = 1 gram per 200 mLConvert to mg/mL1:100 = 1000 mg per 100 mL1:200 = 1000 mg per 200 mL
34Medication ExampleThe 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?
35Universal Drug Calculation Need to convert the ratio to a percentage. 1:100 = 1/100 = .01 = .01 * 100% = 1%
36Universal 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
37Pressures in solutions Solutes in solvents exert a pressureTwo kinds of pressure gradients exist:DiffusionThe passive movement from an area of high concentration to one of lower concentrationOsmoticThe movement of water from an area of low concentration to an area of high concentration.
38Diffusion Solute pushing across a semi-permeable membrane Solute can move across membraneThe movement will continue until there is an equilibrium in concentrations.
39Osmotic pressureSolvent (usually water) moving across a semi-permeable membraneSolute cannot move across membrane.The movement will continue until there is an equilibrium in concentrations.
40Solvent movement is indicated by arrows through the membranes.
41Osmotic pressurePressure 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 shrinksSolution 0.9%Cell 0.5%Solution 0.9%Cell 0.5%Water Movement
42Tonicity 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)
43Hypertonic Higher concentration that cause cells to shrink (crenation) Fluid moves from cells into vasculatureIV 3% saline0.9%0.9%0.9%3%Cells shrink - crenation
44Hypotonic Lower concentration that cause cells to swell (hemolysis) Fluid moves into cells from vasculatureIV 0.45% saline0.9%0.9%0.9%0.45%Cells swell - hemolysis
45Dilution ExampleIf you have 10cc of 20% Mucomyst and need a 10% solution, what do you need to do?Question: How many cc of saline need to be added to 10 cc of 20% Mucomyst to obtain 10% Mucomyst?
46DilutionIf you have 20cc of 0.9% normal saline and need 0.3% saline, what do you need to do?Question: How many cc of sterile water need to be added to 20 cc of 0.9% Saline to obtain 0.3% Saline?
47QuestionsWhen you add more solvent (water or saline) to a medication will you be giving more medication (solute)?When you add more solvent (water or saline) to a medication what will happen to the concentration (tonicity)? (increase, decrease or stay the same)When you add more solvent (water or saline) to a medication what will happen to the time it takes to aerosolize? (increase, decrease or stay the same)
48Pediatric calculations Body surface area (Dubois Chart)(Child BSA m2 / 1.73) x adult dosageFried’s RuleInfants < 1 year(Infant age in months / 150 months ) x adult dosageYoung’s RuleChild 1 – 12 years(Child’s age in years/age + 12) x adult dosageClark’s Rule(Child’s weight in pounds/150 pounds) x adult dosage