-Humidity and aerosol therapy Flashcards
-Humidity and aerosol therapy
-Humidity therapy is the addition of water to the gas delivered to the airways
-Goals of humidity therapy is to provide adequate heat and humidity, treat hypoxia, prevent airway response to cold air, and aid in removal of thick secretions -Otherwise known as invisible water/moisture it is molecular and you cannot see it -Can be cool or heated
-Humidity
-Most medical gasses are 100% dry
-Supplying enough water vapor to make it comfortable for the patient -Heating the gas provide 100% relative humidity at body temperature -Especially when the upper airway is bypasses must heat and humidify to reach 100% body humidity
-Humidifiers Bubblers
-1. Bubbler > 4 lpm flow on NC can be used at lower flow if pt experiencing discomfort
-One of the most common used for low flow -Gas conducted below the surface of water and allowed to bubble back to top -Have a diffuser, device to break the gas into smaller bubbles -Pop off valve set at 2 PSIG or 40 mmHg -Not effective for flows greater than 6LPM ( choose another device)
-Humidifiers -2. Pass-over or blow by humidifiers
-2. Pass-over or blow by humidifiers
-Direct gas over the surface of a body of water -Efficiency- rather than flow -Use maybe some home CPAP. BIpap units
-Humidifiers -3. Cascade
-Advanced type of bubble humidifier
-Was commonly used with ventilators or other high flow conditions -Heating element is submerged into water -Heating control with reference should be used near patients -Monitoring thermometer should be used near patient -Can be used without heat but only provided 100% body humidity if heated
-Humidifiers -4. Wick Humidifiers
-Used with vents and hood, has temp control you set
-Made of substance such as sponge or paper -Absorbs water by capillary action from concha container -Gas passes through or next to wick to take on humidity
-Humidifiers -5. Heat moisture exchanges (HME)
-Short term use (with artificial airway only)
-Place between artificial airway and wye of vent circuit -Exhaled gasses at body humidity enter HME, material absorbs heat and moisture back into PT with next breath -During inhalation, gas passing through the exchanger is warmed and humidified before being delivered to the trachea. Think of this as a artificial nose -Must be removed during aerosol therapy (neb Treatment) -If Pt is not normal temp can not use
-Humidifiers -6. Heated Humidifers/ Heated Wire circuits
-Fisher and Paykel most commonly used with vent
-Heat increases capacity of gas to hold water vapor
-If the upper airway is bypassed, 100% relative humidity is necessary to humidify inspired gasses
-May be necessary to heat above body temperature since gas will coll as it passes through tubing to the patient. Has set temp and actual monitored temp
-As gas cool, condensation occurs
-Must be angled down and away from the patient
-Must be drained to avoid water accumulation
-Problem Solving-Bubbler
-Safety pop-off valve
-Set to 2 PSIG -For crimping/ blockage of tubing -will whistle as indication -Contamination- do not attempt to refill prefilled bubblers
-Problem Solving -Condensation
-Condensation
-Can disrupt and occlude air flow -Cause aspiration if it enters the patient's airway -Position circuit to drain condensate away from patient -Infection risk -Colonized within hours of bacteria -Treat as infectious waste (goggles/ Gloves)
-Measuring Humidity -Partial Pressure
-Because it is a gaseous vapor- excerpts pressure
-Vapor pressure, maximal pressure that water can excerpt at a given temp -As humidity or temp increases, pressure increases -As temp increases, velocity of particles increase
-Measuring Humidity -Absolute Humidity
-Absolute Humidity
-Actual water content of a gas -Determined by extracting water vapor from know volume of gas and weighing water -The common unit of measuring is mg/L -Maximum absolute= 44 mg/L (weight) or 47 mmHg (water vapor pressure in lungs)
Normal body humidity at normal body temp
Normal body humidity at normal body temp= 43.8mg/L (44) or 47.1 mmHg (47) vapor pressure
-Body humidity at normal body temp 37 deg celsius is at maximum absolute (capacity 43.8mg/L (44) meaning it is fully saturated: holding all the water it can.
-Body Humidity- the relative humidity at body temperature expressed as a percent (what we ARe providing the patient)
-Measuring Humidity -Calculation
-Calculation
-1. If we know temp of gas and absolute humidity of gas or pressure of gas -2. Can calculate the % of relative humidity -RH= Content (absolute humidity) / Capacity * 100 -Content will always be given to you
-Example
-The amount of moisture in a given volume of a gas at 31C contains 24mg/L of gas. Calculate the relative humidity. At 31C, the air can hold 32.01mg/L -RH= Content/ Capacity *100 -So 24mg/32.01*100 -=.748*100=74.9 or 75%
-Inspissated secretions ,
secretions thickened because of dehydration
Measuring Humidity -Relative humidity
-Relative humidity
-Percentage expression of the actual water vapor content as compared to the capacity of the gas to carry water at any given temperature -Capacity increases as temp of the gas rises -As temp of water increases, velocity of molecules increases
-Humidity deficit
-Humidity deficit is the amount of water vapor the body must add to the inspired gas to achieve saturation at body temperature (what we are NOT providing)
-Humidity deficit = Ideal- actual -In other words, capacity-content=Deficit -(Ideal) capacity is 43.8 or 44mg/L -Content must be given to you!! -Answer may be converted to % see examples
-Bland Aerosol Therapy
-Liquid particles suspended in a gas, you can see it
-Sterile water, hypotonic, isotonic, or hypertonic saline all used for bland aerosol: -Upper airway edema -Laryngotracheobronchitis (LTB) or croup -Subglottic edema -Post-op management of upper airway -Bypassed upper airway -Sputum induction or mobilization of secretion
-Equipment
-1. Large volume jet nebulizer (aerosol generators, air entrainment nebulizers)
-Most common
-Pneumatically powered (gas powered) -Baffled to keep large particles from going to patient -Can be heated to increase amount of aerosol -FiO2, adjusted via air entrainment port -Higher FiO2 (> equal to 60) -May need to “Tandem” together two devices if not meeting demand or total flow need -Only time you would heat is if pts upper airway is bypassed
-Equipment
-Interface devices to deliver aerosols (of Large volume jet nebulizer)
-Aerosol mask
-Face tent -Trach Mask- used with trached patients -T-Piece/ Briggs adapter, intubated or trached patient -Enclosures, oxygen mist tents and hoods -Problems, CO22 build up and heat retention
-Bland Aerosol Therapy in general uses
-Can be used for sputum induction (USN)
-Short term therapy -Hypertonic saline (3-10%) aerosol -Mobilizes secretions and causes cough get sputum, not saliva -Can be used to gap humidity deficit in PTs with artificial airways when heated -Treat edema when cool
-Bland Aerosol Therapy in general-Troubleshooting
-Most common problems
-Infection, low mist production, overhydration, bronchospasm, noisy -Infection, do not refill water bottles of LVJN, change put equipment per protocol, clean chambers of USN
-Bland Aerosol Therapy in general-Low mist production
-Check for obstruction of jet, check fluid levels in USN/LVJN
-Ensure DISS connection and flowmeter setting is correct may need to increase flow -Ensure water has not accumulated in corrugated tubing of LVJN will increase Fi02 same as ports on venti being blocked
-Bland Aerosol Therapy in general-Bronchospasm
-Every bland aerosol can cause bronchospasms
-Initially assess and reassess patient periodically -If occurs stop treatment, provide 02, start bronchodilator
-Bland Aerosol Therapy in general-Particle size
-> equal to 10 Um impact in nasal passage
-5-10 um impact in oro-hypopharynx -2-5 um deposit in lower airways
-Aerosol Drug Administration
-Dosing of aerosolized medication is imprecise
-Humidity influences the delivery of aerosol medication -Drug formulation dictates which aerosol options are available for delivery of a specific medication
-Aerosol medication delivery devices
-Jet nebulizer (small volume neb SVN, large volume neb or continuous neb)
-Mesh nebulizer (aerogen) -Soft mist inhaler (SMI) -Portable ultrasonic nebulizer (USN) -Pressurized metered dose inhaler (pMDI) -Metered dose inhaler with spacer or holding chambers -Dry powder inhaler -For any inhaled medication-pt or neb chamber needs to be in upright position
-Small Volume medication nebulizers (SVN)
-Pneumatically powered
-Design -Medication reservoir -Baffle -Gas inlet jet -Output port -Also available breath actuated/ breath enhanced
-Large volume medication Nebulizer (LVN)
-Used to deliver medication over long periods of time such as several hour albuterol (continuous neb)
-Brand names= Heart/ Westmed, hope
-Equipment Medication administration
-Low flow medication nebulizers
-Powered by flow of 2-3lpm
-Can run in line with vent circuitry without greatly increasing volumes delivered to patient (NICU) also utilized for 30 min to 1 hour long nebs in ER
-Equipment Medication administration
-SPAG- small particle aerosol generator
-Used to deliver Ribavirin (Virazole) for RSV
-Uses drying chamber to achieve uniform particle size -Hooked gas source such as blender has 2 flowmeters we set (6-8LPM) and PSI to 26-32
-Aerosol Drug Administration
-Mesh Nebulizer
-Use electricity to vibrate a piezo element that moves liquid formulations through a fine mesh to generate aerosol
-The diameter of the mesh or aperture determines the size of the particles generated -Mesh nebulizers are very efficient and result in minimal residual volume
-Aerosol Drug Administration
-Two types of mesh Nebs
-Activate Vibrating mesh , have an aperture plate with 1000-4000 funnel shaped holes vibrated by a piezo ceramic element that surrounds the plate
-Passive mesh utilizes an ultrasonic horn to push fluid through a mesh
-Aerosol Drug Administration
Most common used
Aerogen
-Aerosol Drug Administration
-Soft mist inhaler (Respimat)
-Propellant, free soft mist inhaler
-Utilizes mechanical energy in the form of a tensioned spring to generate the soft aerosol plume -Energy from turing the transparent base to the right one-half turn draws a predetermined metered volume of solution from medication cartridge to be delivered
-Aerosol Drug Administration
-Ultrasonic neb (small volume)
-Available for aerosol drug delivery (Not suspension such as Budesonide)
-May or may not use water filled couplant compartment, with medication placed in a cup directly over the transducer -Advantage, battery powered, so provided convenience
-Aerosol Drug Administration
-Pressurized metered dose inhaler (pMDI)
-Most commonly prescribed method of aerosol delivery
-Used to administer bronchodilators and anti inflammatory agents -Typically single patient use -Has a specific quantity of medication -Requires slow inspiratory flow (<30l/min) with a breath hold needed in sync with a patient able to follow directions. If contains a steroid must rinse mouth
-Aerosol Drug Administration
-Spacer
-Spacer, a simple open ended tube or holding chamber that provides space for the pMDI plume to expand and incorporates a one-way valve that permits the aerosol to be drawn from the chamber during inhalation only
-Great for children or uncoordinated PTs to act as a holding chamber for medicine due to the one way valve
-Aerosol Drug Administration
-Dry powdered inhalers (DPI)
-DPIs, create aerosols by drawing air through a dose of powdered medication
-Flow driven, requires fast deep inhalations -Do not contain propellants -Breath-actuated so dependent on patient -Single dose and multiple dose devices -Ether dispenses a set amount of powder or uses a system that pierces a capsule of powder to be inhaled
-Hazards of medication/ Nebulizer therapy
-Medication, adverse action terminate TX if adverse reaction occurs
120 heart rate wait and switch to xopenex
-Infection, usually gram negative bacilli (Pseudomonas, Legionella pneumophila) from equip not cleaned or changed out appropriately -Airway reactivity -Drug concentration changes during nebulization
Ultrasonic Nebulizers
-Electrically powered
-Piezoelectric Crystal
-Generates aerosol -Converts radio waves into mechanical vibration -Vibration through couplant or directly to solution chamber -Gas enters solution chamber, pick up aerosol, exits
Ultrasonic Nebulizers
-Frequency
-Preset You Cannot Change!!!
-Determines size of particles -MMAD mass mean aerosol diameter -1.24-2.25 MHz=2.5-6 UMs (microns)
Ultrasonic Nebulizers
-Amplitude of signal (aka:output)
-Adjustable
-Determines amount of aerosol produced -Source and flow of gas determines density (mg/L) and total output (ml/min) - Increase flow/ fan= Decrease Density decrease flow/ fans= Increased density
Ultrasonic Nebulizers
Benefits
-Recommended for sputum induction/ thick tenacious
-Has the largest total fluid output of any device
Ultrasonic Nebulizers
-Problems
-Can increase airway reactivity/ bronchospasm due to massive rehydration of secretions
-Contamination due to increased particle size and reservoir
