-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
