ch 39 Flashcards
what is the bodys natural humidification device
nose
what is ISB
Isothermic saturation boundary
how does temperture differ above ISB with inspiration and expiration
inspiration: decrease
expiration: increases
what outside factors can cause a shift in ISB?
*breathing in cold dry air
*upper airway by pass (trach, endo tube)
*minute ventilation is higher than normal
describe body humidity and humidity deficit
body humidity:
*relative humidity @ body temp
*water capacity of 44mg/L @ 37C
*BH=absolute humidity/44X100
humidity deficit
*not fully saturated @37C
*corrected by bodys own humidification system
*HD=44 - absolute humidity
what would happen if temp decreased suddenly?
indications for humidification
*dry medical gases
*bypass upper airway
*treating bronchospasm caused by cold air
clinical signs of inadequate airway humidification
*atelectasis
*dry nonproductive cough
*infection
*increased airway resistance
*increased WOB
*patient complaint of substeral pain & airway bypass
*thick, dehydrated secretions
factors affecting humidifier performance: temperature
increase temp of gas
increased water carrying capacity
factors affecting humidifier performance: surface area
increased gas/water contact area= increased evaporation
factors affecting humidifier performance: time of contact
increased gas/water contact area time= increased evaporation
what is the difference b/w active and passive humidifiers
active: adding heat or water or both to device patient interface
passive: recycling exhaled heat & humidity from patient
what is an active humidifier
adding heat or water or both to device patient interface
types: bubble, passover, nebulizers of bland aerosol & vapor
bubble humidifiers ( what will happen if exceed 4L w/out the bubble)
*dry gas damage
*heat loss
* water loss
*structural damage
*airway irritation
*increased mucus
*ciliary motility reduction
*increased secretion viscosity
passover humidifiers: what is the advantage over bubble
*maintains saturation at high flow rates
* adds little or no flow resistance
* do not generate any aerosols
3 types: simple, wick, membrane
what is the potential risk of using humidifier
airway burns
what can happen if a passover humidifier runs out of water
what is passive humidification
HME
recycles captured exhaled heat & moisture
“artifical nose”
when do we use the HME?
how does it work?
*use for patients on mechanical ventilation
* capture the heat and moisture from air a patient exhales than using to humidify air they inhale
explain dead space? what can cause it
- portion of breathing that doesnt participate in gas exchange (nose, mouth down to terminal bronchioles)
- alveoli that do not participate in gas exchange
how much dead space does HME cause
30-90 ml
what are the temperatures you can set a heated humidifier to? what can happen if temp is to low or high?
33C- 37C,
prevents complication like drying of the mucosa
what liquids can be used for bland aerosol therapy?
- sterile water
*sterile saline: hypotonic, isotonic, hypertonic
indications of bland aerosol therapy
*upper airway edema
* croup
*subglottic edema
*post extubation edema
*post operative management of upper airway
*bypassed airway
*need of sputum specimen
hazards/complications for bland aeresol therapy
*wheezing/bronchospasm
*infection
*over hydration
*patient discomfort
* caregiver exposure to airborne contagions by sputum/coughing
what type of patients can benefit from cool aerosol therapy
*upper airway edema/swelling
*bypassed upper airway
*sputum induction
to set up large volume nebulizer, what equipment do you need
*aerosol mask
*face tent
*t-tube
*trach mask
*drainage bag/containor
how does condensation pose a risk
- patient/caregiver
*block flow of gas through the tube, aspirated water going into the lungs
what can cause cross contamination?
*water in circuit can be course of bacterial colonization
*minimizing condensation is helpful to reduce risk of colonization
*wick-membrane type passover humidifiers prevent formation of bacteria carrying aerosols. change circuit when needed
what is used to monitor the temperature of inspired gas received by patients?
hygrometer-thermometer system
what is the purpose of mist tents/hoods
used to treat children w/croup
*promotes vasoconstriction
*reduces edema
*diminishes upper away obstruction
what are some hazards of mist tents/hoods
*heat retention
*CO2 build up (high flow of fresh gas to washout CO2 and heat)
hazard of aerosol therapy
*infection
*airway reactivity
*pulmonary&systemic effects
*drug concentration changes
*eye irritation
*exposure to second hand aerosol drugs
problem solving: inadequate mist production
check electrical power supply, carrier gas is flowing through device, amplitude control, couplet chamber
problem solving: overhydration
prevention by careful patient selection & monitoring is key
explain croup. who can get it?
how do we fix it? what is a contraindication for this patient?
*effects young children (6m-3yrs)
*narrowing of the airway, swelling trachea
* difficult breathing
Bland aerosol therapy
what is hypertonic saline? why do we use it?
bland aerosol therapy saline liquid
used for sputum inductions
