Resp. therapy equipment Flashcards
Why is SpO2 so important?
- the presence of hypoxia may change clinical management in over 90% of cases
What are the 2 types of pulse oximeters?
- transmission: light passes through tissue to sensor on the otherside
- reflectance: the sensor and the light source are side by side
What law are the principals of oximetry based on?
- Beer-lambert law
- the concentration of an absorbing substance in a solution is related to the intensity of light transmitted through that solution
What are the 2 diodes that emit alt. light wavelengths?
- red light: absorbed by deoxygenated blood
- infrared light: absorbed by oxygenated blood
- ratio of absorption is measured and the O2 saturation of hb is derived
What are the diff. oximeter probes?
- finger
- ear
- hand/foot (Neonates)
- forehead
What SaO2 % = PaO2 of 80 mmHg?
PaO2 50 mm Hg = ?
What is the nomral PaO2?
- 80 mm Hg = 95% SaO2
- 50 mm Hg = 80% SaO2
- normal PaO2 80-100 mmHg
What indicates that there is a good signal on the oximeter?
- dicrotic notch -> 2 peaks
- but without a good waveform the reading is unreliable (dependent on circulation being intact)
What factors may affect the pulse ox?
- skin pigment: darker pigment may sometimes cause erroneous readings
- nail polish: usually not a problem but darker polish may decrease light transmission
- acrylic nails: decreases accuracy
- motion
- ambient or excessive light
- hypoperfusion: may overestimate
- hypoxia: less reliable below 80%
- dyshemoglobinemias: COHb absorbs light in red wavelength similar to oxyhemoglobin (falsely elevated)
- methemoglobin: Fe3+ vs normal Fe2+ (absorbs red and infrared light)
- IV dyes: methylene blue, indocyamine green, and indigo carmine
- anemia: for any given saturation the PaO2 is lower than normal
- cyanide poisoning: will read a high O2 sat which is true because the O2 is bound very tightly with the Hgb but this isn’t the true picture of actual O2 tension in the tissue (very low)
What are indications for use of peak flow meters?
- asthma
- some pts with COPD who have a component of reactive airways disease
What do peak flow meters tell us?
- objective measurement of severity of airway obstruction
- can help providers and pts assess asthma
- may help ID triggers
- peak flow can show changes before the pt becomes symptomatic
- take best out of 3 measurements and determine normals off of chart that comes with the meter
- children and adults use different meters
What should be administered first if on multiple inhalers?
- bronchodilator should be admin first
When are spacers recommended? What is the advantage of them?
- recommend use in elderly and children
- advantage: improve coordination b/t delivery of med from the inhaler and breathing it into the bronchial tubes
- they reduce the amt of med that settles in the mouth and throat
What are the goals of oxygen therapy?
- improve oxygenation
- long term O2 therapy in COPD if needed improves survival, quality of life and decreases all cause hospitalizations. These effects may have an even greater impact on women
Indications for long term oxygen therapy?
- PaO2 less than 88%
- cor pulmonale
What are the different O2 delivery systems?
- nasal cannula
- simple face mask
- venturi mask
- bag-valve mask
- can be delivered with Bi-PAP and CPAP