Resp Therapy Equipment Flashcards
What are the two types of pulse oximetry?
transmission- light passes through tissue to the sensor
reflectance- sensor and source are side by side
How does pulse oximetry work?
Based on the Beer-lambert law (concentration of absorbing substance in a solution is related to the intensity of light transmitted through that solution)
- 2 diodes emit alternating light wavelengths (red light which is absorbed by deoxygenated blood and infrared light which is absorbed by oxygenated blood)
- ratio of absorption is measured and the O2 saturation of hb is derived
Factors that affect pulse ox results
- dark skin pigment
- nail polish
- acrylic nail
- motion
- ambient or excessive light
- hypoperfusion (may overestimate)
- hypoxia (less reliable below 80%)
- dyshemoglobinemias (COHb absorbs light in the red wavelength similar to oxyhemoglobin, falsely elevated)
- methemoglobin (Fe3+ vs normal Fe2+, absorbs red and infrared light)
- IV dyes
Peak Flow Meters
Indications
what is it
Indications
- asthma
- some pts with COPD who have a component of reactive airway disease
What is it
- an objective measurement of the severity of airway obstruction
- uses best out of 3 measurements
- may help identify triggers
Metered dose inhaler
-recommdations for use
recommdations for use
- if on multiple inhalers, administer bronchdilator first
- recommend use of a spacer
Why use a spacer?
- improve coordination between delivery of the medication from the inhaler and breathing it into the bronchial tubes
- reduce the amount of medication that settles in the mouth and throat
Types of nebulizers
hand held hand held with mask blow by home neb unit compact neb
Goals of oxygen therapy
- improve oxygenation
- long term O2 therapy in COPD if needed improves survival, quality of life and decreases hospitalizations
O2 delivery systems
nasal cannula simple face mask venturi mask bag-valve mask bi-PAP or CPAP
What are the methods used to deliver home oxygen?
- compressed O2 (tanks)
- liquid O2
- O2 concentrators
*all inhaled through mask or cannula
A nasal cannula provides 6L of O2.
What percent oxygen does nasal cannula provide?
6L=44% oxygen
How much oxygen does 1L/min flow rate provide? what is the rate of increase?
1 L/min=21-24%
-increasing the O2 flow rate by 1 L/min equates to an increase of about 4% FIO2
2 L/min= 25-28%
3=29-32%
4=33-36%
5=37-40%
How much O2 does a simple face mask provide?
40-60% (5-10L)
*minimum flow of 5L/min needed
What is a venturi mask? Who is it good for?
- mask that accurately controls the proportions of inspired oxygen
- good for patients who retain CO2 and pts who have moderate to severe hypoxemia
How much O2 does a non-rebreather mask provide?
How much is required?
When to use
Provides up to 90% O2
Need flow rates of 8-10 L/min
Used for seriously ill, responsive and spontaneously breathing who require high O2 content. Also used to avoid tracheal intubation if acute intervention produced a rapid change.
Bag valve mask/ambu bag
what is it?
disadvantages
one way valve mask/bag with an O2 for supplemental O2
disadvantages
- mask must be sealed tightly over mouth and nose
- need to coordinate breaths with any spontaneous respiratory effort
Oxygen Toxicity
what is it?
possible adverse effects
What is it?
- parenchymal lung injury due to supplemental O2
- thought to be secondary to the production of oxygen free radicals that result in tissue destruction
Possible adverse effects
- absorptive atelectasis (washout of alveolar N2 and atelectasis may occur if O2 diffuses out of the capillaries faster than entering
- extrapulmonary toxicity (seizures, retinopathy, coronary vasoconstriction, decreased stroke volume and cardiac output, bradycardia and increased systemic vascular resistance)
- accentuation of preexisting hypercapnia (increased CO2 associated with supplemental O2 in pts with chronic compensated resp acidosis
- airway injury (larger airway inflammation, erythema, and edema)
- parenchymal lung injury (destruction of alveolar tissue likely secondary to O2 free radicals causing inflammation and cellular death)
Oxygen Toxicity
Prevention
- FIO2 less than 60% likely safe without toxicites
- aim for PaO2 60-70 mmHg or SpO2 90-93% with therapies
Hypoxic drive pathophys
- chemoreceptors normally rely on CO2 levels to regulate ventilation
- if chronic elevated CO2 levels occur the body resets and becomes less sensitive to elevated CO2 and the drive to breathe shifts over to rely on lower levels of O2
- in these patients the addition of supplemental O2 can decrease the drive to breathe and maintain their minute ventilation leading to worsening respiratory failure.
