ch 42 Flashcards
define hypoxia
abnormal condition, O2 available to body cells is inadequate to meet metabolic needs
* low oxygen in tissue
define hypoxemia
abnormal deficiency of O2 in arterial blood
lab value 80-100mmHg
*low oxygen in blood
what are the clinical objectives for oxygen therapy
1.correct acute hypoxemia
2. decrease symptoms associated w/chronic hypoxemia
3.decrease the workload hypoxemia causes on heart and lungs
indications for oxygen therapy
*documented hypoxemia
*acute care situations in which hypoxemia is suspected
*sever trauma
*acute myocardial infarction
*short term therapy or surgical intervention
what is the PaO2 for a healthy person
80-100mmHg
what is the PaO2 for a COPD person
55-75mmHg
who is at risk for retinopathy
premature infants
PaO2>80mmHg
what happens when exposed to 100% FiO2
*oxygen toxicity
*pulmonary fibrosis&hypertension
*thickening of alveolar capillary membrane
25-30 hours of FiO2 at 100%
decrease lung compliance
increasing (PA-a)O2(A-aGradient)
decreasing exercising PO2
30-72 hours of FiO2 at 100%
decreasing diffusing capacity
nasal cannula
liter flow: 1-6liters
low flow
FiO2: 24%-44%
humidifier for 4L and above
advantages of nasal cannula as low flow device
*tolerable
*comfortable for patient
*easy to use?application
*low cost
*easy disposable
FiO2 levels of nasal cannulas
1L=24%
2L=28%
3L=32%
4L=36%
5L=40%
6L=44%
when would you use a bubble humidifier
4L or above
used to add moisture to oxygen, dry oxygen cause irritation of nasal passage
transtracheal catheters
-placed in trachea
-40-60% less O2 to achieve same PaO2 by nasal cannula
-Liter flow= 1/4- 4L
-requires maintenance & cleaning
-infections are possible
calculate minute ventilation formula
MV=RR x TV divide by 1000 to get liters
minute ventilation=respiratory rate x tidal volume
reservoir cannulas
-two type nasal and pendant
-liter flow=1-10L
-FiO2=24-60%
no humidification
reservoir
partial rebreather
vs
non rebreather
pr- no valve, reservoir
liter flow-10-15L
lowest-10L
CO2 rebreathing
FiO2- 40-70%
non- valve, reservoir
liter flow-15L above
lowest- 10L
CO2 rebreathing
FiO2- 60-80%
Magic Box calculation formula
(100 - FiO2%) / (FiO2%-20)= ratio
(ratio + 1) x liter flow= total flow
ex FiO2 is 40% and flow set is 8L
100-40=60 40-20= 20
60/20= 3L
3 + 1= 4
4 X 8= 32
what can happen if ports are obstructed on the air-entrainment masks
increased FiO2, decrease total output of flow
what are the 4 main functions of high-flow nasal cannulas
- deliver high FiO2
2.meet or exceeds patient inspiratory flow. - carbon dioxide washout from deadspace
4.generates a distending positive airway pressure
blending system
-provide high O2 cencentration flow
-precise control over FiO2 total flow output
-gases mixed manually or w/precision valve
-separate pressurized air&O2 sources are input
bag-mask valve system
-self inflating bag& non rebreathing valve to provide 100% O2
-used in emergency/life support/critical care
what are the 3 āPā of oxygen selection
- Purpose
2.Patient consideration - Performance
hyperbaric Oxygen, physiologic effects
theraputic use of O2 at pressures greater than 1atm
effects-
*bubble reductions-embolism
*hyperoxygenation of blood&tissue vascocontriction
*enhance immune function
*neovascularization
indications of hyperbaric oxygen therapy
Acute- decompression sickness, air/gas embolism, carbon monoxide poisoning, traumatic injury, severe anemia
chronic- diabetic wounds, osteomyelitis, actinomycosis, radiation necrosis
complications of hyperbaric oxygen therapy
Barotrauma- ear/sinus trauma, tympanic membrane repture, gas embolish
oxygen toxicity- CNS toxic reaction, pulmonary toxic reaction
other- depression, claustrophobia, decreased cardiac output
what is carbogen
carbon dioxide and oxygen
what is carbogen used for
hiccoughs, carbon monoxide poisoning, prevent washout of CO2 during cardiopulmonary bypass
evidence of documented hypoxemia
PaO2<60mmHg or SaO2<90% breathing room air
PaO2 or SaO2 below range for specific clinical situation
high flow system differ from low flow
high flow- meeds or exceeds peak inspiratory flow, fixed FiO2, 60L/min
low flow-O2 concentration 22-45%,low cost, easy application, disposable
simple mask
reservior
Liter flow 6-10L
FiO2= 35-50%
lowest liter flow= 6L
CO2 rebreathing
