week3 Flashcards
whats pi02
inspired oxygen
whats PA02
alveolar ocygen
whats Pa02
arterial 02
whats P02
cellualr O2
concentration of O2 in air
21%
whast air barometric pressure
100kPA
whats Po2 of dry air at sea level
21kPa
is tracheal gas higher or lower than inspired o2
less so because it gets humidified. its about 19.9 Kpa alors que inspired is 21kPa
Factors affecting alveolar PAo2
alveolar ventilation
oxygen consumption/Co2 production
what happens to PaO2 when alveolar ventilation increases
increases but will never reach PiO2 bc there will always be some Co2 in the lungs
equation for alveolar Po2
PAO2 = PiO2 - (PaCo2/R 0.8)
factor affecting alveolar to arterial po2 difference
shunting so as in not going through the lungs which causes relative desaturation
whats the nrmal alveolar to arterial po2 difference
less than 1.13 Kpa
normal PaO2 in kpa
11KPA (13.6 - (0.044 x age in years)
shape of oxygemoglobing cuve shape
and three main points
sigmoid
97% hemoglovbin saturation at 10 Kpa
74% hemoglobin saturation at 5.3 Kpa
50 (P50) hemoglobin saturation at 3.5 kpa
what does oxygen delivery depend on
and formula
oxygen satruation
hemogloin conc
CO
Hefners constant
conc Hb x ocygen satu x 1.34 x CO
what are the signs of respiratory failyre
- high respiratory compensattion (tachyponoa, use of acc muscles, nostril flaring, intercostal or sternal recession)
- increase sym tone (tachycardia, hyeprtension, sweating)
- jhemoglobin destaruation (cyanosis)
- end organ hypoxia (hypotension and bradychardia after some time and altered mental state)
- Co2 retention (flap, boudning pulse)
what are the two forms of respiratory failure adn expalin them
type I and type II
in type I you have hypoxemia only (less than 8 Kpa)
in type II you have hypoxemia (less han 8 kopa) and hypercapneia (over 6.5 kpa)
what conditions would present as type I resp failure
pneumonia, pneumothorax, pulmonary embolis, pum ededma, ateeltasis, collapse
what conditions would present as type II resp fialure
type I with fatigue
hypoventilation caused by depressant drugs, neuromuscular dx, brasitem pb, nerve trauma
indication for o2 therapy
resp fialure cardiac or resp arrest tachypnoea cyanosis hypotension metabolic acidosis
types of oxygen masks
Low flow masks
high flow masks
Peak inspiratory volume at rest
15L/min
Peak inspiratory volume at distress
30L/min
low flow masks vs high flow makss
- low flow are like nasal canula, simple face maks or wiht sotrage). deliver variable amounts of 02. deliver less than PIF. so amount of 02 delivered depends on pts ventilator abilites
- high flow like venturi mask (deliver constant ocygen level and more so than PIF)
which maks for post op or pt with normal vital signs
nasal cannula
which maks for pt w astham, pneumonia, sepsis
low flow mask with reservoir bag
which mask for controlled long term tratemnt of COPD
ventiru mask
venturi color and flow rate and 02 delivered
blue 2 24 white 4 28 yellow red 6 35 red 8 40 green 12 60
what to monitor while giving oxygen therapy
ABG
vital signs
critical thresolhf for SPO2
94%. under that is hypoxemia, bc after that any lower drop of Pa02 will give a sig drop in Sp02
what does pulse oximetry tell you
about oxygenation not ventirlation
source of error in pulse oximetry
color skin
nails
poor peripheral perfusion
excessive motion
what should Kpa be if SPo2 is over 94
over 10 Kpa
shoudl you give a lot of extra 02 or a little
minimum sinon oxygen radical s
what are c02 retainers
ppl who retian a lot of co2. due to gas exchange impariemnt
management of pt with unsure co2 reptainer
start high flow oxygen (venturi mask)
moniotr for drowniess, sx of co2 reatiner
check ABG after 30mins
management of pt with SURE co2 reptainer
starts high flow oxygen (venturi mask) chekc ABG ASAP titrate- use lowest 02 possible aim for sat 90 to 92 repeat ABG after 30 mons
when to call for help with patient
requiring 60% to mainting ok vitals severe tachypnoe a(over 30bpm) confusion/LOC Ph les than 7.2 pco2 over 8kpa
use ventialtion to correct hypoxia=?
NOOOO
ventialtion used for hypercapnea
give 02 for hypoxia and ventilate inhypercapnoa
treatment for hypoxia
02
machine of spirometry
spirometer
functin of spirometer
measures expired and inspired air
pt requirements for spirometry test
not tihgt clothers
sitting upright
technique for spirometry
patient tkaes deep in wiht the mouthpiece. then out very quickly, then in and maximum out.
gold standard test for OPD
spirometry
gold standrad test for RPD
DLCO
whats tidal volume
air in / out at rest
inspiratory reserve volume
volume of air you can draw into your lungs
expiratoyr reserve volume
volume of air you can expel from your lungs
residual volume
volume of air that remains in your lungs even after max exhalation
forced vital capacity and formula
max air in and out in 1 resp cycle .
FVC: inspiration reserve plus tidal volume, plus expiratory rserve
what vaues of spiro are reducxed in astham
lower FEV1. lower FVC, lower PEF and reduced flwo rate,
factors affecting spiromteyr
race
height
gender
age
how doe the flow volume loop change in astham
left shifting
how doe the flow volume loop change in COPD
right shifting
what happens to FEV1:FVC ratio in asthma
it dexreases because FEV1 reduces mroe significiantly
what happens to FEV1:FVC ratio in COPD
it increases because FVC reduces mroe significiantly
is lung volume higher or lower than normal in asthma
higher
is lung volume higher or lower than normal in COPD
lower
normal FEV1 value
70-80%
whats the funciton test to measurerespitary gas trasnfer
DLCO TLCO
what does DLCO meaysre
how efficient lungs are at exhcnaging gas
- ability of lungs ot trasnfer gas from inhaled air to RBC
- diffusing capacity of the lungs for CO
how do you perform DLCO
unforced exchakation to residucal volume then rapid inhalation of CO/helium to TLC then rbeath hold 10s then unforced exhalation less htan 4s.
unit of DLCO
ml/min/mmHG
DLCO formula
lung sufarce area availbe for gas trasfer x rate of capillary blood CO uptake (Kco)
which fcotr of the FLCO formula is refuced in ILD
rate of capillary blood uptake of CO
when is the use of DLCO useufl and problematic
useufl for dx of early ILD
not useful bc falsely reduces in individual who fail to inspire to TLC and so significifant refuxitonsl
when are exercise test useful
asssess how mnuch a pt is able to manage
assess benefit fo extras oxgen therapy to hekpo
asses preop fitness
part of rehab progrma
examples of exercises of tests
6 min walk on falt surfce. meausr eox sat after. and assess breahtless shuttle walk (asses distance and speed swlak) cardiopulmonary exercise (assess preop fitness)
test to assess preop fitness
cardiopulmonary exercxse
