Respiration And Respiratory Monitoring Flashcards
Euthermic 70 kg pt, metabolic jumping off point
242 ml/min
Metabolic jumping off point equation
Vo2= W^0.75 * 10 (ml/min)
Respiratory quotient
R=Vco2/Vo2
Resp quotient for metabolically euthermic patient
0.8
CO2 production equation
Vco2=Vo2*R
Vco2 for metabolically normal 70kg pt
Vco2=242 ml/min * 0.8
= 194 ml/min
Co2 produced where in cell?
Mitochondria
Minute ventilation
Total vol of gases moving into and out of the lungs each minute
Minute ventilation for pt w equal tidal volumes (equation)
Ve=Vt*f
Pt w breaths of diff vol, min vent equation
Ve=summation of Vt in one minute
Co2 leaves gas exchange region by
Diffusion
Co2 transported thru conducting airway by
Convection to the mouth and nose
Pressure H2O
47 mmHg at 37C
Pbar at sea level
760 mmHg
Pbar atl
737 mmHg
Boyles law
P1V1=P2V2
Dalton’s law
P1+P2+…+Pn=Ptotal
Fractional concentration
Fx=Px/Ptotal or f1+f2+…fn=1.00
Alveolar ventilation (Va)
Total vol of gases flowing into and out of gas exchange region each minute
Partial pressure of co2 in alveoli
Paco2=40mmhg (ideal alveolar value for a normal eucapnic pt)
Normal range for paco2
36-44 mmHg
Water vapor pressure
47 mmHg
Total pressure of gases in alveoli under dry conditions
Pbar=737-47mmhg=690mmhg
Calculate alveolar ventilation
Paco2Va=pbarvaco2 ==> paco2/Pbar=vaco2/va
Alveolar ventilation (to get co2 out of parynchema) for 70kg euthermic pt
3346ml/min
Faco2=paco2/Pbar for euthermic 70kg pt
0.06
Va=vaco2/faco2
Va=194ml/min / 0.06 =3346 ml/min
Volume of conducting airways
Anatomic dead space
VdANAT
Anatomical dead space calculated based on weight
VdAnat constant
2.2ml/kg =1ml/lb
Anatomic dead space ventilation (V w dot on top) is product of
Anatomic dead space times respiratory rate
For 70kg pt breathing 10 times per min , dead spaces ventilation would be
Vdanat=(vdanat2.1ml/kg)10
Anatomic dead space ventilation
Less than amount needed to get rid of co2 in airway as compared to parynchema
Minute ventilation
Total vol of gases moving into and out of lung each Minute
Minute ventilation equation
Ve=va+vdanat
Minute ventilation for 70kg pt breathing 10x/min
Ve=va+vdanat=3346 +1540 ml/min =4886 ml/’min
How to calculate tidal volume
Vt=ve/f = 4886ml/min /10 ml =488.6 ml (set your tidal vol to this
What’s coming out when we breathe?
Upper, lower, alveolar gasses
Plateau in waveform in capnography
Alveolar has leaving parenchyma
The only true measure of effectiveness of ventilation
Arterial partial pressure of co2 (paco2)
O2 is carried in whole blood in what 2 forms
Dissolved o2 and o2 bound to hemoglobin (in equilibrium w one another)
Where does the gas exchange region begin?
17th generation
Where does the gas exchange region end?
23rd generation
Lung compliance is the
Ability for the lungs to expand
Compliance equation
Change in volume divided by change in pressure
Lung thoracic compliance equation
Clt=tidal volume / airway pressure . (Vt/Paw) in ml/cmh2o
Total Compliance for normal awake pt
100 ml/cmh2o
Smaller the lung thorax compliance number =
Less compliance meaning lungs r more stiff and rigid
Lung and thorax in a series
1/Clt=1/Cl + 1/Ct where these are individual compliance a
Normal lung compliance
200ml/cmh2o
Normal thoracic compliance
200ml/cmh2o
An obese patient more than likely will have a
Small thoracic compliance ie 50ml/cmh2o and can have a normal lung compliance (patients will vary)
