respiratory quiz Flashcards
(38 cards)
Forced expiratory volume (FEV)
- a test which limits the time a subject has to expel vital capacity air.
- Normal 97% in 3 sec
- Reduced in restrictive pulmonary diseases.
Maximal voluntary ventilation (MVV)
- measures both volume and flow rates to assess overall pulmonary ventilation function
- pt inspires and expires and deeply and fast as possible while tidal volume and RR are measured
- look at average volume/respiratory cycle.
- tends to be reduced in both restrictive and obstructive diseases
spirometer
the instrument used to measure breath
spirogram
the record of volume change versus time of breath
tidal volume
- the volume of air inspired or expired during a single normal breath
- ~500mL at rest
Inspiratory reserve volume (IRV)
- the volume of air that can be maximally inhaled after tidal inspiration
- resting IRV is male: 3300mL
- Female: 1900mL
- IRV decreases with
- increased age
- decreased compliance
Expiratory reserve volume (ERV)
- the volume of air that can be maximally expired after tidal expiration
- males: 1000mL
- Females: 700mL
- ERV decreases with
- increased age
- decreased lung elasticity
Residual volume (RV)
- the volume of gas remaining in the lungs at the end of maximal expiration
- does not change with exercise
- Male: 1200ml
- Female: 1100ml
- Residual increases with
- increased age
Inspiratory capacity (IC) =
Tidal Volume (TV) + inspiratory reserve volume (IRV)
Expiratory capacity (EC) =
Tidal volume (TV) + expiratory reserve volume (ERV)
Functional residual capacity (FRC) =
expiratory reserve volume + residual volume
ERV + RV
Vital capacity (VC) =
- inspiratory reserve volume + Tidal volume + expiratory reserve volume
- IRV + TV + ERV
- Sum of the three primary lung volumes
- Vital capacity decreases with
- age
- restrictive disorders
Total lung capacity (TLC) =
inspiratory reserve volume + tidal volume + expiratory reserve volume + residual volume
IRV + TV + ERV + RV
Influencing factors on the rate of diffusion
- partial pressure - directly
- surface area - directly
- thickness of the membrane - indiretly
- solubility of gas - direclty
- CO2 is 20x more soluble than O2
Alveolar ventilation of the lungs
Ideal ratio vs. Real ratio
Why?
- Ideal is 1:1
- Real is 0.8-0.9:1
- Regional airflow assumes all parts of the lungs are equally ventilated and perfused.
- Reality is the base has greater alvealar ventilation due to a number of factors
Influencing Factors for ventilation-perfusion ratios: air flow to the base
- Larger transpulmonary pressure across the lung base
- Increased airway resistance in the upper passages
- Alveolar O2 and CO2 levels
- High CO2 cause decreased blood flow (high levels cause vasoconstriction and low blood flow)
- High O2 cause the greates blood flow (high levels cause vasodilation and increased blood flow)
- Gravity
- Upright position keeps a larger percentage of blood in the lung base
Boyle’s Law
PV = K
Dalton’s law
Pressure = P1 + P2 + P3 + etc
Muscles of inspiration
external intercostals, diaphragm
Muscles of expiration
- Normal expiration = relaxation of inspiratory muscles
- Forced expiration = internal intercostals and rectus abdominus
Compliance is
- CL = V/P
- the measurement of lung distensibility or the ease of stretching
- NOTE: compliance refers ONLY to INSPIRATION!
Compliance curve shows
- the ease of inflatability against averages
- steep slope = easily inflatable
- flat slope = difficult to inflate
Calculation for the transpulmonary pressure
P(Transpulmonary) = P(alveolar) - P(interplural)
Calculation for pulmonary ventilation
Pulmonary ventilation = TV x RR
