Respiratory Mechanics Flashcards
In the pons, the apneustic center has what kind of effect on the respiratory system?
Excitatory
In the pons, the pneumotaxic center may do what in some situations?
Inhibit inspiration
In the medulla oblongata, what complex is responsible for respiratory rhythm generation?
Dorsal/ventral respiratory groups
Pre-Botzinger complex
Label the volumes for total lung capacity:
What is kussmaul breathing?
Rapid, deep breathing at a constant pace that is often associated with a medical emergency with metabolic acidosis such as DKA
In Kussmaul breathing, what components do the peripheral chemoreceptors (primarily carotid bodies - glomus type I cells), detect which increases ventilation via the glossopharyngeal nerve?
Hypoxemia
Hypercarbia
Acidemia
Decreased perfusion
These types of receptors are mostly concerned with circulation, but in severe hypotension can lead to hyperventilation
Baroreceptors
For the 4 non-central receptors that can affect ventilation in kussmaul breathing, where are they located and what are they?
Carotid baroreceptor
Carotid body (chemoreceptor)
Aortic chemoreceptor
Aortic baroreceptor
Where is the central chemoreceptor located in the medulla, which as blood CO2 diffuses into the CSF, it increases hydrogen ions and decreases pH?
Retrotrapezoid nucleus
In kussmaul breathing, what part of the total lung capacity chart is being used to increase TV?
IRV
What determines the movement of O2 and CO2 across the blood gas interface in the alveolus?
Fick’s law
Wall thickness
Surface area
Diffusion gradient / pressures
CO2 is _____x more diffusible than O2
20x
Changes in surface area, diffusion constant, pressure and wall thickness preferentially decrease _____ over _____
Preferentially decrease O2 over CO2
Write Fick’s Law of diffusion of a gas
SA x D x (P1-P2)/T
SA = surface area
D = diffusion constant
P = pressure
T = thickness
What are the transpulmonary, intrapleural and intra-alveolar pressures?
What is the equation for dynamic compliance?
Cdyn = changeV / ChangeP
What is the relationship between change in pressure, resistance and flow?
changeP = R x V*
where V* = flow
What two components of the endotracheal tube determine the pressure drop from Paw to P1?
Diameter and length
Label the pressure waveform:
Define pendelluft?
The movement of gas between two regions of the lung, usually between regions of differing compliance or airway resistance.
Which alveoli (upper, middle, lower) are much lower on curve due to weight of lungs above, and can accept more volume/change in pressure?
Lower
With the numbers of 20, 35, 45, what is the distribution of tidal volume?
Upper: 20
Middle: 35
Lower: 45
What are the 2 components that affect the pressure-volume relationship?
Resistance and static compliance
30kg 6y/o MC MBD
VT = 250mL
RR = 18
Tinsp = 1 sec
PIP = 12 cmH2O
Pplat = 11 cmH2O
PEEP = 5 cmH2O
Calculate Cdyn
Calculate Cstat
Calculate R
Cdyn = VT/(PIP-PEEP)
35.7mL/cmH2O
Cstat= VT (Pplat-PEEP)
41.7cmH2O
R= PIP - Pplat / flow
4cmH2O/L/s
What is the equation for Cdyn using body weight?
Cdyn = BW(kg) + 9
Label the following graph and describe what procedure is being performed:
Expiratory hold
Helps determine air-trapping
