CMV Flashcards
ventilation
normal movement of gases into and out of the lung
external respiration
gas exchange b/w the lung and the blood stream
internal respiration
gas exchange b/w the blood and the cells - cellular level
on inhalation describe what happens in the thoracic cavity
diaphragm descends and enlarges the vertical size of the thoracic cavity, the external intercostals contract and raise the ribs slightly increasing thorax
on exhalation describe what happens in the thoracic cavity
exhalation is passive and diaphragm returns to normal position
what must you have to have flow
must have pressure gradient to have flow
what causes a volume change
gas flow
when is there no gas flow
at end of inhalation and end or exhalation
what pressure do you measure vent pressure in
cmH2O
what reference is equal to 760 mmhg for vents
zero reference
proximal pressure is often called what
Pawo or Pm
unless pressure is applied the upper airway Pawo is what
zero
what is intrapleural pressure (Ppl)
pressure in the potential space b/w the parietal and visceral pleura
Nml intrapleural pressure is what at the end of expiration and what at the end of inspiration
-5 and -10
what changes as intrapleural pressure changes
alveolar pressure (intrapulmonary pressure) Pa
what are the four basic pressure gradients
transairway pressure, transthoracic pressure, transpulmonary pressure, transrespiratory pressure
transpulmonary pressure
alveolar pressure - pleural pressure
transthoracic pressure
alveolar pressure - body surface pressure
transairway pressure
airway pressure - alveolar pressure
transrespiratory pressure
airway pressure - body surface pressure
where do you measure pressure
very close to the mouth or inside ventilator
baseline pressure
usually pressure at end expiration before next breath
what raises baseline pressure
PEEP
peak pressure
highest pressure recorded at the end of inspiration
