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Respiration: The mov’t of gases to provide E (O2) & eliminate waste products (CO2).
4 Stages of Ventilation:
1. Ventilation – mov’t of O2 in & CO2 out of the alveoli.
2. Ex∆ of gases across the alv – cap membrane (O2 to pul cap & CO2 t o alv).
3. Transport of gases in the blood.
4. Ex∆ of gases at the tissue level.
Alv are considered gas ex∆ areas & everything above the alv are ventilated only.
Pul artery carried de O2 blood back to the cap which encloses the alv & hbg becomes O2, the pul vein carries O2 Hgb to the L.A. & then pumps it out to the rest of the body.
Lymph sys is imp with ARDS B/c it cleans up excess debris & fluid in the interstitial spaces.
CHF there is a back up of blood & fluid into the pul vein ↑P in the pulvein so fluid travels into interstitial spaces, usually the lymph system carries it away, but it becomes too much, seeping into alv causing pul edema.
VT =amt of air exhaled after a N inhal N= 7-9 cc/kg
Ie. 70 kg man (7-9 cc/kg ) = 490-630 cc
This calc N tidal vol, but problems arise when vent is obs, pt must ↑RR to move same vol = min vent.
VE= Total vol of air that vent lungs in 1 min N = 5000-10000cc/min or 5-10 L/min
Ie. VE= VT(RR) VT= 500 RR=15 VE =500x15= 7500 7.5 L/min
∆in total vol impacts pt more than ∆ in RR.
1. MECHANICAL PROCESS:
A). Muscles of ventilation: Diaphragm – flattens & pulls down on inhal
Ext intercoastals: pull ribs out & up
Inhal is an active process req E / WOB
Accessory muscles: SCM, scalene assist with forced inhal
Expiration= N passive process not req E. If using abd & internal intercostals = E & WOB for forced exhale.
B). LUNG THORAX R/L:
Plural layer surrounds lungs, it has 2 layers, Parietal plura attaches lung to chest wall & diaphragm at main stem bronci it folds & becomes viseral plura layer. The 2 layers pu...
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