- Joined
- Jul 21, 2013
- Messages
- 234
- Reaction score
- 9
Could someone explain this Uworld graph to me?
Graph of effects of v/q mismatch and pulmonary gas exchange
- Thread starter voicesinmyhead
- Start date
- Joined
- Sep 8, 2015
- Messages
- 283
- Reaction score
- 334
IMO this graph is trying to make clear that V/Q mismatch will result in hypoxemia most of the time , and RARELY hypercarbia . This happens coz you can exchange tons of CO2 in highly ventilated areas and ''overcome'' the mismatch , while with O2 , you can only exchange so much since blood gets saturated quickly , even in areas of the lung that are ventilating at ''maximum'' , so there is less capacity to ''compensate''..
Thats also why , if you do an ICU rotation , you 'll see that when you put someone on the ventilator(and they mostly have huge V/Q mismatches due to ARDS , Pulm Emboli w/e..) , you adjust their CO2 with ventilation changes(tidal volume,RR, pressures etc etc..) , and their O2 by changing the FiO2 % and the PEEP(more peep = more lung ''open'' for gas exchange) . After one point , you can ventilate with 1000L/min , there is no change in O2 at all..
Thats also why , if you do an ICU rotation , you 'll see that when you put someone on the ventilator(and they mostly have huge V/Q mismatches due to ARDS , Pulm Emboli w/e..) , you adjust their CO2 with ventilation changes(tidal volume,RR, pressures etc etc..) , and their O2 by changing the FiO2 % and the PEEP(more peep = more lung ''open'' for gas exchange) . After one point , you can ventilate with 1000L/min , there is no change in O2 at all..
Last edited:
