Great presentation. If I may, the reason why we see such a large difference between PIP and Pplat with the increased Resistance is because of the relationship between Ti and the Inspiratory Time Constant. Theoretically, in a Pressure-controlled mode, set Inspiratory Pressure and Pplat will always equalize given a sufficiently long Ti, no matter how great the Resistance or Time Constant. When Resistance is normal, your Ti of one second is *almost* long enough that the set Inspiratory/Peak Pressure and the Plateau Pressure equalizes. So, if you had a Flow waveform displayed on the screen (instead of Pressure and Volume waveforms), you would've seen that your Inspiratory Flow wave almost returns to baseline prior to Expiration. (Note that the point when the inspiratory flow waveform returns to zero/baseline is the point where the pressures from the machine and the lungs are equal - e.g. PIP = Pplat in PC modes. This is also the theory behind the Inspiratory Hold; e.g. your Pplat is the pressure in the circuit when there is no flow, after a Vt is delivered). When you increased Resistance, you increase the time it takes to fill the lungs (the Inspiratory Time Constant). So in order to achieve the same Plateau Pressure as before (in your case, 450mL) it will either take much more inspiratory pressure or a much longer Ti. However, since PRVC cannot change Ti, it has to substantially increase Inspiratory Pressure, and if you throw up the Flow waveform, you'll see the Inspiratory Flow waveform is no where close to returning to baseline before expiration begins - i.e. the pressures between the vent and the lungs are not at all close to each other (which is why there is still flow). If you increased your Ti to like, 5 seconds, you will see a much smaller difference between PIP and Pplat in PRVC at the higher Resistance.
You are 100% correct and the first person to bring this to the table. I discovered this to be true when diving deeper into the flow pattern and time constants. Where have you been my entire career? Thank you for your contribution to the conversation. I truly appreciate you watching and commenting!
Best presentation so far i have seen . I my self trained by Hamilton and Ndd Switzerland and have trained many in this field and as a mode prvc which is more patented by getinge Maquet has little different definition and controlled parameters . Kindly telly with them by practical use of machine on same mode .as this was life saving mode in covid and many abnormal lung condition such as atelectasis,lung hypoplasia , pulmonary edema and ards where pressure and pressure gradients play vital role and challenge for Interventional pulmonologist. So in any condition lung should not go beyond a certain pressure limit and need to improve volume within pressure as the lung is stiff. My best wishes are with you, as i know hardly few people in this world have a clear concept about the ventilator technology as accepted by many doctors . Which is the major cause of big loss in covid .best of luck .
This is another outstanding presentation. Couch correct me if Im wrong with PRVC the goal to reach target Tidal volume by adjusting PIP and not Pplat. The Pplat has to do only with lung compliance that is why when you changed Resistance there was a difference between PIP and Pplat in PRVC. Thank you for all your hard work and I learn from you
Good morning coach! How to determine the best inspiratory pressure from volume control to change to pressure control mode? What is the normal inspiratory pressure can be applied on the ventilator to set someone on pressure control mode regardless of what type of ventilators?
840 is best .and the matter related to hfnc is diffrent concept with ventilation and saparate device use for hfnc . As it has no role play both segment of ventilator as it is priority for upper respiratory tract system
Great presentation. If I may, the reason why we see such a large difference between PIP and Pplat with the increased Resistance is because of the relationship between Ti and the Inspiratory Time Constant. Theoretically, in a Pressure-controlled mode, set Inspiratory Pressure and Pplat will always equalize given a sufficiently long Ti, no matter how great the Resistance or Time Constant. When Resistance is normal, your Ti of one second is *almost* long enough that the set Inspiratory/Peak Pressure and the Plateau Pressure equalizes. So, if you had a Flow waveform displayed on the screen (instead of Pressure and Volume waveforms), you would've seen that your Inspiratory Flow wave almost returns to baseline prior to Expiration.
(Note that the point when the inspiratory flow waveform returns to zero/baseline is the point where the pressures from the machine and the lungs are equal - e.g. PIP = Pplat in PC modes. This is also the theory behind the Inspiratory Hold; e.g. your Pplat is the pressure in the circuit when there is no flow, after a Vt is delivered).
When you increased Resistance, you increase the time it takes to fill the lungs (the Inspiratory Time Constant). So in order to achieve the same Plateau Pressure as before (in your case, 450mL) it will either take much more inspiratory pressure or a much longer Ti.
However, since PRVC cannot change Ti, it has to substantially increase Inspiratory Pressure, and if you throw up the Flow waveform, you'll see the Inspiratory Flow waveform is no where close to returning to baseline before expiration begins - i.e. the pressures between the vent and the lungs are not at all close to each other (which is why there is still flow). If you increased your Ti to like, 5 seconds, you will see a much smaller difference between PIP and Pplat in PRVC at the higher Resistance.
You are 100% correct and the first person to bring this to the table. I discovered this to be true when diving deeper into the flow pattern and time constants. Where have you been my entire career? Thank you for your contribution to the conversation. I truly appreciate you watching and commenting!
Right on point William Ngai. I was discussing and demonstrated this at work this past Sunday, 10/9
@@RespiratoryCoach Hello there, can explain this more clearly in one of your great videos, please?
Yes!
Best presentation so far i have seen . I my self trained by Hamilton and Ndd Switzerland and have trained many in this field and as a mode prvc which is more patented by getinge Maquet has little different definition and controlled parameters . Kindly telly with them by practical use of machine on same mode .as this was life saving mode in covid and many abnormal lung condition such as atelectasis,lung hypoplasia , pulmonary edema and ards where pressure and pressure gradients play vital role and challenge for Interventional pulmonologist. So in any condition lung should not go beyond a certain pressure limit and need to improve volume within pressure as the lung is stiff. My best wishes are with you, as i know hardly few people in this world have a clear concept about the ventilator technology as accepted by many doctors . Which is the major cause of big loss in covid .best of luck .
This is another outstanding presentation. Couch correct me if Im wrong with PRVC the goal to reach target Tidal volume by adjusting PIP and not Pplat. The Pplat has to do only with lung compliance that is why when you changed Resistance there was a difference between PIP and Pplat in PRVC. Thank you for all your hard work and I learn from you
Thank you so much for all your hard work I understanded this topic very well although it seems to be difficult .
Best presentation ! Can you make a video regarding blood gas abnormalities and ventilator settings!
Good morning coach! How to determine the best inspiratory pressure from volume control to change to pressure control mode? What is the normal inspiratory pressure can be applied on the ventilator to set someone on pressure control mode regardless of what type of ventilators?
Thank you
What view setting on the Draeger allows to have loops on the left and the waves forms??? Ive tried this but cant find the view setting ...
What do you think about the PB 980? At the hospital I have been interning at they have switched to using them with the 840s on standby.
980 rocks ... can also be used w hfnc
as hfnc
840 is best .and the matter related to hfnc is diffrent concept with ventilation and saparate device use for hfnc . As it has no role play both segment of ventilator as it is priority for upper respiratory tract system
Any body who studied or worked on body box plythsmography. Or Multiple breath DLCO system can easily under stand .
Awesome presentation, can I buy you a better audio set up? Lol