Tslope

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The inspiratory pressure rise time or the slope is determined by measuring the time required for the pressure to rise from the end expiratory pressure to the peak inspiratory pressure. In pressure control ventilation, the shorter the rise time (higher slope), the higher and the steeper the peak flow is. At the same time the volume wave will reflect the higher flow with the increase concavity of the curve as a result of a higher volume delivered earlier in inspiration


I typically prefer PC-VG which means the computer in the ventilator calculates the minimum pressure needed to obtain sufficient TV over several breaths.
 
For PS Ventilation the Tslope seems to matter a great deal in terms of the work involved in breathing (joules).

pubmed.ncbi.nlm.nih.gov

Effects of pressure ramp slope values on the work of breathing during pressure support ventilation in restrictive patients - PubMed

Among the four tested slope values, the steepest was that which induced the lowest possible work of breathing in restrictive patients ventilated by pressure support ventilation. In this type of patient, we therefore suggest that the programmed pressure value should be reached by using a steep...
pubmed.ncbi.nlm.nih.gov pubmed.ncbi.nlm.nih.gov
 
www.sciencedirect.com

Clinical management of pressure control ventilation: An algorithmic method of patient ventilatory management to address “forgotten but important variables”

Pressure controlled ventilation is a common mode of ventilation used to manage both adult and pediatric populations. However, there is very little evi…
www.sciencedirect.com www.sciencedirect.com


Pressure versus time waveform​

Fig. 1 is an example of a typical waveform of a patient ventilated in PC-CMV. In this example, PIP 24 cm H2O, TI 0.9 s, f 20/min, PEEP 6.0 cm H2O, Slope 0.20 s. The pressure-versus-time waveform (Fig. 1, Top Waveform) shows that at the beginning of inspiration, the ventilator increases the airway pressure from the PEEP level of 6 cm H2O up to the set PIP of 24 cm H2O; the time to reach this PIP is set with the slope and in this case, it is set at 0.20 s. Inspiration continues until the set inspiratory time of 0.90 s has been reached. At that time, inspiration ends and the patient is allowed to exhale back to the PEEP level of 6 cm H2O.
 
waterbottle10 said:
What Tslope do you like to set on your ventilators and why?
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To achieve an inspiratory plateau, the chosen flow has to deliver the set tidal at a shorter time than the set inspiratory time. Luckily in all ventilator brands these calculations are presented on the ventilator setup screen, so the user does not have to perform them manually.


 
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In my anecdotal experience, patients tend to transition from VC or PC onto PSV more smoothly (less bucking) when the initial TSlope for the PSV is at least 0.2 or 0.3 seconds. Honestly, it just feels more physiologic- and I say this from personal experience. Anyone who has never put themselves on a ventilator and tried different modes is missing a fundamental feel for what these modes are like to a more awake patient with intact respiratory drive- just get a clean circuit, stick the tube in your mouth, pinch your nose, and play around with the settings. PSV with a steep TSlope feels like every time you initiate a breath, the vent turns on and tries to piledrive a bunch of air down your throat... with a bit of a shallower TSlope, the acceleration phase of the breath more closely matches what you might take with a spontaneous breath (and makes you want to spit the tube out a little bit less)
 
Hork Bajir said:
In my anecdotal experience, patients tend to transition from VC or PC onto PSV more smoothly (less bucking) when the initial TSlope for the PSV is at least 0.2 or 0.3 seconds. Honestly, it just feels more physiologic- and I say this from personal experience. Anyone who has never put themselves on a ventilator and tried different modes is missing a fundamental feel for what these modes are like to a more awake patient with intact respiratory drive- just get a clean circuit, stick the tube in your mouth, pinch your nose, and play around with the settings. PSV with a steep TSlope feels like every time you initiate a breath, the vent turns on and tries to piledrive a bunch of air down your throat... with a bit of a shallower TSlope, the acceleration phase of the breath more closely matches what you might take with a spontaneous breath (and makes you want to spit the tube out a little bit less)
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I just leave them paralyzed until the end then sugammadex and spontaneous. No bucking no problem!
 
GassYous said:
I just leave them paralyzed until the end then sugammadex and spontaneous. No bucking no problem!
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I mean, sure, that’s one way to practice. Doesn’t work as well (or at all) if you do neuromonitoring cases, patients with ESRD, women of child-bearing age, etc
 
While sitting my own cases with my patient on pressure support I routinely run slope of 0.5 or so. Less routinely with controlled modes, but that's becoming more routine for me as well. It's much more physiologic (Who here likes to suck in their entire breath as fast as possible all day long?).

If for some reason my patient doesn't already have some slope (i.e. when supervising) and their respiratory pattern is wonky, adding a little slope almost always smooths things out and improves SpO2.

Not all machines give you the option of adding some slope, but if you do, I implore you to give it a try.
 
Hork Bajir said:
Doesn’t work as well (or at all) if you do neuromonitoring cases, patients with ESRD, women of child-bearing age, etc
Click to expand...

Safety and Effectiveness of Sugammadex in Surgical Patients with End Stage Renal Disease: A Multi-center Retrospective Analysis
Douglas Adams, M.D., Luis E. Tollinche, M.D., Cindy B. Yeoh, M.D., Jamie Artman, C.R.N.A., Meghana Mehta, M.S., Dennis P. Phillips, D.O., Gregory W. Fischer, M.D., Joseph J. Quinlan, M.D., Tetsuro Sakai, M.D., Ph.D., FASA
UPMC, Pittsburgh, Pennsylvania , United States

Discussion: There exists pharmacokinetic studies of sugammadex in patients with ESRD that show no instances of recurarization [1,2,3]. In our 158 patients, 136 were extubated at the end of the case. Of these, there were three instances of re-intubation within 48 hours; however, there was no evidence of definitive instances of recurarization. This study does not address the impact of the sugammadex-rocuronium complex which is not cleared in ESRD or with standard forms of HD. Studies with longer follow up are also needed.

Conclusions: Sugammadex appears to be safe without recurarization 48 hours after administration in patients with ESRD.

1617066266668.png



While the Bridion package insert recommends against its use in ESRD, mounting evidence suggests it's safe.
 
Reveler said:
Safety and Effectiveness of Sugammadex in Surgical Patients with End Stage Renal Disease: A Multi-center Retrospective Analysis
Douglas Adams, M.D., Luis E. Tollinche, M.D., Cindy B. Yeoh, M.D., Jamie Artman, C.R.N.A., Meghana Mehta, M.S., Dennis P. Phillips, D.O., Gregory W. Fischer, M.D., Joseph J. Quinlan, M.D., Tetsuro Sakai, M.D., Ph.D., FASA
UPMC, Pittsburgh, Pennsylvania , United States

Discussion: There exists pharmacokinetic studies of sugammadex in patients with ESRD that show no instances of recurarization [1,2,3]. In our 158 patients, 136 were extubated at the end of the case. Of these, there were three instances of re-intubation within 48 hours; however, there was no evidence of definitive instances of recurarization. This study does not address the impact of the sugammadex-rocuronium complex which is not cleared in ESRD or with standard forms of HD. Studies with longer follow up are also needed.

Conclusions: Sugammadex appears to be safe without recurarization 48 hours after administration in patients with ESRD.

View attachment 333716


While the Bridion package insert recommends against its use in ESRD, mounting evidence suggests it's safe.
Click to expand...

Sugammadex is what I give ESRD patients after neostigmine/glycopyrrolate doesn’t work adequately.
 
SaltyDog said:
In order for me to appropriately answer that question, you’re gonna need to provide some additional information like, what’s a Tslope??
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I wasnt aware there were any other settings on the vent other than the APL valve toggle.
Once you flip that over, its chair time so there cant really be any more
 
anbuitachi said:
depends on the patient. somewhere from 0.5 to 1 usually
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I think it depends on the mode of ventilation. Typically, with PC ventilation the Tslope is around 0.2. For PS Ventilation the Tslope can be in the 0.5 second range unless oxygenation is not sufficient then some "experts" recommend a faster rise in inspiration or a Tslope of 0.1-0.3 seconds.

For my cases, I don't need to mess with Tslope. I use the standard setting on my ventilator (typically around 0.2). I use PS for my LMA cases and those patients are NOT critically ill so the Tslope doesn't make much difference as I add only some PS of 4-10 for these LMA cases.

I humbly submit to those on SDN that the Tslope is not clinically relevant for 99.5 % of the cases we do in the O.R. but I did enjoy reading up on it.
 
BLADEMDA said:
I think it depends on the mode of ventilation. Typically, with PC ventilation the Tslope is around 0.2. For PS Ventilation the Tslope can be in the 0.5 second range unless oxygenation is not sufficient then some "experts" recommend a faster rise in inspiration or a Tslope of 0.1-0.3 seconds.

For my cases, I don't need to mess with Tslope. I use the standard setting on my ventilator (typically around 0.2). I use PS for my LMA cases and those patients are NOT critically ill so the Tslope doesn't make much difference as I add only some PS of 4-10 for these LMA cases.

I humbly submit to those on SDN that the Tslope is not clinically relevant for 99.5 % of the cases we do in the O.R. but I did enjoy reading up on it.
Click to expand...

yea agree. sorry i was thinking of PS mode but didnt type it
 
I use whatever the default on the machine is, 99% of the time.

Hork Bajir said:
In my anecdotal experience, patients tend to transition from VC or PC onto PSV more smoothly (less bucking) when the initial TSlope for the PSV is at least 0.2 or 0.3 seconds. Honestly, it just feels more physiologic- and I say this from personal experience.
Click to expand...
And I totally agree with this, it matches my observation.

It seems with a zero or very short slope, with some patients, the abrupt addition of pressure to the circuit causes hiccup-like or cough-like hitches in the respiratory cycle. Anecdotally, making the slope time .2-.3 seconds fixes this.
 
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