Do you work with PA lines often? Are they really a thing of the past?

We use them often in our MICU for pulm htn patients and in CTICU/CCU for most patients. Depends on the unit, but we regularly wedge (q4 for cards patients) and calculate CO #s and have available for the teams. Technically should have an order for how frequently to wedge/run numbers but in reality this doesn't happen. 

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Never only in CTICU.

I use them regularly but only in fresh open-heart patients and mechanical-circulatory-support patients.  And even then, not every OHS patient even has one.

We don't wedge though, nobody should.  The only exception is inflating the balloon to "float" the line into place and possible inflation to confirm positioning.

The reason why routine wedge pressure monitoring is a bad idea, and has been considered generally bad practice since the early 1980's, is that it has a high risk of killing someone and yet offers little if any benefit in clinical decision making that isn't already available from other hemodynamic data and assessments.

The rate of pulmonary artery rupture with each balloon inflation is 0.2%, or about 1 in 500.  Half of those patients, even when taken emergently to the OR, will die.  So that's one death for every 1000 balloon inflations.  That may not sound that bad, but consider a medium sized OHS program might do 500 cases per year, if wedge pressures are obtained on these patients 4 times during their recovery then that will kill 2 of them per year.  For a not particularly useful number.

The ICU I currently work in uses them from time to time in severe septic patients or those with impellas. We get maybe one a month, unit is 20 beds.  That's very odd that RNs and even some MDs can't wedge.  When we have Swans, we obtain wedges and other values at a minimum q4h. 

It is my understanding the cardiac ICUs use them much more regularly. I know some places have gone away from them because you can obtain a lot of the same information with less invasive measures like FloTrac using an arterial line or Cheetah NICOM. Can give you numbers like strove volume, cardiac output, cardiac index, etc. without needing the invasiveness of a Swan. 

I've only seen them sparingly used, usually we use the less invasive methods (though they are less accurate) but I don't think in most cases of general ICU medicine they make that much of a difference in outcomes from the studies, Of course this may change. Seems like we have all these cool tools in medicine but a lot just don't pan out to be helpful in most cases. I can't speak for the post op CV service though as thoracic surgery manages those patients.

Often used in our cardiothoracic surgial ICUs. Patients are risk profiled before surgery via pre-op heart function, and I'm sure the MDs have an algorithm for which patients to swan before cardiac surgery. They provide useful information in assessing cardiac function when serial echo's are not feasible. For example, when a patient comes out of OHS with sluggish LV function, Epi is started intra-operatively. But once they come to the ICU, how do you wean the Epi? It would be silly to do Q2 TTE's just to wean Epi. So it becomes useful for us to assess CI either by thermodilution or Fick calculation, to wean inotropes to a quantifiable measure.

I agree that wedging is a thing of the past unless you are a heart failure ICU with rapidly changing LV function and volume status. MunoRN makes a great point. However, Swan's still serve a role in the cardiothoracic world and as a replacement for serial echo's when monitoring cardiac output.

In a undifferentiated shock case in the MICU, I can see why a swan is obsolete. For those patients, a TTE and POCUS is usually all they need.

Hmmmm now you have me curious why hemospheres and ev1000's are hooked up to a swan vs an Aline... Does anyone know? Swan more accurate? More info? in our CVICU we use swans all the time. Nurses cant wedge even when a doc says to. The nurses are trained to say "look bro I cant wedge so you have to come in and do it yourself". I've been told that once you have your paop and it correlates to your pad you rarely have to rewedge just trend pad. I've rarely done ficks and thermodilution haha there was literally dust on our thermodilution equipment XD when I had to use it - and even then I only used it because a new doc put in the wrong type of swan for the EV1000. But yeah a lot of the ctsa pt's have one and a lot of the pump failure peeps. I guess my biggest question is there a time you cant use flotrac? 

On 12/18/2021 at 3:41 PM, BigDaddy007 said:

Hmmmm now you have me curious why hemospheres and ev1000's are hooked up to a swan vs an Aline... Does anyone know? Swan more accurate? More info? in our CVICU we use swans all the time. Nurses cant wedge even when a doc says to. The nurses are trained to say "look bro I cant wedge so you have to come in and do it yourself". I've been told that once you have your paop and it correlates to your pad you rarely have to rewedge just trend pad. I've rarely done ficks and thermodilution haha there was literally dust on our thermodilution equipment XD when I had to use it - and even then I only used it because a new doc put in the wrong type of swan for the EV1000. But yeah a lot of the ctsa pt's have one and a lot of the pump failure peeps. I guess my biggest question is there a time you cant use flotrac? 

Flotrac doesn't directly measure any parameters except for arterial BP, it uses an algorithm to approximate CO/CI, SVR, etc.  I think it's fair to say, and not particularly surprising, that Edwards might overstate the usefulness the benefits of these devices and systems that basically guestimate hemodynamic values.

The clinical studies that Edwards promotes makes the Flotrac sound more clinically useful than it probably is.  Other studies show that it's really only useful in a very narrow set of patients, and definitely not in CT surgery patients.  For one, the values aren't reliable in patients on pressors, particularly where those pressors are being titrated frequently, and it's algorithms basically assumes a patient's CI is better than 2.1.  

It's primary use is in patients who have normal cardiac function to determine volume status, although there are others methods that are at least, if not more, reliable.

We use the EV1000s in our CT surgery program, although we've sort of come full circle.  At one time we only used "manual" thermodilution (where you shoot 10mls of room temp fluid into the RA with a thermistor downstream in the PA).  The facility bought the EV1000's (initially Vigileos) at the request of a few surgeons we had at the time.  Those surgeons have since left (rumor is it had something to do with kickbacks they got for convincing the hospital to buy the Edwards monitor systems) and the current surgeons all prefer the old fashioned manual thermodilution, but get pressure to continue to use the EV1000's.  

Personally, I also prefer the manual thermodilution.  The readings are real time and more reliable.  The continuous CO/CI use a small heating filament on the catheter that produces a relatively small change in blood temp that in then reads downstream.  Manual thermodilution uses a change in blood temp that is exponentially larger, it's like the difference between a clinical trial involving 3 subjects and one involving 30,000.  Obviously the one with 30,000 subjects is going to be more reliable.

This is why when you start up an Edwards continuous CO/CI it can take as long as 15 minutes before it gives you a reading, it recognizes that none of it's individual readings are all that reliable so it takes many of them before it spits out a number.  This also means that whatever number it's giving you includes data from as long as 15 minutes ago.  So long as the patient's CI never changes then eventually this is comparably reliable to manual thermodilution, but it's pretty rare for a fresh open heart to have no changes to their cardiac output.

I find the lack of real-time data problematic when recovering open hearts as well.  Lets say you've got a patient who's HR is 50.  Epicardial wires aren't always optimally placed so a paced rate of 60 or even 70 probably isn't going to be more effective than an intrinsic rate of 50.  The only way to determine that though is to shoot an index in their intrinsic rhythm and then again in a paced rhythm.  With manual thermodilution you get your result immediately, with the continuous CO you'll have to start pacing and then wait 10-15 minutes and see where you're at then.

On 12/21/2021 at 8:30 PM, MunoRN said:

Flotrac doesn't directly measure any parameters except for arterial BP, it uses an algorithm to approximate CO/CI, SVR, etc.  I think it's fair to say, and not particularly surprising, that Edwards might overstate the usefulness the benefits of these devices and systems that basically guestimate hemodynamic values.

The clinical studies that Edwards promotes makes the Flotrac sound more clinically useful than it probably is.  Other studies show that it's really only useful in a very narrow set of patients, and definitely not in CT surgery patients.  For one, the values aren't reliable in patients on pressors, particularly where those pressors are being titrated frequently, and it's algorithms basically assumes a patient's CI is better than 2.1.  

It's primary use is in patients who have normal cardiac function to determine volume status, although there are others methods that are at least, if not more, reliable.

We use the EV1000s in our CT surgery program, although we've sort of come full circle.  At one time we only used "manual" thermodilution (where you shoot 10mls of room temp fluid into the RA with a thermistor downstream in the PA).  The facility bought the EV1000's (initially Vigileos) at the request of a few surgeons we had at the time.  Those surgeons have since left (rumor is it had something to do with kickbacks they got for convincing the hospital to buy the Edwards monitor systems) and the current surgeons all prefer the old fashioned manual thermodilution, but get pressure to continue to use the EV1000's.  

Personally, I also prefer the manual thermodilution.  The readings are real time and more reliable.  The continuous CO/CI use a small heating filament on the catheter that produces a relatively small change in blood temp that in then reads downstream.  Manual thermodilution uses a change in blood temp that is exponentially larger, it's like the difference between a clinical trial involving 3 subjects and one involving 30,000.  Obviously the one with 30,000 subjects is going to be more reliable.

This is why when you start up an Edwards continuous CO/CI it can take as long as 15 minutes before it gives you a reading, it recognizes that none of it's individual readings are all that reliable so it takes many of them before it spits out a number.  This also means that whatever number it's giving you includes data from as long as 15 minutes ago.  So long as the patient's CI never changes then eventually this is comparably reliable to manual thermodilution, but it's pretty rare for a fresh open heart to have no changes to their cardiac output.

I find the lack of real-time data problematic when recovering open hearts as well.  Lets say you've got a patient who's HR is 50.  Epicardial wires aren't always optimally placed so a paced rate of 60 or even 70 probably isn't going to be more effective than an intrinsic rate of 50.  The only way to determine that though is to shoot an index in their intrinsic rhythm and then again in a paced rhythm.  With manual thermodilution you get your result immediately, with the continuous CO you'll have to start pacing and then wait 10-15 minutes and see where you're at then.

That's awesome info. The Edwards rep failed to mention the 15-minute delay... It's funny you say thermodilution with a saline flush is more accurate as one of our older docs swears by it yet none of the young docs have a problem with flotrac/hemosphere. 

On 12/28/2021 at 10:36 PM, BigDaddy007 said:

That's awesome info. The Edwards rep failed to mention the 15-minute delay... It's funny you say thermodilution with a saline flush is more accurate as one of our older docs swears by it yet none of the young docs have a problem with flotrac/hemosphere. 

It's not always 15 minutes, it can vary based on the proprietary algorithm that it uses to determine the reliability of the readings it gets.  This is almost worse than a strictly defined delay since you don't really know the timespan that the number it's currently giving you is based on.  

A manual, or 'old fashioned' thermodilution uses 10mls of room temperature fluid to drastically change the temperature of the blood moving through the right heart.  The continuous CO catheters uses a heating filament on the catheter that produces changes in blood temperature that are extremely small compared to manual thermodilution.

Our older Docs prefer manual thermodilution and it seems like it's come full circle because our 'youngest' CT surgery Docs and anesthesiologists will only use manual thermodilution.  There seems to be a group in between that bought into the gimmicky nature of some of these products but the younger Docs aren't buying it.  

The only Docs I've worked with that were really enthusiastically for FloTrac and Continuous CCO (Edwards) were also getting big kick-backs for getting their hospitals to buy these systems.

I am on a cardiac anesthesia rotation and saw probably the second one since I started residency. Only certain ct surgeons even use them anymore