CVC vs Swan

[Trogghunter]

An attending mentioned in passing that due to the mixing of blood at the coronary sinus and flow from the IVC, the O2 from a CVC in the RA is incorrect enough to warrant widespread use of Swans. Ive rarely seen swans used, in my experience at a few ICUs as a student, but the argument makes sense, especially in sepsis where lactate and blood with dec O2 flows right back at the site of the CVC. Might be getting terminology off, but you get the idea.

Can I get some clarification/confirmation?

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[Bostonredsox]

If your talking about resuscitation goals and ionotropitc targets in sepsis, their are different numbers. The central venous saturation, ScvO2, derived from CVC in the RA, has a higher target # then the mixed venous saturation, SvO2, derived from a PA catheter/swan. This is understandable as the extraction of oxygen to tissues from hemoglobin continues as you travel from LV around to RV so the lowest saturation will be at last station before "reloading", the pulmonary artery. Many CVC tips are a bit short of the RA as well. The 20-30 cm difference between the cavoatrial junction and one of the main pulmonary arteries can be several percentage points worth of saturation. So whether you use a swan or CVC, you just have to use the corresponding titration target.

Swans do give you the added value of cardiac output continuously if you need it.

 

[Hernandez]

Swans do give you the added value of cardiac output continuously if you need it.

That's debatable.

 

[Hernandez]

An attending mentioned in passing that due to the mixing of blood at the coronary sinus and flow from the IVC, the O2 from a CVC in the RA is incorrect enough to warrant widespread use of Swans. Ive rarely seen swans used, in my experience at a few ICUs as a student, but the argument makes sense, especially in sepsis where lactate and blood with dec O2 flows right back at the site of the CVC. Might be getting terminology off, but you get the idea.

Can I get some clarification/confirmation?

In what setting and why are you looking for a scvo2? In sepsis? In RHC for cardiac reason? For ****s & giggles?

 

[Bostonredsox]

That's debatable.

Well it's not debatable that they have the ability with thermodilution to directly measure cardiac output. It's debatable whether or not you need to measure cardiac output for anything which was my point

 

[Hernandez]

Well it's not debatable that they have the ability with thermodilution to directly measure cardiac output. It's debatable whether or not you need to measure cardiac output for anything which was my point

The inter-operator variability and nursing experience makes even thermodilution very prone to errors. And at the end of the day, there has never been any studies in ICU pts showing any benefit,. CO/CI helping may be helpful, that's what may be debatable, but from swan has no ICU benefit

 

[Hernandez]

Ironically, I'm sitting in a board review that just covered this, here are references they listed

Polanczyk CA, et al. JAMA 2001;286:309 &#8211;&#8239; 4059 pts&#8212;major elective noncardiac procedures •&#8239; PAC&#8212;3x &#8593; major postop CV events (15.4% vs. 3.6%; P<.001)

Richard et al; JAMA 2003;290:2713 &#8211;&#8239; RCT 676 pts => shock and/or ARDS&#8212;no outcomes differences

Sandham, et al, NEJM 2003;348:5 &#8211;&#8239; RCT 1994 pts => abd, thoracic, vasc, hip fx surg&#8212;no outcomes differences, more PEs in PAC group

Harvey S, et al. Lancet 2005;366:472 &#8211;&#8239; RCT 1041 ICU pts => thought to need PAC&#8212;no outcomes differences; 9% with PAC had related complication

Binanay C, et al. JAMA 2005;294:1625 &#8211;&#8239; RCT 433 pts => CHF&#8212;no outcomes diff, more PAC complic

Shah MR, et al. JAMA 2005;294:1664 &#8211;&#8239; 5051 pts, 13 trials&#8212;no outcomes differences

 

[jdh71]

The cardiologist may find some benefit and so can the surgeons but for MICU gomers, no benefit to a swan.

They've demonstrated correlation and essentially equivalence for central venous catheter O2 saturation and lactate clearance. Pick your end point. Whatever. Patients get better or worse often independent of what we do because what we do is really ham fisted and barbaric when you think about it and supported by really only kind of decent evidence for some things. The rest we just do.

I think if I had an attending trying to sing the praises for the swan and how everyone needed one, I'd just smile, nod, and agree with him until he was off service.

I won't be using swans in my practice, mostly because I'm not trained with them, at all, but also because I don't believe in them.

 

[Bostonredsox]

The inter-operator variability and nursing experience makes even thermodilution very prone to errors. And at the end of the day, there has never been any studies in ICU pts showing any benefit,. CO/CI helping may be helpful, that's what may be debatable, but from swan has no ICU benefit

Ct surg patients are routine in our ICU and the post cabg pts with swans measuring their co/ci is where I routinely see them. I have never used a swan for any type of measurements in a septic pt.

Thanks for the lit review though ill peruse through the papers

 

[Hernandez]

I won't be using swans in my practice, mostly because I'm not trained with them, at all, but also because I don't believe in them.

The only place I use them is if I honestly have no idea wtf is going on, which is rare with combo physical exam, echo, and history.

 

[deleted116380]

Ct surg patients are routine in our ICU and the post cabg pts with swans measuring their co/ci is where I routinely see them. I have never used a swan for any type of measurements in a septic pt.

Thanks for the lit review though ill peruse through the papers

The only time I've had pt's with swans was in med school during my CT surgery month in the SICU similar to your experiences. Never in our MICUs. We used a non-invasive monitor for CO/CI, SVR/SVI in our MICU pts. Forgot the name of it, but it only used leads to somehow come up with the numbers. I finished my MICU rotation last month at my intern year hospital and we used something else for CO/CI monitoring, but I think it was minimally invasive and not completely non-invasive like the one in med school.

 

[nlax30]

The only time I've had pt's with swans was in med school during my CT surgery month in the SICU similar to your experiences. Never in our MICUs. We used a non-invasive monitor for CO/CI, SVR/SVI in our MICU pts. Forgot the name of it, but it only used leads to somehow come up with the numbers. I finished my MICU rotation last month at my intern year hospital and we used something else for CO/CI monitoring, but I think it was minimally invasive and not completely non-invasive like the one in med school.

FloTrac?

 

[group_theory]

Ironically, I'm sitting in a board review that just covered this, here are references they listed

ACCP in San Antonio?

 

[deleted116380]

FloTrac?

Yep, that's the one we used last month in the MICU. Might actually be the same one we used in med school as well, but I think FloTrac was minimally invasive while the other was non-invasive.

 

[Hernandez]

ACCP in San Antonio?

You here?

 

[ORL10]

I think PAC can be helpful in some situations. Not every run of the mill septic MICU patient needs one, but patients with RV dysfunction and sepsis, PH, valvular dysfunction and difficult habitus for quality echo etc.. can possibly benefit. I put a PAC in when I have a specific question that I don't think I can get the answer to with echo and it will change my management.

Not sure how to feel about flotracs accuracy yet anyone else opinions on this?

 

[souljah1]

This is a very good review of the strengths and weaknesses of a central venous sat.

Keith R. Walley "Use of Central Venous Oxygen Saturation to Guide Therapy", American Journal of Respiratory and Critical Care Medicine, Vol. 184, No. 5 (2011), pp. 514-520.

 

[sluggs]

If you are titrating an inotrope in a sepsis resuscitation because there is evidence of low cardiac output failure (which happens in septic patients, especially those with pre-existing heart failure) having a continuous cardiac index to target can be helpful, especially with the problems of using Scvo2 (you can have an Scvo2 of 70 and still need inotropes). In these circumstances a swan can be helpful. Is there data to support this? Not really. Is it true? yes. Do not use them routinely in septic patients, but occasionally. Just my 2c

 

[Bostonredsox]

If you are titrating an inotrope in a sepsis resuscitation because there is evidence of low cardiac output failure (which happens in septic patients, especially those with pre-existing heart failure) having a continuous cardiac index to target can be helpful, especially with the problems of using Scvo2 (you can have an Scvo2 of 70 and still need inotropes). In these circumstances a swan can be helpful. Is there data to support this? Not really. Is it true? yes. Do not use them routinely in septic patients, but occasionally. Just my 2c

agree entirely. no data to support or refute, but i find the CI/CO useful in pts on ionotropes

 

[sluggs]

Scvo2 is not a perfect surrogate. Take a patient with and EF of 25% and an Scvo2 of 70. Would still need inotrope in septic shock. What do you titrate to? CI!

 

[jdh71]

Scvo2 is not a perfect surrogate. Take a patient with and EF of 25% and an Scvo2 of 70. Would still need inotrope in septic shock. What do you titrate to? CI!

Someone should do that paper.

 

[jdh71]

Though if the lactate isn't climbing, then the lactate isn't climbing.

 

[Bostonredsox]

Though if the lactate isn't climbing, then the lactate isn't climbing.

this is what it ultimately boils down to to me. If your clearing lactate, your perfusing adequately....end of story.

 

[sluggs]

Totally agree. You don't use Swans in resuscitations that are going well.... only in resuscitations that have lost their way...

 

[TrustMe]

this is what it ultimately boils down to to me. If your clearing lactate, your perfusing adequately....end of story.

Agree. If you are providing your tissues enough oxygen to stave off anaerobic metabolism then you shouldn't be producing much lactate anyway. If they are maintaining their BP reasonably well, aren't acidotic, and have a low lactate, I don't really care what their ScvO2 is because if those other things are normal I'm not going to treat a low ScvO2 just to make the number better. What's that...you want me to give a unit of PRBC and start some dobutamine because their ScvO2 is low....how about I just stop checking it since they are clinically completely stable. (Sorry, I took over ICU on a Monday morning a few months ago and the staff that had it over the weekend came around in the afternoon just following up on patients and told me I needed to get a patients ScvO2 up because it was still low, even though pressors were off for 48 hrs, pH was normal and lactate was 1.)

While I'm on my soapbox, I feel the same way about urine output. Keep getting called by nurse because UOP is "low" this hour. If their renal function is at or near baseline, they are reasonably resuscitated, their electrolytes are fine, and they are on room air, I don't really care that they only made 20cc of urine last hour. Please just document "MD aware" and stop expecting me to do something just to make a number look better when clinically the patient is totally fine.

Done. Sorry.

 

[Stank811]

70% of our patients in the CVICU come to us with a Swan in place to titrate gtts post-op. If the numbers don't make sense I have the nurse redo them and get a MVO2. We do not wedge and if we see a complication it usually was secondary to the placement of the CVL not floating the swan. Flotrac is terrible measure of CO in patients with swings in SVR.

 

[Bostonredsox]

70% of our patients in the CVICU come to us with a Swan in place to titrate gtts post-op. If the numbers don't make sense I have the nurse redo them and get a MVO2. We do not wedge and if we see a complication it usually was secondary to the placement of the CVL not floating the swan. Flotrac is terrible measure of CO in patients with swings in SVR.

This is where most of my swans are too, post cabg. They have continuous CI, CO, SVR, CVP rolling on them. Titrate the Epi based on the CI, neo based on the SVR.

Apart from that I only use them when I am not sure wtf is going on.

Although today, had an old gomer who was basically a trauma pt, fell down stairs with INR of 10, hematomas everywhere, hypovolemic shock yadda yadda. Anyway so he got better over the last few days. But his trops popped to like 0.9, negative mb, as you'd expect, from some demand ischemia as is afib was in RVR whilst he was in shock. So one of the old terrible stand alone cardio guys gets consulted at family request, as they think he's the shiznat and he sees the pt on the outside....tells me this morning we have to hold the IVC filter (pt had dvt 2 months ago) until he does a RHC and LHC.

What? (In my head thinking)....You want to cath this 80+ year old fat bedbound dude who just nearly Hemorrhaged to death and who has a femoral stent graph and retroperitoneal hemorrhage? Your really gonna put this dude on brillinta if you find something? And why can't we just do a jugular swam for the RHC and a radial LHC as an outpt?

Answer one, wallet biopsy is in effect. Two, he can't do radial caths. So I tell my attending intensivist and the cv surgeon prepping for the IVC filter the cardio dudes plans and they are like wtf? Wallet biopsy?

So to piss him off....I exchanged my jugular CVC for a sheath, floated a swan, wrote down the pressures and my attending text them to him. Eat that **** you money grubbing troll.

I like swans. Just sadly don't have as much utility thanks to modern echo capabilities.

 

[jdh71]

Again in the MICU gomer population there really is no need for a swan. If you're doing your normal stuff and you still are having a problem with lactate clearance, put an U/S on their chest and if the heart looks like it's struggling add some dobutamine. If you can't sort out what is going on with the gomer MICU patient with the U/S and some judicious use of dobutamine plus your chest imaging, then I'm not convinced that a you'll be able to use a swan to help you do anything.

 

[Stank811]

Again in the MICU gomer population there really is no need for a swan. If you're doing your normal stuff and you still are having a problem with lactate clearance, put an U/S on their chest and if the heart looks like it's struggling add some dobutamine. If you can't sort out what is going on with the gomer MICU patient with the U/S and some judicious use of dobutamine plus your chest imaging, then I'm not convinced that a you'll be able to use a swan to help you do anything.

I am not necessarily advocating using the swan to diagnose but more to manage. In the particular gomer you illustrated above I would use ECHO to diagnose any potential cardiac pathology and then float a swan to guide management of gtts...I just think I am more efficient titrating gtts to CCO or thermodilution CO compared to titrating same gtts to lactate or placing TTE on patients chest to access change in CI every time I make a change to gtts.

 

[jdh71]

I am not necessarily advocating using the swan to diagnose but more to manage. In the particular gomer you illustrated above I would use ECHO to diagnose any potential cardiac pathology and then float a swan to guide management of gtts...I just think I am more efficient titrating gtts to CCO or thermodilution CO compared to titrating same gtts to lactate or placing TTE on patients chest to access change in CI every time I make a change to gtts.

Efficiency has nothing to do with it. If the patient looks like they need some dobutamine, give it to them. If the lactate clears, it clears. You don't have to keep looking. That was my point. You should be able to infer lots of information without using the swan, which it is completely unnecessary in the MICU gomer population and there is enough evidence that shows that despite people thinking they are doing the gomer good by using the swan, they are not. Medicine is like that sometimes.

 

[Bostonredsox]

patient from Last night. fulminant ards. still tenuous, not improving like we would hope for unclear reason. attending thinks might b wet. chest film is extensive alveolar infiltrates, hard to tell if there's a lot of edema. echo - " poor study, ef normal, no segmental abnormalities. attending asks for swan. i oblige.

RAP 22 RV 55/20 PAP 60/35 PCWP 29.
answer......diurese.

2 shots of lasix, put out almost 4L. oxygenation much improved.

to me, this was a pt where the film, exam and echo really didn't demonstrate just how much interstitial edema thislady was carrying.

swan took me 30 min and definitely helpedtoguide therapy in a new direction.

pressures this am after the lasix.... RA 12 PA 41/20, PCWP 17. win

 

[jdh71]

patient from Last night. fulminant ards. still tenuous, not improving like we would hope for unclear reason. attending thinks might b wet. chest film is extensive alveolar infiltrates, hard to tell if there's a lot of edema. echo - " poor study, ef normal, no segmental abnormalities. attending asks for swan. i oblige.

RAP 22 RV 55/20 PAP 60/35 PCWP 29.
answer......diurese.

2 shots of lasix, put out almost 4L. oxygenation much improved.

to me, this was a pt where the film, exam and echo really didn't demonstrate just how much interstitial edema thislady was carrying.

swan took me 30 min and definitely helpedtoguide therapy in a new direction.

pressures this am after the lasix.... RA 12 PA 41/20, PCWP 17. win

Or you could have looked for extensive B-lines on pulmonary U/S.

 

[Bostonredsox]

Or you could have looked for extensive B-lines on pulmonary U/S.

of course I could have looked for the "cosmic rays". that coupled with the chest film and my exam is how I typically diagnose pulmonary edema. however, there are a lot of ICUs that do not have their own ultrasound or a provider that knows how to do bedside ultrasound. in that case the swan is very useful.

I of course, can use the ultrasound. but I need swan numbers for credentialing so I wasn't going to pass it up

 

[Stank811]

JDH71...how do you wean the dobutamine once the lactate clears....take away the dobutamine and if the lactate comes back put it back on? Serial TTEs?

 

[jdh71]

JDH71...how do you wean the dobutamine once the lactate clears....take away the dobutamine and if the lactate comes back put it back on? Serial TTEs?

Titrate down the dobutamine recheck the lactate. Though usually in septic situations where you are trying to optimize oxygen delivery decreasing pressor requirements is a good indications you've managed to get ahead of the fire with your resuscitation and antibiotics. And if that seems to be the case just turn of the dobutamine and see how they do. You always could put the U/S back on them too but I usually don't. Maybe I should to see how much this correlates with my non cardiologists gestalt of wether the pump function is coming back or not.

 

[mrpankration]

this is what it ultimately boils down to to me. If your clearing lactate, your perfusing adequately....end of story.

Though Manny Rivers argues against that point fervently in favor of trending Scv02. Could it be just to line his pockets? Maybe.

 

[Stank811]

Titrate down the dobutamine recheck the lactate. Though usually in septic situations where you are trying to optimize oxygen delivery decreasing pressor requirements is a good indications you've managed to get ahead of the fire with your resuscitation and antibiotics. And if that seems to be the case just turn of the dobutamine and see how they do. You always could put the U/S back on them too but I usually don't. Maybe I should to see how much this correlates with my non cardiologists gestalt of wether the pump function is coming back or not.

With a swan you would know way before the pt starts producing lactate if you needed to increase your dobutamine. You would also be able to titrate off your dobutamine much quicker by following CI with your swan. In my opinion: swan is more efficient, requires less lab draws, does not require anaerobic metabolism to occur before I restart/increase my gtts all of which makes me happy to float a swan in patients in which requires medical cardiac support or mechanical I guess. Dont have data to support but I would imagine a swan would be cheaper too.

 

[jdh71]

With a swan you would know way before the pt starts producing lactate if you needed to increase your dobutamine. You would also be able to titrate off your dobutamine much quicker by following CI with your swan. In my opinion: swan is more efficient, requires less lab draws, does not require anaerobic metabolism to occur before I restart/increase my gtts all of which makes me happy to float a swan in patients in which requires medical cardiac support or mechanical I guess. Dont have data to support but I would imagine a swan would be cheaper too.

The data is not on your side though. I know you can see neat numbers, but seeing those neat numbers has NEVER translated into better outcomes for patients, (nor less expensive outcomes) EVER.

Science.

Is a bitch.

Peace.

 

[souljah1]

Put your hands on their feet. Are they cold? Check an ScvO2. Low? Echo probe. Hypocontractile? Add the damn dobutamine.

How's the feet. Warmer? Scvo2 higher? Urine output better? Cont the damn dobutamine.

Everything at goal? ween the dobutamine. Still at goal? ween dobutamine.

The only time I really reach for a Swan is when I have a patient with legitamate real-deal severe pulmonary hypertension and they are in septic shock. Too much fluid resuscitate and they die.

Oh, and CVP is dumb.

 

[Hernandez]

Put your hands on their feet. Are they cold? Check an ScvO2. Low? Echo probe. Hypocontractile? Add the damn dobutamine.

How's the feet. Warmer? Scvo2 higher? Urine output better? Cont the damn dobutamine.

Everything at goal? ween the dobutamine. Still at goal? ween dobutamine.

The only time I really reach for a Swan is when I have a patient with legitamate real-deal severe pulmonary hypertension and they are in septic shock. Too much fluid resuscitate and they die.

Oh, and CVP is dumb.

And FYI, Semi-invasive methods of measuring CI/CO are likely better in vasodilatory/septic shock as well than in cardiogenic high SVR states