Anyone getting VQ scans any more?

[Rendar5]

Our hospital ( a nationally regarded hospital ) dosent believe in CIN from IV dye. They will give contrast to mid 3s. They think intraarterial contrast can cause CIN but not IV dye. They also refuse to read any VQ scan as other than indeterminate. So I just stopped getting them. I also won't request them to try to make do with a little less dye as they will read it as inadequate bolus , unable to rule out peripheral PEs. So I just get the regular CT if I have high suspicion with a liter bolus of saline.

Thankfully your hospital allows you guys to do that. Question is what do you guys do for someone who's got IV contrast allergy? Are you stuck in a VQ scan and having the radiologist not give you an adequate read?

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[Nephro critical care]

Thankfully your hospital allows you guys to do that. Question is what do you guys do for someone who's got IV contrast allergy? Are you stuck in a VQ scan and having the radiologist not give you an adequate read?

True contrast allergies are rare. At my previous hospital they would get all antsy about shellfish allergy and not want to give dye. At this place though it seems they don't believe that most pts have a true dye allergy. I once was told by a patients wife that put couldn't get IV dye and reviewing notes he had gotten dye thru the VA previously recently because they were blissfully aware of the allergy. I gave solumedrol and Benadryl and he just fine without as much as an itch.
I guess if I had a pt with a verifiable anaphylactic allergy to dye and had no previous pulmonary issues ( like COPD or pneumonia) I could get a VQ and they might give me a low/high probability scan which I could use in the clinical situation. Otherwise I'd use Doppler / Echo for RV dysfunction / and clinical probability to make my decision and give heparin in the interim. This would not be in the ED setting it would be while admitted to the ICU.

 

[southerndoc]

Our hospital ( a nationally regarded hospital ) dosent believe in CIN from IV dye. They will give contrast to mid 3s. They think intraarterial contrast can cause CIN but not IV dye. They also refuse to read any VQ scan as other than indeterminate. So I just stopped getting them. I also won't request them to try to make do with a little less dye as they will read it as inadequate bolus , unable to rule out peripheral PEs. So I just get the regular CT if I have high suspicion with a liter bolus of saline.

I really wish our radiologists would get on board with this. We CT to creatinine clearance of 30. Anything below they won't CT with contrast (except dialysis patients).

 

[deleted109597]

I guess if I had a pt with a verifiable anaphylactic allergy to dye

This beast doesn't exist. It's an anaphylactoid reaction. Prior reactions, if they happen, don't have bearing on future reactions.

 

[Rendar5]

This beast doesn't exist. It's an anaphylactoid reaction. Prior reactions, if they happen, don't have bearing on future reactions.

I'm sure it exists, it's just very rare unlike the comparatively common anaphylactoid rxn. Some ppl are just prone to allergy development.

 

[meister]

Shocking that ED literature supports something that'll help length of stay metrics. In any case, I doubt CIN is a concern with modern contrast agents. Unfortunately, medicolegal crap results in many of these rules taking forever to get changed. If your pretest probability for PE is high then the medical necessity of the test could easily outweigh the likely dated specter of CIN. Blanket bans for GFR < 30 are dumb.

Something to consider - can we rule out PEs with a non contrast chest MRI?

No.

 

[xaelia]

The CIN issue is pretty entrenched, but not above question – otherwise, we wouldn't see this sort of literature. The battleship is slow to maneuver, however, and the ED isn't at the helm. It also doesn't help the evidence is retrospective, observational, and prone to bias. What's probably needed is a cluster-randomized trial at a Kaiser-type health system where certain institutions lift restrictions on IV contrast while others do not.

I'm obviously on the CIN-is-overblown side of things:
http://www.acepnow.com/article/medi...sk-contrast-induced-nephropathy/?singlepage=1

I'm not very aggressive in my pursuit of PEs, so I don't find much value in V/Q scans. I'd consider use in someone with a normal chest x-ray and such a legitimately high pretest likelihood that I'd empirically anticoagulate. I'm also on board with tricks like doubling the D-dimer to reduce the number of patients undergoing imaging:
Adjusting D-Dimer Test Thresholds Could Reduce Unnecessary Imaging - ACEP Now

... but when you gotta scan, you gotta scan.