MAC, Cordis, Sheath Introducer – What’s The Difference?

As a cardiothoracic anesthesiologist and intensivist, I routinely place large central lines for resuscitation, vasoactive/inotrope administration, and to facilitate additional monitoring (ie, Swan Ganz catheter). Over the years, I’ve heard “MAC”, “sheath introducer”, “Cordis”, etc. used interchangeably but incorrectly. Let’s break these terms down!


A “sheath” or “introducer” refers to any line (arterial or venous) that contains a port allowing a proceduralist to “introduce” (hence the name) transvenous pacing wires, Swan Ganz catheters, intravascular ultrasound (IVUS), intra-aortic balloon pumps, single lumen infusion catheters (“SLICs”), etc. The introducer lumen has a one-way diaphragm that prevents back bleeding and can often be capped with an obturator when not in use. The MAC and Cordis are two examples of venous introducers.

The following is a 9 French percutaneous sheath introducer (PSI).

Manufacturer: Arrow/Teleflex
Catheter: percutaneous sheath introducer (PSI)
Lumens: introducer + one infusion port

Compared to the 9 French MAC (see below), the PSI is shorter and therefore a better massive resuscitation line due to better flow rates as per Poiseuille’s Law. The big drawback is that it only has one side lumen.


Manufacturer: Arrow/Teleflex
Catheter: multilumen access catheter (MAC)
Lumens: introducer + two infusion port (brown distal, white proximal/side)

The brown lumen looks larger, so it makes sense that at baseline, it flows faster than the white lumen. When we take a closer look at the MAC’s flow rates, notice how if there’s a catheter inserted into the introducer (ie, a Swan-Ganz catheter), this steals real estate from the brown lumen and now makes the white lumen the faster flowing option. In this example, if the introducer is occupied with an 8 French catheter, the distal brown port’s flow is reduced from 33,000 mL/hr to 10,500 mL/hr making the proximal white port faster (13,000 mL/hr)! Always read your catheter’s flow rates as this can vary from one version to the next!

Even though this MAC is listed as 9 French in size, that’s only the case at the very distal tip of the catheter. Notice how as you move proximally, it quickly gets larger. Gotta make some room for that second infusion lumen!

MACs are placed with the dilator inserted through the introducer in one motion rather than sequential steps to facilitate the speed of placement. Once the MAC has been fully inserted, the dilator and guidewire are removed. This style of placement is the same for many introducers.


Manufacturer: Cordis (a Cardinal Health Company)
Catheter: AVANTI + Sheath Introducer
Lumens: introducer + one infusion port

Cordis AVANTI®+ Introducer (Image:

“Cordis” is actually a company and the AVANTI introducer is the catheter name. Similar to the PSI above, this catheter has an introducer and one side port.

Drop me a comment with questions! 🙂

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  1. Hi Rishi,

    Great article, I’ve followed you on Instagram and am always learning from your page. I’m curious about your thoughts on bedside CVICU RNs placing SLICs. I cannot seem to find any articles relating to this, and am concerned that this falls outside their scope of practice. Thoughts?

    • Thanks for your support! I don’t know the policy, but personally if you ask me, it’s riskier taking out a Swan than putting in a single lumen introducer catheter (SLIC) since the catheter can only go in where the introducer has already been placed (e.g. subclavian vein). It’s a 60 second, low-risk procedure whereas placing the original introducer (sheath, MAC, etc.) has many more risks.

  2. Hello,

    I am unable to find ANY info on the PSI or Flow Ratings for the Cordis Avanti + Sheath Introducer. Do you have any documentation stating the PSI or Flow Ratings? We are wondering if we can use it for CT Contrast injection rates of 5 ml/sec which translates to 18,000 ml/hr. So in the above information on the MAC, we are only able to use the brown port. I need to know the rating of the Cordis and if it more like the brown port or the smaller ones from the MAC that we cannot use.


    • Hey Sarah! Though I use the PSI and MAC regularly in practice, the Cordis AVANTI is not a catheter I have ever used. Unfortunately, I don’t know the flow rate nor was I able to find anything through a quick search.

  3. Good explanation, thank you.
    I am wondering if the 3 lumen catheter use for PSI is the same one used for MAC, or if we can use indistinctly ?

    • I’m pretty sure the “companion catheter” (up to 3 additional lumens) can be used for either one. ARROW definitely makes one for the MAC which I’ve used countless times, but off the top of my head, I don’t know if it definitively fits the PSI.

  4. Hi Rishi!
    I was googling and I come across your face! Thanks for this info. Helped with my documentation. Hope all is well! -BWH RN

    • You can, but there isn’t a way to “lock” the CVC into the introducer since they’re not designed for such a purpose. There are specially designed catheters (ie, SLICs) which interface with the locking mechanism on the introducer and should be used instead.


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