MAC 3 or 4? What do you use and why?


What laryngoscope blade do you commonly use in your intubations? I have been having an email discussion with a couple of anaesthetists about this over the past week. The feature image shows two of my personal laryngoscopes I currently use. My favourite is the disposable Trulite MAC 4 bladed LED laryngoscope pictured. Note the LED light is much brighter than the second laryngoscope, despite being AA alkaline battery powered. The smaller MAC 3 bladed laryngoscope has a German low profile steel reuseable blade with an acrylic light bundle. The handle is a micro length design using CR 25 lithium batteries common to cameras and a standard bulb. The lithium battery produces a higher intensity light but that still does not equal the LED from the Trulite.
Trulite costs $12 ea in all the common blade sizes inc straight blades. The German Profile blade is about $70 ea and micro handle about $25 ea.
Dr Levitan recommended me first off the German profile MAC blade and micro handle and it works well but for 2 years now I discovered the Trulites after he showed one to me at a workshop he did for us. I have been using them ever since and they just work well in my prehospital setting.

Anyway MAC 3 or 4? does it matter? I think it does. I prefer MAC 4 first pass, use a careful midline approach and steadily acquire anatomical landmarks, searching for the epiglottis. If I need the length, its there already. If I dont then I end up using maybe only half of the blade but I am used to that now. My colleagues argue MAC 3 straight up as it works for most adults and gives you best mechanical advantage of tip into vallecula.

What do you use and why?

20 thoughts on “MAC 3 or 4? What do you use and why?

  1. As I’ve been discussing with Minh this week, I advocate using the shortest blade that is long enough. All things being equal if the 3 is long enough to position correctly in the vallecula fossa, it will give you more lift and a better view. This isn’t a matter of opinion it’s simple physics. The further the tip gets from the handle the harder it is to lift the tip of the blade. Imagine how hard it would be if the blade was 3 feet long! But even with the small difference in length between the 3 & 4 the mechanical difference is significant. See for yourself – get someone to hold a 3 & 4 blade in each hand (they can even put the 4 in their dominant hand) then push down on the tips of both and see which one they find easier to resist. The results are pretty dramatic.

  2. Measure at the mandible; If a 3 will reach I go for 3. Lifting force is better. There is a recent study, but I am pulling my hair out trying to find it.

  3. Mac 3 is my go to, I find it easy to provide enough lift and it works for most patients. That said, we have a large population of Sudanese where I work and intubating a 7 foot tall Sudanese lad definitely needs a 4 (sometimes I think a 5 would be nice)
    I must admit I have never measured up before, just eyeballed the patient and had another blade/handle ready.

  4. My view polar.

    Longest/biggest blade always. Especially when I’m teaching. It enforces that the laryngoscope is a device to push toungue away and not some pivot tool ! It enforces too not to insert blindly, but under careful and considered vision. Importantly it demonstrates that the handle should always be horizontal to the chest.

    Try it on mannequin if you don’t believe me …

  5. Minh, I love the debate that this is generating. Like all things in medicine there probably ain’t one right answer and it depends. Also probably does not matter most of the time! I do prefer Mac 4 low profile german style with good steel and a short light to tip distance with LED brilliant lighting. Not all such things are in all blades and so sometimes it is a compromise (some Mac 4’s have a horrible large base/flange profile and a long light to tip distance). The levering potential of Mac3 is a great reason, however I think that might be offset by technique like using ELM (which drives the blade tip into the valleculae engaging the hyoepiglottic ligament and lifting the epiglottis maximally) which will also allow effective easier levering with a Mac4. In addition, all those other things with airway positioning will help expose the larynx well: ear-notch (ramp in ++BMI), face-parallel, rev-trendel (++BMI gravity pulls redundant tissues down airway instead of squishing to posterior pharynx), JAW THRUST(! one of most effective airway maneuvers and using two hands on laryngoscope blade might help!), and head elevation 8-10 inches. Note that when you can’t do these things, this is when IL (indirect laryngoscopy or image based laryngoscopy which includes VL, AirTraq etc) may win over DL in the great DL vs VL/IL debate. Here is where the 90 degree and hyperangulated blades and optics in the airway (as long as none of the enemies of blood/vomit/secretions overwhelms it) allows one to see the target that DL may not be able to whether Curved Mac 3, 4 or straight blade techniques. Given all this though I think I would always choose a Mac4 first for that best initial attempt if going DL route, as you never know if the person’s epiglottis might be so floppy that you need the extra blade of a Mac4 to use the Mac like a Miller and pick up the epiglottis to see the larynx. Something that a Mac 3 might not be able to do if it is sized to fit only to engage the blade tip into the valleculae. IMHO. Thanks. Yen

  6. I prefer to size the blade to the patient rather than go with the same blade all the time. By measuring the laryngoscope blade like an oral airway and adding 1 to 2 cm, this allows you me to pick the correct blade for each patient. Using too long of a blade put the light in the incorrect position, often not allowing maximum lighting of the glottic opening. I often see people go deep with a Mac 4 and pull back. In my opinion, this creates unnecessary tissue trauma and when you do get the tip of the blade back to the optimal position, the light is often not in position to provide optimal light on the glottic opening.

    Like many, I do tend to use the Mac like a Miller and directly lift the epiglottis with the blade, so many times the Mac 4 does become the size of choice, but I see a lot of people skipping over the the Mac 3 when it would be the optimal blade.

    1. I think great points about using a Mac 3 if it fits and it will likely work 90-99% of the time, however my worry is that one cannot predict what you will encounter at the epiglottis so my preference is to have the Mac 4 in a crash situation or when it really counts (no time or little time, difficult airway in terms of anatomy, disruption or physiology).

      The Mac 4 IMHO, has a built in Mac 3 with extra blade at the back if you need it. With techniques of proper positioning, epiglottoscopy and laryngeal exposure, a german style low profile Mac 4 with short light to tip distance is equivalent to the Mac 3 in likely 99.999% of the time (in terms of lighting too and even tho the Mac3 might be a better lever in the right sized airway). But if you need the extra blade to Miller it, the Mac 3 comes short (tho this is likely a rare circumstance in most adults).

      With either Mac 4 or Mac 3 or any blade (IL. VL, or DL), plunge and pulling back is not ideal and potentially traumatic. Epiglottoscopy and progressive landmark exposure should be used with all blades whether IL/VL/DL and I think this is the best technique (from the Levitan school of Airway). I also agree that midline approach with the blade tip is best, especially when stakes are high and airway is difficult as the tongue is your highway to the epiglottis which is “the on-ramp to the larynx”. Once you see the tip of the epiglottis then I would focus on tongue sweep to the left as needed with the body of the blade. Going into “no man’s land” by being too deep to start may be problematic especially in tough airways and also in pediatrics where the “pseudolarynx” might fool you in the adrenaline charged situation. But I ramble …


  7. Dear Minh prehopsital providers (like we both are) have no time for Mallampati, or measuring the mandible (I wish I could) so I go straight to Mac 4, but with a right lateral and gradual approach. Move the tongue and go central, visualize the base, after advance gently till the epiglottis and go steady into the vallecula and here it’s the cords (and it works well with VL too). In Italy we say “Nel piĆ¹ ci sta il meno” that can be approximately translated as “Shorter is contained in longer”. Ciao

  8. Difficult airway? It’s Miller time.

    My goto blade is the #3 Miller or Wis-Hipple. It makes easy intubations a little harder and difficult intubations easier – a good trade-off. I also find that I can more reliably pick up the epiglottis directly with the straight blade.

    Also, being more comfortable with the straight blade helps when the need arises to intubate an infant.

    That said, I’m the only one in my shop to reach for the straight blade.

  9. Difficult airway? It’s Miller time.

    My goto blade is the #3 Miller or Wis-Hipple. It makes easy intubations a little harder and difficult intubations easier – a good trade-off. I also find that I can more reliably pick up the epiglottis directly with the straight blade.

    Also, being more comfortable with the straight blade helps when the need arises to intubate an infant.

    That said, I’m the only one in my shop to reach for the straight blade.

  10. Mac 4. Disagree with the assumption that the mechanical advantage of a Mac 3 is of an important utility. This makes the assumption that force is an important component to direct laryngoscopy, which doesn’t accurately reflect a procedure in which the tissue and muscle tone in a paralyzed patient requires very little force, unless you are attempting to put a patient in an ear to sternal notch position during the procedure by lifting his head and neck off the bed (easier ways to pull that off almost every time). So while I do agree that a Mac 3 is mechanically favorable, it’s benefit is outweighed by the cognitive unloading provided by choosing a Mac 4 that in my experience has provided first past success without any potentially advantages I could see from a Mac 3 (granted I’m a relatively bigger than other people, however I swear I apply almost no significant force during the procedure instead relying on ELM/bimanual manipulation, ear to sternal notch, etc). I will say a Mac 3 is more likely to help a novice intubator by preventing passage over the cords with the blade and is fine for anesthesia who practice controlled intubations outside of critical care environments and have plenty of experience to develop good decisions on proper blade size, otherwise not convinced by anyone so far that a Mac 3 has any advantage for optimizing first pass success.

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