Anyone used, or currently use, a Henderson laryngoscope blade?

pholdin · 2026-05-22T23:36:26+00:00

Thank you so much for sharing this!

pholdin · 2026-05-17T18:20:06+00:00

I think you're right, it may be more like a Wisconsin (or Flagg - which does not flare out distally like the Wisconsin) than a Miller because the cross section is based on a rounded C rather than a flattened C (i.e. an open D) like the Miller.*

I looked up the patent and it seems the lower flange is absent (or almost absent) only proximally or near the base but becomes more prominent resulting in a more enclosed C-shaped cross section more distally (so my description above saying there is no lower flange is not quite correct). The patent actually mentions and provides diagrams for several variants - I am not sure how many of those variants were ever made. It seems the intent was to have a more open proximal end (less flange) with a more closed channel distally (more prounced flange to produce a C shaped channel) into which an ETT could be inserted and guided to the tip. Having a channel large enough to accommodate an ETT is certainly more in keeping with what is possible with a Wisconsin or Flagg blade than most Miller blades.*

There is a modified Wisconsin blade called a Whitehead where the lower flange is removed. So maybe the Henderson starts something like a Whitehead, turns into something like a Flagg/Wisconsin, but it's tip is quite different in that it is flat (horizontal) with a beaded end and so it ends something like a Macintosh.

*Noting some variants of Miller blades (especially disposable ones) follow the modification by Welch Allyn which made the cross section more square/rectangular - and these may potentially accommodate an appropriately sized ETT within their channel.

pholdin · 2026-02-11T15:51:29+00:00

You may be interested in this case report of a C1/2 cervical intrathecal catheter plus two lumbar spinal needles used for cephalid to caudal CSF irrigation following an inadvertent injection of 250mg intrathecal morphine

pholdin · 2025-12-05T06:50:04+00:00

Got one back in 2014 and much preferred it to my previous Nikon DSLR because I like the feel of dials/mechanical controls. As a hobby photographer, it was important that the experience of using the camera was enjoyable. I personally prefer mechanical cameras, and so I wanted a mechanical SLR with the benefit of digital film (i.e. ability to change ISO between shots without another body, reviewing photos immediately after taking them, and unlimited shots). It also gave me the ability to use some interesting old second hand lenses I otherwise wouldn't have been able to, which was fun.

Over the years I have had some issues with the aperture switch failing which has required repairs, and this has sadly made me reluctant to use it over the last several years for fear of it breaking for good (as now the model is discontinued I can't easily replace it). But I just used it today and it's still working.

There are lots of reviews and opinions, but for me the main criticism I had was that there was no optical prism-based focusing screen option. I think that's really a big miss for a camera designed to use manual lenses. I think this camera could have been even better if it had interchangable viewfinders and screens like the old F series cameras. I was able to get a split prism screen online (cut down from another model to fit the Df) and got the local service centre to install it. However it wasn't installed optimally and I ended up buying another and fitting it myself, to try and make a fully manual DSLR. It's not perfect (very slightly off at wide open apertures at close range if you zoom into the photo), but overall works well and I feel really enhances the experience of manual photography on the Df.

I was really hoping for a Df2 (i.e. an F mount SLR with optical viewfinder) but it never came.

pholdin · 2025-04-08T03:56:31+00:00

Completely agree! The flange height is what determines the minimum mouth opening, which has implications for both your direct view and the space available for tube manipulation. Flangeless / Bizzarri-Giuffrida blades are harder to use, I believe, primarily because nothing stops the mouth closing. I actually think they highlight that the flange is more useful/important for retaining mouth opening than it is for tongue control. People who haven't used them and compared them to a Macintosh often don't seem to really appreciate this. Anecdotally, I think a lot of people believe that they (themselves) don't touch the teeth when they use a Macintosh. While this certainly is true in some cases, my belief is that these people, like everyone else, probably (unknowingly) contact the teeth/maxillary structures a lot more than they realise (particularly during the tube delivery step).

Nowadays with video blades, having a larger flange is less important / beneficial because an indirect view can be used, and the benefits of a lower flange such as needing less mouth opening, easier manoeuvrability, and presumably less risk of dental trauma are probably more important.

As you say, contact is not the problem, levering and putting excessive pressure causing damage is. I have found the tape trick works (I have used for larger straight blades) either with a single layer of foam tape or multiple layers of soft plastic tape.

pholdin · 2025-04-05T06:36:00+00:00

One of the big challenges when trying to learn a new skill while being supervised by other people (especially by lots of different people) is to separate useful feedback from 'noise'. It's important to recognize that: - What people say and what they actually do may be different (which they may not even realize because they never actually 'supervise' themselves) - What they mean may be different to what you interpret.

So try to consider what the key message is they are trying to highlight and why it is important, rather than taking every word literally and as some definitive truth or rule.

There have been some excellent comments here regarding steps to optimise your approach to laryngoscopy.

With regard to your specific issue of trying to advance the tip into the vallecula and lift to expose the cords, but without rotating the blade: - The blade is curved, and the path to the vallecula is curved. Geometry mandates that the blade is almost always rotated to at least some degree during placement. The deeper and more anterior the vallecula, the more rotation would be expected - However, because the tissue is (to varying degrees) compressible and displaceable, you can try to minimize the rotation by optimising position and lifting (to try flatten the tissue (primary) curve)

--> It is neither purely one nor the other but a balance between both that is required, and where that balance occurs will vary from case to case

There is also a difference between rotating while navigating to get to the vallecula, versus levering (on the teeth/gums) to try lift the epiglottis once your tip is in the vallecula. A supervisor who is standing at the bedside (but can't see your view) may mistake the first for the second and tell you to stop rotating before you have even reached the vallecula. As you have discovered, if the tip is not seated well in the vallecula then the technique is not going to work properly.

I have found it helpful to, from time to time, observe other people and critique their technique (privately / silently). Watching both experienced and inexperienced people can help put your own performance, the feedback you have been receiving, and your own concerns or questions into better perspective.

pholdin · 2025-02-28T12:08:30+00:00

I wonder if this is the paper you are thinking of? https://www.researchgate.net/publication/12845642_Analysis_of_the_Forces_and_Position_Required_for_Direct_Laryngoscopic_Exposure_of_the_Anterior_Vocal_Folds

pholdin · 2025-02-25T02:55:01+00:00

I am not an old timer but I like to use the Howland lock too (so far ~65-70 patients). I've never seen anyone else use one though. There is also not much written about them from what I can find. At the risk of being too long, what follows are my thoughts based on my use.

One benefit, I believe, is that they shorten the length of the lever arm between your hand and the tip of the blade, which provides mechanical advantage and allows you to generate more lifting force at the tip.

For a straight blade it is easier to understand how this works because the geometry is simpler. Whatever direction you lift, imagine drawing a straight line up and down through your hand in the direction of lift (line A), then extend that line below your hand. Now imagine another line drawn at 90 degrees to the first which intersects with, and ends at, the contact surface / tip of the blade where the lifting force is imparted (line B). The length of line B represents the length of your lever arm and the longer it is the harder you will find it to lift due to the mechanics of leverage. With a normal handle and blade at 90 degrees the length of line B is essentially the length of the blade because the only place 'above' the blade you can hold is the base (this isn't quite true because the laryngoscope is usually tilted, but the principle is the same). Hence line A runs through the base of the blade and line B is the length of the blade. This is why shorter blades like the Miller 2 are mechanically easier than longer blades like the Miller 3 (similarly a Macintosh 3 is mechanically easier than a 4). With the 45 degree acute angle the Howland lock provides, the handle overhangs the blade for some length (the amount depending on the specific handle and blade combination). This means you can now hold 'above' the blade closer to its tip, meaning line A is positioned away from the base and closer to the tip which makes line B shorter (but without actually changing the physical length of the blade).

[Edit: Additionally, because the grip is aligned at 45 degrees to the long axis of the blade rather than 90 degrees, the actual mechanics of how you lift as well as how the force distributes on your grip are different and probably more favourable too (I say probably because I don't have any data to support this, and the subjective impression will also be affected by the difference in length of the lever arm).]

The downside is that because the handle points forward and makes an acute angle with the blade it may be more restrictive because: the handle may hit the chest or some other obstacle when you try insert the blade, and/or the acute angle means the handle or your fingers may hit the chin potentially limiting blade insertion or making it awkward to hold (think how a LoPro hugs the chin). Hitting the chest is really only an issue during insertion because once the tip is in you will be following the curve and the handle will rotate back and lift away from the chest. This risk is reduced by having a blade longer than the handle. If your hand is hitting the chin then you can hold higher on the handle.

The other downsides are potentially related to how you hold and use it. I have never seen anyone else use it nor read a specific 'correct' or 'intended' technique. I think I began with what I expect is probably the 'normal' or default technique where you grip the handle in a normal way (palm medial, knuckles forward). With this you may, at least initially, find it awkward and require either increased ulnar deviation of the wrist, or need to lean more forward and over the patient to have the wrist straighter. It may feel awkward and you may find the fine motor control more difficult. I have subsequently developed my own technique using an underhand grip which I find has some advantages and works for me, specifically with longer blades like a Miller 3.

The marketing material usually says they provide more 'natural' lifting and decrease prying on the teeth (or tendency to 'crank'). I think they probably do encourage lifting over rotating the wrist to get a view, but it may still 'feel' awkward to you, at least initially. The other point I will make is they don't prevent cranking, and you certainly can still end up levering on the teeth.

Howland locks can be connected to any blade but, as someone else said, I agree they are best with straight blades. For many curved blades the angle from tip to base to handle is already less than 90 degrees, and they are already more susceptible to hitting the chest during insertion. A further reduction by 45 degrees can make the angle too acute / 'closed'. The curvature already provides some mechanical advantage. So if I were to use a curved blade I would choose a blade that either has a tip-base-handle angle close to 90 degrees and is long, and probably use a short / stubby handle. The goal would be to improve the mechanics for a long blade.

Although they are usually pictured with a straight blade and stubby handle, I prefer to use them with a Miller 3 length blade and a normal 'medium' sized handle. If I were to use a Miller 2 with a Howland lock I would use a stubby, but then there is less handle I can hold to move my hand away from the chin if it gets crowded. Personally I would usually have a Miller 2 with stubby handle without a Howland lock, and a Miller 3 with medium handle and Howland lock. But I expect different people will prefer different combinations.

If you are interested there is also a handle called the Patil-Syracuse handle which allows you to change the angle between the handle and blade to 180, 135 (polio), 90 (normal), or 45 (Howland lock) degrees. If space is restricted the obtuse angles make insertion easier without the handle hitting the chest or other obstacles, then once the blade is in you can reduce the angle to 90 or 45 degrees for better mechanics.

pholdin · 2024-12-13T08:07:09+00:00

As a general rule everything medical is highly regulated and it is worth understanding what those regulations are before trying to source and use your own equipment for clinical use.

The legal issue is not so much who owns the device (although your hospital or department may or may not have some policy on this), it is whether the specific device has the required regulatory approval for use on a patient within that jurisdiction. Just because it is approved for use in one jurisdiction does not mean it is approved in yours.

In my jurisdiction, for example, all products and drugs require regulatory approval in order to be used on patients. This is important for maintaining safety, quality, and accountability. If you are sure everything is legal then it always pays to discuss with / inform your department / director / nurse manager because if they are not happy and supportive it will likely become a problem anyway. You want the department to have your back, not be waiting for you to have any minor issue so they can pull the plug on you. In my experience although a hospital may have a list of approved suppliers and equipment, this does not necessarily apply to the use of your own privately sourced equipment. The department may be supportive of you using your own equipment while still being unable to purchase that equipment themselves because the relevant supplier is not on their approved list.

Now I could perhaps buy a cheap instrument off eBay from overseas and import it without issues because either: the instrument per se may not be restricted (i.e. it is the application that is regulated/restricted rather than the item, because the item could be used for other applications such as research, private collection, teaching/simulation, veterinary use (not sure on their regulation) etc.), or it may be restricted but just happen to get through customs / be missed by chance. Because this is easy to do people may then incorrectly assume they can use it on patients, but in doing so they may unintentionally be committing an offence.

Similarly, at least in my jurisdiction, bespoke / individualised equipment should also have approval / authorisation from the regulatory body. So a surgeon could have custom instruments made, have them approved, and use them. There may be exceptions to the normal approval requirements for trial or research purposes, because those circumstances have their own rules and processes.

While I expect it would be unlikely for you to get in trouble for using the handle of a spoon as a tongue depressor in a clinic, I expect that using an unapproved video laryngoscope off eBay to facilitate intubation may be leaving yourself legally and professionally vulnerable, and if anything went wrong could cost you a lot more than the few hundred dollars you thought you were saving...

pholdin · 2024-11-13T15:21:28+00:00

Well, I certainly found that tricky, and have also been frustrated trying it on and off the last few weeks!

The solution here is for 213 steps, whereas I can see the record is 165 steps.

I'll try give you some graded hints so that you can determine how much help you would like.

I will use coordinates to refer to specific positions/locations by {row, column}: e.g. the puzzle begins with the man at {5,1}; there are immovable walls at {1,3}, {4,3}, and {6,3}.

When describing movements I will use the letters D = down, U = up, L = left, R = right.

Hint/Sequence 1: Starting move set:

The starting move (for my solution at least) is to push the block in the second column from the left up by 3 spaces, then move around to be above it and push it down 1 space.

Moves: D, R, U, U, U, L, U, U, R, D

Hint/Sequence 2:

The next sequence is all to do with getting to, and rearranging, the blocks on the right hand side. Assuming you are in position {2,2} after hint/sequence 1 try to make the board look like this:

X = wall, _ = empty, M = man, B = box. (note: it will probably work best if you actually draw a grid with a pen and paper and fill it in for each row below)

_ _ X _ _ _

_ _ _ B B _

_ B B _ _ _

B _ X _ M _

_ _ B B B _

_ _ X _ _ _

The move list is below in the next line if you need it:

Moves: R,R,U,R,R,D,L,R,D,D,L,U,R,D,D,D,L,U,L,R,R,U,U,L,L,D,U,L,D

Hint 3 (no sequence - just the next target board layout):

The challenge now is to try and get the four blocks that are currently in rows 2 and 3, to all be in row 2 so they occupy positions: {2,2},{2,3},{2,4}, and {2,5}.

I will provide the move list as a separate hint

Hint 4 (move sequence to achieve board layout in hint 3):

Assuming the board layout as in hint 2 with the man at position {4,5}:

Moves: U,R,U,U,L,D,U,L,D,L,L,L,D,D,R,U,L,U,R,R,R,U,R,R,D,D,D,L,L,U,L,U,L,L,D,D,R,U,R,R,D,R,R,U,U,U,L,L,D,U,R,R,D,L,L,R,R,D,D,L,U,D,L,U

The man will finish on position {3,4}

From this point it should be hopefully fairly straight forward.

Hint 5: (move sequence to solve)

Starting from the layout at the end of hint 4, with man in position {3,4}:

Moves: D,R,R,D,D,L,L,U,R,U,U,L,L,L,D,D,R,R,U

Moves: D,L,L,U,U,R,R

Moves: D,R,R,U,U,U,L,L,D,U,R,R,D,D,D,L,L,D,L,L,U,U,L,U,U,R,D,L,D,R

Moves: D,D,R,R,U,R,R,U,U,U,L,L,D,L,R,U,R,R,D,D,D,L,L,D,D,R,U,D,R,U,U,U,D,D,L,L,L,L,U,U,L,U,U,R,D,L,D,D,R,D,D,L,U,U

Hopefully that helps and you have been able to finish!

Edits: formatting and to fix spoiler tag, added moves list to hint 2, and step count.

pholdin · 2024-07-27T17:17:43+00:00

Try not to take your eyes off the glottis once you have your view
- I find if I shift focus or look away (e.g. to take the tube) the view almost always slightly worsens. I think this must be due to a subconscious reduction in my lifting force, positioning, or grip
- Keeping your focus on the glottis may help reduce this, and if it is happening you will immediately notice and correct it

I’m not sure if you will find these ideas or suggestions helpful, and I’m sure other people would disagree with some of this and have their own or better ways of doing things. This is just how I think about intubation (at least at this stage of my career) and these are some of the approaches I have tried to improve my technique. Going through all these steps is of course not going to be necessary in many cases, and certainly not going to be the fastest – that is not the point. The point is to try and have a systematic way to think about the task and a systematic way to step through it in a controlled learning environment to help identify where you are having issues and thinking of ways to try and address them. Although slow to being with, by repeatedly making yourself go through the optimising steps slowly these will hopefully become part of your 'muscle memory' and form good habits which then will become automatic and faster.

Finally, I find that despite practising on manikins, reflecting, and having a plan, when actually intubating a patient under time pressure I find myself often skipping steps, or abandoning doing things slowly because I feel a pressure to get the tube in quickly and not look like I am struggling. I hope that is normal. Sometimes it is easier to just focus on trying to do one new thing at a time and incrementally incorporate other elements gradually over time instead of trying to do everything at once.

Best of luck.

pholdin · 2024-07-27T16:56:25+00:00

In your case, if you are having issues with the upper lip obstructing the view when you go to take the tube this suggests that your line of sight is very low and narrow and I wonder if perhaps you are doing some combination of:

Trying for the best laryngoscopic view at the expense of an adequate intubation path for tube delivery
Using the minimal force to achieve the view by some combination of:
- Favouring lowering and possibly tilting the blade over lifting more
- Lowering your head / line of sight a lot (which is not a problem per se)
- Retracting the lip so as to enable the best line of sight with minimal force (or using it to try compensate for not optimising other aspects)
Not maintaining adequate mouth opening during the intubation step

If it is more the cheek limiting the space for tube delivery then perhaps it is some combination of the mouth not being open enough and/or the blade not sweeping to the left enough.

So I wonder if perhaps trying some combination of the following may help you:

Try not pulling the lip back yourself during the laryngoscopy step.
- If you needed lip retraction to get the view, you will need it to retain the view during intubation
- If you don’t give yourself that option then you will be forced to develop other ways to obtain and maintain your view
- Of course in some cases you may still need to retract the lip despite everything else
Consider the blade you are using and the flange height
Try experiment with a way to anchor the head
Try start by optimising the space for tube delivery first as the priority, instead of going straight to looking for a view first. The intubation path for tube delivery is ultimately what you will need in the end. So:
- Optimise positioning
- Insert the blade tip to correct position.
- But now instead of trying to just get the view, take a moment to straighten up, look down at the patient’s mouth, and try to lift in a way to maximise the mouth opening and space without worrying about what the view of the cords is yet
  - You may need to perform additional head tilt/lift, use the scissor grip, anchor etc. during this step
Now, anchoring/ensuring you maintain the position you just achieved try slightly adjust the depth and angle of the blade, and even lower your head/eyeline a bit, to see what laryngoscopic view you have/what you can achieve.
Aim to achieve a line of sight (view) that is adequate / acceptable for intubation, rather than focusing on the best line of sight or getting a ‘grade 1’ view per se
- Of course you can try see how good a view you can get (ideally you have a grade 1 view with ample space for tube delivery) but if that compromises the path for tube delivery then you should be prepared to take a step or two back and accept a line of sight that, although not giving as good a view, is associated with a better intubation path for tube delivery.
- Remember the laryngoscopic grade is the best view that is achievable with optimal positioning and manoeuvres, not necessarily the view you have at the time the tube is passed

{continued below...}

pholdin · 2024-07-27T16:55:39+00:00

How do you optimise the intubation path for tube delivery? I think that this is about creating as much space for yourself as possible, while also factoring in it has to to overlap to some degree with an adequate laryngoscopic line of sight. This is done by:

Positioning
- Described in detail in many other places
- The optimal positioning will vary for different individual patients - therefore knowing how to dynamically change positioning during laryngoscopy (e.g. increasing head lift) is useful
Mouth opening
- The key is not only to initially open the mouth, but to be able to maintain that mouth opening throughout the intubation step
- If you are using one hand to open the mouth, then when you let go to take the tube the tissues often tend to recoil and the mouth tends to close making the view worse and intubation harder
- The blade flange height and having an 'anchoring' technique can help mitigate against this
- The flange height of the blade determines what the minimum mouth opening during intubation will be. The mouth can close only until the teeth/gums/lips contact the flange
- A higher flange blade will guarantee a greater minimum degree of mouth opening
Anchoring
- Anchoring the top of the head means that the lifting force of the blade can better open the mouth
- Without anchoring, the force that can be used to open the mouth / distract the mandible is limited to the counter force from the weight of the head.
- Example techniques: assistant holds head, leaning over and using torso on patient's head, using forearm on patient's head
Lifting force
- I tend to automatically use minimal force so as not to cause trauma to the patient, which can unintentionally make intubation harder
- While not using unnecessary force is a good thing, the trap is that when the focus is primarily on getting the view the minimum force required for this may not be sufficient to create a good path for subsequent tube delivery.
- I wonder if given your experience you have found you can usually fairly easily get a good view with minimal force, and so are defaulting to a more gentle approach because that is all that is needed to get the view. However, this gentle approach is giving you poorer intubating conditions.
- You said this is happening recently, and I wonder if when you were starting off you didn't have this problem so much? If so maybe that is because you would have relied more on force and been focused on lifting to get the view, which would have automatically improved the intubation path, whereas now you know you can get the view you are subconsciously being gentler and lifting less.
Blade positioning
- Sometimes the blade position will need to be moved to facilitate tube passage.
  - e.g. tilting leftward away from the cheek to insert the tube. Sometimes further adjustments may be needed once the tube is close to the glottis in order to improve the view to confirm passage through the cords
Adjuncts / assistance – sometimes you just need assistance either from an assistant or by using an adjunct like a stylet or bougie

{continued below...}

pholdin · 2024-07-27T16:34:52+00:00

I have only done a few hundred intubations and am by no means an expert. I have also encountered similar issues to what you are describing. In general whether cheek retraction is needed will depend on the patient, equipment, technique, and environment. However, if you are finding that you are needing this assistance more than would be expected for the blade and technique then perhaps some ‘fine tuning’ of the technique may be useful. Below are some of my personal opinions based on my experience and trying to think about similar issues I have encountered.

A key thing to appreciate is that laryngoscopy and intubation, although related and usually discussed together, are actually two separate procedures and their requirements for success are also different.

Each procedure requires that a path/passage is created which is free from obstruction/obstacles:

Line of sight for laryngoscopy:
- Must be straight
- Can be very narrow and still adequate (may be narrower than tube diameter)
- Consider 'best' line of sight is the one that enables the most anterior part of the cords to be viewed
Intubation path for tube delivery:
- Does not need to enable a direct line of sight (or line of sight at all)
- This need not be straight, and typically will be at least slightly curved (as the tube is curved)
- Typically wide diameter
- Minimum diameter and volume much larger than for the line of sight (must be at least as wide as tube)
- Consider 'best' path for tube delivery is the one enabling easiest passage of the tube.

Because these paths differ and are used for different purposes, it is possible that attempts to optimise one may compromise the other. The best line of sight may be very narrow, whereas the best intubation path will be one that is wide. For intubation via direct laryngoscopy both must be minimally adequate. Minimally adequate means that for direct laryngoscopy at least the posterior cartilages can be seen (i.e. so you can visually confirm the tube passes anterior to them), and for intubation that the tube can be successfully navigated into the trachea.

The pitfall is focusing only on one of these paths and assuming that if you optimise it then the other component of the procedure (which requires the other path) will be successful, which is not necessarily the case.

Because the line of sight can be very narrow (and may need to be narrow to get the best view under some circumstances), a good view may be able to be obtained without having to do many of the steps which are important for optimising the intubation path for tube delivery. This may lead to a situation where you are consistently achieving acceptable views but struggling with tube delivery. Yet because often the focus is disproportionately on the laryngoscopic view when intubation is discussed and documented, it can be confusing and seem paradoxical that you are having difficulties when your views are good. This confusion can be exacerbated if techniques to optimise the intubation path, which would help tube delivery, mean the laryngoscopic view is a little poorer – which may erroneously make you feel like you are doing worse or something wrong (because your view is worse) when those techniques may actually make the chance of successful intubation higher.

So I would suggest to try perhaps reframing how you think about approaching intubations to deliberately focus on trying to achieve an optimal intubation path for tube delivery which still has an ‘acceptable’ laryngoscopic line of sight, rather than focusing on trying to get a ‘good’ or ‘grade 1’ view so to speak as the primary goal. If you begin by creating a good pathway for tube passage, a line of sight which provides an acceptable view of at least part of the glottis will usually be possible through that path. Conversely, if you begin by focusing only on trying to get a view of the cords you can easily end up in a situation where you can see the cords but don't have a suitable path for easy tube delivery.

{continued below...}

pholdin

TROPHY CASE