Its a Sign

The chief of my department approached me about the lack of a sign on the intensivist’s call room.

Rather than wait 6 months for facilities management to provide a new sign he requested that I design and 3D print one instead. Since the call room is in a non-patient accessible area, I decided to add some mild humor to the sign. Here is the initial design that I came up with:

To make this a quick project I utilized some open source resources. I obtained the defibrillator SVG pictogram from freesvg.org where it was listed as public domain. I utilized the free to use IMAGEtoSTL converter to convert the SVG file to STL, then imported into my project. I could not find quality ECG vector images of ventricular tachycardia/sinus rhythm so I imported some ECG images into photoshop and isolated the lines; I then used IMAGEtoSTL again to produce STL images of the rhythms and imported into my project. This is the first project that I used an automated raster to vector converter and it worked surprisingly well on the ECG lines.

I sliced the image in Prusaslicer and printed on a Prusa i3 MK3s+ at 0.3 mm layer height in black and white Hatchbox brand PLA.

The print came out well and I affixed it to the call room door:

My chair was happy with the result.

RIC Lines – Very Large Bore Peripheral Intravenous Access

Rapid Infusion Catheters, or RIC Lines, are a product line of large bore peripheral IV catheters designed to be placed easily and rapidly in hemorrhaging patients. The catheters come in 2 sizes: 7 Fr (13.3 Ga) and 8.5 Fr (11.8 Ga). By using a 20 Ga IV to upsize to the RIC Line via seldinger technique, one is able to easily place a large bore RIC Line catheter into a medium sized vein which could otherwise be very challenging.

Skip to the bottom of the page for a thorough video of RIC line placement steps and considerations.

A 14 Ga IV catheter compared to the massive 7 and 8.5 Fr RIC Lines.

The Kit contents (pictured below) include 3 items:
1. RIC Line catheter with integrated skin dilator.
2. Guidewire in a plastic sheath.
3. Skin scalpel.

In addition to these items you will need:
1. Existing in-situ 20 Ga IV catheter.
(Or)
A. Tourniquet.
B. Skin antiseptic.
C. New 20 Ga IV catheter to be placed.
2. IV infusion tubing

7 Fr RIC line kit package contents. The 8.5 Fr kit is the same but the hubs of the catheter and dilator are blue.

Placement is fairly straightforward. Use an in-situ 20 Ga IV catheter or place a new 20 Ga IV catheter to act as an introducer for the guidewire. Remove the 20 Ga catheter, make a small skin nick with the scapel and place the integrated RIC Line and dilator into the vein, followed by removal of the dilator and guidewire.

Major considerations of the procedure
1. If you are placing a new 20 Ga IV catheter, try to avoid “bloodless” style catheters as the diaphragm that prevents back-bleeding, can also impede advancement of the guidewire.
2. Since this if often a used as a trauma line, utilize the maximum cleanliness that you have time for. If the patient is hemodynamically unstable, a quick swipe of an alcohol pad is appropriate; however, if this is being placed for an elective case, sterile technique can be used. You will be touching the guidewire and catheter with your hands, so the increased cleanliness is appropriate if the extra time is clinically appropriate.
3. If the patient is conscious, anesthetize the skin with local anesthetic.
4. Since the kit feels similar to a central line, it can be tempting to make a large skin nick, but this will result in damaging the superficial upper extremity vein. Be mindful to make a small 2-3 mm, superficial skin nick.
5. Despite the large bore, you may get little to no bleed-back and you may not be able to draw off the catheter. This results from 2 issues: The catheter may occlude the vein enough to impede proximal flow and the catheter may be larger than the vein and as such will suction the walls of the vein when drawn back. This feature is compounded by patient hypovolemia.
6. Remove the dilator! The dilator has a leur-lock connector and will flow at least as well as a 20 Ga IV if left in place. If not removed, the stiff dilator can produce significant damage to the vein.

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3D Printed Repair: The Modern revival of the ancient Japanese art of Kintsugi

Kintsugi is the ancient Japanese art of repairing broken pottery with gold, silver, or platinum. The philosophy of Kintsugi celebrates the history of an object by highlighting its repair instead of disguising it. The repair not only makes the object functional again, but also beautiful through its uniqueness.

A bowl repaired with lacquer and gold in the Kintsugi fashion.

Although the art of Kintsugi still exists, a modern offshoot of this art is evolving as part of our everyday lives due to the increasing affordability of 3D printing. Due to differing properties of the polymers used for printing and inability to make perfect color/shape matching, it has led some modern makers to highlight their repairs with unique shapes and colors just as with Kintsugi. In an age where almost everything is standardized and disposable, modern 3D Kintsugi is a breath of fresh air that, in addition to breaking the cycle of consumerism, adds beauty to our lives with unique objects that cannot be purchased on Amazon.

The evolution of 3D printing as a reparative art is in its infancy and a community devoted to these designs has yet to evolve but one can find a number of examples of it in 3D printing communities such as Reddit’s Functional Prints. A few examples are listed below:

A pair of scissors with 3D Printed handle repair. (From Reddit user: badatchopsticks)
A 3D Printed replacement stand for this LED mirror. (By reddit user: aqa5)
A laptop charger repaired with 3D Printed part. (From reddit user cafeBreak24)

As far as my own creations in the medical and hospital space, most of my creative interventions are not reparative in nature but a few of my creations do fit the bill and can be found here:

Here, this McGrath laryngoscope battery, which costs $50, had a broken removal tab to allow removal of the battery but still had 2/3 of the battery left. This $0.05 repair allows the additional $33 of the battery to be used.
When the pharmacy changed from large to small vials of clindamycin, instead of reprinting my entire emergency drug tray component, I simply made an insert to allow for organized storage of the new smaller vials.
A simple 3D Printed replacement of this epidural pump screw clamp bushing in white TPU.
A 3D printed Knob that I made for the anesthesia office toaster oven.

It is my hope that 3D Kintsugi will continue to evolve as a modern functional art form, extending the longevity of our possessions and adding unique and beautiful elements to our lives.

Anesthesia to the rescue….. In a flash!

Due to an unfortunate workplace injury, my friend, colleague, and anesthesia intensivist, the great Pavan Sekhar, MD, needed to use a knee scooter for a few months. In order to better facilitate his job, I designed and 3D printed an organizer for his scooter to allow for better organization and delivery of drugs, procedural equipment, and caffeine.

Here is the design that I conceived of in CAD:

The model contains places for drug vials, syringes, a box of epinephrine, small misc items, and large misc items, as well as a central cup holder for convenient infusion of intensivist caffeine.

Due to Dr. Sekhar’s affinity of the Marvel and DC universes, plus the speed at which he zoomed around the ICU on his scooter, I added a flash emblem to encompasss these traits. I sliced the flash emblem in PrusaSlicer to be used on a Prusa i3 MKS multi-material extruder setup to allow for multicolor printing without intervention.

The Prusa MMU2 utilizes a filament manifold to allow for multicolor 3D Printing.

I printed the box component at 0.3 mm height in PETG for strength and the flash emblem at 0.2 mm layer height in PLA for detail. Here is the final product:

Dr. Sekhar was happy with the final product and it will hopefully improve his organization and provide him with a few extra seconds during emergencies when seconds count!

A quick 3D print for pharmacy safety

Recently our hospital standardized a number of the adult vasopressor infusions. Our usual 10mg/250mL phenylephrine bags for infusion were eliminated and replaced by 20mg/250mL bags. Since phenylephrine is our primary vasopressor infusion for most anesthetics, our pharmacy drug trays include both a premixed bag of phenylephrine and a backup 10mg/1mL vial to mix into a 250mL saline bag if that initial bag is depleted. Pictured here is the backup concentrated phenylephrine 10mg/1mL vial in the drug tray:

For the transition to the more concentrated phenylephrine bags, the pharmacy now needed to supply 20 mg of concentrated phenylephrine in order to make backup phenylephrine bags. The two options were to include a larger phenylephrine vial (the next size up being 50mg/5mL) or adding an additional 10mg/1mL vial to the tray for a total of 2x 10mg/1mL vials. When the department was presented with the first option, many attendings were strongly against the 50mg vials since then worried that the less experienced residents may make a life threatening error with such a large, concentrated dose of phenylephrine. As for the second option, the pharmacy was against having 2 vials in the tray as there was no spot for the second vial and the pharmacists were worried about having a “free floating” vasopressor vial in the tray, especially an vial type which is shared by many other drugs. Replacing the blue tray foam inserts was not an immediate option as they had just been replaced a couple months prior and are prohibitively expensive to replace.

In order to expand the single phenylephrine vial spot into one big enough for 2 vials, I conceived of, designed, and 3D printed a quick and simple solution:

The cylindrical portion would slide easily into the vial spot and the rectangular portion would hold 2 horizontal vials. I printed the model in 2 parts to maximize speed and negate the need for 3D printed supports. The final part would be pressed together with a dab of glue. Between 3 Printers, I was able to complete the project overnight so that the pharmacy could implement the project immediately.

The pharmacy was satisfied with the solution and impressed with the speed at which the project was completed. This project, which used approximately $5 worth of materials, is an excellent example of how in-house 3D Design and Fused Deposition Modeling can be used to create immediate and useful solutions to problems that would otherwise require compromise or take months to implement.

Small Medication Ampoule Organization

On more than one occation, when in a hurry, I have broken a few glass medication ampules. The all glass amps can be broken fairly easy when opening a storage or omnicell drawer as they tend to roll around.

In order to reduce the risk of broken glass and save the expense of wasted medications, I designed a couple varieties of organizers to prevent these issues in the future.

Here are the CAD designs that I conceived of:

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The first desgn was intended mostly for lidocaine amps in the anesthesia carts while the second was intended for displaying the amps more clearly in the omnicell.

Here are the 3D Prints and their implementations:

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I have yet to break an amp since implementing this organizers. One of the pharmacy techs commented that they thought the main pharmacy had purchased these from a supplier rather than a 3D printed item that I had made on the fly.

Pediatric Anesthesia Mask flavor Organizer (3D Printed)

In order to ease the fear and discomfort of an anesthetic mask induction, we often use essential oils (we refer to as “mask flavors”) to add a pleasant smell to the oxygen mask which helps to, at least partially, cover the unpleasant smells of the plastic mask and sevoflurane anesthesia. One problem with our work flow is that the flavor vials are typically held in the equipment carts like so:

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This method of storage is suboptimal. The vials often tip over and spill, they must be picked up in order to read the label, and the anesthesia techs can not easily tell which vials need to be replaced. Inserting a simple 3D printed organizer would be an easy and cheap solution in order to improve the organization and delivery of this tool. 

I conceived the following design in my CAD software:

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The model was designed to fit nicely into the existing space. Two rows are positioned to display the vials in an orderly and easy to read manner while the back portion would allow for the storage of a few extra vials.

I printed 2 prototypes on a Prusa i3 MK3S in PLA with 0.2 mm Layer height.

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Here is the model in use. It serves its purpose as designed and my anesthesia group was pleased with the upgrade.

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Along with one of my colleagues, I continued to print these organizers for the remainder of the anesthesia carts.

Further Reading:
Use of essential oil to promote induction of anaesthesia in children (A brief research article on the benefits of essential oils for inhalational anesthetic induction in children)

3D Printed Emergency Drug Tray for Endoscopy Suite

Due to the popularity of my OB 3D Printed Emergency Drug Tray, members of my department asked if I could help standardize an emergency drug tray for the endoscopy suite. I polled the CRNAs and attendings that frequently work in endoscopy and made a layout that would include all the important and frequently used drugs to have on hand. Since I had previously measured the sizes and created layouts for all of the drugs in my previous emergency drug tray, creating the new model was straightforward.

3D Model Design:undefined
I Printed the Components in 2 parts so that I could have 2 distinct colors: 1 for paralytics (Succinylcholine in this case) and 1 for the other emergency medications. The halves were simply glued together with some standard cyanoacrylate glue. I added non-slip feet to the bottom so the tray can be removed from the drawer and placed on top of the cart if desired.

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Why Your Anesthetic Gas Analyzer Detects Halothane When You Administer Albuterol

Have you ever administered albuterol (aka salbutamol) to a ventilated patient and witnessed the anesthetic gas analyzer detect halothane even though there hasn’t been a bottle of halothane in your hospital in decades? How can a machine so advanced make such an error?

The gas analyzer on your anesthetic machine is an underappreciated technological marvel found in every operating room in every industrialized country in the world. It consists of a paramagnetic analyzer to detect oxygen and a gas phase infrared spectrometer for all other gases. Because oxygen does not absorb infrared light, it can not be analyzed by infrared spectroscopy and requires its own analyzer. All companies that produce anesthetic gas analyzers use Paramagnetic and IR technology.

In a chemistry lab, when we try to identify a molecule with IR spectroscopy we may be trying to identify an unknown molecule from a possible list of millions of molecules. In the operating room, we are only concerned with around 5 molecules. Instead of scanning the whole spectrum and identifying all possible peaks; an anesthetic gas analyzer only scans 2 limited areas of the spectrum and instead of searching for hundreds of possible peaks in these areas, the analyzer will only search for a few specific peaks in those ranges. By limiting the scanning spectrum and recognizing only a handful of absorption peaks This allows for a rapid response time on the order of milliseconds.

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Albuterol and halothane have very little structural similarities. Most importantly Albuterol’s structure contains double bonds and hydroxyl groups that will produce unique infrared absorption peaks not found in halothane.

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And if we look at the IR spectrums we continue to see little similarity
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So if the machine isn’t detecting albuterol, what is it detecting? One clue lies in the fact that albuterol administration via metered dose inhaler will result in halothane detection by the gas analyzer but albuterol administration via nebulized solution will not. Perhaps the inhaler contains an extra ingredient that is similar to halothane. That ingredient is HFA. HFA, the propellant in most albuterol inhalers, stands for hydro fluoro alkane.

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 Interestingly, halothane contains the components of a hydro flouro alkane. If we reference the albuterol HFA package insert, we see that the specific HFA used, is HFA 134a. Now this molecule looks quite similar to halothane. Interestingly, HFA 134a is an anesthetic of moderate potency, and was investigated for use as an inhaled anesthetic in humans in the 1960s.

Loooking at the IR spectra, we can clearly see that it is HFA-134a and not Albuterol that is responsible for your anesthetic gas analyzer reading Halothane.
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