Category Archives: Anesthesia Equipment

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.
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. It 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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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.


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.


And if we look at the IR spectrums we continue to see little similarity

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.


 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.

3D Printed Multi-Patient Ventilator Adapter

The 3D printing of an adapter to connect multiple patients to single ventilator is a concept that has been floating around in the news over the past few weeks. Conceptually, the setup is simple, use two 4-way splitters to connect the inspiratory and expiratory limbs of a ventilator to 4 intubated patients. Although the implementation and management of patients ventilated in this manner is not as simple. The first mention of this concept comes from a 2006 article from the Journal of Academic Emergency Medicine entitled “A single ventilator for multiple simulated patients to meet disaster surge.” The first reported implementation occurred in 2017 when Emergency Physicians at Sunrise medical center in Las Vegas successfully placed two patients on a single ventilator after an influx of intubated patients overwhelmed their ED during the Las Vegas Shootings.

Currently, at least one hospital in New York is attempting to place multiple patients on single ventilators during the COVID-19 crisis. It seems unlikely that this technique will be successful in patient with severe lung disease; however, there are groups that are working on more complex valve systems to make the process function better.

Here is my video discussing the 3D printing of a simple Multi-Patient Ventilator adapter:

Here is a great article from PulmCrit discussing the mechanics of performing multi-patient ventilation:

The General Public Does Not Understand How Surgical Gloves Work.

A large pet peeve of mine is seeing the general public use surgical gloves incorrectly as a means of infection control and protection. I most commonly see gloves being worn by grocery checkout attendants and by law enforcement. Gloves offer little direct protection from day to day interactions and provide a false sense of security that prevents the wearer from performing hand hygiene as frequently as they should.

In order to protect oneself and prevent the spread of infection, an individual needs to clean their hands between each interaction with a new individual. The typical use of gloves by non-medical individuals involves continuing to wear the same gloves for hours or even days at a time. Every time the wearer touches a new surface, object, or person, their gloves pick up whatever was there; when they touch the next surface, object, or person with those gloves, they transfer it and facilitate the spread of disease.

In addition to spreading the disease to others, most people subconsciously touch their clothing and face constantly throughout the day and since they have interacted with hundreds of people with their gloves, its like hundreds of people have touched them.

When I care for a patient in the operating room I use hand sanitizer, don gloves, interact with my patient or dirty equipment, remove my gloves, then use hand sanitizer again before I can interact with a clean environment again. Although we seem pretentious when we do it, we should constantly be reminding the people that wear gloves in public, to change their practice. Grocery workers and law enforcement such as the TSA are facilitating the spread of disease to countless people every day though ignorance of basic hand hygiene techniques.

Here’s a video I made addressing similar concerns over every day, seeing dozens of people wearing surgical gloves in public during the COVID-19 crisis:

3D Printed HEPA Filter Adapter for 3M 6000 Series Respirators

**Disclaimer: Personal protective equipment (PPE) for use in the medical field is extensively tested and FDA approved; any non-FDA approved PPE should be used only in emergency situations when no FDA approved device is available. The information provided here should be considered educational in nature and not medical advice.

The spread of COVID-19 in the US has revealed a severely inadequate supply of personal protective equipment, especially N95 masks. The dwindling supply has lead some healthcare providers to search for creative solutions for respiratory protection. One emerging method is to purchase a reusable 3M 6000 series respirator for use in the hospital environment, however, the cost of replacement filters is high and availability of all N95 filter types is low. With the CDC currently recommending that masks be disposed of after every COVID patient interaction, the cost and availability of replacement filters makes use of these masks impractical.

Small HEPA filters are inexpensive, in high availability, and filter 0.3 micron particles with greater efficiency (> 99.9 %) than N95 masks (95%), making them at least as safe as CDC recommended masks. To utilize these filters I designed and 3D printed an adapter cassette to use inexpensive Roomba vacuum HEPA filters with a 3M 6000 series respirator. With the filter, PLA Filament, and silicone sealant, the final product comes to a total of about $3 each. I also propose that one mask port be capped with a 3D printed cover so only one filter needs to be used with each patient interaction.

In this video I discuss the design, assembly, and testing of a 3D printed cassette to adapt inexpensive HEPA filters to a reusable respirator:

If you would like to replicate this project here are the items that you will need:
1. Filter Cassette 3D Models
2. 3M 6000 Series Respirator
2. HEPA Filters
3. Silicone Sealant
4. Quick drying adhesive

List of tools that you will need:
1. 3D Printer
2. Clamp

How to make a replacement power supply for the Oridion Microcap and Nellcor N-85 portable capnometers.

The oridion and nellcor portable capnometers are valuable tools offered by Medtronic for continuous etCO2 monitoring outside the OR. I frequently bring the handheld device with me to floor intubations and codes allowing for rapid troubleshooting of ETT placement and monitoring of effective chest compressions.

At the time of this writing there appears to be an abundance of AS-IS devices available on eBay for minimal cost; the majority of the devices do not come with the power cable. I was betting that these items were sold AS-IS because the device uses an unusual RJ-45 (Ethernet) based charging cable and the sellers did not want to invest $200+ on a new cable from Medtronic to test the devices.

I purchased a lot of 3 Oridion Microcaps sold “AS-IS for parts only” from eBay for $75.00.

Since we have a couple of the Nellcor devices at our institution I was able to use the OEM power brick as a reference. The brick has all the necessary info to produce a similar device:


I purchased the following power supply from amazon and wired up a rough adapter following the wiring diagram on the OEM power supply:


The result? All three Microcaps are fully functional. The last component was to produce a more finished product:


Items used for this project:
– Universal DC adapter.
– Female 2.1mm x 5.5mm connector Amazon item listed as an example, however, I purchased mine off eBay for $1 (if you don’t mind waiting 1-2 months).
– Ethernet Cable You likely have one of these sitting around, unused.
– Electrical Tape or wire heat shrink for a nicer appearing repair.
– Wire stripper.