Handcuffs…er Manual Handling aid

We have recently started moving our manikins on and off beds and various shelves using a typical spinal board.  Nothing new here.  We often wrap them up in a sheet which works really well to keep everything contained and keeps the dust off for longer term storage.  For quicker moves – particularly for BLS practice on the floor where you don’t want a sheet (like you would on a bed), the manikins become a bit more awkward with their arms falling down.

The solution to this was a simple strap with loops in the ends like a set of handcuffs.  This is easy to store and use and prevents the arms from falling down while rolling on/off a backboard whether it’s onto the floor or a bed or shelf.

Once on the backboard, ANY trolley/cart will serve to help move them around.  Much more maneuverable than a bed or even an ambulance barouche.

The strap is about 600mm long with about 150mm ‘long’ (300-400mm circumference) loops in each end.  About 1 meter of simple webbing = $1.

IMG_20140611_090345

IMG_20140611_090522 IMG_20140611_090325

There has been a new requirement to label heavier manikins with warning signs indicating two-person handling was required.  We have added these signs to the handcuffs.

handcuffs and sign

Mobile LearningSpace cameras

We use CAE Healthcare’s Learning Space as a video capture and playback system.  Typically, recording is done in dedicated clinical simulation spaces with fixed cameras and microphones.  For a variety of reasons, we need some additional cameras that can be temporarily placed in one of several other teaching spaces on an infrequent, as-needed basis.

To do this requires a camera, audio encoder, microphone and some sort of stand to put it all on.  When we were first investigating use of IP cameras, we used an old IV pole as a temporary mount with a simple aluminum bracket on top.  For these mobile cameras, we acquired some additional IV poles from EvoCare in Brisbane, model EV3501C75H4 $215 ea incl GST & shipping.  This pole has a removable top section that holds the IV bag arms.  When this section is removed, the top of the pole is just a straight piece of tube (just under 20mm diameter) with a spring-loaded locking button to hold the top section in place.

overivew

 

On the top, I created a simple folded aluminum bracket with a piece of 20mm ID tubing tie wrapped under the ledge.  Conveniently, the bolt spacing for the camera and audio encoder were the same, so they could be mounted back to back using the same holes.

The camera is an Axis M3006 HD IP camera.  The audio encoder is an Axis P8221 and the microphone is an AudioTechnica Pro44.  A short adapter joins the microphone cable to the encoder.

audio encoder camera microphone

A nice hook from Ikea was attached to the middle of the stand using more tie wraps and some double-sided foam tape.  The IV stand manufacturer cautioned that this thin wall tubing was not suitable for mounting IV pumps, so we started with something lightweight.  The point of this hook was simply to hold the cables and microphone when not in use.  A plastic cup was used to hold the microphone and the cables (mic + 2x Ethernet) were coiled and hung on the hook.

A hole near the top edge of the bracket serves as a strain relief for the microphone cable.  The ethernet cables just hang.  The Microphone cable is nearly 8 meters long, so can go virtually anywhere in the room.  The Pro44 is a carotid pickup boundary mic, so sits on a flat surface like a table or the wall/ceiling.  If you really want to use the ceiling, the Pro44 can be mounted to a small piece of cardboard using double sided tape and slipped under the edge   of a ceiling tile.

ceiling mic

 

 

wrong fitting

We were having problems with my modification to the air leg on the ALS manikins.  I had put in what I thought was a check valve (SMC KCH06-00).  But whenever I disconnected the air source, the leg tank would drain.  Hmmm, not checking…

After a quick visit from Jason from SMC today, it turns out that I had the wrong fitting.  The KCH06-00 only checks flow when the tubing is removed.  The correct fitting is AKH06-00.  $13.50 ea.  I will modify the MCKelly – ALS post to reflect the proper part number.

Now we can fill the leg tank easily and disconnect from the wall to do mobile scenarios (i.e. between the operating theatre and recovery).

DRE skill trainer

This is a custom skill trainer for doing digital rectal exams.  It was created by the staff at the CSSU at Flinders School of Medicine before my time, but I rebuilt it a few years ago with some various improvements.

The idea is to practice the finger sweep necessary for a DRE and to be able to describe what is felt in a standardised way.

Construction is based around some PVC plumbing parts (gutter downspout and 1″ pvc pipe) with various objects at different places to be found and described.  A balloon is placed over the mouth of the pipe and extended down into the pipe.  A lubricated, gloved finger into the balloon provides a surprisingly good analogue to the real thing.

We have two sets of two gutters with three practice holes each (total of 6 different holes).  The gutter is ~750mm long with the tubes spaced ~230mm apart (one in the centre).  These are not critical dimensions.  Do what suits you for storage, portability and student access.

IMG_20140128_100154

Each tube is 25mm (1″) nominal size.  This means an OD of ~33.5mm and varying ID depending on the pressure rating or schedule.  This can range from 30.45 to 28.05mm ID  The thinnest pipe is fine for this application.  The tube lengths are about 115-120mm.  Again, this dimension is not critical.  Ours extend past the gutter by a centimeter or two.  An oversized hole (~35mm) is drilled into one side of the gutter.  The tube is held in by a bolt (1/4″ x 60mm) cross drilled through both parts near the bottom.  The bolt size was driven by the availability of the dome nuts.  I got bolts to fit the nuts.  You don’t have to use dome (acorn) nuts, but I think they make a neat finish.

IMG_20140128_084108 IMG_20140128_084213 IMG_20140128_085027

Previously, these tubes were glued to the gutter section, but this made maintenance very difficult.  The drawback to using bolts and nuts to hold the tubes in is a compromise on horizontal use and stacking for storage.

Inside each tube, there is a different arrangement of things to feel.  The first two are single 3/16″ dome nuts (with short bolt) at two different angles and depths (65mm and 75mm from the top of the tube).

IMG_20140128_084538IMG_20140128_084516IMG_20140128_084937

The third hole/tube simulates a fistula with a hole off to the side using a 1″ PVC Tee piece.  Construction of this one requires a slightly larger hole in the top to accommodate the Tee fitting OD and another hole in the bottom to allow for assembly.  Place the Tee in the gutter sticking through the upper hole.  Then insert the length of tubing through the bottom hole and secure with the bolt.  I recommend placing this one near the end of the gutter section for ease of assembly.  No glue is required.

IMG_20140128_084439IMG_20140128_084459

The next tube has two nuts at different angles and depths. 40mm deep at 45º and 70mm deep at 135º.

IMG_20140128_084310

The next tube has a lady bug decoration glued into the tube at a random angle.  This provides a different shape to describe, and has a groove along the top edge to simulate a prostate.  Something about this size with a groove – be creative!

IMG_20140128_084250  IMG_20140128_084626

The final tube is lined with some anesthetic corrugated hose to provide yet another texture to describe.  We often put a lump of bluetack in the balloon in either this one or the one with the ladybug to simulate some poo.  Being in the balloon, the bluetack is mobile and can be easily replaced.  All the balloons do have to be replaced regularly when they break (every ~8-16 students).

IMG_20140128_084336     

The following text is placed on the table as “answers” by each tube that students can uncover to check their description.

Station 1:
There is an object that protrudes <1cm from the side of the pipe.
It is 9mm wide and the tip is rounded and firm for the first 5mm.  Then the sides are sharp and angulated.    It is mobile.
It starts 5.5cm from the opening (it was screwed in at the 6cm mark)
It is a “dome” nut.
Clearly it is important to know the length of your index finger.  Measure your finger.
Check it out again and get a feel of how far 5.5 and 6cms are.

Station 2:
It is very important to be able to accurately describe the location of an abnormality.  The current practice in Australia is to use the clockface and the distance from the anal margin.
If the back of the patient is 6 o’clock, then their front is 12 o’clock, their right is 9 and their left is 3.
Please see whiteboard.
There is an object that protrudes <1cm from the side of the pipe.
It is 9mm wide and the tip is rounded and firm for the first 5mm.  Then the sides are sharp and angulated.    It is mobile.
It starts 6.5cm from the opening (it was screwed in at the 7cm mark)
It is also a “dome” nut.
The end of the nut is at 9 o’clock, 7cm from the opening.
In station 1, the end of the nut was at 12 o’clock

Station 3:
The pipe has an opening at 3 o’clock, 3cm from the opening.
The opening is about 2.5 cm wide, circular in shape and has a firm edge.
It goes from about 1 o’clock to 5 o’clock.

Station 4:
There is a lump on the side of the pipe at the 12 o’clock position (in D4 but about 11 o’clock in C4).
It starts at about 2cm from the opening.
Closest to the opening, there are two lobes separated by a groove in the centre. The lobes are symmetrical and increase in width from where they start to about 1cm wide each at the widest (3cm from the opening) with a total width of 2.2cm.
These lobes end in a groove running across the lump followed by a lobe 1cm by 1.5cm. This lobe finishes with a knob of 7mm by 5mm.
Total length of 5cm
It has the same consistency in all lobes: firm, hard with a smooth surface but rougher at the top. It is not mobile.

Station 5:
There are two lesions
Finding one lesion doesn’t mean the end of the examination, you must complete a thorough examination.
The two lesions are at:
4cm at 7o’clock
7cm at 11 o’clock

MCKelly – ALS part 2

I have nearly finished the upgrade of one of our MegaCode Kelly’s as referenced here.  Well, that’s not for the faint of heart.  I’ve seen the ResusAnne Simulator SimPad upgrade kit which is very complete.  All of the little bits and pieces (cable ties, anchors, hoses, etc.) which are included in that kit need to be worked out and sourced independently for this upgrade.

This does require a complete tear-down of the manikin.

The main board mounting plate needs to be re-drilled to accommodate the larger main board.  The lower left corner stays in the same place and holes are drilled to match.  The load board moves directly up to clear the main board.

main board drill pattern

Here’s a photo of what it should look like when re-installed in the manikin.  Notice that the load board extends over the edge of the cutout in the manikin.

IMG_20131001_124449

The next big modification is the chest.  The lung occluder servos end in a fitting 13mm OD.  The end of the trachea (just past the bifurcation) is 19mm OD.  The original ALS has a molded adapter tube to join these parts.

IMG_20130925_162124

I made up a stack of flexible PVC hoses (13mm ID, 16mm ID, 19mm ID) to make this transition.  There was also a change in lung design at some point.  I really like the idea of a screw connector to replace the lungs, so kept our old grey lungs for the time being.  Eventually, we’ll switch to the new white style lungs.  I cut a 20mm sprinkler riser in half to make this connection. It screws into the end of the lung occluder assembly and secured to the lung with a cable tie.

IMG_20131001_171207The connection to the pressure sensors uses about 300mm of 3mm ID PVC hose.  This hose also fits the connections on the chest rise bladder and the hose from the thigh tank.  It has a larger OD, but opening out the chest plug with a drill worked OK.

Finally, the thigh tank reservoir.  I couldn’t stand the schraeder valve (bicycle) connection and wanted this to interface with our standard wall air setup.  This required some slight modifications to the thigh tank assembly.

I removed the schraeder valve and the rest of the components temporarily.  Note that this assembly consists of the fill valve, reservoir tank, relief valve, 10 psi regulator, 8 psi regulator and finally a solenoid valve.  I have no idea why Laerdal chose to put in two regulators set so closely together.  I also noted that the locking nuts on the regulators came loose fairly easily and needed to be re-tightened.

IMG_20131001_154646IMG_20131001_154527IMG_20131001_155021IMG_20131001_155827

On the first leg I managed to break the hose barbs off both the inside of the schraeder valve and the Tee fitting that screws into the tank.  Note that the clear hoses are 1/4″ OD and DO NOT fit into 6mm push on-fittings.  Thankfully, 6mm soft poly tubing has the same ID as the original and fits nicely.  The Tee replacement I used was a 6mm x 1/8″ thread tee from SMC pneumatics.  I also installed a check valve in the thigh assembly between the tank Tee and the external fill hose since the QD we’re using doesn’t seal on the plug end.

IMG_20131002_091844IMG_20131002_091907

I drilled a couple holes in the side of the fill penetration for a cable tie to hold the fill hose securely.  The fill hose ends in a KK3-P quick disconnect which I put down the trouser leg for connection to the wall air source.

SMC parts used in this modification included:

  • KQ2T06-01NS (only if you break the original Tee) $5.40
  • KK3P-06H Quick disconnect plug end $6.10
  • KK3P-06S Quick disconnect socket end for the hose that goes to the wall – this is self sealing so you can change manikins easily without disconnecting from the wall. $16.70
  • KCH06-00 AKH06-00 Check valve with 6mm push-on fitting at both ends $13.50
  • KK2F06-01-X2 straight 6mm – female 1/8″ thread to connect to the hose barb which comes out of the wall $4.70
  • From other suppliers: 1/4″ x 1/8″ thread male tailpiece (hose barb), a bit of 1/4″ ID hose and a hospital wall air nut.  The photo below shows a slightly different arrangement of fittings, but does the same job.

IMG_20130618_104909

The compression sensor had to be soldered to the cable end left conveniently in the chest plate.  The hall effect sensors in the head are still a work in progress.  I need to go look at the original again to confirm exact placement and may have to fabricate a mounting plate.

Not particularly difficult, but there’s lots of steps and bits and pieces to sort out and source, so it took some time.  We’ll see how it holds up over time and abuse by medical students.

Chest Drains

Recently, I received a request to develop a simulation involving a chest drain on SimMan Classic.  I thought I had seen some posts somewhere on how others had done this.  Here’s one post from the SimGhosts 2012 DIY Video contest.

I also referred to some excellent material from SimCentral.  Their SuperAnnie 3 product seems really good, and there’s some good chest tube info there.  However, as usual, I needed a solution that was really cheap and available instantly.

The scenario being planned needed to show swinging in the drain and ideally some bubbling.  Chest tube insertion wasn’t an issue, it was already in place.  We have the Ocean 2002 UWSD from Atrium.  Much to my delight, it still had blue dye in the chambers.  Not sure if this one had ever been used.  Hooking up to suction caused bubbling in chamber A (suction control).  Blocking off the drain line brought the bubbling under control and I could adjust the suction to get just a trickle of bubbles.  Attaching a 60 mL syringe to the end of the drain line provided enough volume change to move the ‘bubble & swing’ ball in chamber B throughout its range.  The beige irrigation tubing I mentioned in the IV Setup post fits nicely on luer fittings.  I used a whole roll (10m) on the end of the drain and the 60 mL syringe worked fine.  This will let me put the syringe in the control room for remote activation.

A dual size adapter I found in the cupboard made a very neat connection between the drain and the long irrigation tube.

Adding a Y connector and an IV roller clamp as suggested by the SimGhosts video allows for a variable air leak.  Put the roller clamp near the free end of the tubing so you can cut off bits as the tubing gets crushed over time.

I visited ICU this afternoon to get some personal experience with chest drain swinging and bubbling – not something I normally see as a paramedic.  In a drain setup without suction, spontaneous inhalation will cause, the ball and water column in chamber B to rise.  This will be more pronounced the larger the breath and the larger the pleural space.  Generally, this swing can be around 10 – 15 cm up the column (negative pressure).  Apparently, patients with asthma can draw 50-60 cm water – hence the long drain tube and the low placement of the drain below the patient.  Remember, these are pleural pressures, not lung pressures, although they are related.

In patients who are externally ventilated, the pressures are generally positive (i.e. positive pressure ventilation).  This is particularly true of patients who have a PEEP (positive end expiratory pressure) set on their ventilators.  This keeps the pressure in the lungs always positive.  But what is happening in the pleural space depends on its volume.  Gas (a compressible fluid) in the pleural space will transmit pressures from the lungs.  As the pneumothorax is resolved and the volume of the pleural space approaches zero, the pressure transmitted into the chest tube will decrease to zero on positive pressure ventilation.  The pleural space pressure is limited by a relief valve in the drain and the height of the water in the bubble chamber C.  Large positive pressures in the pleural space are bad (tension pneumothorax).

With suction applied to the drain apparatus, the reference point is decreased to the level of vacuum being applied.  Thus the pressure in the pleural space (relative to atmospheric) is -20 cm H2O + whatever is shown in column B (negative for spontaneous ventilation and generally slightly positive for external ventilation).

What this all means is that the changes I can make to the drain display with my big syringe and variable leak from the control room will closely mimic what actually happens.

Operation of this system involves moving the syringe plunger with each spontaneous breath or setting a slightly positive pressure when externally ventilated. It would be nice to integrate this somehow with the SimMan pneumatics to operate automatically.  I’ll post an update if/when I work this feature out.