Resuscitation Outcome Consortium

[Donut]

We here in BC Ambulance are in the midst, like most EMS agencies I'm sure, of converting over to the new CPR guidelines.  Along with the new CPR, we're part of the ROC studies in Canada, along with Ottawa and OPALS.  Two things that people here might find of interest that are being introduced are studies on the Impedance Threshold Device (ITD) for use during CPR, and a hypertonic saline/dextran study for truamatic brain injuries and hypovelemic shock.

The ITD is a valve that prevents air from entering the lungs during the compression phase of CPR, theoretically lowering the intrathoracic pressures and increasing cardiac return.  This study will be by regions, with each region enrolling for 6 months with the ITD, and then stats being collected for the following 6 months without the ITD/dummy ITD in use.

The Fluid Resuscitation study is a little neater (from my perspective, anyway)

A 250ml bolus of a study solution will be infused to all trauma patients with a BP of 70 or lower or a BP of 71-90mmHg and a HR of 108 or greater.  If BP is still below 90 we will continue our normal fluid resusc protocol.  For the TBI study, hx of blunt head trauma and a GCS less then 9 get the study fluids.

The three fluids to be studied are NS, 7.5 % Saline (HS) , and 7.5% Saline with 6% Dextran (HSD).

Should be pretty neat, maybe we'll meet evidence based medicine criteria for what we do.
I'll try to keep posting info as it becomes available, but I suspect it'll be some months before any updates come from our trial coordinators.

DF

 

[Adam]

ParaMedTech, can you describe how this ITD valve works?

 

[Donut]

The ITD is a valve placed between the bag-valve and mask or the bag-valve and ETT.  Once in place, you must maintain a complete mask seal over the pt face;  it attempts to "...increase the degree of negative thoracic pressure during decompression thus increasing venous return and cardiac output."

It works by raising the threshold of pressure required for air to enter the lungs, so when you squeeze the bag you reach the threshold, but the pressure changes during the compression-decompression of CPR that threshold isn't hit. It tries to mimic the thoracic pump's effect on cardiac output.

I hope that's what you were looking for as an answer, more info next month, as I'm away on leave for the next couple of weeks.

DF

 

[DartmouthDave]

Hello,

I hope the study shows that hypertonic NS has a role in fluid therapy. 

From my experience, %3 NS was used for symptomatic hyponatremia.  It was considered dangerous to infuse at greaterthan 20-30 cc/hr due to risk of causing a pontine stroke (not sure of the patho of it ) and to a lesser degree hypernatremia by over correcting.

This was the policy at the QEII in Halifax and the U of A in Edmonton (well, the areas I worked at least). 

David

 

[The Heathen]

Why a pontine stroke specifically?  To my understanding, a pontine stroke shares the same pathology as any other stroke, but is characterized by the conscious mind being trapped in the unconscious body.

kind of a red herring question.

As for the original topic, as well as being a reservist, I'm working towards my honours degree in physiology.  Fluid resus. is a field my supervising PhD and I are looking towards, and I'm doing some reading in regards to what has been done.

Specifically we're looking towards adding more than just electrolytes the IV mixture, things like Caffiene or NO, and obversing their effects on survival.

Of course, we're starting on rats.

 

[Adam]

Wow!  where do you start an IV on a Rat?

 

[MommyMedic]

Um guys, where do you find the rats? Remember you are not allowed to find "volunteers" passed out in the shacks on the weekend... In all seriousness, pls keep posting your findings.

 

[rogsco]

Pontine stroke related to hypertonic saline isn't quite correct. The problem is potential central pontine myelinolysis which is a risk when correcting severe hyponatremia (depleted sodium). Infusing hypertonic saline can cause hypernatremia which can lead to neurological symptoms (seziure-coma-death) and possiblty CPM. To prevent this theoretical problem in the hypovolemic/hyptensive penetrating trauma pt, the rate of infusion is controlled. Not to mention you don't want to go crazy with fluid shifting between intra and extracellular compartments.

You will find in ACLS guidelines for electrolyte disturbances that in all but the most extreme electrolyte disturbances that aggressive electrolyte replacment is rarely indicated. A nice rule of thumb with electrolyte disturbances is that it took time for the problem to develop, so take time to fix it to prevent complications. The majority of trauma pts should not be at risk because they probably don't have an pre-existing electrolyte problem.

Consult your health care provider or medical control physician for more info (that's my don't blame me if it all goes wrong disclaimer - ha ha)

 

[The Heathen]

In starting an IV on a rat, you have to do a cut down, usually tying off the jugular from the rostral (head) end, then running a suture down the vein until it is loose, then, using zoom in goggles, lift the lower suture, snip the vein with microscissors, then slide in the cannula.  Once the canula is in, tie off the bottom suture to hold it in place. 

It's not easy.  If you screw it up, you can go for one in the leg whose name escapes me at present. 

Nice post Rogsco,  I learned something new.