Post quoted from theemtspot.com

With that thought in mind, how important should it be to keep the saline we infuse into our patients whom we want to keep warm at something close to body temperature? I hadn’t really given the question much thought until I got an email from Scott.

Scott’s one of those SWAT medic types. He works with his local SWAT team to provide on site medical interventions if the need arises. Scott had an interesting experience with an accidental infusion of ice cold saline. I’ll let Scott take it from here:

“I am on a tactical medic team.  The temperatures here have dropped recently (as they always do this time of year). We recently had a call out. Most all of our medics have an entry bag that stays in their vehicle and a main bag that stays in the response vehicle. As you can imagine, neither of these are heated or cooled, “temperature controlled” environments.”

“On this call out, we had an officer who was walking through the neighbors yard to provide perimeter security when he obtained a fairly significant laceration on his lateral right leg. As most officers would, he brushed it off, vowing to deal with it after the incident. After about 45 mins he finally called for a medic. We replaced him with another officer and escorted him back to the command post. “

“The officers leg from the laceration down was soaked with blood, pant leg, sock, everything. This officer was being particularly hard headed and said he would go get it looked at in the morning and asked us to simply bandage it for him. My partner was able to talk him into an IV because of the blood loss. I was focused on bandaging his leg while my partner started a 500 cc normal saline bag. I left to go back to the perimeter after finishing with the bandage and my partner stayed back to monitor him and finish his IV. “

“I was at the perimeter for all of 20 minutes when I was called back to the command post for assistance. When I got back the officer was lethargic, his extremities were cold to the touch his teeth were chattering, and he was slightly confused. “

“My first thought after, “Oh shit!” was shock, but I had a brief moment of sanity before the panic set in. I took my partners glove off and told him to grab the IV bag. As you guessed it was freezing cold to the touch. He had put the officer into hypothermia by giving him a sub-zero fluid bolus. “

“We quickly called for a unit, covered him up, took vitals and proceeded through our hypothermia protocols. “

“It had not even occurred to my partner that his IV equipment has been in his freezing cold trunk all night, and even when the patient went down hill, he didn’t see the obvious signs of hypothermia. In treating this officers laceration he nearly caused a more serious medical emergency. “

“Most agencies keep their trucks in a climate controlled bay or have a solution to heat their units or bags. However there are some that don’t. I thought this might be worth sharing with you. “

Thanks for the story Scott. And yes, it is worth sharing. I’ve mentioned before the importance of keeping trauma patients warm. As winter sets in here in Colorado, I can imagine all kinds of scenarios where this mistake could play a significant role in the patients outcome. Our medic units use warming plates for our IV bags, but the one in the kit remains unheated.

I also consider how many times I’ve started IV’s on the side of the road in a snow back or deep in the back-country. IV bags get left outside on special events and coverage situations like the one Scott describes here all the time. The next time you’re outside in the cold or pulling an IV bag out of a kit, don’t forget to feel that solution. Induced hypothermia does have its applications, but most of our patients will benefit from warm fluid

Human blood temperature is 38 degrees C or 100.4 degrees F – and average blood volume is 6 liters – it would follow then that infusing a liter of saline that is even at room temperature (72F) could lower body temperature somewhat. Infusing saline that’s even cooler than that could have adverse effects especially on sick patients. Something to think about especially now as the weather gets colder..…

Just learned some really fascinating things about shock and volume resuscitation and the importance of crystalloid solutions. I found this lecture by Dr Jeffery Guy while going through the PHTLS class and found it to be a real eye opener (and a great lecture). (More great PHTLS lectures here)

Third Space Resuscitation

Consider the following; in a study a number of dogs were allowed to bleed into Level III shock and then they were all transfused with all their own blood that was lost. They all died shortly thereafter. They tried this again, this time giving them an infusion of an isotonic crystalloid solution before transfusing their blood back and many more of them lived and recovered. What they discovered was that in a state of hypovolemic shock, the body initially compensates by shifting fluid from the interstitial spaces and intracellular fluid into the vascular space to try and maintain plasma volume. Therefore for a favorable outcome,  it is imperative to resuscitate the third spaces as well. This is achieved by infusing hypertonic solutions of which only one third remains in the vascular space with the remaining two thirds moving out into the interstitial and intracellular spaces within an hour. If only blood or colloids were used this third space resuscitation would not happen and the patient would die.

Permissive Hypotension

He speaks about how much is the right amount to infuse in the field, the short answer is just enough to maintain a systolic BP of around 90, or even just enough to maintain a palpable radial pulse. The point of permissive hypotension can be illustrated by filling a balloon with water and making a small hole in it. The more the balloon is squezeed (increased pressure) the faster water will spurt from the “wound” also clots that may have formed can be blown out by higher pressures. Therefore until bleeding can be definitely stopped (i.e. surgery) permissive hypotension will go a long way to enhance patient outcome.

ARDS, Systemic Edema

Another complication of overhydrating shock patients is the development of ARDS and other systemic edema. These situations typically arise days and weeks after the initial trauma and can then cause death. Many organs are susceptible such as the lungs, kidneys, liver and brain. Many protocols therefore speak of switching to a colloid or hypertonic solution once a defined amount of isotonic crystalloids have been infused.

Increased Respiratory Rate in Shock

I always thought that the primary reason for increased respirations in a shock patient was due the patient’s need to hyperoxygenate their remaining blood supply to maintain tissue perfusion. While this may be true, Dr. Guy mentions another reason for the tachypnea. He mentions the “bellows effect” of ventilation whereby the negative pressure created in the chest during inspiration also draws blood up through the vena cava into the heart. He states that this is the reason for tachypnea, to help increase preload and  cardiac output by creating more negative pressure in the thorax.

Normal Saline Vs. Lactated Ringers

PHTLS and many other sources mention that Lactated Ringers is the fluid of choice in hypovolemic shock yet many locales (including NYC and Hudson Valley) generally use normal saline. The reason that LR is the fluid of choice is because prolonged infusion of NS will cause the the patient to become acidotic, impairing many important metabolic functions. The reason given for use of NS is because LR is not compatible with blood products and since the patient will most likely need a transfusion this might be problematic. Dr. Guy mentions that many blood banks use blood that is compatible with LR and also that LR itself is being refined to be more compatible so hopefully many more of us will start using the preferred fluids. (I find this whole thing a bit bizarre, can’t we coordinate with the hospitals and blood banks in order to benefit the patients who need this most?)

I always wondered about whether C Collars were really effective at stabilizing the C-spine, now it turns out that it may actually cause more harm than good. I always wondered because of how many times I’ve seen improperly placed c-collars, but this study says that even, or specifically, properly placed c collars actually lift the head off the neck and can cause vertebral separation at C1-C2 of 7.3mm! Do we go back to manual stabilization and then stabilize to backboard with head blocks only? Interesting stuff.

See these the study published in JEMS this month.

‘Distracting’ Injuries Immobilization study presents wake-up call

Also see this discussion about the study.