Lessons Learned: “Four Hours of Tourniquet Time”
Below is an excerpt from a lessons learned compilation titled “First to Cut: Trauma Lessons Learned in the Combat Zone.” Though it is geared toward FST surgeons and forward medical providers, some of the lessons are applicable to tactical medics and mountain rescue. The larger take-away point is that the physiology occurring distally to a tourniquet applied for a long duration needs to be considered when changing or loosening, especially in environments where medical care may be limited (e.g., Third World).
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“Four Hours of Tourniquet Time”
“26 y.o. male with foot traumatic amputation and
multiple frag wounds to the right leg with a high thigh
field tourniquet in place. Arrived to the CSH with SBP of
100 HR of 120. we had no report on duration of the
tourniquet. We took down the tourniquet and he promptly
coded. We put the tourniquet back up, intubated him and
gave him fluid and bicarb and he came back. We found
out later that the tourniquet had been in place for over 4
hours….”
The use of tourniquets – while rare in civilian trauma is
very common in combat injuries. Tourniquets are the
number 1 instrument that a medic can employ to lower the
KIA numbers. The use of tourniquet with application until
the absence of a distal pulse by default causes distal
ischemia. Release of a functioning tourniquet after several
hours can result in the release of acidic fluid and potassium.
The patient intubated and without a head injury can be
briefly hyperventilated. Before taking down a long
duration tourniquet make sure the patient is well hydrated,
resuscitated, adding an ampule of sodium bicarbonate or
THAM can prophylax against the release of “bad humors”,
lactic acid, and potassium. Also release the tourniquet
slowly – if the rare arrhythmia arises re–employ the
tourniquet and retry after further bicarb and fluid. If the leg
is necrotic remember “life before limb” and perform an
amputation.
Lessons Learned:
–Prolonged tourniquet times can result in the release
of acidotic fluid and hyperkalemia
–Perform 4 compartment fasciotomy with all lower
extremities with significant tourniquet times
June 1st, 2010 at 5:55 pm
I don’t think medics on the ground should loosen tourniquets just for the simple fact that if they don’t know where the bleeding is coming from, than they can’t properly discern whether or not it should be coming off in the first place. Plus, I don’t remember when I had sodium bicarbonate in my aid bag, which brings me to a question. Would the use of Sodium chloride, or lactated ringers have the same affects as the sodium bicarb?
June 6th, 2010 at 3:05 pm
Strange how doctors need studies to tell them what we have known for years in the combat medic’s ranks.
No shit… If you leave a Tq on for an extended period of time the affected limb will release acidi fluids and potassium. Yeah, it’s dangerous, but can be fixed some what easily and sure as hell beat try to bring back a guy with no pulse and no blood.
June 22nd, 2010 at 11:01 pm
Mike S. LR or NS would not replace the bicarb.Its primary use is as a buffering agent to combat acidosis(it has additional uses in certain over doses).The LR/NS might alter the pH through dilution ,but it would be minimal compared to the bicarb.
August 18th, 2010 at 11:31 am
Total ischemia of a limb, regardless of the reason, results in anaerobic metabolism and the accumilation of lactic acid, both within the cell and in the extracellular fluid distal to the TQ. Orthopedic literature has suggested that two hours is the upper limit for at TQ to be up before cellular changes due to lack of oxygenated blood delivery occur. It has also been suggested that up to 90% of bleeding due to clot formation (and possibly relative hypotension) will have occured in a bleeding limb after one hour of TQ application. Hence, under the right conditions, release of a TQ within the two hour time limit, even for five minutes, buys you another two hours of TQ time. This concept must be vetted through the operational/battlefield filter, where factors such as darkness, light discipline, use of blankets to prevent hypothermia and transport issues often prevent continual observation of the TQ and wound.
Often in the OR during orthopedic procedures, that utilize a TQ, release of the TQ will be accompanied by a drop in BP on the arterial line and an increase in the ETCO2 as lactic acid is converted to CO2 in the blood. Bottom line, if a TQ is up for more than two hours, literature and experience suggest care be used prior to TQ release and probably should be done with EKG and BP monitoring. This also underscores the importance of good/great communication regarding care given to the casualty.
NS or LR would not impact the acidosis other than to treat the vasodilation that occurs and that is partially responsible for the hypotension that occurs with TQ release after prolonged application. Vascular reactivity and cardiac contractility is pH dependent and once the pH is below 7. 2 things go to shit. Bicarb and fluids are effective along with Neosynephrine; all things not available to the medic. Hence, the importance of paying attention to TQ application time and making sure the TQ remains tight. IMHO.
May 20th, 2011 at 1:58 pm
Something else to consider….how long does it take the normal hemostatic process to occur? For individuals without coagulopathy, most clotting takes 5-15 minutes to occur. Wilderness Medical Associates recommends that, in a prolonged care setting, tourniquets be slowly released after about an hour to assess for re-bleeding. If no re-bleeding occurs, does the TQ REALLY need to be left on and risk this reperfusion injury?
May 20th, 2011 at 2:20 pm
That is a great point. I think the context does matter. The reason most tactical medicine instruction favors leaving it on is the short evacuation times and the possibility of having to move the patient often. Most quality programs do teach to evaluate the wound and change to a pressure dressing when applicable, while leaving the tourniquet in place so that you can re-tighten it if needed.
Thanks for the comments.