AANEM Connect

I have used all of them except heating lamps and also have used warm water baths in the deep sink especially for the hands. Others work better for the feet. As Dr Dumitru mentioned in one of the previous posts, if you are doing comparative studies in the uppers for CTS you may not need to do any warming. However, if you are working to diagnose PPN, you may want to warm the limbs. Dr. Halar had published in the late 60s or early 70s about corrections that could be used in the normal limbs and nerves, however, this cannot be used for patients with sensory or motor symptoms as there is no way of assessing the amplitude, latency and CV changes in the diseased nerve because of multiple variables. There is no standard for warming that is accepted by AANEM.

My favorite way is to fill an exam glove with hot water and tie it off to make a little hot water balloon. It works great for hands and feet and patients love it!

We use MediBeads following a recommendation from our Neurology EMG division. 12 by 16 inch pads, microwaveable, wrapped in a towel or pillow case. They work well, safer than HC packs, reusable  and inexpensive. 

Libby mentions the best way that we found too, so convenient and easy to fill a couple exam gloves with warm/hot water.  Remember the specific heat of water is much higher than air (water transfers heat 25 times faster than air!).  Pretty easy to tape in place on the foot/ankle area or keep in place under the hand (and on top).  We could fill them fast using the hot water dispenser and mix in a little cool/cold water as necessary if too hot.  The problem with 'heat lamps' is that you get yourself hot working under them, and you need to keep them going because the limbs usually cool back down rapidly as soon as you move the lamp away.  Once warmed up, those little HotHands Hand and Body Warmers (can order from Amazon) will often keep the limb warm enough for testing (it must be the 'hand and body warmer' size, because the 'hand warmer' size is too small).  Hydrocollator packs are great if you have them, but they are cumbersome.  Immersing in warm bath is great if able, but can be tedious and time consuming.  Hair blowers are not as good as you might think, and you have to keep them going like the lamp, and they are annoyingly noisy.  One final tip:  Keep the exam room warm.  We also had space heaters to supplement warming if needed; not all of our lab sites had independent room temperature control.

We use warm to mildly hot water from the sink for hands.  Unfortunately this may need to be repeated from time to time.  We also have a towel warmer that can hold around 20 folded towels for use on the distal lower extremities and elbows which can become surprisingly cold in some cases. There is of course some expense in laundering the towels but they are safe in terms of any risk of thermal injury and the patient's really love them–sort of a spa treatment.  The Medi beads and hot water filled gloves are intriguing and imaginative solutions- worth trying.

Thanks!

Filling a glove with warm water! Brilliant! We've started using hair driers. We had three hydrocollators and found the towel laundering expense to be literally thousands of dollars per year. I'm foind to try the hot glove technique too! Thanks all. 

This is an important variable to control whether the pathology is focal or generalized. We all get fixated on this for nerve conductions, but it is also important in muscle (cooling for myotonia) and NMJ disorders as well. The topic is excellently covered by our colleague, Dr. Seward Rutkove (M&N 2001;64:867-882).  For nerve (i.e., distal extremity), immersion in warm water for a few minutes then wrapping is overall optimum to ensure consistent warming of deep tissues, then wrapping in a warm blanket to retain limb warmth.  We have the luxury of a dedicated custom-built two level sink that can simultaneously do both arms and legs.  Prior to this, we used deep containers so that feet up to the the mid distal legs and hands up to distal forearms are warmed. Of course any limb with suspicious dermatologic issues should not be subjected to this. You may think this is a bit one and a half, but I see a lot of outside studies that look suspicious (being in WI, I look at the date of the study) and it is often that dubiously large SNAPs simply reflect cool temperature.  A standard way of dealing with this saves a lot of patchy quick fixes.  In bilateral studies, it assures symmetric warming.

There are really no "quick fixes". Anything electric (hairdryers, heating pads) invites potential electrical interference, a subject near and dear to Dr. Dumitru who is no doubt trolling my comments.  I attended a workshop of his where he used a heating pad to demonstrate this. Microwaveable pads are a runner up but a suboptimal fix and carry the caveat that the beads inside may become unevenly heated and have the risk of skin burn (so I have read), especially where skin might be easily subject to breakdown as in diabetics. We used to have hydrocollators at the VA years ago, but the VA infection control squad deemed them unsuitable. Another point regards temperature probes. Some that are handheld, work on infrared and sold commercially have a disclaimer that they should not be used on humans. I suspect this is to avoid them being called a medical device. Last point regards the various formluae published to correct for cool skin temperatures.  This is all well and good, but does not necessarily apply in pathology.

Paul Barkhaus

When using hydrocollator packs one always covers them with towel such that it does not contact the skin. If infection control folks had problem with it, then they have never been in a PT gym where they are used routinely on a daily basis. Towel goes to wash and the hydrocollator pack goes bck ito very hot water that kills any bacteria, althogh there will be none as there is no contact with skin. Of course, it should not contact with the skin, as it will burn the skin due to it's heat. I like the idea of gloves filled with water but have to make sure it is not too hot to cause a burn. Beware of using the heating pads or any other heat modality in patients with loss of sensation that could lead to local burns.

My heretical thoughts pursuant to the issue of near-nerve subcutaneous tissue temperature modification and Electrodiagnostic Medicine evaluations have been thoroughly expressed in other posts on this forum and there is certainly no need to recapitulate my heterodoxy.  Should you wish to take the “red pill” and travel down the illusory” rabbit hole” of  temperature do so at your own peril and read my other posts on this topic.

So as to not disappoint my esteemed colleague from the great state of Wisconsin, fellow co-author and friend Dr. Barkhaus, a comment is warranted related to his opening statement: “This is an important variable to control whether the pathology is focal or generalized.”  Hmmm, “control”, really?  I don’t think so.  If one is under the illusion of controlling subcutaneous near-nerve temperature with non-standardized off the shelf warming devices of one type or another and delivering who knows what type of heat and to what degree below the skin while measuring some surface location with non-calibrated thermistors of one type or another, then I would submit you are “tilting at windmills”.  To “control” would imply an ability to make a change and accurately monitor that change to modulate the desired end-goal within certain restricted parameters and maintain that temperature window over some specified time.  At best, we can be said to modulate the subcutaneous tissue temperature to some unknown degree within an unknown temporal window following the institution of some type of heating method for some timeframe and assuming some type of qualitative and definitely not quantifiable direct correlation has been achieved and further assuming that continuous cooling does not recur within the time it takes to re-establish NCVs.  Not.

If we had something akin to a continuous glucose monitor but instead measuring subcutaneous near-nerve temperatures continuously, then we could apply some type of off-the-shelf external heating source and accomplish something quantitative.  Currently, whatever external temperature corrective measure you are employing is grossly qualitative at best and perhaps marginally or not effective at worst.  Again, see my previous posts for a multitude of objections to the current “state-of-the-art”.  We should be able to do better.

In response to Dan, I would agree with the limitations of our current approaches to heating the limbs and determining temperature; however the experience is that most of the time when using the heating pads (we use the PT dry heat pads- maybe not as good as moist heat hydrocollators) I find that sensory latencies significantly improve and many sensory CTS ( done without heating) turns out to be within normal limits after heating. The problem is when the latencies don't improve- is the heating inadequate? Does the surface temperature reflect the temp of the nerve? Or is this truly an abnormal latency? Always be skeptical of prolonged latencies with normal amplitudes- more likely cold hands/feet than pathology.

So- as inadequate as this may be- heating the limbs remains an important thing to do. And recording surface temps still is appropriate.

Hello Richard!  Always good to hear from you.  We go way back to Norfolk General Hospital in the late 80’s.

 As noted in multiple posts on this forum I do not heat the limb, do not document the temperature, or attempt to alter the temperature.  However, I do believe temperature is a critical aspect of EDM and we must be thoroughly familiar with its consequences with respect to not only cool but also excessively warm limbs not only for NCVs but NMJ evals as well.  I doubt any other author has devoted as much verbiage to temperature as I have in my textbook with tons of references.  I think I have a pretty good handle on this issue.  I just happen to disagree with the majority of EMGers on how to address this issue in patients.  As I noted above, I have detailed my thoughts and approach to this subject and how I handle this issue in clinic elsewhere in other posts on this forum and there no need to rehash it here.

 Richard, you and I shall agree to disagree.

 Hope you and your family are doing well.

 Best Regards

Dan

In our lab we have hand warmer packs that we use to heat limbs. They are disposable to keep cleanliness with in the lab and for the patient. We 'break' the pack then apply to the limb-securing with guaze tape. The life span of the pack is typically long enough to get through a whole test before it loses the heat and should be disposed. They are relatively inexpenive to purchase as well.