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Friday, January 13, 2012

Draper Ultrasound+Pack Articles

I believe the concept of preheating muscle tissue before application of US treatment showed the best evidence of increasing the baseline temperature of the muscle. With the presented articles I do believe that cooling a muscle before US provides poor evidence of heating a tissue (which, as stated, is the main goal).

With this, the question of whether or not application of a hot pack before US treatment is truly beneficial arises. Is applying a hot pack for 5-8 minutes worth charging a patient's insurance? To add, you would also be losing treatment time with your patient. Looking at the room temperature vs hot pack article, I would determine that the differences seen at between these treatments is not worth the time of applying a hot pack to a patient, as long as the sole purpose is to heat deeper tissue.

It should be mentioned, that with different patients, they may, or may not "feel the heat" of the US giving them a tendency to favor the hot pack alone because of the sensational feedback of the heat. Depending on the patient's preference or the physical therapists judgement, it could be debated whether hot/cold packs should be used at all, along with ultrasound.







34 comments:

  1. Please place additional blogs as comments to the blog started by Luke. Lisa VH

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  2. I agree with Luke's comments and conclusions, especially whether or not applying a hot pack is even worth the extra time. I can't remember if it was in one of these articles or elsewhere (like the book) that stated that by applying a hot pack before US, the therapist had the opportunity to leave the patient and see other patients and therefore be more efficient. I think that is very poor justification for using multiple modalities. However, if as Luke mentioned, the patient does not feel the heat with US, hot pack prior to US may be good for the patient, even if it only had a pyschological-therapeutic effect rather than sound physiologic evidence.

    Also, when I read the US+cold pack article I thought it seemed to be closer in results to contrast bath than raising the overall tissue temperature since it created the larger temperature gradient and alternated between extremes. Maybe the physiologic effects of cold pack + US should be compared against contrast bath rather than hot pack or straight US. However, since US treatments are supposed to be limited in number/exposure time, this could prove difficult if you wanted to alternate between cooling and then heating with US without over-exposing the subjects.

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  3. In regards to the US and cold pack article, when I read in the procedures that the researchers only iced the area for 5 minutes, I thought that was a little odd. I am curious as to why the researchers chose 5 minutes instead of the standard time of about 15 minutes. There's a graph in our textbook on page 293 that shows the duration of ice application and temperature change, and it looks pretty clear that there's still quite a bit of temperature change after 5 minutes. It might not be significant to the findings of the study, but I do think it would be worth investigating.

    I agree with Brianna's comment about the psychological benefit of applying the heat pack prior to US. It is important to know the evidence behind modality use, but it is also important to consider patient comfort and preferences. Even if the added benefit of applying the hot pack prior to US is minimal in a physiological sense, if it makes the patient more comfortable then I definitely think that is worth the extra time.

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  4. I felt the article about cold packs + US presented good evidence that using a cold pack before US was not beneficial for increasing the temperature of the tissue during US.

    I agree with both Brianna and Luke concerning the hot pack + US article. Although the results of the study show that preceeding US with a hot pack for 15 minutes significantly increases the temperature of the tissue, they did not address whether or not the physiologic benefits of the temperature increase were great enough to justify using 15 minutes of the patient's treatment time to apply a hot pack.

    As my classmates above have said, it is important to consider patient preferences about sensational feedback with the hot packs. Also, the article brought up the point that when a hot pack is used, the deep muscle temperature increases 2-3 minutes faster during the ultrasound, which can decrease the sonation time. This may be useful for patients who may be more sensitive to US.

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  5. I agree with the discussion about the billing of two modalities being unnecessary, if the goal is simply to raise the tissue temperature. However, if that temperature needs to be sustained for a certain amount of time to produce the therapeutic effect, the use of the hot pack, specifically with the 1cm depth, resulted in a more constant temperature during the ultrasound treatment.

    As for the cold packs, I agree with Brianna, in that it seems more similar to the contrast bath, then being beneficial to the outcomes of the ultrasound. Also, one reason they may have chosen to use the ice for only 5 minutes, rather than the more standard 15 as Angie mentioned, was to prevent a numbing of the tissue, as decreased sensation is a contraindication for the use of ultrasound. That being said, I don’t believe ultrasound would be a good choice of modality for alternating heating and cooling, due to the contraindication mentioned.

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  6. I feel that cold pack treatment in combination with US cannot be justified for the purpose of causing an overall tissue temperature increase. I agree with Sarah regarding the tissue numbness that ice may cause being a contraindication to US. In my opinion, this outweighs pain reduction benefits that the combination may provide. While cold pack treatment + US does not show significant benefits for tissue heating the book mentioned that combining the cold pack + low intensity US may promote soft tissue healing through the benefits of reduced blood flow caused by the cold pack and the non thermal effects of the low intensity US.

    While the article discussing hot packs + US did show tissue temperature increase I thought the book made an important point that hot packs decrease the density of the medium for US transmission which may decrease the depth of US penetration. While this should be considered, I agree with my classmates that patient preference and comfort is important when determining treatment.

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  7. The second article seems to make it pretty clear that cold pack treatment before US keeps the tissue from reaching its threshold temperature, and therefore is not beneficial. Cold pack treatments have their own benefits, but not in coordination with US for heating purposes.

    As for the hot pack + US article, I agree with some of Luke and Brianna's previously stated points. If the only goal truly is to get the muscle heated, then it would seem as though the hot pack before US doesn't make enough difference to do and charge the pt for it. However, I do think that pt's often need the immediate feedback from the treatment they are being given. They can feel the heat from a hot pack (whereas sometimes a pt doesn't feel anything with US even though it is working), which may relax the pt. If the pt prefers heat before other treatment/US and feels like it helps them, then I think it is justified to charge the pt/insurance for it.

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  8. Draper et al's 1995 paper about what the effects of using an ice pack prior to ultrasound left me with a "No kidding?" feeling: "You found that tissue you've precooled is not going to warm up as much as if you didn't precool it? No kidding?"

    I see the value of doing the study because it appears that some clinicians had taken an earlier study by Lehman et al that showed greater tissue temperatures using cool-conducting ultrasound media and extrapolated that they could either replicate or enhance those effects by icing patients prior to using ultrasound (p. 156, near bottom of first column, in Discussion section). If clinicians really did confuse icing with using a cool ultrasound gel, it shows how important it is to be mindful in one's practice of why and how something works (gel is a conducting medium for the ultrasound, not a therapeutic intervention in itself) and why you use a particular intervention in the first place (ultrasound is for heating; if you precool the tissue, you probably won't get as much heating.)

    The last paragraph in his conclusion puzzles me, though. Despite this study's small, self-selected, and unrepresentative subject group, it's really not necessary to see "what other forms of cold . . . might have on ultrasound." If these other forms of cold make the tissue colder, we know what effect they'll have on ultrasound. And it's not additive.

    I feel the conclusions listed at the end of Draper et al's 1998 paper either have little clinical significance or aren't supported by his data:
    1. "Overall temperature increases occurred with application of both hot pack and ultrasound." At both tissue depths, the hot pack/ultrasound combo produced less than 1 degree more heating than the room-temp pack/ultrasound combo.
    2. "The hot pack made more of a profound impact in temperature increase at 1 cm." It's not clear if this is in comparison to the room-temperature pack (which is hardly a surprise) or the ultrasound (where the difference is less than one-half of a degree), but in either case, the clinical implications seem negligible.
    3. "The ultrasound made more of a profound impact in temperature increase at 3 cm." Compared to room-temperature packs and hot packs, it certainly did. But this wasn't really something we needed to determine, was it?
    4. "The overall heating at 1 cm was greater than at 3 cm." I take this statement to be in reference to Table 2, not Table 1, because in Table 1 the total temperatures attained at 3 cm are greater than those at 1 cm. So, looking to Table 2, it is clear that for both modalities there is greater heating at the superficial depth, but, one has to ask: (1) wouldn't it be a surprise if heat administered from the outside-in didn't heat the outside more than the inside? (2) are the differences observed, even if statistically "significant," physiologically or, more importantly, clinically significant?
    5. "Hot packs reached their maximum heating effect at 15 minutes application." Well, actually, hot packs might reach their maximum heating effect at 16, 20, or 23 minutes application. But, as this study design limited their application to 15 minutes, all we know is that the tissues were heated more after 15 minutes than at any previous measurement.
    6. "Vigorous increases in deep muscle temperature (>4 degrees C) can be reached with 2 to 3 minutes less total sonation time when the area is preheated with a hot pack . . . " Draper and his colleagues may have observed this. I have no reason to doubt it. I have no reason to believe it, either, as there isn't a shred of data to support it. (One can't count the graph in Figure 2; a graph is a representation of data, not data).

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  9. When looking at the big picture, it’s important to take into consideration whether the findings are worthy of putting into clinical practice. Time is very valuable and so it’s important to remember what your priorities of treatment are. Could similar benefits to the hot-pack theory be achieved through therapeutic exercise, meaning that simply performing US at the end of a treatment would save time?
    Some variables seem to be unaccounted. For example, what were the subjects doing directly prior to the experiment? Many college students could have exercised prior to or walked from a faraway dorm room in cold weather. Could the hot pack study findings be applied to other age groups?
    Like some of the previous comments, I've observed that people are more comfortable with a hot-pack versus a cold one. So the question becomes: are the benefits from a cold pack prior to US great enough to compromise patient comfort?

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  10. I agree with Sarah's statement in regards to only applying the ice pack for 5 minutes. Decreased sensation would definitely be a contraindication for using US. I also agree with Kelci in that cold packs are beneficial but not necessarily in conjuncture with US. With that said, I liked that the article did list certain circumstances where the ice and US combined could be beneficial.

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  11. Draper mentioned that a 1 degree Celcius increase was mild, 2-3 degrees was moderate, and 4+ was vigorous. He also noted that around 3-4 degree Celcius increase was needed in order to stretch the connective tissues. His study about using US after a hot pack or room temp. pack concluded that after the 10 min. of US tissue 1cm and 3cm deep were heated 3.5 degrees or more, with the exception of 1cm after a hot pack (which was heated an increase of 3.8 degrees by the hot pack alone). So, it would not be time efficient for the PT or pt to use 15 min. preheating before using US.

    Precooling an area before using US is not effective. Draper's study showed that 5 min. of ice dropped the temp. .5 degrees, and then US increased the temp. 2.3 degrees, so a net increase of 1.8 degrees. This is not enough to benefit the pt.

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  12. First of all, I would just like to echo Dr. Hill on the "no kidding"-feeling. In Draper's defense he probably had to make the statement regarding the precooled tissue taking longer to reach the optimal temperature for treatment, but as Dr. Wernel put it (very "to the point" I might add) "a net increase of 1.8 degrees...not enough to benefit the pt."

    As Dr. Wernel pointed out, Draper ranked the temperature increases with 4+ being the most aggressive, 1 or less being the most mild and everything in between being fairly moderate. If the goal is to have the greatest and deepest temperature change then I see no purpose for preheating the tissue. In Table 2 of the 1998 Draper publication the end result of 25 minutes at 1 and 3 cm for both the heat pack group and the room temperature group is roughly a 4 degree C increase, and most of that temperature increase (with exception of the 1cm hot pack) came with the 10 mins of US.

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  13. I agree with Rick and Zac's "no kidding" statement regarding the 1995 Cold/US article. However, I thought the theory this study proposed was interesting: because of lowering the temp of the tissue, it temporarily increases the density of the tissue, and therefore increasing the effects of US. I believe it would be interesting to see some research regarding this theory.

    In regards to heating then using US, I found I agreed with Brianna's point on how leaving the patient to be more efficient, is a horrible reason to use this technique. I do, however, agree with Kelci when she states that if a patient prefers the heat + US, because they can "feel it better," then why not please the patient?

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  15. With regards to preheating tissue prior to US application, I pondered one other method not mentioned in the journal articles. I volunteered in a clinic where heated US gel was used during US application rather than preheating the tissue. I always assumed this was for patient comfort, which may be a solution to what Natalie alluded to above(that heat may be applied for those sensitive to US) and which can be preheated in advance. But I also found an article that supported using heated gel at a precise temperature (25 deg C= 77 deg F)that significantly reduces time for intramuscular temperature to rise. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1323367/pdf/jathtrain00004-0027.pdf

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  16. I found that the evidence seemed pretty solid for the hot pack prior to the US, however, it does raise the issue regarding insurance and whether it's appropriate to bill for extra modalities. I also had the same thoughts as Kate regarding whether doing exercises prior to the US would have the same benefits as doing a hot pack. Also having an idea of what the subjects were doing prior to the experiment (just got done with a work out, did they have to walk in the heat/cold, etc). It may also be interesting to consider the difference in tissues. Some individuals may have thicker tissues and more easily penetrated by heat.

    In regards to the preicing prior to US, I agree that it's probably not the best route to go since it lacks any significant benefits. Near the end of the article they did mention a few theories which seemed plausible, but the results showed differently.

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  17. This is similar to others' posts, but I feel the same on most points. In the article with the hot-pack+US, Draper showed that although increasing the length of the hot-pack to 15 minutes did slightly increase muscle temperature, it was not enough to really be significant. I agree that if it makes the patient feel better then it would be best to use the hot-pack as long as there is time. In addition, I feel like the cold-pack+US article sort of addresses the fact that sometimes we can't get too caught up with our in-depth reasons for doing something, like increasing density of tissues, and ignore simpler bigger pictures, like the fact that if we make something colder it's going to take longer to heat it back up.

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  19. I agree with what most of my classmates have previously stated. I completely agree with Rick and his "no kidding" feeling, but then I liked Michael's point about seeing more research in regards to the cooling actually increasing the density of the tissue and what benefits that holds. I think that cooling the skin before US would not be beneficial when the point is to have as much deep muscular temperature increase as possible. Along the lines of what many of you have already said, I believe it would not be worth it to charge the patient extra and waste more of your time with the patient to have them use a hot pack before US. It saves time and money to not use the hot pack and you can still get the deep muscular temperature increase needed for the treatment with US.

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  20. While I don't disagree with my classmates, I do wonder what prompted the use of the cold pack prior to ultrasound initially. Someone had to have used it on a patient just to try it (and believe me, with some patients you will try anything) and had a positive response, or why else continue? While I think it is rare, some patients don't tolerate heat well and prefer cold. And in my experience, most people don't feel the "heating" effect of ultrasound. I like Brianna's thoughts about patient's pyschological effect and maybe it goes for both the hot pack and cold pack. It sounds like a stretch, but I think it's possible. The mind is a powerful thing.

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  22. Like everyone else commented I agree with the article that precooled tissue and US are not complementary of each other. Also, skin can be sensitive to hot and cold changes so going from cold to hot could make the patient uncomfortable.

    As far as the article about adding a hot pack or room temp pack before US, the results didn't show enough benefit for the patient. When doing PT it is important to get the most benefit out of the session with the patient. Like some of you mentioned, wasting 15 minutes on pre-heating before US doesn't seem necessary unless the patient really wants it and knows they will be billed extra for it. Also, it seems that heating can only go so far before a plateau is reached. The article mentioned that the local temperature's in the body might have a "set point" so you can only heat the tissues to a certain amount before a plateau is reached. Kate's comment about prior activity to treatment made me wonder if there would have been any differences in findings if the muscle had been exercised first before doing the treatment compared to if they had been rested.

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  23. At this point it is difficult to state anything that has not already been brought up by others, but I would be curious to find if there were an "optimal" pre-heating time before ultra-sound to make the most of the post-ulatrasound time with the patient. If performing the treatment in the most optimal time frame allowed for other treatments during the allotted period, this seems to be the most benefit for the patient's "money".

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  24. In regards Draper et al. (1998), I thought that it was interesting to see that there was very little difference between the hot pack and the room temperature hot pack with US. I believe the resistance of the tissue is going to affect the ultrasound, I do not know if there is a way to measure the change in the resistance of the tissues due to the heat, but it would be interesting to see if the heat changed the tissue and if that then affected the ultrasound. It makes sense that the ultrasound would penetrate deeper than the hot pack because the hot pack is using conduction of energy. I think there are clinical applications in knowing that heat and then ultrasound does not change the target tissue. However, if the patient receives relief from the combination of the two (heat and ultrasound), I think it is beneficial. I know in my clinical experience (very small amount), the patients who received ultrasound did not feel any change in temperature or in immediate relief.

    In regards to the other article, I believe that ice would cause contraindications to ultrasound. If the patient has decreased sensation it could end up damaging the tissue. I also am curious what caused people to think ice and ultrasound would be an effective treatment. If you cool the tissue it will take longer for the tissue to heat.

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  25. I have to say I agree with what most people have posted. I think that what the patient wants, as well as what the research states, should be considered. If that patient thinks a hot or cold pack before ultrasound feels more comfortable or yields better results, then it should be taken into account when determining a treatment plan.

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  26. I think the Draper article about the ice/US combination reinforces the need for EBP in PT. As stated in the article, "No studies were found in the literature pertaining to the effects of ultrasound on precooled tissues, yet this procedure is quite common in the clinic". This is an older article (1995), and shows how things used to be, and how things are now moving in the right direction with EBP.

    With the US+ hot pack article, I dont believe the 15 min hot pack is justified as Jimmy referenced that a 3-4 degree Celsius change was needed to stretch the tissues, and US alone reached 3.65 degrees (4.44 with HP)at 1 cm and 3.58 degrees (4.42 with HP) at 3 cm. I dont think the 0.79 and 0.84 degree C differences are worth the extra 15 min of hot pack when the temperatures of US alone heat the tissues enough.

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  27. Years ago, while shadowing and doing work as a tech, I had been instructed to use ice before ultrasound. I had always felt that this was counterintuitive since you are cooling something, just to heat it back up. The logic makes sense (cold creates a denser medium which will cause more absorption of the ultrasound beam and a greater increase in heat) but the evidence does not support this theory. The medium may become denser due to the ice, but the tissue is still trying to overcome the temperature deficit created with ice prior to ultrasound. It was stated in the article that patient tolerance may increase due to impaired sensation from icing. I feel that it could also cause decreased patient tolerance (an example would be if your fingers are cold and you run them under warm water, the water feels hot). As the article stated, it would be interesting to see if there are changes in mechanical effects of ultrasound with prior cooling.

    In the article that looked at heating before ultrasound, heating first only seemed to be effective in deep muscles, and the change was minimal. I agree with my classmates that less than one degree of difference isn't really worth fifteen minutes to use a hot pack, since therapeutic levels were reached with ultrasound alone.

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  28. I agree with what has been said by most people on the blog. It would be hard, at this point, to state a profound and original opinion. From reading the articles, I think that the use hot and cold modalities and US are beneficial to patients. Now, whether or not a therapist uses a hot pack before US would be up to the PT and the patient. As many have already stated, I would not suggest using a cold pack before US. Some patients might prefer the use of heat and US and some might prefer the use of only one. I feel that whichever the patient is more comfortable with is what should be used.

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  29. For the article concerning the hot packs prior to ultrasound, I think it comes down to a timing issue and patient preference based on the fact that there was minimal net difference in temperature in the two groups. As many have noted, many patients prefer to have a hot pack because it feels good to them and, as a tech, the response that I get from the therapist often times is: "Ask the pt what they prefer". As for the timing issue, it sort of depends on the resources and schedule of the clinic. Does the therapist have a strict schedule or can pts overlap? I've seen both types of settings as a tech and in my first clinical. Something else to consider is whether techs are available to perform US. If there is a tech there who can spend a longer time period performing an US than it might more efficient way to spend the pts time.

    Initially before reading the Draper article, I had the same thought process as many of you did; it seems counter-intuitive to cool something that will you are going to heat up. But as I read more, it makes logical sense that cooling a tissue prior to US could be beneficial because it would condense the tissue. The article states that more dense tissues better absorb US beams. The study clearly concludes, however, that this is not the case. I find it very interesting that this is commonly used especially because the article states that icing before US is "just a theory."

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  30. I agree with what everyone else has been saying as well. I was not convinced that using an ice pack before US is beneficial. In my experience in the clinic, I saw heat used before US if anything was used. Often neither heat nor ice was used before US. I agree with Kate and had similar thoughts that the therapeutic exercises will warm up the muscle already for a lot of patients. One clinic I worked at also used the heated gel. I assumed that was for patient comfort but it also makes sense that it would help with heating up the tissues. However, just like others mentioned, the time issue is a factor. It does not always seem worth it to use the available time to pre heat the area with a hot pack. An exception would be when the patient requests it and really feels like it helps them. If it works for the patient it is worth it more than if they do not feel a difference.

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  31. There seems to be consensus surrounding the idea of cold packs prior to US have significant benefits. In fact, they seem to take away from the heating effects produced by US shown by the average increase in temp between the treatment groups. Likewise, the benefits of a hot pack prior to US have been proven in this article. This seems to be an important finding because not only will the patient reap benefits of increased heating effects, the therapist benefits from decreased individualized tx time needed for US: 2-3min decrease reported (Draper et al).

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  32. Most people have already posted they agree with the article that icing before US seems to have no positive benefits and I am not going to be any different. As Christine said earlier the idea of icing before trying to heat the muscle seems counterintuitive.
    The article about pre heating seemed to show some added benefits from pre heating before US. The only question is whether the benefits of pre heating are significant enough to make it something a PT would want to do instead of spending time with the patient doing something else. That seems to be a decision a PT therapist would have to make on their own after reviewing the research.

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  33. Kate brought up a good point about therapeutic exercise possibly having similar benefits to the hot-pack theory. I found an article in the same journal that Draper's Hot-Pack+US article was published that looked at temperature changes in deep muscles during exercise. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1320425/pdf/jathtrain00011-0021.pdf

    Active exercise was shown to increase intramuscular temperature in working muscles. Fifteen minutes of jogging on a treadmill resulted in an increase of 2.2 degrees Celsius at a depth of 5 cm. It would be interesting to see how the combination of therapeutic exercise and US compare to the effects of hot packs and ultrasound.

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  34. According to these articles, using a hotpack prior to US does allow for a greater deep heating temperature. However, this is not the question. The data clearly shows that yes, the temperature of the targeted tissue will increase if it is subject to pre heating, but this is only a minor increase. The question is whether or not it is worth the effort of the PT, PTA, or tech to go through the trouble of setting the patient up with a hotpack treatment. In some situations I would guess that yes it would be helpful in saving time and in other situations I will assume that no, the hotpack is not worthwhile.

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