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Do Hand and Foot Warmers Work?

Ski season is upon us. There is no greater relief on a frigid winter day than warming cold, painful fingers and toes. In a recent issue of Wilderness and Environmental Medicine (2009;20:33-38), William Sands, Ph.D. and colleagues authored an article entitled, “Comparison of Commercially Available Disposable Chemical Hand and Foot Warmers.” The objective of their study was to characterize the thermal behaviors of 14 commercially available hand and foot warmers.

The warmers were studied in pairs in a laboratory setting, not in frigid conditions. Each warmer was monitored with a rapidly-responding thermister to determine its external temperature. One of each pair of warmers was placed in a boot or glove. Temperature was recorded until the heat output of the devices ceased and the temperature was determined to be identical to ambient temperature.

The results were quite interesting. There was variability both within and between manufacturers and types of warmers. Some of the devices exceeded packaging claims, while others fell short. The greater the mass of the warmer, the longer the duration of heat production.

Commercially available disposable warmers rely on a chemical reaction involving iron powder, water, salt, activated charcoal and vermiculite. One such brand is Grabber warmers. The iron in the mixture is exposed to air when the packaging is opened. The iron oxidizes with salt as a catalyst. Carbon helps disperse the heat, while the vermiculite helps act as an insulator to control the rate of the reaction. Once the iron converts to iron oxide (similar to rusting), the reaction ceases.

Based on the variability of the warmers in their thermal behavior, and the fact that all hand warmers and body warmers showed longer durations of heat production than did the foot and toe warmers, the authors made recommendations:

1. Do not rely upon a single warmer to reduce cold exposure. Carry several warmers to compensate for failures and short duration of warming.
2. Do not expect the devices to work if they become wet via submersion into liquid.
3. The heavier the device, the longer the heat production. This has implications for foot and toes warmers, that must be constrained in size in order to fit within a shoe or boot. For foot and toe warmers, a greater number of warmers should therefore be carried, to replace warmers that are no longer warm.

This post, Do Hand and Foot Warmers Work?, was originally published on Healthine.com by Paul Auerbach, M.D..


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Richmond, VA – In an effort to simplify inpatient medical billing, one area hospitalist group has determined that “altered mental status” (ICD-9 780.97) is the most efficient code for use in any patient work up.

“When you enter a hospital, you’re bound to have some kind of mental status change,” said Dr. Fishbinder, co-partner of Area Hospitalists, PLLC. “Whether it’s confusion about where your room is located in relationship to the visitor’s parking structure, frustration with being woken up every hour or two to check your vital signs, or just plain old fatigue from being sick, you are not thinking as clearly as before you were admitted. And that’s all the justification we need to order anything from drug and toxin screens, to blood cultures, brain MRIs, tagged red blood cell nuclear scans, or cardiac Holter monitoring. There really is no limit to what we can pursue with our tests.”

Common causes of mental status changes in the elderly include medicine-induced cognitive side effects, disorientation due to disruption in daily routines, age-related memory impairment, and urinary tract infections.

“The urinalysis is not a very exciting medical test,” stated Dr. Fishbinder. “It doesn’t matter that it’s cheap, fast, and most likely to provide an explanation for strange behavior in hospitalized patients. It’s really not as elegant as the testing involved in a chronic anemia or metabolic encephalopathy work up. I keep it in my back pocket in case all other tests are negative, including brain MRIs and PET scans.”

Nursing staff at Richmond Medical Hospital report that efforts to inform hospitalists about foul smelling urine have generally fallen on deaf ears. “I have tried to tell the hospitalists about cloudy or bloody urine that I see in patients who are undergoing extensive work ups for mental status changes,” reports nurse Sandy Anderson. “But they insist that ‘all urine smells bad’ and it’s really more of a red herring.”

Another nurse reports that delay in diagnosing urinary tract infections (while patients are scheduled for brain MRIs, nuclear scans, and biopsies) can lead to worsening symptoms which accelerate and expand testing. “Some of my patients are transferred to the ICU during the altered mental status work up,” states nurse Anita Misra. “The doctors seem to be very excited about the additional technology available to them in the intensive care setting. Between the central line placement, arterial blood gasses, and vast array of IV fluid and medication options, urosepsis is really an excellent entré into a whole new level of care.”

“As far as medicine-induced mental status changes are concerned,” added Dr. Fishbinder, “We’ve never seen a single case in the past 10 years. Today’s patients are incredibly resilient and can tolerate mixes of opioids, anti-depressants, anti-histamines, and benzodiazepines without any difficulty. We know this because most patients have been prescribed these cocktails and have been taking them for years.”

Patient family members have expressed gratitude for Dr. Fishbinder’s diagnostic process, and report that they are very pleased that he is doing everything in his power to “get to the bottom” of why their loved one isn’t as sharp as they used to be.

“I thought my mom was acting strange ever since she started taking stronger pain medicine for her arthritis,” says Nelly Hurtong, the daughter of one of Dr. Fishbinder’s inpatients. “But now I see that there are deeper reasons for her ‘altered mental status’ thanks to the brain MRI that showed some mild generalized atrophy.”

Hospital administrators praise Dr. Fishbinder as one of their top physicians. “He will do whatever it takes to figure out the true cause of patients’ cognitive impairments.” Says CEO, Daniel Griffiths. “And not only is that good medicine, it is great for our Press Ganey scores and our bottom line.”

As for the nursing staff, Griffiths offered a less glowing review. “It’s unfortunate that our nurses seem preoccupied with urine testing and medication reconciliation. I think it might be time for us to mandate further training to help them appreciate more of the medical nuances inherent in quality patient care.”

Dr. Fishbinder is in the process of creating a half-day seminar on ‘altered mental status in the inpatient setting,’ offering CME credits to physicians who enroll. Richmond Medical Hospital intends to sponsor Dr. Fishbinder’s course, and franchise it to other hospitals in the state, and ultimately nationally.

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